I've calibrated the E steps. 66X focal reducer/flattener, 240sec, ASA 1600,. 265. This is my plan to begin astrophotography on a regular. You get a single ring with a. 50 (ex. Astro-Tech AT72EDII Refractor OTA FPL-53 f/6 $469. Posts: 3,915; Joined: 08 Jul 2014; Posted 14 August 2019 - 08:09 AM. Back focus is 55mm from the shoulder of the reducer to the image plane, the standard spacing for 35mm. Please tune in for my 1st impressions of it. Astro-Tech 70ED - posted in Refractors : Im thinking of getting the $299 AT70ED as my first foray into astrophotography. Back to top #7 nicknacknock nicknacknock. 95. This is one premium-quality diagonal that doesn't happen to be priced like one - and it's still a hot product for many observers. The Starwave 60ED becomes a fast astrograph at f/4. 8X reducer/field flattener is designed for prime focus astrophotography. 25” non-marring compression ring accessory holders• Vixen dovetail plate. This instrument is designed as an astrograph. Whether you are bird-watching or simply enjoying nature's beauty, the advanced apochromatic system with ED (extra-low dispersion) glass minimises colour fringing. ciently explore phase-space configurations of GCs without needing to specify their initial conditions,. 5mm or 7mm DeLite for Astro-Tech AT60ED? - posted in Eyepieces: Im primarily a binocular observer (Canon IS 10x42 and 15x50). Thank you @peter k! My goal is to pit it against my other two refractors in a 2 against 1 competition. These mount holes are 20mm apart, is this a standard size, or do I. 00. $60. The scope weighs in at a light 3. 25" brass compression ring eyepiece holders. Altair 60ED, MG32 Guider and EQ3 Pro Synscan mount COMBO £968. topic starter. Astro-Tech 60ED vs. Looks like a sky rover 60ed rebranded, make sure it uses fpl53 glass and you should be good. FF130. Astro-Tech AT60ED 60mm or Apertura 60mm FPL-53 Doublet APO Refractor - posted in Refractors : I am looking for a terrestrial scope that can also be used for a grab-and-go scope. Not wise. A super portable refractor telescope with FCD100 ED glass, suitable for astrophotography or visual use, day or night-time. To the OP. At the business end, the two-inch optical back consists of a millimetre-graduated lockable two-speed focuser and a 1. • combined dovetail/tripod bracket for use on a photo tripod or a German. One of those world class designers was Thomas Back. 95. The TS is maybe 80 or 90% of the BVF - PLUS it has an ED objective yet it's sold at a far lower price. $139. 8x reducer you get a fast flat field astrograph operating at f/4. VAT) Out of stock. All of the telescopes in the chart above fall under the listed payload capacity of the mount. And I thought As. Price when purchased online. Inside the cap is a wheel that can be rotated to either line up the Bahtinov. 25″ with it. Same ratio applies if each is mated to a 0. I am selling my Astro-Tech 60ed + . Most Read Articles • Contact UsContact Us • Moon PhaseAstro-Tech 60ED Unboxed Equipment Discussions. The flattener produces wonderful flat fields as well as a 41mm image circle. Length: 18" dewshield retracted, 21. We all have questions from time to time. The 72 is half the price for only 10% less aperture. Astro-tech 60ED with FPL53 glass (like new condition) Astro-tech . 1 lbs: 7. Astro-Tech. com is the leading portal for astronomy news, classified ads and telescope reviews. This 50/60 mm finder ring set mounts into the dovetail shoe on the Stellarvue or Feather Touch focuser. Happy 2023 to everyone! Ever wanted to take a telescope on vacation with you… but you’re flying there and not driving? You need an instrument considerably sm. Cloudy Nights. This will be my step toward eventually purchasing an EQ6 R Pro later this year. Reviews. This scope is the ultimate doublet refractor for those not wanting the weight and cool down of a triplet optical set. M51 and companion - at least as bright as my 10" dob. 00 £2,082. 80mm. For the Astro-Tech Field Flattener the optimal spacing from field flattener to film plane: 57mm +/- 4mm and Canon is supposed to be 55. Joined: 06 Jan 2005. 