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ASTRO-TECH 8-INCH IMAGING NEWTONIAN center of the primary cell is a 12-volt fan to help the mirror cool. This is supplied with a battery pack for eight 1.5-volt “C” cells. The telescope comes with two properly-sized split rings. These hold the telescope in place well enough and also have enough felt glued on the inside to keep the tube from getting marred. The rings could use a bit of “fit and finish” work (basically upgraded washers and screws), but are more than adequate for the task. The rings have attachment points at two opposing flats with M6 threaded holes in one set and 1/4-20 holes in the other. I chose to mount the rings with 1/4-20 screws leaving the M6 at the top for accessories, although the reverse would have been fine as well. The only other item shipped is the plastic dust cover for the front end which fits a bit loosely, but that does the job. This is a large and heavy-duty optical tube that is up to 3 kilograms heavier than the more standard 8-inch f/4 Newtonians available from other sources. The additional weight is due largely to the generous tube extension in front of the focuser and the baffling system that the extension houses. Those considering the AT8IN may therefore require a larger, more robust mount than those that are normally matched to more standard 8-inch Newtonians. First Light First light for the AT8IN took place at my friend Doug’s place in Indiana. After mounting a 13-inch Vixen-type dovetail bar to the rings, the scope was collimated with the Cheshire and mounted on a Celestron CGE Germanequatorial mount. Having adequate access to the focuser to align the mount meant that some thought needed to be taken in placing the AT8IN in its rings. I eventually settled on having the focuser point straight down when the scope was aimed north. This seemed to work well enough and provided ready access to the focuser when the scope was pointed south-ish. As I mentioned earlier, the scope would not come to focus with eyepieces and the supplied 35-mm extension tube. Fortunately my kit includes a 50-mm extension that I need for my Stellarvue refractor, so I was able to get my 9-mm illuminated reticule to come to focus to align the mount. Photographic Function There were a few false starts in the first imaging session with the AT8IN as I fiddled with the collimation (it’s been a long time since I owned a Newtonian), but eventually things settled down and the scope worked like a champ. I ordered a Baader MPCC coma corrector the same day I ordered the telescope and was imaging with this unit in the optical train. The MPCC requires that the collimation be spot-on. This can be hard to achieve with any focuser that has enough Three Incredible Values, All Under One Roof! iOptron iEQ45 Mount Astro-Tech AT8RC Carbon Fiber RC Astrograph ASTRONOMY PRODUCTS AstroTech AT72BK Black ED Refractor We Are Now A Tele Vue Dealer! World Class telescopes, eyepieces, mounts and accessories. Get Your Ethos Eyepiece in Time for Spring Viewing! GREAT RED SPOT LAYAWAY PROGRAM • Credit Cards are over-rated! • Interest-Free Layaway • No service fees and administration charges as with other online layaway programs • 3, 4, and 6 month layaway plans on purchases over $100 Visit our website for our full line of astronomy products 54 <strong>Astronomy</strong> TECHNOLOGY TODAY
ASTRO-TECH 8-INCH IMAGING NEWTONIAN play to allow something to be inserted into it, but I think I was close enough. I know now why laser collimators are so popular. Using the Cheshire is a bit of a pain in the dark, but it is quite accurate. I finally succumbed and bought a laser which I use with my Celestron Ultima Barlow. It works beautifully day or night. Image 3 shows stars in all four corners of a Canon DSLR frame along with one from the center. The top-right image seems to show some elongation while the others are fairly free of this. Was the camera slightly cocked in the focuser Who knows My targets for the night were the ever-elusive Crescent Nebula (NGC6888) and the PacMan Nebula (NGC281). The Crescent continued to be elusive and, until I decide that narrow-band imaging is in the cards, it will remain so. PacMan on the other hand gave up its photons nicely as demonstrated in Image 4. For anyone interested, that is ten 5-minute subs processed with darks and flats. None were discarded. The AT8IN/MPCC duo gave me an image with very nice stars (not perfect) to the corners. Any remaining bits of