• ●  The iStar Phoenix WFT 204 “Comet HUNTER"...

        by James Edwards / Elk Grove CA

     

    A New Dimension in a BIG Refractor!

    If there are any here who remember my numerous articles, you will know that when it comes to astro gear and how it performs I know a good telescopes when I see one!

    After owning 47 telescope types since 2001, ranging from SCT Meade’s and Celestron’s to many many Takahashi’s in both reflector and refractor types (Yes I am the Originator of the Mewlon 250S), I wanted to conclude my hobby on a high note, NO I am far from ending my pursuit of amateur astronomy but this last refractor is the end of the road for me, and after 26 years and a tons of evenings out viewing the sky it’s come down to one last refractor!

     

     

    The iStar Phoenix WFT 204:

    I looked at a number of incredible refractors before I elected to go with an 8” version. Often times I go back to the previous types I’ve owned, Meade Ed’s and Takahashi’s and many more I have had the privilege and honor to view though and enjoy. I also looked at many types currently being offered, but it still came down to what I A. wanted my last refractor to perform like B. Size does Matter and C. the overall performance and quality, which the iStar 204 more than exemplifies!

    The day it arrived I was astounded by its size, having never seen an 8” refractor in real life, but also the crate in which it was shipped in, engineered perfectly for its weight and the travel distance to get here, all in one piece and ROCK Solid!  As I unwrapped the crate and looked inside, immediately my heart was racing, “ man that is ONE BIG scope”  and as I pulled it from the crating not only was I impressed by its workmanship but by its finish, Big Black Sleek and a total BRUTE, OH YEA LETS VIEW!

    The paint scheme is awesome, black pebble finish like, durable with a superb coating along with its blue dew shield ring and bezel which is also at the focus end, the same sweet blue finish, what a combination, especially for my mounting platform, a Solid Black set UP! (Enter in Darth Vader music)

     

     

    The Total Set UP:

    The Phoenix 204 comes with excellent machined felt lined tube rings, perfectly matched with an ADM “D” series dovetail which fit perfectly on my Losmandy G11 Gemini II mount ( my 5th G11 ) I also use a 12” pier extension because of the 204’s length and naturally my 11 is fully GPS!

    The Phoenix 204 comes with an ungraded Moonlight rotatable focuser, with a 10:1 micro focuser, a 1.25” reducer and each end piece comes with copper inserts to reduce wear and set screw marks. I have and always will be a Feathertouch Fan, but the Moonlight is no slouch, it is buttery smooth and solidly built, no complaints here!

     

     

    Test Night One…Talk about CRUMMY SKIES!!

     

    I had read the weather reports forcasting marginal conditions with a chance of rain, but never the less with a gap in the clouds, I was hell bent on taking the 204 out with crummy skies and all!

    After the counter balance was set and everything was a go, it came down to only a few deep sky objects for us to look at. M31 and M32 were very good, not anything to get excited about but with 1 out of 5 transparency and a ton of moisture in the sky, both views were exceptional, the Phoenix was more than up to the task… We spent the remainder of the evening checking out M51 and again the double cluster in Cassiopeia, pin point stars between 180 and 300 power, the 204 performed flawlessly, what a BRUTE this scope is it was meant for bad skies or good, we were all very impressed!!!

     

     

    Test Night Two…Clouds again but BUT well worth IT!!

     

    Again we faced marginal skies (2 out of 5 transparency), but even with partial cloud cover the 204 performed flawlessly. My make shift dovetail for my Telrad was alright, but one thing I will need to address to get a better finder platform. Overall the Phoenix was a marvel, star clusters looked very tight (Caldwell 14, M 22, 25, 54 to name a few ) and very detailed not what some may think about a doublet refractor, but again it’s an 8” Brute so the lack of a third lens more than compensated with its aperture!  We waited for Orion to show (3am), and took a last look for the evening, it’s was very good but again the moisture and clouds brought in the overall transparency marginal at best.

     

     

    Night 3 – Finally a NIGHT to BEHOLD!!!

     

    The clear sky clock was solid all day (Saturday October 5th.) showing 5 out of 5 transparency and super dark seeing after 11 pm. I packed up the truck and headed to one of our local viewing spots, Wilton CA (not too bad for the outer farm lands)

    Once the sky was at its darkest, I was immediately swept to the few objects I had previously looked at, I wanted to see how the 204 performed with great sky conditions, I was utterly impressed, THIS Scope ROCKS!!

    The list of objects the 204 I was most impressive with, were open clusters and galaxies, on a planetary scale the jury is still out, but Mars and Jupiter looked good (3.5 out of 5)

     

     

     

     

     

     

    Moonlite 10:1 focuser with iStar 2” diagonal

    w/custom Telrad sight

    (note: Televue 41mm Panoptic)

     

     

    My seeing list:

    M31 / 32 / M101 / M51/52 / Double cluster in Cassiopia

    Triangulum galaxy M33 /M 81/82 / The Swan M17 / the Dumbbell M27

    The Hercules Cluster (M 13/ Abell 2151) / NGC 404 - MIRACH'S GHOST

    The Orion Nebula - M42 / Comets: Linear - Ison – Lovejoy

     

    Sunday Oct. 6th @ 6:02 am, the International space station flew right

    over  head  just  as I snapped  this  photo… what a way to  end a night

    of Astronomy!!

     

     

    Conclusion and overall rating:

    My conclusion and rating is simple. I give the iStar Phoenix 204 a 5 out of 5 rating in its class (Achromatic) and overall a 5 out of 5 in performance, fit and finish and the cost!!! Yes it is a big scope, but my G11 handles it perfectly, as would an AP900 or Celestron CGEM, and well worth the time and effort it takes to own a refractor of this size.  1 thing that iStar needs to improve on is the front lens cap, yes the stock cap more than amply covers the front objective BUT it won’t stay on securely. I had Joe at Astro Zap make a custom fit aluminum end cap for me, I have to tell you Astro Zap Rocks, it fits over the dew shield perfectly just like a glove and well worth adding it to my 204 set up…False color is prevalent on brighter objects (planetary, moon and larger stars) but guess what? The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense, WHAT the 204 gives you is breath taking views that more than compensate for any color that shows… This scope is a beauty to aspire to, the stock aluminum rings are excellent as is the iStar 2” diagonal and all in all this is one scope that will more than give you a life time of viewing excitement and pleasure… Owning an 8” refractor brings a new dimension in owning a refracting telescope but I highly recommend it to astronomers looking to upgrade, you're going to LOVE this Beast!!

     

    Type: Achromatic / Number of Elements: 2

    Lens Diameter: 210mm / Clear Aperture: 204mm

    Focal Length: 1200mm / F/ ration: 5.9

    Lens Coating: Fully Multi-coated

    OTA Weight: 24 lbs. / OTA length: w/dew shield 48 inches

    Lens diameter: 210 mm / Clear aperture: 204 mm (8")

    Focal length: 1200 mm / F stop: F/5.9

    Lens elements: Fully Multi-Coated

  • ●  150 F8 R35-S ATM OTA, Superb Quality

        December 2013, by Steve M

    It's been a couple months since I've bought my 150mm f8 R35 and I wanted to let you know that I couldn't be happier. About a week ago I took my first look at Jupiter through the scope and I have to say that I've NEVER, ever, had a better view. The image was sharp, bright, and full of contrast. I had the power up to 70x per inch and the image was still holding together real well. I also put the scope to work on double stars and it performed like a champ. Finally, I took a color photo of the Crab Nebula through the scope (on a rather hazy night) and that image revealed internal structures I've never seen before in other pictures.