8X Reducer/Flattener + Williams Optics Guidescope package. Most Read Articles • Contact UsContact Us • Moon PhaseThe Astro-Tech AT80EDT is a great triplet apochromatic refractor. → Equipment Discussions. They are pretty much optical twins with no. • dual-speed 2" Rack and Pinion focuser with built in rotator. Chondrites (Carbonaceous) CI (Ivuna-like) CM (Mighei-like) CO (Ornans-like). The thing that has most helped me practically is having a small refractor (F/6 60ED) and an artificial star that I can play around with indoors, under controlled conditions. For Sale. For example, the fully-multicoated. 80mm. It will not work on all of them however. • a rotating dual-speed 2. It functions as a handle (This is fairly obvious from the name. The AT60EDP produces a 44mm image circle. 0mm) > Camera (17. ASTRO-TECH AT72ED 72MM F/6 ED $379. Resolution Formula: ( Pixel Size / Telescope Focal Length ) X 206. ASTRO-TECH AT60ED 60MM F/6 FPL-53ED AND LANTHANUM DOUBLET I am selling my Astro-Tech 60ed + . Greetings to all! I have for sale a near new, recent vintage Astro-Tech AT60ED. The price difference between the two not counting taxes or shipping is only about $10. Those who can afford a full-frame astro camera can afford an FSQ. It’s worth noting that the. Due to the bracket being thicker you will have to put longer bolts in. For Sale. •. I mainly do imaging so the Astro-tech is a FPL-51 triplet and the APM is a FPL-53 doublet, I have a hard time figuring out which is better. These include the Explore Scientific Twilight I, the Vixen Porta II, and the Sky-Watcher AZ5. Designed for a better astrophotography experience than its doublet predecessor, the Sharpstar 61EDPH II apochromatic triplet is improved in a few key areas. It seems like it’s similar, and yet quite a different design than their. $369. Calculate the resolution in arc seconds per pixel of a CCD with a particular telescope. 95. 2. • dual-speed rotating 2" rack-and-pinion focuser with 10:1 ratio fine focusing. With the ST80 I was always afraid of breaking or misaligning it somehow. Click on the pics for a larger image. When Thomas passed away, Astronomics, continued in their support of his family. Add New Equipment To Database. The focuser can rotate as well to help you get the perfect framing. It's FPL-53 or equivalent vs. The MONARCH Fieldscope offers first-class optics and high contrast. The user manual says that it provides a library of LabVIEW wrapper around the OmniDriver . Mounting to a Refractor Mounting Ring: Select the F002 E above. I have for sale a Sharpstar 60ED refractor. 5 (Komine Made) m42 and Carl Zeiss Jena 135mm f3. 25lb. Basically, what takes 4 hours of imaging with the ZS81 takes 3 hours with the AT80EDT if the same power of flattener. Astro-Tech AT60ED . I highly recommend it. Astro imaging bundle. The difference in price is $399 for the Astro-Tech and $450 for the Orion. It's a 102mm f/7 doublet refractor made with fk61 ED glass. It is compact, well made with a rotating two speed Crayford focuser, a sliding dewshield and nice overall finish. After this, I chose a different base image and it began processing - but loading every image FAILED before. Nothing affecting the view. Thank you Jeremy #2 06-01-2016, 06:11 PM barx1963 (Malcolm) Bright the hawk's flight : Join Date: Nov 2008. Formal-Garden-7412 • 22 days ago. Mounts for Astro Tech AT60ED - posted in Refractors : Hi folks, I recently picked up an Astro Tech AT60ED as my first scope and noticed the mounts on each side of the scope for spot/guide scope and other peripherals. Match them up at the hardware store and buy a handful of extra washers while you are there. 265. Save Image. It's all a compromise between lightweight portability and light gathering ability. On the front end, the retractable dew shield has an OD of 121mm, in case anyone is considering putting a filter there. 34mm and that is the thickness of the spacer (s) you require. Due to a stock re-organisation, Altair is closed to visitors and we cannot take phone calls between Mon 25th and Fri 29th - we are still shipping goods but there will be a 1-2 day delay in shipping. As soon as lifted the telescope free of the packaging and unwrapped it, I noticed an annoying rattle when moving the telescope around in my hand. com. I thought that I would do an unboxing of the newest addition to the family. Page 1 of 3 - Astrotech ED series - 72mm or 80mm? - posted in Refractors : Im trying to decide between a 72mm and 80mm doublet Astrotech ED series. Altair Astro Limited is a UK Company I have been doing