Losmandy G11 Gemimi 2
High Guiding Accuracy, Amazing Mechanical
Stability, High Weight Capacity
As you can see in the picture, I have put together a 150mm Takahashi weighing 15kg, a 71
mm Takahashi as a guiding scope. The total weight of the equipment was 25kg including
When I purchased the equipment, I was warned by the seller, that the equipment was too heavy for the specific mount. After using the equipment, and analyzing the results of the photographs that were taken, I have noticed that the stars were elliptically shaped instead of clear round shape stars as expected, also small and faint details in the nebulae were missing and generelly, the photographs were not clear and sharp. The same results were reflected after analyzing graphs using “phd” guiding software.
A friend of mine, having the same Losmandy G11 Gemini 2 mount, with a Takahashi 130 mm telescope and a Takahashi 88 mm guiding telescope assembled to it, suggested that by reducing some weight from the equipment and implementing some mechanical improvements to the mount, I could possibly achieve optimal results…
Results before Mount Improvements:
The following graph describes the results of the guiding process using equipment weighing 25kg, under conditions of clear sky and no wind
In order to improve the system
(mount and the assembled equipment...) performance, being affected by the system weight, the tube rings securing the equipment to the mount were first modified by the milling of the rings. Secondly, the "Dov Tails" which were the base, have also been modified (milled).
In addition, the mount's balancing rod was extended and the weight of the counter weights was reduced in order to increase the stabilizing moment value. During the work to improve the mount, backlash was observed in the Dec axis and R.A., which led to the conclusion that it is not enough to modify the tube rings and "Dov Tails" base. In order to cancel the backlash, I have replaced the original mount clutches with conical clutches that I prepared myself in both axis – Dec & Ra. In adition to that I replaced the shaft encoders with more accurate ones (instead of the originals).
After the mount and equipment modifications were completed, the system performance was tested for several months in order to examine the reliability and the accuracy of the guiding process…The results were amazing!
Analysis of the results revealed a deviation smaller than 0.25 pixels throughout a whole night of guiding! The results are reflected in the following "PHD" guiding software graph
Dec & Ra Calibration
Less then 0.25 pixel error all night
Getting the high guiding results allows a long exposure (30 min for each frame…) which allows photographing using a "H-Alpha" 3 nm filter with a cooling unit (generating -15c) and DSLR6 camera for much longer time (all night…).
Modification of all the system allows:
Using a load that is heavier then the specified weight for the mount.
Increasing the guiding accuracy by reducing weight, cancelling backlash and using more accurate encoders and reliable conical clutches.
Getting clear and high resolution pictures with a deviation no more than 0.25 pixels (Also in wind condition…).
The modification was implemented in another 5 losmandy mounts systems, getting the same results. by using the same "modification kits" (Built specially for those purposes) getting same high guiding accuracy results!!!
After the mount and equipment modifications were completed, the system performance was tested for several months in order to examine the reliability and the accuracy of the guiding process…The results did not disappoint.
performance over the last few months
**** Following picture of ic 434, was photographed using our Losmandy modified systems****
Target - Ic434 Horsehead
Filter - Halpha 3nm
cooling - -15 Celsius
Camera - Canon 6d modded
Data: - Every frame is 30 Min - Total 9 Hr data
Location - Israel , Negev desert.