    To sum it all up, this is one great telescope.  Thanks for working with me to make it happen!

     

    Merry Christmas

    Steve M.

  • ●  First Light Report of ATM OTA Equipped with 100mm F12 iStar Optical Achromatic

        December 2013, by Stanislas Maximovich, France

    The last events about your 100mm lens F12. I did the tube construction during last saturday with a simple chimney smoke steel pipe mat black painted both side, 130mm diameter. No internal baffles. I recuperate the 2 ends of the previous tube for the lens cell installing and for the crayford ring installing. Tube rings and 50mm finder too. Alignment was simple with a collimated laser beam. Remains the collimation of the lens on sky. The first light was impressive. I pointed Algenib of m2.0 magnitude and observed the diffraction patterns of the star, intra, extra focus, at focus. Intra-extra pattern looked like a semi apo figure of same image. At focus until 300x magnification, the blue halo, rather a violet halo was very discreet and confidential with a clear first diffraction ring slightly of miscollimation (to be retouched with a 1/10th turn screw at the cell). Surprisingly the figure at 300x was clear without blurring (the vixen 102 didn't go beyond 270x). This could mean high acurate optical surfaces level. Sky conditions were height of Algenib around 55°, seeing 3-4/5 Danjon scale, transparency 6/6, windy.

    I had a look on Uranus with 240x, the disk was knife-edge limb, The south pole of the planet seemed clearer, but difficult to say firmly. I had views of Jupiter, being only 15° above the horizon. In spite of the elevation I noted seeing "holes" where seeing level reached on few seconds period 3-4/5. Without filtering with 133x magnification the disk color was whitish (as with apo like ED design), the limb was surrounded by a thin violet halo of narrow width, almost absent when at focus.

    GRS was near the limb, it appears alone with a narrow gap from the tropical band. Color was without doubt deep orange color. Banding was very clear with so many festoons and nodes in EZ when seeing was at its best. Comparing these results with the TAL 100 and the Vixen 100, I would say the present 100mm is more performing, more acurate, more neutral for the overall coloring of the planet Jupiter. It reminds me the Unitron quality with less chromatic aberration.

    About the quality levels, the TAL 100 is a L/4-5 (coloring yellowish), the Vixen L/5-6 (coloring yellowish) and the iStar probably >L/6 (coloring whitish). These are only numbers coming from comparisons (the TAL and the Vixen being measured).

    I would like to complete the tests with more time on Jupiter, on stars (for a complete star test), on Venus to see what can be performed on clouding features in blue, green and red channels (The TAL performed), on Mars too same channels.

    As a first conclusion in spite of the short period of this first light, this is promising, it seems, the lens doublet seems to be an accurate one with extra low CA amount. I asked a F10 doublet, I got a F12 one. I think we can leave the order as it is with regards to these results. I will do a report with the use of the OTA nextl with a certain period of observation on planets.

     

    My best regards.

     

    Stanislas

     

    2013/12/19 stanislas maksymowicz   < stsma78@gmail.com >

     

  • ●  Test of iStar Optical 150mm F15 achromatic refractor

        by Bartolomeo Montrucchio, Italy

     

     

     

     

    Source >

  • ●  Perseus AT 150-15 OTA

         Report by member „Rutilus“ at www.cloudynights.com

    Very short report on my istar 150mm f/15.

     

    Last night I was observing a few double-stars and the scope was taking high magnification very well. The scope seems to have a real sweet spot at powers ranging from 250 - 350x.

     

    epsilon Bootis - Good clear split at 112x. Best view was at 325x, but powers up to 500x were very good indeed. I used a 2.5mm eyepiece for 900x and was very surprised at just how good the Airy disk and Diffraction ring pattern was. While past it's best, the view was still usable.

     

    gamma Virginis - easily split with no problems, as was the 1.6" wide Struve 1932 in CrB.

     

    gamma CrB - a real tough one at 0.6 - 0.7". At 500x, no split was visible, but the star displayed an odd shape with a bump on one side.

     

    The only DSO I observed was M13. The view was much better than that of my 4 inch f/13 Carton or that of my now gone Tak-TSA 102. Bigger aperture showing itself here, over the 4 inch scopes. The cluster appeared as a mottled misty patch with many individually resolved stars visible. The view was very nice indeed at 70 and 90x powers.

     

    Star-Test - Needs more than one night of testing but this is an initial finding with a green filter used. Racking the draw tube inwards, a nice set of well defined rings, the very outer ring was brighter than that of the others.

     

    Racking the draw tube outwards - A less well defined view, the rings were harder to see, and the outer ring was much fainter. The pattern was quite ragged.

     

    My initial thoughts are that the lens shows some under-correction, but I want spend more time using the scope before coming to a conclusion.

     

     

    FOLLOWING NIGHT:

     

    Had another night with the f/15 on double stars. Out of interest I fitted the lens wth a 100mm aperture mask to see how it compared to a Tak TSA-102 and FS-102.

     

    The views were simply wonderful, with the most delcate first diffraction ring. The scope was in cruise mode at powers from 300-500x. The views were every bit as good as the Tak scopes.

     

    To finish off, I went back to full aperture and observed Eta CrB. At powers of 643 and 900x, two Airy disk visible with a tiny black line between them. Looking at orbit charts for this star, I think the separation is around 0.8-0.9" at the moment.

     

    REACTION BY CN MEMBER “7331Peg”

     

    "To finish off, I went back to full aperture and observed Eta CrB. At powers of 643 and 900x, two Airy disk visible with a tiny black line between them. Looking at orbit charts for this star, I think the separation is around 0.8-0.9" at the moment."

     

    Pretty good shooting with that istar cannon, Rut! Eta CrB is even tighter than that.

     

    I was just looking at it a couple of weeks ago, and when I pulled up the WDS Ephemerides, it listed the 2013 separation at 0.667" (!)

     

    Here's a link to the WDS figures -- starting with the first column of numbers (175.5 0.623), the years are lined up from left to right as 2011, 2012, 2013, 2014, and 2015.

     

    (link)

     

    Eta is the first one at the top of the list (STF 1937AB). I show the Dawes' limit for a six inch lens at .76" -- very impressive!

  • ●  iStar Optical 150 F 5 Binocular ATM project

        by Bill Faatz, Sky and Telescope, April 2013 issue

  • ●  iStar Optical 150mm F/8 R30 versus Meade

        January 2013, by Victor, Canada

    I can just say: Oh boy, oh boy it is amazing view that I saw couple of nights ago through my iStar 6" R30! Finally the Yukon had a warmer weather, just about -4 Celsius. I took the scope outside well before dusk. A little ice-dew shattered on the tube and the 2" diagonal. but when it became dark, I was ready for observing my favorite Jupiter. I can tell that the planet's stripes were amazing in my 16mm Zeiss eyepiece (75x)! I was so excited about the view that I started to push the magnification quickly and gradually to 120x, then to 200x, then even to 300x!