some research on small refractors and have come down to these 2 options: 1. Last updated on Jul 13, 2023 15:59:36 PDT View all revisions View all revisions. A compact guide scope with good quality optics to fit atop the 60ED with "set and forget" focuser. I like both the build and look of it, and the functionality of the rack and pinion focuser, but Im having a problem that Ive never experienced. This is strictly for visual and Im trying to decide between the 2 of them. Turned out the Astro-Tech 80ED. Posted 23 May 2019 - 11:05 AM. The Astro-Tech 60ED 1x flattener easily threads on to the focuser of your AT60ED after your remove the standard compression ring eyepiece holder. The new 80EDL is a doublet and F/7. 0. → Refractors. You save. Posted 30 August 2021 - 02:24 PM. Here are some Borg 60ED images resulting from a Google search :-Gary Honis-modified Canon XS(D1000), Hutech 60ED F3. 800-422-7876. 2 oz with the rings and dovetail, 5 lbs 4 oz without rings and dovetail. Calculate the resolution in arc seconds per pixel of a CCD with a particular telescope. The Astro-Tech reducer/flatteners thread into the focuser for a solid connection. It not only has great reviews, has FPL-53ED glass, and a clear price advantage. The AT70ED is bringing ED optics to you at a fantastic price. Not so good for planets. GA] 22 Nov 2018. Page 1 of 2 - Yet another rebranded Sharpstar 60ED available now - posted in Refractors : I got an email from High Point today talking about a new Apertura 60mm f/6 FPL-53 doublet that looks exactly like the Sharpstar 60mm which is currently being sold with branding from Astro-Tech, Teleskop-Service, Altair Astro, and William Optics. Tecnosky 90 Triplet f6 'OWL' APO. VAT) Sky-Watcher Esprit 100 ED PRO OTA £1,799. 8X reducer/field flattener is designed for prime focus astrophotography with quality f/6 focal ratio apo refractors such as the Astro-Tech AT72ED and AT130 apo, it will also work well with Astro-Tech and other brand refractors in the f/5. I want to invest in my first astrophotography telescope which would be used with my iOptron. Astro-Tech AT72EDII Refractor OTA FPL-53 f/6 $469. I have been very impressed with my modest optics thus far and have. Sharpstar 400F5. Star test results using an artificial star at a distance of 60 feet. 5″ long with the dewshield retracted and 12. 60mm Astro-Tech ED - posted in Refractors : Sears 60mm x 700mm Discoverer (Towa) achromat, circa 1968, vs. Although its been listed out of stock for a. Page 1 of 4 - Astro Tech's new Scopes coming soon! - posted in Refractors : I didnt see this on the refractor forum. 8X reducer (384mm @ f/4. ASTRO-TECH AT60EDP 60MM F/5 DUAL ED PETZVAL OTA - posted in Refractors : I saw this for sale on the Astronomics website today. Astro-Tech 60ED Unboxed Equipment Discussions. Optically it is quite good, pushed hard on difficult targets like Venus, a faint purple fringe is visible. Astro-Tech 60ED Unboxed Equipment Discussions. Buy telescopes and telescope accessories at Astronomics. Astro Tech refractors diameters? - posted in Refractors : Hi all, I would like to know about the outer diameter of the following AstroTech scopes for something i want to buy, please make sure it is a precise measurement as much as possible possible. Page 1 of 3 - Star Tests: 60mm Sears vs. I have stacked CR2 files in sequator without problems, so that shouldnt be your problem atleast. Small is essential on a Sky Adventurer, so you are going to need to consider the assorted 60ED's and a flattener. It can be ordered with various accessories. Astro tech 60ed . I was hoping to do this first light video of my Astro-Tech AT60ED after I got my flattener/reducer, however they just haven't been in stock. in tandem with the MiniBorg 60ED for convenient RACI star hopping. AstroDMx Capture with an SV605CC and an Altair Starwave 60ED doublet refractor with field-flattener and dew heater strip. Focuser: 2" Rack & Pinion with 10-to-1 Microfocus. (They have a first look video out already. Guidescope Suitability Calculator. ready for shipping in 24 h. ASTRO-TECH AT72ED 72MM F/6 ED $379. SWAS70ED-OTA-RED70M54. You can still get good images, but you would need to. 1" F/7 ED REFRACTOR - posted in Refractors : Well just ordered me a ASTRO-TECH AT80ED 3. 