Astronomy Product Reviews by Michelle Stone
Losmandy G11 Equatorial Mount

I purchased the G11 mount by itself. It is made by Losmandy for Celestron and is available mail order from several sources.

Personal Biases

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 is 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.

Description

The mount is a moderate weight German Equatorial mount. I say moderate as compared to other high quality mounts. It is made by Losmandy and distributed under the Celestron label. My mount came on with a heavy duty aluminum tripod with adjustable legs, and a single 22 pound weight. Azimuth and altitude adjustments also helps with alignment. The mount comes with an electronics package that uncludes motors for RA?and DEC, a hand paddle to control the motors, and a drive control unit that allows a selection of drive rates and for connecting other devices (like DSC?or autoguider). All of the metal work is finely anodized and the mount presents itself as a finely crafted machine.

Transportability

The mount did not come with a case. I ordered a general purpose Pelican type case. With most of the foam removed, the head barely fits into the case. The case sold for this head is the same case that I purchased. You should note that it is NOT?a specially designed case for the head. The head weighs 35 pounds or so (just guessing). I prefer not to carry it too far. The tripod breaks down into 4 pieces; 3 legs and the mini pier which holds the drive control unit. I keep the mini pier in its original shipping box and carry the legs in a Rubbermaid tote I purchased at the local hardware store. Together, the mount is very heavy, the individual pieces are manageable.

Field Assembly

To assemble the tripod, I turn the mini pier upside down on a scrap of carpet (to protect the finish) and screw the legs in. This is a pretty quick process. There are no tools required for this part of the assembly.

The head mounts quickly to the tripod with 3 hex head screws to the top of the tripod. I tried to replace the hex heads with screws with handles, but the handles got in the way of the functionality of the head. It looks like I am stuck with using an Allen wrench.

The weight shaft easily screws in to the mount and then you can slide on and lock the weights. The dovetail design for attaching your equipment makes it very easy and quick to mount or replace scopes and cameras in the dark.

Polar alignment

The mount does not come with a polar alignment scope. You must purchase it separately. I have found that if you depend on a critical polar alignment, the polar alignment scope is a necessity. The alignment reticle has 3 positions for 3 stars in the northern hemisphere. If you get those 3 stars in the right place, your scope is precisely polar aligned. This is the most fool proof and most accurate alignmennt I have performed witha polar alignment scope. Checking the drift after following proper procedure gives me good results. I have only had to alter the alignment very slightly after doing a drift check. And these adjustments are very easy with the large handle on the DEC movement and the fine adjustment mechanisms on the azimuth. I am very impressed with this design.

Function

The mount comes with motorized controls. The control box is mounted on the side of the mini-pier and offers tracking rates in various speeds. Those of particular interest to me are the sidereal and moon tracking rates. The others have some use I'm sure (my ignorance is showing here I'm sure ;). You also have a choice to make for the default slewing speed from .2x to 16x.

The hand paddle has the standard directional keys. Two switches allow you to reverse either the RA, DEC?or both to help you set up the paddle for any viewing angle. In addition, pressing both RA?or DEC?keys together, slew the mount in its maximum speed. The direction is dependent on which key you press first.

To center an object in the field of view. 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 better than most other mounts I have used. For the most part, the movement is smooth and quiet. Astronomical objects seem to magically glide into view. I have noticed some periodic error in the RA?motor. The mount has a PEC circuit and logic to handle this but I have not seen a need to engage it. The PEC?works by manually guiding a star through a full motor cycle. It learns the adjustments you make.

The mount is rock solid. I have had visitors trip over one of the tripod legs and watch the vibration dampen out in less than a second. A tap on the mount sends the scope into only 3 or four minor oscillations. This is the most stable of all of the tripods that I have used.

Mounting your scopes

The mounting saddle has a very nice dovetail mounting system. Losmandy manufactures mounting plates for most commercially available OTA's. Specialized items for guide scopes and cameras are also available. OTA's when fitted with a dovetail plate easily slide into the mounting assembly. Balancing is also very nice because you can move your plate to just the right suite spot.

I have a dual saddle adaptor that allows me to mount two scopes side by side. This is particularly useful to mount an 8" SCT?and a 4" refractor side by side. The refractor is great for the bright planets and moon and the 8" for more deep sky work. The disadvantage here is that there is no good way to make both scopes point exactly at the same point with the saddle mount.

How much can it handle?

I have used the mount in the dual configuration (SCT?and refractor) mentioned above on several occasions. I have never had problems mounting a heavy SLR, guidescope, and ST4 camera on top of that. I?will be taking delivery of a C11 OTA?this week. Since the mount was designed for this scope, I anticipate similar operation.

Conclusions

This is a fine sturdy mount for the advanced amateur. It is a beauty to behold and operate. It's motorized controls are well designed and function reliably. A good line of accessories are available to complement the mount without incurring expensive machining charges. I recommend this mount to anyone wanting a reasonanbly priced platform for photography and smaller aperature instruments.