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iStar Optical

More than a Telescope Manufacturer

iStar Optical is known for the design and manufacturing of quality telescopes and lenses for individuals and the astronomy industry. No less than a half dozen professional telescope builders and manufacturers in Europe and the US now implement our lenses in their telescopes. We have produced a number of objective lenses for Universities and observatories around the world including Mount Stromlo observatory in Canberra Australia, INAF-Osservatorio Astronomico di Brera in Italy, Swarthmore College in the USA, Hohenkarpfen Observatory in Germany, Pic du Midi observatory in France and Université Libre de Bruxelles in Belgium.

What you may not know is iStar Optical also designs and produces lenses for “Opto Mechanical” and “Opto Electronics” applications. Lenses and optical assemblies were recently produced for the physics departments of MIT in Massachusetts USA, L3Harris Technologies, and Caltech in Pasadena California USA. Specially designed lenses for Holographic applications were delivered to L-3 Communications EOTech in Ann Harbor Michigan USA. Recently iStar Optical became a registered supplier of optics for the prestigious STAR Labs of Lockheed Martin Aerospace and Defense Company.

Call or email today to find out how iStar Optical can provide solutions to your optical needs.

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iStar’s 140mm F/6.5 Super APO Triplet

HIGHEST CONSISTENCY

IN TOP OPTICAL & MECHANICAL QUALITY!

HOMEMADE / DIY TELESCOPES

Using iStar objective lenses

Solar telescope with iStar 204m F/8.8 achromatic doublet

PHANTOM FCL 140-6.5 REVIEW

by Josef Ladra, September 24, 2021

iStar Optical has been successfully manufacturing 127-250mm F5-F15 achromatic lenses for many years. These lenses are also purchased by various professional manufacturers of achromatic telescopes, as well as by amateurs who build refractors for themselves.

Technologically advanced achromats with the designations R30-T, R35-S, and R50-S (Anastigmatic, T-thick, S-slim) are also very well known because the optical design reduces chromatic aberration by 30-50% when compared to Fraunhofer’s conventional achromat designs. This is due to an improved false color correction due to incorporation of a dense flint (type of an ED glass) in the design.

ASTRO IMAGES

IC434 (Horsehead Nebula)

by Robin Lim

M101 (Pinwheel Galaxy) - before moon rise

by Dan Kahraman

Sun

by Robin Lim

Saturn

by Jose Restrepo and Dan Radulescu

SH2-308 (Dolphin Head Nebula)

by Robin Lim

M51 A (Whirlpool Galaxy)

by Dan Kahraman

IC2944 (Running Chicken Nebula)

by Robin Lim

M20 – Trifid nebula

by Jose Restrepo and Dan Radulescu

NGC2070 (Tarantula Nebula)

by Robin Lim

IC 405 (Flaming Star Nebula)

by Arnaud van Kranenburg

Jupiter

by Jose Restrepo and Dan Radulescu

NGC3372 (Eta Carinae Nebula)

by Robin Lim

See stunning photos taken with iStar Optical instruments

MATCHING YOUR TELESCOPE TO YOUR ASTRO CAMERA AND FEW WORDS ABOUT SAMPLING

(by Scott Tucker of Starizona)

Lets begin with the question received recently by a customer

(Click to see the full article)

Hello,

I don't want to distract you from your work but I have two questions that have arisen on the Mallincamsky Group site as a result of the ATT article on APOs giving the best results for imaging

People are simply dismissing it.(see the section in red beow)....IMO a triplet APO likely has fewer aberrations and concentrates more of its energy into the Airy disc even more so if it is very well made (Strehl values approaching 1.00)

The second question arose from the size of the pixels in the camera. Mallincamsky has a camera that uses the SONY IMX432LLJ and IMX432 LQJ sensors (mono or colour)

The pixels are 9.0 micron in size in diagonal 17.6mm in length for a total of 1.7M pixels. Would the Phantom 140 FCL 140-6.5 be ideally suited for this camera?