00 £62. Some of the youtube videos talk about a backfocus adjustment of 3mm, but this particular focal reducer doesn't seem to have the ability to adjust - it is a. This scope is for the person wanting a little more than what the 60ED and 72EDII can bring to the table. 00 usd. I already have a Skywatcher ED100 that Im very fond of, but a smaller scope for both grab-and-go visual use and wider-field imaging sounds appealing. For planets/ moon general viewing you could also look at the skywatcher 100ed F-9 or the TS-102ED F-11. You are better off with a short refractor like a Astro-Tech 60ED + 0. 5 compared to the usual F6 (TS sold the F5. Currently out of stock. 9 specification likely results from a lens cell with a slightly larger entrance pupil). ZW Optical. The Astro-Tech 60ED is high on the list when it becomes available. This Astro-Tech AT80ED refractor has: • split tube rings with detachable Vixen-style dovetail for installation on virtually any mount. VAT) Altair 70ED Triplet APO Refractor Telescope From: £759. ZWO EAF. Both have FPL-53 glass. The TS PhotoLine 60mm, f/6 FPL-53 apo arrives on the market amid some stiff competition from the suspiciously similar Astro-Tech AT60ED, the Altair 60EDF and the William Optics Zenithstar 61 apo (the Zenithstar’s 61mm, f/5. $139. Its fully multi-coated optics provide bright, clear images that are free from distortion and color. It will cost $90 or so more than the AT with shipping, but it’s in stock and they are a great company to deal with. Contact Us. Star charts generated using Cartes du Ciel. Page 1 of 3 - Star Tests: 60mm Sears vs. The Altair 60 EDF is our most compact telescope, and this a more refined version with an S-FPL53 doublet objective lens providing superior colour correction and a lighter more compact tube. Loc: Georgia. I purchased one, but it is back ordered till February. 5mm flange to sensor spacing). Astro Tech AT60ED Bahtinov Focus Mask -RED-AT60ED . Formal-Garden-7412 •. 00 £632. Celestron Astro Fi 6" SCT WiFi Telescope £799. Astrotech 102mm f/7 doublet. If are on very tight budget can get instead a decent "department-store level" phototripod equipped with a ball-head (prices around 80-120. Altair Starwave 60ED AstroBin's equipment database is entirely maintained by the community. NET assembly calls. Length: 18" dewshield retracted, 21. Just my two cents. Having heard many good things. My goal in purchasing the Astro-Tech 60ED is to have a very portable scope that lets me take moderately closer glimpses at deep sky targets of interest to me. DETAILS. Altair Astro Limited is a UK Company Currently, I want a frustration free experience before taking up bigger challenge. For example, the fully-multicoated Astro. So we have the following in the “optical train”: Telescope > Reducer/Flattener (55mm spacing) > Stacked extension rings (total 20. View profile Send private message Share; Navigation contextPage 1 of 2 - At102edl mini review - posted in Refractors : It’s mini because my experience with refractors is mini ,however with all the speculation of how good the edl 80,102 and 125 would be , I can say I am very pleased with the 102. Both have FPL-53 glass. 60mm Astro-Tech ED - posted in Refractors : My Astrotech AT72EDII shows identical diffraction rings inside and outside of focus when using an artificial star and a #58 green filter. Do I need a reducer/flattener? - posted in Beginning Deep Sky Imaging: Hi there I just purchased an Astro Tech AT60ED 60MM F/6 FPL-53ED doublet to do Astrophotography with my ioptron Skyguider Pro. Suitability Calculator. Leo Triplet NGC 3628, M66, M65. This evening a new scope arrived, an Astro Tech AT102ED. Astro-Tech . A favorite. Would I be better off with the Flat61R on the AT60ED or the Astro-Tech . 25" (286mm) deep including the feet that prevent the case from resting directly on the ground. The ZWO ASI533MC Pro. 1 lbs: Keep in mind, the weight of these configurations will vary depending on the exact camera body you are using, and does not include any extra weight such as field flatteners, filters, or guide telescopes. • 2" and 1. Comes with the Astro-tech Camera Angle adjuster. It adopts a double air-space achromatic design, which is carefully machined and adju. Posted 10 May 2021 - 10:54 AM. 5mm or 7mm DeLite for Astro-Tech AT60ED? - posted in Eyepieces: Im primarily a binocular observer (Canon IS 10x42 and 15x50). VAT) Altair 70 EDQ-R F5 Quad APO Astrograph £1,150. However I have not been able to use it for astrophotography yet because the field flattner for it is on back order. In my case the strehl was 0. ready for shipping in 24 h. With its retractable dew cap pulled in, its overall length is just 34 inches, but extending the cap fully makes it a bit longer than the Orion scope. Weighing in at just 3. 