    Well, far better images than in my Meade. In other words, they are not even comparable on planets. I have actually never seen the Jupiter so crisp and detail in my Meade refractor compared to my new r30 anastigmatic lens! In addition, the sky was partially cloudy, so that the Jupiter got faint frequently because of the high atmosphere cirrus clouds passing by! Can you imagine what this scope can do in an actually excellent night? The same night I tried to put in my 5x powermate in the focuser then I slid my 25 mm orthoscopic eyepiece in it. The image of the planet did not fell apart, however the sky conditions limited my useful magnification to 250x.

    I am very satisfied with this lens. In addition, using the scope in warmer temperature yielded way less colouring than in minus 40 degrees temperature. I did not see ANY false colour using the 16 mm eyepiece. When I pushed the magnification higher, I started to notice some faint violet colour around Jupiter but it was so insignificant and faint that it did not even bother me at all.

     

    Victor

     

    Read more here

  • ●  127mm F/8 Achromatic Doublet OTA vs. a 127mm F/7.5 APO Triplet

        January 2013, by Brian from Darwin, Australia

    Good bit of to and fro here guys , All the tech talk is as Matt says is mostly above my head but I have owned a North Group 127mm f7.5 triplet up until mid 2012 and now have an iStar 127mm doublet f8 .

    I think I have now used the iStar ( 2 months almost now , on every clear night ) to make a quick comparison between the NG triplet and iStar doublet .

    Ok the NG definitely has better controlled CA , that’s to be expected ( over $2k , compared to $630 total cost of build ) so is the triplet 3.5 times better , not on your life it was very good but not 3.5 times better , more like 1/2 x better .

     

    The moon ,

    the iStar shows a faint color fringe , the NG none , but the views are identical apart from that .

     

    Jupiter .

    same as the moon , but I feel the iStar shows more intricate detail in the bands and GRS .And the CA disappears for me very quickly once I start observing the planet .

     

    Saturn ,

    nothing between them up to 250x when the NG pulls away slightly. Both max out at about 340x .

     

    M42 ,

    Identical in every way .

     

    Deep sky , Double stars ,

    As above .

     

    No , I am more than happy with my 127mm iStar Doublet and don’t miss the NG triplet at all , and I had the pleasure of building my scope myself, total satisfaction .

    Thanks Ales and Mike for a world class product .

    I will do an in depth review with photos soon.

    You cant compare oranges with apples without trying both first .

    Brian.

     

    Read more here

  • ●  iStar Optical’s FORFAX LTT 140-12 APO Refractor

        February 2012, report by Ryan W., USA

    PART I

     

    Hi all,

     

    I posted a first light report a week or two ago, but I figured I would give an update. When the scope came the nighttime temps had been hovering around 10-15F, cooling from ~30F during the day. My first night out I had some cooling issues because of the huge amount of high density glass up front. I went out both last night and the night before, 2 nights ago for 2.5 hours and 1.5 hours last night. The temperature during the day was about 55F, warm for this time of year, luckily the temp in my garage stayed around45F so when I took the scope out at night there was almost no cooldown needed. The temperature hovered around 40F both nights while viewing.

     

    My set up is as follows:

    Scope: iStar optical 140mm F12 apo, FL=1680mm

    Diagonal: iStar Dielectric 2"

    Eyepieces: Denk 21s and Denk 14s

    Nagler 3-6mm zoom and Panoptic 24mm in mono mode, yielding 280x-560x and 70x respectively.

    Binoviewer: Denk II binoviewer with power x switch

     

    I took the scope out earlier in the week to determine the magnification factors achieved with the Denk II power switch. I was forced to thread the OCS into the nose of the diagonal instead of the body, yielding rather high magnification factors. I have a WO quartz diagonal on order that will allow me to screw the OCS onto the diagonal body, reducing the magnification factors by 0.1-0.4x (it will bring the OCS 2" closer to the BV by doing this).

     

     

    These mags are as follows:

    Power factors:

    Low=1.6x

    Medium=2.46x

    High=3.76x

    (I know these seem high, but were checked twice)

     

    Magnifications achieved

    21L = 128x

    21M = 197x

    21H = 300x

     

    14L = 192x

    14M = 295x

    14H = 451x (too much ;-) )

     

     

     

     

    I took the scope out around 8pm EST the first night, let it sit for 20-30 minutes to try to get rid of any cooling issues. The set up includes a red dot finder, and a Tak fs-60c as a super finder with a 24mm panoptic yielding a 4.6* TFOV and 15x.

     

    Lets start with a picture of the set up? Everyone likes pictures! I also added a second 1' pier extension to the Losmandy HD Tripod.

     

     

     

    Sorry for the poor quality pics, tough to get good ones at night.

     

    Oh, my mount is a DM6 on Losmandy HD tripod.

     

    Here we go:

     

    I enjoy mostly Lunar and planetary observing. I have owned a pair of 30x100 binos, a Meade 6" Ar6, AT111 EDT, WO Zenithstar 66, AT72ed, Z12 dob. My main scope as of late had been my Tak fs-60c while waiting for the iStar to arrive.

     

    I decided to start with Jupiter, it was very high in the sky. Seeing was so-so and transparency was good at moments, but due to very high intermittent clouds, variable. I put the D21s in on the low power setting and took my first look. The image was much better than the first night out, very steady and contrasty. Here is when things got a little fishy, I pushed the power switch to the middle setting and noticed a little color around the edge of jupiter...this was odd to me because the first night out I easily hit 400x on Jupiter especially looking for color and found not even a hint. It occurred to me that the Denk IIs might be the culprit (maybe a collimation issue). Before checking I took the power up to the high power setting (300x) sure enough, a little color. I switched the whole scope into mono mode to try to find the color problem.

     

    I stuck the Nagler zoom into the diagonal on the 6mm setting, 280x. This was close enough for me for a direct comparison to the high power D21 setting of the bino. There was not even a hint of color in mono mode. I cranked the power up to 336x on the zoom, still no color. I concluded at this point that the color (albeit a small amount) was being induced by the Denk IIs, I think they need collimation.

     

    I decided that the color with the binoviewers was a small enough amount to observe with. I moved back to the binoviewers.

     

    I started again with the low power setting of the binoviewers with the D21s. Great detail, even at this low power. I could clearly see the two main equatorial belts defined as well as a few fainter belts and shading near the poles. I have never gotten the planetary directions down (north, south east west) so bear with me. I could glimpse darkening and bulges in the two main equatorial belts. I pushed the D21s to the middle setting, 197x. The image was still very pleasing, with even more detail. The darkening in the main belts began to resolve. One bulge became an ovalish shape, i believe in the southern eqt belt (i may have things backwards, I will figure it out). I pushed the power to the high setting, but the seeing wouldn't allow it. I went back down the the medium power and stuck with jupiter for another 30-45 minutes. There were moments of better seeing in which more detail came in and out of view. The moons surrounding jupiter looked distinctly different than the surrounding stars. Even at only 200x the moons looked tiny and disc like. I wanted to get a better look so I put in the D14s. The view of Jupiter was very nice at 192x in low, just like the D21s on Medium. I quickly went from 295x on medium and to 451x on high. The view was boiling and bubbling, but i pushed the scope over to Europa and Ganymede anyway. They were clearly discs, boiling discs, but discs non the less. I wish the seeing would have let me push the power more on Jupiter.

