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Home / Stellarvue 80/9D Refractor and Other Topics
by Blair Slayton 06/28/05 | Email Author

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Stellarvue's 80/9D and Other Topics

About two years ago I found I had the time to use, and the resources to buy, a telescope. I've had a pair of 80mm binoculars since the Halley Comet days so I knew most of the major constellations and quite a few of the Messier objects.

I tried many of Orion's telescopes and this is what I found out about them and myself.

I found the 90mm f/10 scope on the AZ-3 mount useful and enjoyable for about a year and then aperture fever hit.

My key viewing spot (when my neighbor's porch lights are off) and my secondary spot are both unlevel and grassy. This immediately made dobsonians difficult to use as they really need a level surface for the tracking to work smoothly. Plus, I found it uncomfortable when using the finder (both a straight thru and a right angle version) when searching for an object. I tried a 6 inch f/8 and a 8 inch f/6 dobsonian.

I tried the 6 inch f/5 and 8 inch f/5 reflector on an equatorial mount but the weight became an issue almost immediately. Plus, when looking south the viewfinder would get so close to the ground to become unusable and when I tried rotating the tube balancing became an issue. Also, standing to view was not my idea of fun.

I then decided that the 90mm had been a good scope so I opted to buy another refractor but with better optics. So, I bought Stellarvue's 80/9D which is an 80mm f/9 Achromatic refractor. BUT I quickly found that despite the quality of the objective 80mm is still just 80mm not 100mm or more.

I then tried Orion's 120mm scopes but found the f/5 too poor on the planets and the f/8 version too cumbersome and heavy since I have to move about my yard to avoid trees and streetlights depending on what part of the sky I wish to look at.

So, I decided to try Orion's Maksutov-Cassegrains (Mak). The 127mm is a nice scope but required too heavy of a mount and its less than 1 degree field of view was annoying when trying to find objects. The 90mm Mak didn't have enough aperture to improve over the 80/9D. The 102mm Mak I liked best as it didn't require a real heavy mount and I found its 1300mm focal length handy in allowing the use of longer focal length eyepieces for general viewing BUT the 80/9D out performed it on the planets especially on Jupiter. At about 100X (which is typically the highest power I can go on Jupiter and maintain a sharp image because of seeing conditions) the 80/9D showed a very razor sharp image where the 102mm Mak's view was mushy, quite a bit less sharp (this is after proper temperature adjustment time and a very nice star test to insure proper collimation). Also, it suffered from the field of view issue of the 127mm. The 80/9D with a 1.25 inch 32mm Plossl with 52 degree field of view gives about a 2 degree field of view for finding objects or for looking at the Double Cluster or the Pleiades. So, I returned all of the Maks.

During this time I found I liked colorful double star viewing. Stars like Izar, Almach and Rasalgethi looked very nice through the 80/9D. I also found I liked looking at big objects like Open Cluster Cr 70 (area around Orion's belt) and the Open Cluster Mel 20 in Perseus. The 80/9D with a 2 inch diagonal (Meade's UHTC) and a standard 50mm 50 degree 2 inch Plossl eyepiece (I think I paid about $70 for it from Stellarvue) gives about a 3 degree field of view which is nice for the above mentioned objects. Being an f/9 scope the image is pretty much sharp up to the edge.

So, the scope most useful for my key interests that didn't cost a fortune, like an APO scope, is the 80/9D. On Messier objects, that get very high in the sky, the 80/9D does a decent job especially considering the street lights around my house. A very good night of seeing for me is seeing a magnitude 4 star in Ursa Minor with direct seeing by my eyes. Often I can only see magnitude 4 stars with averted vision. Fortunately, the 6X30mm viewfinder can usually see magnitude 7 or fainter.

I also found that starting at about 12mm of focal length the eye relief of Orthoscopic and Plossl eyepieces start to get bothersome and I don't wear glasses. I tried Orion's ED-2 and Celestron's X-Cel eyepieces at focal lengths below 12mm and found them to be mushy; noticeably less sharp than a comparable focal length Orion Sirius Plossl eyepiece. Also, the view through Orion's shorty-plus barlow with some longer focal length Ortho and Plossl eyepieces did not match the quality of view of a matching focal length eyepiece. Plus, I really didn't like the added height added by a barlow nor was putting it in front of the diagonal an option as this put the eyepiece too far away from the viewfinder (the reason I use a 2 inch diagonal even though I use mainly 1.25 inch eyepieces is to keep the eyepiece closer to my Right Angle Correct View viewfinder so it is easy to go from one to the other without the need for standing or too much back bending).

I recently bought a Vixen 4mm Lanthum eyepiece which has 20mm of eye relief and 45 degrees field of view. In the 80/9D the 4mm gives a very nice view of Izar and the 20mm of eye relief made it easy to keep my eye lined up for a good view. I've decided to try the 6 and 5mm ones even though I must admit my Orion Highlight 6.3mm Plossl gave a very nice view of the Double Double last night but I really want that extra eye relief.

Objects that the 80/9D gives nice views of: M81 and M82, The Double Cluster, The Orion, Omega, Dumbell and Ring nebula. Many colorful double stars. The Moon of course. Jupiter and Saturn. I easily detected the GRS the other night at about 100X (Jupiter is pretty close now). Many of Messier's Open and Globular clusters.

Galaxies are the main weakness of the 80/9D partly because of its 80mm objective and partly because of the light pollution in my backyard. Most of the time I can barely detect M65 or M66 and then they constantly fade in and out. But M94 is very visible when near the apex of the sky. I usually look for it after checking out the colorful double star Cor Caroli. I can see the cores of M51 but none of the connecting material. I can detect M33 but it is nebulous like and I can not see any detail in its arms.

So, in summary I have settled on Stellarvue's 80/9D because of its portability, its ability to show 3 degrees field of view and then go to about 188X to give a nice view of Izar and the quality of its objective over the Chinese made, Orion 90mm.

Final Note: I have used the 80/9D on Orion's AZ-3, Skyview Pro, and Astroview mounts. For high power use I prefer the Skyview Pro mount. For quick looks and when I don't want to deal with the weight of an equatorial mount I like the AZ-3. The Astroview was good for the price but I like the Skyview Pro better as it has very little to almost no dampening time at 188X when I refocus.

Blair Slayton
June 05

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