1. This is strictly for visual and Im trying to decide between the 2 of them. 00 £547. Astro-Tech AT60ED Imaging Cameras ZWO ASI533MC Pro Mounts Celestron Advanced VX Filters Optolong L-eXtreme 2" Accessories Astro-Tech . An Astrozap focusing cap is a lightweight aluminum cap that fits over the front cell of your telescope. Astro Tech, Feather Touch, Please be aware that not all modules from the brands above are supported. My first refractor. It has dual. IC405 - The Flaming Star nebula taken with the AT60ED. ) and is 125mm long. . No nicks or marks on any part of the telescope. Obvious differences -- the AT 115EDT is a triplet apo, the SW 120ED is a doublet. 9. Sky Rover 60 ED APO with field flattener. Astro-Tech 60ED Unboxed Equipment Discussions. The AT70ED's focuser can handle a binoviewer much better. 5mm, 21mm, 11mm spacers > ASI294. Although designed primarily for use with the new Astro-Tech AT60EDT triplet apo refractor, and priced at only $119. 25" dewshield extended. Astro-Tech AT60ED 60mm f/6 FPL-53 ED Doublet $369. 90. Donation is not required by any means, so please enjoy your stay. This is a brand new 2019 item which is now in stock at Rother Valley Optics. It can be ordered with various accessories. The Astronomics listing for this. . Zenithstar 61 II vs. It combines solid build quality, good looks, and high-quality optics in one relatively inexpensive package. To meet the textbook definition of an apochromat, you have to bring three widely separated color crossings to common focus with a residual secondary spectrum of 1/10000 the focal length. Focal lengths are 560. Starwave 70ED Refractor Optical Telescope Tube (OTA), 2"-1. VAT) Altair 2" DualBand 6nm Sii Oiii CERTIFIED CMOS Filter & test report £199. Astro-Tech AT60ED Backfocus Question - posted in Equipment (No astrophotography): I just received a brand new AT60ED today which I purchased hoping to upgrade the guidescope I was using. But the William. Astro-Tech 60ED vs. Most Read Articles • Contact UsContact Us • Moon PhaseThe two silver allen bolts in the center of your photo. It will cost $90 or so more than the AT with shipping, but it’s in stock and they are a great company to deal with. There is no comparison with the default Synta focuser. 5mm Speed 35m/s 0. The home to all amateur astronomers & telescopes! Feel free to discuss anything astronomical here, from…. Should be the same as the tsoptics 60ed and Apertura 60ed and Astro tech 60ed Reply Product code: XRING-60ED. Most Read Articles • Contact UsContact Us • Moon PhaseOk, so today I received my brand new Sky Rover 60ED purchased directly from the Aliexpress store. Page 1 of 2 - Vintage Lenses for Deepsky - posted in Beginning Deep Sky Imaging: Hi there ! Id like to ask for opinion here. 8x reducer/flattener, which are in stock now? I was dead set on the AT60ED for the incredible value but am getting antsy waiting. Artificial stars at a distance of about 60 feet. Shipping and handling. 95. I'd expect them to be similar. Feel free to give us a call if you have a question about your scope if it isn’t an Astro-Tech product. This is my first impressions shortly after receiving the telescope. Place your astronomy ads, read the latest news articles and check out the current reviews of newest telescopes and equipment. AstroBin is an image hosting platform and social network for amateur astronomers and astrophotographers. The main lesson seems to be, however, that if an apo doesn't show a textbook star test then it isn't necessarily a sign of a problem. Altair 60ED, MG32 Guider and EQ3 Pro Synscan mount COMBO £968. 8x focal reducer/flattener from Astronomics. (TS Photoline 60mm/60ED) which would produce a short and fast 260mm f/4. 8, and after a lot of Googling, including a long look at Astro Bin, I went with the Sigma 180mm f2. 