     

     

    The moon was near it's high point for the night so I decided to point the scope over that way. I started with the D21s on low. I could just barely get the whole lunar disc in the FOV. The view was very steady and crisp. Just a side note: at this point I had been using the Tak fs-60c as a low power finder and really enjoy seeing the objects in context before moving to the iStar scope. I moved to medium power and decided to cruise the terminator. I was just picking objects on my moon map and pushing the scope their way. My favorite of the night was (i believe) Walter, which is a crater with two small, stacked craterlets that look vaguely like a tiny snow man. The view was steady here at 195x so I pushed the scope to 300x. Apparently the moon can handle a bunch of power, because the view held very well. I kept moving up and down the terminator and spent a while away from the terminator on mare serenitatis looking at the tiny craters strewn around the gray plain. The colors were great, bright bonish whites to the ash like gray of the plain. I had a lot of fun picking craters like Bessel and Linne on the plains in the low contrast areas (away from the terminator) on the map and then easily finding them. The seeing stayed good enough for 300x for another 30-45 minutes before it started boiling a bit. I just dropped down to 195x (medium with the D21s) and continued viewing.

     

    Another side bar, I had heard of a book titled "xx most difficult lunar objects to find" or something like that. Does anyone know what I am talking about? If so, let me know what it is please.

     

    I then decided to try a few deep sky, but at this point the high, thin clouds were becoming more consistent. I pushed the scope to the orion nebula and stayed on the low power setting. The nebula was framed very well at 128x and the four main stars of the tapezium were clear and steady pinpricks of light. I also took a look at the double cluster in perseus, which was pleasing, but due to the high power produced by the Denks, I could not frame them both at once. Still, very tiny pinpricks of light. At this point the high clouds and brightness of the moon began to wash out any DSOs quite a bit so I started to pack it in.

     

    After the first night I decided that I will probably pick up a 48mm brandon eyepiece. I do not do too much deep sky observing, but really enjoy open clusters. The brandon in mono mode would yield a 4mm exit pupil, 35x and I believe a 1.4 degree fov. Sounds nice.

     

    Well, That was the first (full) day and all I have time to write at the moment. I will get to more later.

     

    Feel free to ask any questions!

     

    -Ryan W

     

     

    PART II

     

    I am going to try to finish my report on my second of the two days in a row. Tonight (2/1) I had a plan for my observing as opposed to the night before. I decided to focus on Jupiter to start because it was very high in the sky. Then spend a little time on the moon again and finish up looking at the orion nebula, double cluster and give the andromeda galaxy a try. For the Dsos I decided to go in mono mode to try for a wider TFOV.

     

    A new note: I just received my WO quartz diagonal and measured the new magnification factors achieved by screwing the OCS directly into the body of the diagonal.

     

    The new factors for low, medium and high are:

     

    low = 1.45x

    medium = 2.1x

    high = 3.2x

     

    I only got the diagonal yesterday, so the old factors were the ones used for the second night of observing.

     

    Here goes:

     

    I set the scope out to cool for 20-30 minutes. The temperatures tonight were very similar to the prior night, but there was easily less wind. I pushed the scope over to Jupiter and started again with the D21s on low, 128x. It was clear that the seeing was at least a little better than the previous night. Jupiter showed just a little bit more detail at this power than the night before so I pushed to the medium setting, 192x. The image was stable as the night before but I could make out a little more texture on the globe. I could just barely see some banding instead of just shading nearer to the poles. The night before I 300x, or the high setting just plain didn't work.

     

    Tonight I decided to push it to 300x and stay there for at least 10-15 minutes. Before when I tried to view at high power I would just go to a given power, and if the view wavered at all I would drop back down. Since my last serious sessions I have read as many observing reports here on CN from some more experienced observers. I learned (I think) to be a little more patient at high powers and wait for the seeing to come to me. I would say I would have about 10-20 good seconds out of every minute, given, these were not in a row. In the moments of good seeing the bands seen at 195x became a little more defined. The image scale (to me at least) seemed huge, I had never used much more than 200x on my previous scopes. I think that the scope could have held rather steady at 230x-250x tonight, but I didn't have an eyepiece combo that would work. I took the power back down to low and decided to just enjoy the view for a few minutes. The scope just presents a pretty view of Jupiter, I can't wait to test it on the other planets!

     

    I coasted over to the moon. Tonight I wanted to start with my lowest power setting. I wanted to try to fit the whole disc in the FOV, but was just barely unable to. This led me to the conclusion that I need another 24mm panoptic... ;-) The 2nd panoptic (now on the way) and the low power setting with the new diagonal will give me 0.67* fov and 100x, which will be great for full disc lunar, and some great DSOs, but I digress.

     

    Back to it! I jumped straight to the high power setting on the D21s and got to cruising the terminator, looking for nothing in particular. I did this for about 15-20 minutes, the view remained very steady. Great, sharp contrasty views. I took my eyes away from the eyepieces and noticed (thanks to the light of the moon) some clouds rolling in on the western horizon.

     

    I coasted over to the moon. Tonight I wanted to start with my lowest power setting. I wanted to try to fit the whole disc in the FOV, but was just barely unable to. This led me to the conclusion that I need another 24mm panoptic... ;-) The 2nd panoptic (now on the way) and the low power setting with the new diagonal will give me 0.67* fov and 100x, which will be great for full disc lunar, and some great DSOs, but I digress.

     

    Back to it! I jumped straight to the high power setting on the D21s and got to cruising the terminator, looking for nothing in particular. I did this for about 15-20 minutes, the view remained very steady. Great, sharp contrasty views. I took my eyes away from the eyepieces and noticed (thanks to the light of the moon) some clouds rolling in on the western horizon.

     

    I figured I probably had about 15-20 more good minutes so I quickly switched into mono mode with the 24 pan in the focuser. I moved over to Orion and stayed for 10 minutes. The trapezium was tight and the nebulosity extended further than I expected. I didn't push the power at all because my time was running out.

     

    I moved over to the double cluster. Beautiful view, little tiny jewels in the sky. I couldn't quite fit all of both in the FOV, but could easily center one and see the middle of the other. I think this type of viewing is where the 48mm brandon would shine. I stayed on the double cluster for 5-10 minutes and began seeing clouds. No time for andromeda, and with the moon up I hadn't expected much anyway.

     

    Next night out I am going to put the scope through it's paces on double stars. Any suggestions on that front would be much appreciated! What is a good test for a 140mm scope?

     

    I hope you enjoyed it, i sure did!

     

    -Ryan W

  • ●  Making of ATM-style scope with iStar 150mm F/15 achromatic doublet

        by Eden Orion, Israel

    I've got the lens after a Skype conversation and payment. The lens was sent immediately and after less than two weeks it was at my post office.

     Making the telescope was a great job, some obstacles, but not too much. Finally it was tome to set the exact place of the lens. I've checked it with a first quarter Moon. The first view was fantastic. Very sharp, nice shadows. Than after the lens was set in place and a collimation process was made, I've checked it again.

    It was a Full Moon night and i did not hope to see a lot. but as I've pointed the scope to the moon my jaws dropped! NEVER in my life I was able to see so much details in a full Moon! I was so in shock than a month later I've took the picture enclosed. I was with one of my friends Mr. Adi Cohen which is one of the most professional photographers in the country and also a deep sky photographer. He was also amazed by the contrast and lack of false color that we got.

