Losmandy G11 Equatorial Mount with Gemini
I purchased the G11 mount by itself. It is made by Losmandy and is available mail order from several sources.
Personal Biases
I favor 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. My mount came with a heavy duty aluminum tripod with adjustable legs, and a single 21 pound
weight, * Replaced with Casady Stainless Steel Weights* Azimuth and altitude adjustments also helps with alignment. All of
the metal work is finely anodized and the mount presents itself as a finely crafted machine.
Gemini System
Losmandy
Gemini system is a DC servo motor based GOTO computerized positioning system designed for the Losmandy HGM200, G-11 and G-8
mounts. The system can be ordered with all new Losmandy mounts, or easily retrofitted by users who already own a G-8, G-11
or HGM200 mount. The new Gemini system simply replaces the existing stepper drive motors and electronics, with hex keys plus
a small pair of pliers being the only tools required to upgrade the drive. The Gemini system has many features designed to
quickly and accurately point the telescope to an object, then track it with even higher precision than the previous digital
stepper drive used by Losmandy.
The Gemini system has
an impressive list of features
*Very High Precision pointing to less than 1 arc minute
*Object
search mode with user definable search radius
*Sidereal, Solar Lunar and King tracking rates
*User
brightness adjustable LED display
*Up to 256 alignment stars permitted either side of the meridian
*Menus
are accessed by the standard Losmandy 4 button hand paddle
*An optional deluxe hand paddle that repeats
the Main panel display information
*RS232 serial port control by a PC using software such as The Sky,
Guide 7.0 or Palm Planetarium
*T-Point (Software Bisque) Compatible
*Internal real time clock
that displays, UTC, Local Mean Time an Sidereal Time
*Up to 10 degrees per second slewing (G-8)
*User
definable Guiding, Centering Slewing and GOTO speeds
*Permanent Periodic error Correction
*Allows
manual telescope movement with optional shaft encoders
*Retains position information after power off (for permanent
observatory use)
*EPROM upgradeable software
Transportability
The mount did not come with a case. 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. 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 replace the hex
heads with Losmandy Tripod Knob Set ( TKS ).
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,Losmandy
Polar Scope ( PS ). 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 alignment I have performed with a 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. 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 sweet spot. I have a dual saddle adaptor that allows me to mount two scopes
side by side. This is particularly useful to mount my Meade AR-6 and Orion ED80 refractors side by side. Using one or the
other as a imager and the other as a guidescope.
How much can it handle?
I have used the mount in the dual configuration mentioned above on several
occasions. I have also used it with the Orion XT10 mount by itself. Recommended weight is 60lbs. For astrophotography I would
recommend no more then 45lbs.
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.I do feel that the stock Losmandy 21lb counterweight does not do the mount
justice in appearance. I replaced this with Casady Stainless Steel Counterweights and a Stainless Steel Safety Stop on the
end of the counterweight shaft. I also added a GPS unit from StarGPS. No more user input for Lat and Long or time. This
is very helpful when traveling to dark sites and star parties.
Optional Accessories that I added:
*Polar
Scope (PS) Losmandy
*Clutch Knobs (CKS) Losmandy
*Tripod Knob Set (TKS) Losmandy
*Dual Saddle Plate Losmandy
*Casady
Stainless Steel Counterweights
*Casady Stainless Steel Counterweight Safety Stop
*Star GPS
