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 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 and their staff of engineers and opticians can provide solutions to your optical needs.

Best price on iOptron CEM25EC

$200 USD OFF the retail price!!


CEM25EC-HC (1.5” tripod) - ONLY $1,699.- USD

CEM25EC-HC (   2” tripod) -ONLY $1,799.- USD



iStar 150mm F/5 R50 Semi APO Doublet Mounted in Custom Made OTA by Skylight Telescopes of London

I have had a liking for low power wide field telescopic views as long as I can remember. I was looking for a telescope to supplement my Istar 200/1200 WFT that would be portable enough to easily transport in a compact car and utilize a 3" format 30mm 100° field eyepiece.  The Istar 150/750 semi-apo lens was perfect as it would give me 25x and a huge 4° true field of view. I had Skylight Telescopes of London, England design and build the telescope around the Istar lens and a 3.5" Feathertouch focuser.

I have now had several opportunities to use the telescope under clear and relatively dark skies. The first time out with the ES 30mm 100° 3" eyepiece and diagonal was a real joy and confirmation that the project was a success. Milky Way fields through this eyepiece with its 4° field of view are amazing.

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2015 Solar observers meeting in France Featuring iStar 204 F8 TCR Refractor

We had great success with the 204mm F8 TCR at the R.O.S. meeting! People were amazed with the open design, the good looks and care taken in producing it. Many people observed the Sun through it.

One guy had a personal made refractor with a 150mm Istar lens…of course now he has a mind to buy a 204-8. We had intermittent  weather some clouds, but no rain.

This year there were 120 participating amateurs surpassing the 60 attending last year. This attendance did not include the who also enjoyed viewing the Sun through our instruments. This event is increasing in notoriety every year with also very interesting lectures. Here are 3 photos. Stay tuned!





Bernard Durand, FRANCE

The iStar 204/1200 – Second Generation 2014

from John Croker, Australia

I’ve always had a liking for refractors. My first serious instrument was a Vixen 102 ED SS, a beautiful 660 mm focal length lightweight refractor, easily supported on the Vixen GP mount. Almost made for each other. Since 2001 its been the best portable telescope I’ve used. In subsequent years I have acquired a Vixen NA 120S (a Petzval designed 120 mm / 800 mm FL), and a WO 66 triplet which is a great travel scope. I had always wanted a bit more aperture yet liked short tubes for maneuverability  so when I saw a 6” Antares in 2006 I went ahead and bought it. I’ve had a few good years of observing with this scope, mainly from my house in the northern suburbs of Sydney, with its attendant light pollution. I decided I wanted a bit more but I could never quite bring myself to order anything I felt justified in spending upon until I noticed the iStar range.

A little research and I was hooked. In Feb 2014 I placed my order and sent over three and a half thousand USD to Mike at Istar and settled back to wait. I also sold my Antares – I had to make room.

Nearly 11 months later the Istar finally arrived. I had picked the f/6 “Comet Hunter” model. Part of the delay was in remaking the tubes, as Istar had found the original assembly just too heavy. I have to say I appreciated this as the new scope was 16 kg (35 lbs) down from 20 kg (44lbs). 9 lbs is a lot extra when you are trying to get it onto a high dovetail on a G 11 or similar mount! The scope was well packed in a thick cardboard carton with the scope itself surrounded by aerated foam blocks. Istar is clever in their packing and had placed the 3.5” WO focuser, in its own  padded box, between the  lens  end

 of the scope and the box, making extra protection for the lens. The focuser was fitted with William’s new Rotolock eyepiece / diagonal lock system which is a self centering double opposed taper. I have to say this in its present form is one of the best eyepiece locking systems I have used.

This second generation iStar comes with an extendable dew cap, some 400mm long offering excellent dew shielding. A flat lens cap snaps in place with embedded magnets holding it to the outer ring of the dew cap. The white tube (I asked Mike for white because you can see it better in the dark) is held in 2 lined quick release tube rings, with several M6 tapped holes.



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iStar WXT 204-6LT refractor review

“My God! It’s full of stars!” proclaimed David Bowman, as he approached the monolith in the classic science fiction movie 2001: A Space Odyssey. That’s the feeling I had whilst experiencing the new iStar WXT 204-6LT rich-field refractor under a dark, country sky. Before I elaborate on this, it is important to define what ‘rich-field observing’ is all about.


Small-aperture telescopes with short focal lengths are excellent for low-power, ultra-wide-field observing. In contrast, large aperture, long focal length telescopes are the instruments of choice in the pursuit of high resolution targets such as the Moon, planets and double stars. Rich field occupies the niche in between the two. The ideal rich-field telescope will have a decent aperture and present moderately large fields of view in order to probe the depths of the deep sky at intermediate image scales.

Arguably the ideal rich-field telescope will present unobstructed images over a field of view of approximately two degrees. While a fast (f/5 or faster) Newtonian of 200mm (eight-inch) aperture or more is a good rich-field telescope, an achromatic refractor of similar specifications can do considerably better, owing to its lack of a central obstruction and maintenance, as well as its provision of a wider true field. Enter the iStar WXT 204-6LT.


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iMoonraker Nebula Class 4-inch f/12 refractor featuring iStar 100 F/12 Achromatic Doublet

Moonraker, not the best known, but known by the best... We take great pride in creating each and every telescope and we all know that the the engine driving the OTA is the objective. In this regard we use classic optics both old and new and Istar create stunning classical doublet objectives with a modern twist at a great price that deliver stunning well corrected vistas... Period!


"Moonraker are proud to use iStar optics in many of our telescope builds."