    You might see some slight color on the edge of the Moon, we both not sure that this is chromatic aberration, since it is more yellow that all other colors.

     

    Eden Orion, Israel

     

    (Note from iStar Optical: yes, the slight yellowish halo is indeed the false color / chromatic aberration. It is indeed very low and practically insignificant especially when compared to other brands of scopes. We are proud to offer a very inexpensive Classic doublets with truly excellent resolution and extremely low level of chromatic aberration).

     

    See the entire build here.

  • ●  iStar Optical 5" F8 Achromat

        January 2012, by  Dave Gibbons

    PART I (8th January 2012)

     

    iStar 5” refractor, an honest review.

       Some of you may remember I purchased an iStar5” f8 Achomat objective last winter and spent a little while constructing a scope machining various bits and modifying a meade ar5 tube adding a moonlite focusser and the promise of a review to follow. Well here it is!

    Firstly I am not an optical expert or a great one for technical analysis with strehl ratios and p-v wavefront figures, I have, however, owned several dozen scopes and been an avid visual observer for 40 years and I know where the iStar sits optically within the Jumble of extensive data catalogued in my head- I just have a bit of trouble finding which bit goes with which scope these days!

    I won’t go into construction as I have posted on this already.This post is all about what the scope can give under the night sky. Suffice to say It is a really substantial bit of kit fully collimatable with a genuine 127mm of clear aperture.

    I had hoped the scope would prove to be a versatile, quick cooling good all rounder. In particular I had built it with binoviewing in mind and had cut down the donor tube to allow enough in travel to accommodate the extended light path binoviewers require. As It turns out I have had to reduce the tube length by a further 50mm and now do not require an ocr or barlow when binoviewing. It also sits nicely on my cg5 mount.

    I was fortunate to own a truly excellent Tal 125r achromat refractor and I have always said if the iStar objective could match that I would be very happy. I’ve also owned several Meade Ar5 refractors- indeed one these supplied the tube used in the build, it had a poor objective.Also owned half a dozen Synta 6” f8’s as well as Tal 100r and 100rs, so have a good idea what Chinese and Russian optics are all about.

    First thing I will state is that on highest power lunar, planetary and double star observation it comes a close second to the Tal 125r. The Tal could be taken to over 100x per inch on doubles on the very best of nights the iStar is good for 75x but then gets a little soft round the edges. Star tests are good but it definitely loses the stellar tightness before the Tal did. It is on par with the best ar5 I owned which is pretty good as this had a longer focal length of f9.4. I must add that last observing session I thought I detected the objective is not in absolute perfect collimation ,something I will address , but I still believe it would come just behind the Tal.

    At f8 false colour is of course present on brighter planets and the moons limb. It is in my mind a tad less than is evident on the synta 6” f8’s and one thing I have noticed is when you do crank the magnification up it does not become overwhelming and is not an issue , I must add I have always found it easy to ignore false colour in an achromat but appreciate that some people can’t stand it and will never see past it. Although I would not wish to look through an achromat shorter than f8 !

    It is very similar to the Tal125r on CA but is a magnitude worse than the f10 Tal 100’s as you would expect. Most definitely colour correction is slightly better than the Synta f8’s. It’s a trade off though with the iStar giving wider fields than the f10 scopes.

    Where I have been blown away by the iStar is in it’s use as a wide field sweeper. I recently purchased a 2” skywatcher 38mm panaview eyepiece and it is a match made in heaven. I know it’s not in the league of super high end eyepieces but with the unchallenging f8 focal length it gives very sharp widefield images across 90% fov.

    The fov just covers Orions belt with Alnitak and Mintaka being on the absolute edges of the view this is really impressive, a little under 3 degrees. The views of open clusters and starfields the double cluster etc, are absolutely stunning .Ah the colours of the stars are almost too beautiful for words, this is something people often miss about achromats but once you are looking at less than 1st mag stars the colours on show are jewel like and very vivid. I thought I had seen it all but many hours are going to be spent using this scope looking at galactic clusters and star fields and picking out brighter deep sky targets.

    It’s wide field performance has surprised me, in as much as it has taken me in a direction I didn’t expect having always thought of myself as more interested in targets such as double stars, lunar and planetary observation, I just didn’t realise just how magnificent discovering the bits in between can be!.

    I am so impressed I’ve decided to buy a sky tee alt-az and stick with pure star hopping and visual observation. I realise now that although I thought I knew my way round the sky and I do , there is so much I just have not seen.

    Finally Binoviewing with the iStar , what it was made for. Lunar viewing is a joy the amount of detail 2 eyes give is just stupendous. Looking at Plato 4 craterlets are evident and a hint of another. The contrast and texture of the lunar surface looks almost powder like I can see the dust! A wealth of detail is visible in Jupiter’s cloud system and the 4 inner moons show different colour and tiny perfect discs. It was worth putting the scope together for this alone.

    Building the scope has been a really fantastic project, I even got to do most of the machining myself on tube and counter cell, a real labour of love that was. You will never see this in the for sales section as it is the only one in the world and it’s mine, make your own!

     

    Here's a few more pics.

     

    cheers

     

    Dave

     

     

    PART II (16th January 2012)

     

       Collimation is now bang on! scope absolutely on par with my TAL 125R.

       Showed 6 Trapezium stars with ease last night and shadow transit on Jupiter stunning in binoviewers. Error was with Moonlite focusser not sitting square on the tube. Happy camper!

     

    Dave

  • ●  First impressions of the new Perseus AT 150-8

        January 2012, by Doug Herren

    PART I

     

    Newbie here to this forum... thought anyone interested in these scopes would like to see one. Fantastic build quality, and excellent optics... I'd estimate at least 1/6th wave at the eyepiece comparing to other scopes I have that have 1/6th to 1/8th wave at the eyepiece. Takes a little time to get one, but well worth the wait!

     

    Doug

     

    (see more)

     

     

    PART II

     

    It took about a week after the adapter came to install my Moonlite for the clouds to clear so I could finally get a chance to look at something more than telephone pole wires and insulators.

    The scope really has amazing optics, no doubt about it.  I've used scopes of various makes with wavefronts at the eyepiece from 1/6th wave to 1/8th wave, and this refractor's optics exhibit the same sharp, small diffraction rings as these instruments, so while the test report puts it a hair under 1/5th wave, it looks like it's only because of a spike on one small edge, the optics perform closer to 1/6th or 1/7th wave.

    Can't say enough about the build quality of the scope. It really exceeds what I expected and the photos on your website do a pretty good job indicating what one should expect.

    Thanks so much for such great service and all your help, the scope is really just fantastic!

     

    Doug

  • ●  Becoming a refractor addict after 35 years of dealing with SCTs  and other mirror based scopes

        January 2012, bty Frank Theys, Belgium

    This is the first time I post in this forum and would like to introduce myself (I have been following the CN refractor forum discussions closely though since a few years and have learned a lot doing so).