I will try to rebut or respond to the board based on my good understanding of your reply.

The area of contention seems to be oversampling or undersampling of the objects involved and that this determines the suitability of the telescope (I think they must mean focal length) and camera combination.

How are all these variables combined and reconciled with the article?

Dan

People tend to make a bigger deal of sampling than really matters. Proper sampling *only* matters if you are trying to get the most high resolution detail out of an object. I (and many other people) have taken gorgeous astrophotos with, say, a 135mm camera lens which is massively undersampled. And it doesn't matter, the pictures can be amazing. But if you are trying to resolve tiny detail in a small galaxy, clearly a 135mm lens is not the system to use.

If you *are* trying to get the most detail, you would ideally match your pixel size to your seeing conditions. If you had 2 arcsecond seeing, for example, you would ideally want pixels that are 3 times smaller than that or about 0.7 arcsec/pixel. With a typical modern CMOS with 3.76-micron pixels, that would require a focal length of 1100mm. So a typical midsized apo could be a good choice for that.

9-micron pixels are huge by today's standards. So to get ideal sampling, you need a very long focal length of 2650mm, and now something like a 12" RC or CDK becomes better suited. But if you just want pretty pictures, those big pixels on a 140mm f/6.5 give 2 arcsec/pixel which would have great sensitivity. I assume that is the idea with the Mallincam: lower resolution but high sensitivity, better for EAA and such.

Here is one of my images at a resolution of 2.6 arcsec/pixel, and here is one at 5.7 arcsec/pixel.

Doesn't affect how good a picture you can get, just how much resolution you have. And resolution is rarely the primary objective.

—

Regards,

Scott Tucker

Newly Designed & Precision Manufactured

Line of Super APO Triplet OTA Refractors

RUNNING OUT OF BACK FOCUS?

iStar’s newly designed and produced Phantom FCL 140-6.5

is the first-ever imaging Super APO refractor with fully

detachable 80mm rear section to allow for the use

of binoviewers, and imaging equipment requiring

extended back focus distance.

Fast 140 mm clear aperture F/6.5 FCD100 & Lanthanum Optical System,

Outstanding High Resolution Image Quality & Color Reproduction

Based on recent reviews and customer feedback I wanted to inform everyone that we have resolved the issue with the slipping rotary lock grip in some units. From now on every single unit will be equipped with a special soft metal strips assuring strong solid grip even on the largest eyepieces and heavy imaging systems.

Thank you everyone for your support!

Ales Patrick Krivanek

iStar Phantom FCL 140-6.5 Super APO Triplet

For Full Frame (FF) imaging use William Optics Flattener 68III.

To attach WO Flattener 68III to Phantom FCL 140-6.5 requires a custom made adapter. For all of your adapter needs please contact Starizona.

for APS-C imaging use Starizona Apex ED L 0.65x Reducer/Flattener

WE OFFER 5% OFF

WHEN PURCHASED TOGETHER

(140mm F/6.5 Lens in Cell and Apex ED-L corrector)

$ 2,799

$ 2,659

BUY NOW !

ATM built - iStar Optical 140mm f6.5 Super APO Triplet

Robin Lim

Hi all,

Just want to share with you all my experience on building my own APO Triplet refractor. I always wanted to build my own refractor, I did it recently by purchasing a skywatcher esprit 80ED lens and build the tube around it, but then I wanted a bigger scope with longer focal length.

My aim is to build myself a refractor with APO Triplet lens. It is hard to get the manufacturer that sell the lens cells alone so when iStar Optical released their first batch of 140mm APO Triplet lens, I did not put any hesitation and take a bold jump to be the first adapter of this lens.

It took me 2 months to get the lens from ordering to delivery and meanwhile, I communicated with iStar optical to get the detailed lens drawing as well as the focal length data I need to determine the tube size.