Mark  Thurstan-Turner

Viktor Zsohar Proudly Presents the iStar 228mm F/7.7 ATM Build

This telescope is a great performer in its class, and is a joy to use! It is awesome for observing deep-sky and fantastic for the Moon! CA? Yes, the CA is undeniably present on bright objects, but I think it is up to a person how much it is tolerated or not? For example, I could not take off my eyes off the Moon for an hour or so, even when CA was present, because I was immersed so much in observing the craters and other fine surface details! Is this telescope good? Yes, darn good :-) Actually, this refractor may be the perfect outreach kind of scope!

I am very happy with it!


The focuser is an AP 2.7" with greased rack and   pinion  and  I  added  an  AP


extension between the focuser and the tube so that it can be exchanged later on for a 4" AP focuser if needed. The length of the system is exactly as planned. I have 7" from the end of focuser to the focal point and it comes into focus with a diagonal even for me who wears strong glasses. The 7" back focus also makes the telescope bino friendly, however, this will need to be verified. The tube mounting is a 15" AP ribbed plate with Parallax rings. The tube is not heavy considering its size. My AP 900 is good enough to hold the refractor, but I have to balance it carefully.



Whitehorse Canada

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iStar Phoenix WXT 204-6 LT

Strongly Reduced Chromatic Aberration doublet

with a near SEMI APO performance.

iStar Ares WFX 150-5 R50 SLIM

iStar is proud to introduce an all new, second generation Ares WFX 150mm F5

with exciting features our customers were asking for.


  The Heart of this wide field Comet Hunter is a recently designed 154mm F5 R50-Slim improved Achromatic doublet.

This new lens is substantially lighter and Chromatic aberration is reduced to near Semi APO levels with unmatched

resolution. New white tubes with all inner parts completely re-designed for reduced weight. Split construction counter cell

with fully retractable dew shield, bayonet style locking mechanism and slim lens cap held by neodymium magnets. Each OTA is

shipped with 360° fully rotatable dual speed 2.0” WO Rack and Pinion focuser in white finish and a set of 160mm “Fast Lock” Mounting

Rings. All scope parts are precision CNC machined in the European Union out of aircraft grade alloys and powder coated. All this for only $2085.



  Watch for the release of our next generation line of super lightweight 8" Refractors the Phoenix WXT 204mm F6, Perseus AXT 204mm F9 and Asteria AXT 204mm F8 R45-S.

Stay tuned!

Test Driving the iStar Perseus 150mm f/8 Achromat

Tested and Reviewed by Neil English

Over the last several years, iStar Optical has established itself as a market leader in providing high quality achromatic and semi- apochromatic refractors at fair prices. Over this length of time, I have watched the company grow and innovate in new and exciting ways, providing customers with objectives for ATM builds or complete telescopes in traditional or truss tube formats. Recently, the company has been introducing exotic glass types into their designs, thus providing large aperture with improved colour correction to sate a growing demand from the amateur community.


Having fully test driven several iStar refractors, I eventually settled on acquiring one of my own; a beautiful 127mm f/12 R30 Asteria (aka ‘Tiberius’) which has given me immense pleasure in the pursuit of my hobby. Earlier this year, iStar owner, Ales Krivanek, contacted me inquiring about whether I would be interested in test driving yet another product from their first generation stock; a 6 inch (150mm) f/8 achromat. Naturally, I obliged and the following is a summary of how I got on with it.


Fit ‘n’ Finish

The optical tube assembly arrived in perfect condition having travelled across Europe to Scotland from its source in the Czech Republic. The instrument – a first generation iStar model – was very carefully packed and a quick examination of it confirmed that all was well. Just a few moments of casual inspection of the telescope will convince you that the workmanship that went into fashioning the tube assembly is light years ahead of the more ubiquitous Synta designed CR6.


While many have complained that the original, first-generation iStar tubes were over-built and too heavy, I have come to like them an awful lot. For me, they are reassuringly sturdy and reminiscent of the days when quality achromatic refractors were being built by the world’s famous optical houses. They feel old fashioned and look old fashioned.


Like all iStar objectives I’ve had the pleasure of using, the one that accompanied this tube was perfectly assembled within its high quality, adjustable aluminium cell. The crown and flint components are properly spaced, fully-multicoated and are surrounded by a massive dew shield that protects the lens and all but guarantees hours of hassle free observing without the need for a dew band.

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iStar Ares AXT 150-5 R50 First Light Report

Hello guys,


My new Ares 150-5 R50 arrived in a perfect condition and I finally had some time to test it. Before started using my new iStar Comet Hunter, I had a special guide frame build around it. An Alt-Az mount which is nice for star hopping. I've also build a sort of frame for in case I use the scope for contrail spotting, a frequent waste of time of mine...

This  'grip'  and  the  use  of  a  binoviewer, the Maxbright 'Terrestrial', which comes with a special prism (build-in glasspath corrector) to get easy focus, this is fantastic!

I use the bino with 2 Hyperion 24mm eyepieces. in combination with the glasspath corrector this gives me a magnification of 60x. Planes show up far bigger then stars or planets, even at high altitudes, so CA is not disturbing.

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J.P. Brahic - French amateur astronomer

achieving professional quality images using his iStar 228 F/9 H-Alpha Optimized Doublet


ATM Build by Jack, September 2014

It’s been obvious for several years that my TV85 and cheap 6 inch Dob in our Florida home consistently outperform (on the usual lineup of urban targets) my TV102 and 10 inch Dob - Newt with a premium mirror in our upstate NY home. Atmospheric and local seeing is very good most winter nights on the east central coast of FL, and poor (on those few nights when stars are visible) in NY. So I transported...


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"The universe is full of magical things

patiently waiting for our wits to grow sharper."

iStar Optical

Eden Phillpotts