     

    I am 47 years of age, live in Belgium and have been in astronomy since almost 35 years now. I have possessed numerous telescopes so I have acquired quite some observing time spent behind the eyepiece and especially (well, 90% of the time) dabbling in astrophotography (without getting really great pictures to show off). I have gone from the simple 114 mm reflector to a 150 mm reflector, then a C8 followed by a C9.25, a Vixen VMC260, a 300 mm reflector and finally a C14. This in combination with the necessary photographic equipment going from the 35 mm film SLR to a digital SLR and CCD cameras. During those 35 years there were also times that astronomy was more in the background, for the common and obvious reasons : study, work, family, house, etc... The last years it has come more to the foreground again. I had a lot of fun during those times but also a lot of frustrations especially trying to obtain pictures with long focus telescopes and CCD's. In fact, the last year or 2 I have become to find astrophotography less fun and more of a chore, certainly the processing afterwards.

     

    Now you all wonder "What has this to do with refractors?", I am coming to that. For a long time I have considered refractors useful only as guiding telescopes and rarely viewed through them. That is, until I bought myself a Vixen 114mm SS ED-doublet which was at the time considered as one of the better good buys for astrophotography (I am talking about the pre-digital era). Although primarily used for photography I also occasionnaly used it for visual observations. I liked it but I wasn't overly impressed compared to the views in my bigger 'guns'. When the digital era started this telescope was no longer state of the art and he disappeared more or less in a cupboard, to be used once or twice a year.

     

    Two years ago, during the summer holidays, all this changed! Following a few frustrating months with my equipment (focus and guiding problems) I decided that I wouldn't bring along all my equipment but just my little refractor equiped with a new Moonlite 2.5" focuser, mounted on a specially acquired Giro II Alt-az mount. I also brought along some other pieces of the during all those years acquired equipment : a quality 2" diagonal mirror, quality eyepieces (Pan 35, 24, 19, Nagler 9,...) and a UHC-S filter.

    It was during the preparation for the first observing session that I realised that it was for the first time that I would be using my refractor with those quality accessories (before that I used it only with a off-the-shelf 1.25" prism diagonal and simple eyepieces), on a simple Alt-az mount and ... under a dark sky. Mmmm.... interesting. The following hours would be one of the biggest WOOW! moments in my life! For the first time I was able the observe the North America nebula in al its glory with the 4° field of perfect pinpoint stars in the 35 mm Pan and UHC-S filter, the Veil was unbelievable, just panning the overhead MilkyWay with the Giro mount was a treat with all the stars and dark nebulae visible. Also observed were M31, M33, the other usual showpiece objects and some lesser observed objects. I had a total of 3 observing nights under very good (for Belgium that is) dark conditions and it was the best fun I had had in astronomy since decades!

     

    SOO, after this experience I began to be more interested in refractors and visual observing and I began to follow more closely the CN refractor forum and other places dedicated to refractors. One thing lead to the other and...

     

    *** I have to admit that I have now become a REFRACTOR NUT ! *** All those funny tubes with reflecting surfaces and light bouncing in all directions that need frequent collimation are gone and are replaced with REAL telescopes!

     

    I have now a 70 mm TS ED (similar to Stellarvue 72 mm), a 80 mm F11.3 Vixen, an older 90 mm F14.4 Vixen, a 102 mm F11 TS achro (similar to AT102), a 114 mm ED SS Vixen, 130 mm F7 ROBTICS triplet (similar to Astro-Professional, the new MEADE triplet,...) and a 150 mm F5.9 TS achro (similar to AT150). A 200 mm F6 istar telescope is on order !!

     

    What's more : I USE those telescopes often and I do now most of the time visual observing and only occasionally widefield photography with the 70 mm ED and DSLR. I also started to (re)appreciate observing the moon and planets with all those telescopes and can have as much fun with the 80 mm Vixen achromat on a PORTA mount as with the 130 mm triplet on my equatorial ATLUX GOTO mount. My motto is now "KEEP IT SIMPLE, STUPID!" and in doing so I am having more fun than ever. After all life is complicated enough as it is.

     

    In that context I have to admit something else, something worse and probably not so popular on this forum : this motto has lead me in becoming a *** ACHROMATIC REFRACTOR NUT ! ***

     

    Yes, you will have noticed there are quite some achromats in my telescope list. I am foremost a deepsky observer and it is a fact that aperture IS important for that kind of observing, so since big APO glass is very expensive I got myself a achromatic 150 mm F5.9 telescope which gave me such good quality images under dark skies (maybe more about this in a later post) that I am convinced that you don't need an APO for satisfying deep-sky observing. Don't get me wrong, an APO may be a bit better than an achromat but a slightly larger aperture can neutralise that difference and you would still have a less heavy telescope and a lot of money left on your bank account! In fact I have done some observing with my triplet 130 mm and the 150 mm achro, both mounted in parallel on the GiroII mount and to my eyes the latter is the clear winner on deepsky, even under medium to higher magnifications (180x with 5 mm Nagler). It is no surprise then that I have now a 200 mm achro on order.

     

    When I am at home, under a mediocre light-polluted sky, I limit my observations mostly to the moon and planets, double stars and sometimes, when I am really itching for it after a long time without dark sky, the brighter deep-sky objects. For that I use the 130 mm triplet for those longer observing sessions and the smaller telescopes for 'grab and go' observing of the moon. That is until recently because I had another one of those eye-opening moments again.

    I won't go in too much detail but on two consecutive nights my 100 mm F11 achro beat the 130 mm APO by a large margin! This even after a 2 hour cooldown of the latter (from the unheated observatory). I attribute this to the fact that the APO couldn't cope with the descending temperatures after sunset where-as the achro had no problem what so ever with it. I also clearly noticed the effect of the larger focusing depth of the achro : even when the image was oscillating due to the seeing the sharpness mostly remained as opposed to the APO who even when under good temperature equilibrium shows more unsharpness during those oscillations. I am now a believer of the long focus achromatic refractor for moon and planetary observations, at least under my climate conditions with rarely long stable weather conditions (thank you Neil English for putting me on the right track with your great articles here on CN). I admit the CA bothers me but in the end I prefer a colourfull stable sharp image over a colourfree unstable and often unsharp image. And besides, I discovered a secret weapon against the CA : my Denkmeier II binoviewer! Yes, using this binoviewer the CA was spectacularly reduced, to the point that it didn't bother me anymore and the details visible were not that far from those in the APO used under better conditions. So I am now also lusting after a 5" long focus achromatic telescope. D & G ? Or istar ?

     

    I think that after 35 years I have finally settled on the type of telescope that I really like for my observing habits and conditions : the short achromatic refractor for deep-sky observing and the long focus achromatic refractor for moon and planets! Not that I would mind the odd APO.

     

    AMEN !!

     

     

    Frank Theys, self-professed refractor addict

  • ●  iStar Optical 150 F/5 Classic Achromatic Doublet in ATM style tube assembly

        by John Jarosz

    I'll resurrect this thread to further report on the objective performance.

     

    I was out at my in-laws in Iowa over Christmas. It's a rural area with a good dark sky. Christmas night was spectacular, clear, no moon, 40 degrees. Keep in mind that I'm using the Baader semi-apo filter in front of the 2" diagonal. My view of M42 had the most nebulosity I have ever personally seen visually. I now see how Stephen O'Meara actually can see the stuff he sketches. I'll never be able to see like him but I get the idea after my session on Christmas. Pleiades and Hyades were excellent as well.