coma I saw in the corners were most likely due to imperfect collimation. Star colors were faithfully rendered in my Canon/Hutech 500D and there was ample contrast. I’ll bow to the marketers and attribute this to the long snout and baffles. Visual Function I wanted to test the AT8IN visually so, one night when the local club was gathering at our dark-site, I loaded up the scope and my modified Sky Watcher HEQ5 and voyaged off into the gathering dusk. (Note: The coma corrector was not in the optical path as I don't have the correct accessories to use it visually; all of the reports are with a “naked,” uncorrected f/4 optical system.) Eyepieces I used several eyepieces on objects from Saturn to M104 throughout the night. I don’t prefer huge amounts of space around what I’m observing so I can’t give you any reports on the scope’s performance using high-end wide-field eyepieces that are wellcorrected for best performance at f/4. My single 2-inch eyepiece is not optimized for f/4 and therefore delivers a lot of ‘seagulls’ very quickly as you move from the centre of the field; some of these are due to astigmatism of the eyepiece and some due to coma inherent to the very-deep mirror. On the other hand, my Tele Vue Plossls worked exceedingly well in the telescope, as did my Burgess/TMB Planetaries. The Plossls run from 15 mm to 25 mm and the stars in the field were excellent close to axis and remained very good out to the field stop. I have two Burgess/TMB Planetary eyepieces in 9 mm and 5 mm. The 5-mm Planetary combined with a Celestron Ultima 2x Barlow showed no breakdown in image at a magnification of 40x per inch. When the seeing steadied objects appeared painted on the sky. Now, the AT8IN is a Newtonian. This means that when mounted in a German-equatorial mount the eyepiece is never where you want it to be. Like any tube with split rings, rotating it into position can be a major pain, unless treated to a modification such as that of the “Wilcox-rings” configuration (ATT, April 2007). Fortunately, the AT8IN and accompanying rings are a perfect match for the Wilcox-rings application. As noted earlier, the tube assembly is heavier than that of a more-standard 8-inch Newtonian and it requires more mount. I had it mounted on my highly modified HEQ5 for this visual outing and, while the mount handled the heavy tube nicely, it still showed the effects of the weight, especially while focusing. The Views M13 in Hercules was beautifully framed with my 15-mm Tele Vue Plossl and I found that the colors of the two stars framing the cluster were well rendered and quite vivid. I mentioned this to another experienced observer who, on looking, claimed the color “refractor like.” The cluster itself was classic “diamond dust on black velvet.” Perhaps this was due to the baffles and extended snout of the tube in action, but, what- <strong>Astronomy</strong> TECHNOLOGY TODAY 55
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ASTRONOMY TECHNOLOGY TODAY Your Com
Page 9 and 10: Contents Cover Story: Pages 35 - 38
Page 11 and 12: The Supporting CAST The Companies A
Page 13: For me, after viewing through many
Page 16 and 17: INDUSTRYNEWS ENTHUSIASTS’ EFFORTS
Page 18 and 19: INDUSTRYNEWS LUNÁTICO ASTRONOMÍA
Page 20 and 21: INDUSTRYNEWS STARIZONA Adds HyperSt
Page 22 and 23: NEWPRODUCTS SCOPESTUFF NewStuff fro
Page 24 and 25: WE SAID PLAY BIG, NOT PAY BIG. No m
Page 26 and 27: NEWPRODUCTS ORION TELESCOPES & BINO
Page 28 and 29: NEWPRODUCTS ORION TELESCOPES & BINO
Page 30 and 31: NEWPRODUCTS INCANUS LTD Introduces
Page 32: NEWPRODUCTS MAGNILUX MX-1 Telescope
Page 36 and 37: THE WILLIAM OPTICS MEGREZ 120-MM RE
Page 38 and 39: THE WILLIAM OPTICS MEGREZ 120-MM RE
Page 40 and 41: CELESTRON SKYPRODIGY it knows how t
Page 42 and 43: FIELD TESTING THE TMB-92L SIGNATURE
Page 45 and 46: AG OPTICAL SYSTEMS 18-INCH NEWTONIA
Page 47 and 48: AG OPTICAL SYSTEMS 18-INCH NEWTONIA
Page 49 and 50: Astro-Tech 8-Inch Imaging Newtonian
Page 51 and 52: ASTRO-TECH 8-INCH IMAGING NEWTONIAN
Page 53: ASTRO-TECH 8-INCH IMAGING NEWTONIAN
Page 57 and 58: A 3D CAD Primer From Papyrus to 3D
Page 59 and 60: A 3D CAD PRIMER than the competitio
Page 61: A 3D CAD PRIMER Image 5 do it once
Page 64 and 65: THE “HOME DEPOT” SCOPE Image 2
Page 66 and 67: THE “HOME DEPOT” SCOPE New ATT
Page 68 and 69: PROTOSTAR’S FLOCKBOARD Image 2 Im
Page 70 and 71: PROTOSTAR’S FLOCKBOARD Image 5 in
Page 72: ASTRO TIPS tips, tricks and novel s
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