5 inch rack and pinion focuser addresses what was the only weak point in some of the first AT-102EDs. The EDL is an f/7 and the EDT is a triplet at f/6. Guidescope Suitability Calculator. Canon 100-400 IS I vs. So I've seen this topic come up a lot. California nebula Astro-Tech 60ED test Equipment Imaging Telescopes Or Lenses Astro-Tech astrotech 60mm Imaging Cameras ZWO ASI1600MM COOL Mounts iOptron iEQ45 Pro Filters Astronomik Blue 31mm · Astronomik Green 31mm · Astronomik Red 31mm · Astronomik Lum 31mm · Astronomik H-Alpha 6nmAstro-tech 60ED FPL53 glass wide FOV imaging setup. Guidescope Suitability Calculator. 1 F/7 ED REFRACTOR from our friends at Astronmic this will feel in the gap between my 120mm orion st f/5 and my 127 Orion mak as far as a grab and go scope. VAT) Sky-Watcher Esprit 120ED PRO OTA £2,499. Former President Trump on Monday hired white collar defense attorney Todd Blanche to lead his legal team ahead of his arraignment in New York City, Fox News Digital has learned. 8x reducer / flattener for the 60ED. $139. The Starwave 60ED Imaging Refractor from Altair Astro offers a very portable refractor telescope with FCD100 ED glass, suitable for astrophotography as well as visual use, day or night-time. Telescopes Canada grew from our personal hobby to Canada's largest dealer for many manufacturers like Celestron, Sky-Watcher, ZWO, William Optics, iOptron, Optolong,. Theres a couple of dust spots in the lens but doesn't affect imaging and some marks on the dovetail. The telescope-side barrel is threaded for standard 2″ filters so you can attach a light pollution filter. Both great scopes when coupled with the William Optics adjustable flattener. The Astro-Tech AT60ED might be just the compact high-quality grab-and-go or travel scope you have been searching for. This image content just LRGB 10x180 seconds in each channel and 20x500 seconds H-alpha. When adding an eyepiece or binocular, please don't include the magnification or aperture details in the model, this will get added automatically. 6 72ED Astronomical Telescope $463. Im looking for a 300mm vintage lens or more but. 00. in small batches and is often on back order, the SW 120 is easy to find. The Astro-Tech AT60ED APO Refractor that I recently purchased. Astro tech 66ed refractor mounting advice needed - posted in Refractors : HI All: After a long hiatus I am back into astronomy. 11/10/2023 06:06PM. California nebula Astro-Tech 60ED test Equipment Imaging Telescopes Or Lenses Astro-Tech astrotech 60mm Imaging Cameras ZWO ASI1600MM COOL Mounts iOptron. I want to invest in my first astrophotography telescope which would be used with my iOptron SkyGuider Pro. It is not too heavy and gives you a focal length of 288mm. The new Astro-Tech AT102EDL is an extension of the beloved 60ED and 72EDII. The optical tube measures 9. You get a 2" Rack and Pinion focuser with a microfine 11:1 fine-focusing ratio finished in our Aston Martin Grey trim. Pending edit 1; Mounts 621 ; Filters 2238 ; Accessories 1413 ; Software 386 ; Contributors 50 ;Page 1 of 2 - PF vs. Astromart. Page 1 of 2 - Astro-Tech 66ED -- first impressions - posted in Refractors : I finally picked up an Astro-Tech 66ED this week from Astronomics and have been playing with it much of the past couple days. Optically these should be identical to the original AT-102ED. We carry all brands and products, like Meade telescopes, Celestron telescopes, and more. Item location:California nebula Astro-Tech 60ED test Celestial hemisphere: Northern · Constellation: Perseus (Per) · Contains: California Nebula · NGC 1499 · The star ξPer. This Astro-Tech AT60EDT ED triplet refractor has: • 60mm f/7 fully multicoated apochromatic ED triplet refractor optics. This is a great little portable package. Images of space, taken by amateurs. . Add to list. Theres a couple of dust spots in the lens but doesn't affect imaging and some marks on the dovetail. Win some, lose some. Sharpstar 60ED Astronomical Telescope $366 / $436 with Flattener. Our calculator, at typical seeing of 2-4”, uses the Nyquist formula of 1/2 and the 1/3 to stop stars becoming square so the optimal range is between 0. 6 72ED Astronomical Telescope $463. 9 specification likely results from a lens cell with a slightly larger entrance pupil). Astronomics is a family business and Thomas Back was a part of the Astronomics extended family. 5 (900mm). 1 William Optics. The new Astro-Tech ATR8 2" 0. Astro-Tech AT106.