     

    The istar objective has more contrast than my 6" F4 reflector. I'm a believer, but I couldn't tell under city skies, I had to get out to the country with a good clear transparent night.

     

    So thumbs up all around for the iStar glass.

     

    John

  • ●  Perseus AT 150-12

        December 2011, by Sky at Night Magazine, United Kingdom

  • ●  Huge observatory class 250 mm clear aperture F/11 R30 Anastigmatic Doublet objective lens mounted in an ATM-Style OTA

        First light report by Mike Carman

    PART I

     

    Well last night my istar 10" F/11 R30 stunned the sox off me. Bear in mind it has not been collimated as one person cannot do it alone properly. First light candidate....Altair. A bright pretty blue white star. At 110x with my 25mm plossls and binoviewers CA was not apparent. Only at about 180x did CA start to show. Unlike my 8" F/13.3 Brandt the istar exhibited a warmer hue closer to my lavender hued Jaegers. The Brandt has a deeper blue violet hue. I was afraid even with the R30 glass that this 10" was still going to show more color than the 8".

    To my astonishment it actually shows very slightly less color if you can believe it!! I get no more color with a scope that normally would be physically over 30" longer in focal length. That's the real bonus for me. A normal 10" F/11 would be more colorfull than my old 8" that's for darn sure. Jupiter's moons all had tiny flares at the bottom because of the collimation issue. But man could I see detail much easier than with the Brandt. Much better contrast with more saturated colors in the belts. The seeing was soft to boot. The really big surprize that in urban skygow I could easily see the the star next to M57...I could only detect it with averted vision with the Brandt. Globular clusters M15 and M2 were text book perfect and easily resolved across their entirety.

    Tonight Jupiter is a fuzz ball so not much is going to happen there. I should have the scope collimated in a few days. The diffraction pattern inside and outside focus has the same exact perfect rings that the 8" has. Only difference is there is a slight elongation in the pattern that is easier to see closer to focus. But collimation will take care of that. All in all I'm extremely pleased. Ales Krivanek has come thru with high marks on a large lens this time. All other lens reports up to this have been highly positive also. I can tell everyone that as an experienced refractor user if anyone can best Ales more power to 'em but I don't see where istar could be outdone in this category for the money. Again Ales and US rep Mike Harden...

     

    Thanks, Mike

    (link)

     

     

    PART II

     

    My oh my is all I can say! Hot damn man! The minute I viewed Altair I knew full well what this lens was capable of so no further use of the lens was needed. ;D Just a little wry humor to get your goats. Anyway this larger aperture shorter FL lens is outdoing the Brandt 8" F/13.3 on CA. There are flares and spikes at the bottom of all stars and Jovian moons. This because it hasn't been collimated yet. With a laser we also still have to adjust the 10"x32" tube so that it is perfectly on the optical axis. But even so the lens is showing as much detail and more between seeing turbulances. What really took me by surprise was the ease at which I could look straight at the star close to M57.

    With the Brandt I had to use averted vision in this urban sky. Ales you and Zdenek will have a tough time besting this. Maybe you boys just got lucky....but what do I care now. ;D ;D I was able to get a 10" F/14.3 into my existing space.....that's what I was after. I even got the tube length correct so my binoviewers had an inch of in travel left with 25mm plossls and no barlow for star filled low power dark contrast sweeping in urban Omaha skies. That alone is worth the price of admission. Therefore to say that I'm a satisfied customer is the understatement of the day. Thanks to Mike H. for double checking those "other" two. ;D

     

    Mike

    (link)

     

     

    PART III

     

    Well I just finished three hours of test observing tonight with the new istar lens. It was cold and windy but the atmosphere was calm and transparent. I used that Brandt 8" F/13.3 for over 30 years and would have put it up against anyone's scope in that aperture range and would have come in second to noone. Tonight however I confirmed two things and several obvious. First of the obvoius is it's a larger aperture. So right off we know to expect twice as bright of an image and second the airy discs should be smaller or tighter....and they were. Now on to the confirmation that this lens is indeed better corrected for CA. In the normal scheme of things if you were to say that CA would increase dramatically going from an 8" F/13.3 to a 10" F/11 you'd be right on the money....right? Not so fast some of you self proclaimed experts. It is so very obvious to me that the 10" R30 is actually controlling it more.

    Before replacing the Brandt I carefully estimated the extent of the bluish purple halo around Jupiter to be slightly broader than the S. Equatorial belt but not nearly as well defined gradually diffusing outward. The istar lens shows a much tighter purplish lavender almost to the extent of the N. Equatorial belt and sharply defined. The Baader Semi-Apo filter gives me the same "look" thru this 10" F/11 that I see thru my Tasco 4-1/4" F/15. That to me makes me an extremely happy camper with this lens. Lastly I have never seen Epsilon Lyrae like I did tonight. Those airy discs were beyond perfect. Absolutely stunning.

    Pi Aqulae one of my favorites was not only brighter but the darkness between the pairs was easily more pronounced. The seeing conditions were close to 8-9/10. Some slight softening every moment or so like the focus was drifting was evident. I felt like if it had just got to a 9+/10 I could've seen white ovals if any were present in the polar regions of Jupiter. Well that's enough rambling for now. Tomorrow nights forecast doesn't sound promising. We'll just have to wait for my DSO in Pegasus another night. Oh I forgot to mention Vega! There is CA but nowhere near what the Jaegers or the Brandt showed. The Brandt had it's usual bluish purple. The istar not only was it's usual lavender purple but Vega itself was a white. In the Brandt there was a yellowish white look. Delta Gygnae never showed the companion better. The secondary was a pin *BLEEP* lavender star...beautiful to say the least.

     

    Mike

    (gallery)

  • ●  Replacement refractor on Mt. Sromlo Observatory, Australia. / iStar Optical 220mm F/15 Achromatic Doublet

        by Tim Wetherrel

     Finally got chance to test the telescope on some terrestrial targets late in the day and the news is all good! The day was a bit hazy so we used a tree about 200m away as a target to cut out atmospheric effects as much as possible. Was very impressed with the lens, it created sharp contrasty images just as one would expect from a good quality large refractor. Using the 65mm wide angle eyepiece it was quite spectacular. When you get to higher magnifications 250x upwards there's a slight violet halo at the edge of branches just as you'd expect from an achromat but the image remained crisp and true. We wound the magnification up to 550x with a 6mm ethos without any real degradation except a little false color, which I'd imagine a minus violet filter would completely eliminate - just didn't have one handy. So in short, I'm very happy with the lens. We'll do some testing on artificial stars when we get the chance but I can tell just from the quality of the terrestrial images that it's a really nice lens.

     

    Tim Wetherell

     

    Gallery

  • ●  Perseus AT 210-9

        by  James Ling, Malaysia

    Here are my little comments that I want to tell both of you with regards to the 8" iStar achro performance, for the night… whereby is a bit cloudy , and cooling night, as there is heavy clouds in the day... (strange no dew till the morning)

     

     

    1. M57 is of much better contrast then my Ultima 8" at 200x which I have been watching for the 2 past weeks, outside my home.

     

    2. M31 this time, is much better than the view I seen through my C14, at the same place, a year ago... The background stars are clear when I only use a TV 55mm eyepiece, on this 1800 mm scope. The contrast on M31 is no longer just a blob of light I seen previously.

