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A product review prepared by: Michelle Stone
November 5, 1997
My GP mount came with the Vixen 102mm flourite. I?am separating my reviews of the mounts and scopes because like many astronomers, I use different scopes on this mount.
I favour the German Equatorial mount over a polar aligned fork mount. GEM's seem to be a bit more stable, slightly more accurate in tracking, and are certainly easier to view with when looking at the northern part of the sky.
For photographic work, I feel that the GEM?mount is better than the alt/az fork mount. If you are not doing photographic work, and alt/az fork mount is a good choice.
These biases are for mounts that track the sky with motor assist. For just plain old viewing and knocking around, nothing is as simple as the good old alt/az "Dobsonian" style mount. These are ultimately the most simple to set up and use of all mounts.
The mount is a light weight German Equatorial mount. It is distributed by Orion for Vixen and is painted sort of a light green pastel sort of color. The components are well made and solid. The only thing that I do not like at first glance about the aesthetics of the device are the vernier marks for the setting circles. They are stickers and prone to come off. My mount came on an aluminum tripod with adjustable legs, an accessory tray, and a single weight. The mount has a polar alignmnet scope. Azimuth and altitude adjustments also helps with alignment.
The mount did not come with a case. I?made one from an old Pelican case that I pulled from the trash where I?worked. I?purchases some nice foam and cut out holes for all of the pieces (except the tripod and accessory tray). The case comes close to my weight limit to carry around an airport. But then again.. a good solid mount should have weight. So, with a medium sized case, the tripod and accessory tray, I have three pieces to worry about. This isn't bad. If I did have to travel with it, I would find a case that would carry the tripod and tray together.
The mount fits together very nicely in the field. The only loose parts you need to worry about are the accessory tray and its screws. These are not mandatory for visual work although the tray helps make the tripod a bit more stable. The head mounts quickly to the tripod with a knob/screw combination located underneath the top of the tripod. The dovetail design for attaching your equipment makes it very easy and quick to mount or replace scopes and cameras in the dark.
The mount comes standard with a polar alignment scope. You must know how far away from the time meridian you are for this to work properly. This can be confusing. Once you have the figure (which is "10" where I?live), you turn the head in RA?until your time and date match the meridian setting. Then you look through the polar scope and make fine adjustments to the altitude and azimuth settings to put Polaris in the little circle. The whole process only takes a couple of minutes. For you folks who live in the southern hemisphere, there are some nice little patterns to match up with your side of the sky.
The mount comes with manual controls. These work without flaw and are a delight to use. I?have installed the DEC?and RA?motors with the hand controller. I?strongly suggest that if you do not intend to spend a great deal of time looking at objects, that you not get the motors. The reason for this is that once you get the motors, any fine adjustment by hand is difficult. Once the motors are installed, you must unlock the clamps in RA?and DEC, move the scope to where your object is, tighten the clamps, and then do final composing through the eyepiece with the hand paddle.
Movement with the motors is as good as most other mounts I have used however there is a great deal of backlash when you move the scope in the opposite direction. You may wait several seconds for the motors to engage.
The hand paddle for RA?and DEC?control (with the motors) has a bright annoying green LED. It is so bright that I had to put electrical tape over it to not destroy my night vision. When the battery starts to die, the LED?will change to a pleasant red color minutes before you lose power.
Once polar aligned, the mount tracks very well for visual use. I have had a scope pointed at Jupiter for hours at star parties without the need to make adjustments. I have to say that the support provided from the aluminum legs is not good. They allow the mount and scope to jitter with the slightest touch. I like the aluminum tripod for other reasons however, it folds up into a nice small light package. So, you have a trade off. If you can deal with a larger package and weight, I would recomend that you get the Celestron version of the mount with hardwood legs. This seems to be much more stable. In either case, I strongly recommend the use of anti-vibration pads.
The Vixen 102mm came with mounting rings. So that was no problem for me. Orion sells rings for the 102 and a 90mm OTA. In addition, I was able to purchase a dovetail rail which easily attached to my C8. The C8 required an additional weight which I purchased through Orion. For smaller instruments, I was able to fabricate dovetail blocks from rock maple. These were very simple to make by cutting a stick the right width and making an angle cut on one side to match that of the dovetail. I drilled 1/4" holes for my Pronto and 35mm cameras in various blocks and walla!... I now have mounting brackets for all of my instruments.
The mount handles my C8 well enough with a 9x60 finder scope and the additional weight. With the scope balanced on the mount, I have no problems with tracking or moving the scope via the motors. The 102mm refractor is sized just right for this mount. I have friends who use this mount for a variety of small instruments including 6" maksutovs. I would not recommend using instruments of a larger size.
I think that this is a good overall general purpose mount. I think that if you are serious about astronomy and think that you may acquire an assortment of instruments, it might be a good idea to get this mount. It is reasonably priced, easily found used, light weight, reliable, and a delight to use.