     

    3. Jupiter is the best, as compared to my previous 2 observation, at the same place, although this time it did not shine brightly due to thin layer of clouds. Jupiter can only power up to 225X with my Baader planetarium 8mm to 24mm zoom eyepiece. My 9mm Nagler eyepiece shows the best view at 200. Surprising, through visual, the CA is not noticeable this time, perhaps due to the sky condition is not a very clear night...

     

    4. M6, 7, 8 and M44 are great, when seen through this scope...

     

    5. It splits the double-double easily near Vega...

     

    6. Albireo double stars is so beautiful, if the person is not an experience triplet guy, no one will ask why the 4 points star like has two color, red on one plane and blue on the other...

     

    7. M42 and the trapezium are easily seen, although the sky is not very clear even during the moment of good seeing...

     

     

    James Ling, Malaysia

  • ●  iStar Optical 204mm F/11.7 Achro

        First light report by Leslie Hess, Arkansas, USA

    I am proud to say that I now own one of only a handful of 204mm f11.7 achro lenses produced by iStar Optical. After much discussion and considerable deliberation I settled on this lens for my ultimate scope, initially I had decided on the 6 inch f15 objective and even placed the order. However, I changed my mind and contacted iStar the next day to change the order. iStar agreed to produce a single lens. This is not normal stock for iStar, but the single lens was produced at no extra charge. It was delivered on time in about 6 weeks. I cannot stress enough how superb iStar customer service is.

     

    I have been an optics-geek since I was a kid. About 10 years ago I built my first entry level scope. A 10 inch Dob which I used for several years.

     

    As I unpacked the lens it proved to be in perfect condition. The coatings were beautiful and flawless. Initial star tests showed no coma or astigmatism and had good surface quality. The lens was slightly over-corrected which is fine with me as it proved not to be an issue. Quality of the lens overall is quite good.

     

    After months of constructing my OTA, I was finally ready to test in the real world. I double checked the OTA collimation to ensure all was square, mounted the 7 foot assembly to the base and waited for dark. Cloud cover was clearing and I was hopeful for a triple play.

     

    The eyepieces I used are the ones I use in every scope I own. This eyepiece set includes the Russell Optics 11mm swa, 32mm konig, 19mm uwa, and my cheap 2x Barlow.

     

    Before the moon rose I had a break in the low cloud cover to get a clear view of M42. Absolutely the best view I have ever seen, bar none. The young star cluster tightly grouped so perfectly even the 5th faint star in the tight 4 star cluster was easily resolved. I saw more detail in the cloud itself than ever before. Absolutely no coma or astigmatism was present leaving superb contrast. Only the brightest stars in the sky had slight chromatic aberration, which could be due to the cheap eyepieces I was using.

     

     

    The star test proved to be dead on. The lack of chromatic aberration, coma and astigmatism conspired to make this a genuine joy. I have to keep reminding myself that this is an f12 scope!

     

    A cloud bank rolled in and took an hour to clear. By this time the moon was at about 40 degrees high. This scope is so eager to magnify. The 2400mm focal length and the 11mm barlowed by 2X yielded 430X. Boy does it add up fast. The moon was at 98 percent full; I had one cratered edge to enjoy. With the 32mm, the moon was gigantic, super sharp and totally CA free edge to edge. With the 11mm the detail really began to pop out, now we are getting down to business. I added the Barlow and pushed very high power. Sky conditions were far from ideal but the clarity, sharpness, contrast and total lack of CA blew me away. I am positive this instrument would have yielded much higher useful magnification but I ran out of sky and eyepiece possibilities. The clouds rolled in. Unfortunately, it was cloudy by the time Saturn rose.

     

     I made the perfect choice for my purpose and would purchase this lens again. Within the last 12 months I looked through a 24 inch truss reflector, 8 and 10 inch dobs and several large aperture compound scopes. This 204mm objective most closely compares to a 14 inch compound scope. I ended up with a superb telescope and look forward to years of use.

     

    Fast forward a couple of weeks and I have finished the scope and mount. I am taking off work Monday to see Saturn and report to my friends here at Cloudynights. But the clouds rolled in again the same as last time.

     

     

    -- Leslie Hess

    Gallery

  • ●  iStar Optical 150mm F/15 Achromatic Doublet in Cell

        First light report by Eden Orion, Israel

    Two days ago I've tested my 6"/15 scope for the first time. As I've wrote before I've tested it before, just to see the correct place for the lens. But the night before yesterday was the first real test.

     

    Before the test I did (With my son) the collimation process . In the book "Build your own telescope" the process was described well but It looked to me, after years of using laser collimators on Reflectors not so accurate...

     

    Well, After four of my friends, each one of them have "some" experience with Telescopes (all kinds of) the final verdict was "pinpoint sharp".

     

    Moon was fantastic. almost fool with a lot of details on its face , thanks to the wonderful contrast of such scope. Jupiter was AMAZING, very sharp with a lot of true colors of the belts and some ore details with am 26 mm eyepiece.

      With an 14 mm eyepiece, Albireo was spread for a noticeable part of the field with it's blue and yellow stars like pin-points.

     

    Now I'll go into the painting job. I think it will take another two weeks or so.

  • ●  Comment posted on Cloudy Nights

        September 2010, by Leslie Hess, Arkansas, USA

    I have been looking for larger retractor lens for some time now. I found the iStar and here on CN and did some research on the company and found nothing but good. Some impressive builds have already been documented. I really joined up because of Sean’s Jill build.

     

    I decided on which lens to purchase. I know aperture and fl are what I am after plus acceptable lens quality. I contacted Ales at iStar via email. I really expected a generic response like we have all become accustomed to. Generic was not what I got.

     

    I must have asked a hundred questions and I must say Ales answered every single one of them. Not a single email of a dozen or so went unanswered. I wish all companies could deliver service like iStar and Ales and Gay on the Arizona side.

     

    After ordering the 6 inch f/15 I had reread the volume of emails I received from Ales. I ended up changing my order to the 8 inch f/11.7. iStar is making a single lens production run at no additional cost as this lens is not normal stock. I am stoked. Eta 45 days.

     

    Rock on iStar.

  • ●  Perseus AT 150-10 OTA report

        by Steve, Darwin, Australia

    Ales has done it again.

     

    Last week I received this beauty, delivered to my door. The packing was superb and it arrived in perfect condition. This is hugely important to prospective buyers. I have included a photo of packing. I received lens and focuser separately. Equally well packed.

     

    Putting together was simple. Fit and finish excellent. The machining is a work of art. The scope is completely CNC machined. Even the holes are CNC made!!

     

    I wanted this scope baffled for higher magnifications. The baffles are all bolted in, no glue. Very solid.

     

    I went for the F10 as the best compromise (IMO) between size, mounting and optical performance.

     

    1st light was a delight. The correction is about as perfect as I have seen with any telescope. Everything lined up perfectly. Jupiter was on hand for some critical viewing and it did not disappoint. Resolution excellent and CA very unobtrusive.

     

    Considering the price, this is one great buy.

     

    Well done iStar.

     

     

    PS I ordered the 3.5" focuser which is a delight to use but I believe Ales will not be selling anymore of these, which is a shame.

REVIEWS