|Gemini-2 and Gemini-1 Telescope Mount Controller|
|There is a new Question and Answer Wiki section where you can ask searchable questions.|
|This is the Start-up and Alignment proceedure|
This page only applies to firmware dated August 16,
2011 through Dec 28, 2011. A new
Semi-Automatic-Assisted-Alignment-method was added after Dec 28,
2011. I recommend you see that for doing your alignments. Of
course the alignment procedures on this page still work, so if you
prefer to use them you are more than welcome to. In previous
version of the firmware, there was a Initial Alignment and additional
Alignment buttons. The Initial Alignment was used on the first
star, and additional alignment was use on all stars after that. With
the August 16, 2011 version, both buttons was replaced with one button
Definition of terms: The Definition of terms have been moved to definitions page.
Here are the suggested steps to get started building a model the first time.
It will take you through adding two stars to the model.
Note: If you need to have the mount start up on the opposite side of the mount, "that is do a flip to get to the target", you cannot use the Menu->Align->goto bright star as outlined in steps 7 and 9 below. You will have to use the GOTO menu selection instead. So select GOTO, then Catalog, then BSL.guc, and then type in the name of the star you want to go to. When that name comes up, there will be a selection box at the bottom called flip. Check this box, then select goto. wait for the mount to stop and then center star. Goto next step in list below.
Additional comments about building a model.
This section is René Görlich's explanation of how the to build
a model using the current firmware, and how it works. He also goes
into the guiding process. |
Alignment is much simpler now and a bit safer, because you cannot delete the model by pressing "Initial Alignment" instead of "Additional Alignment". The Alignment buttons does everything automatically. If you already have a model built (on this side of the pole) it will do the "Additional Alignment", if not, it will do the Initial Alignment. Crossing the pole changes between the 2 models. They are completely separated. So if you've build a model working nicely and then flip to the other side, there will be no model and the pointing will be off! So you have to do several (not only one as before) Alignments on the other side of the meridian, too. This is a bit more work, but the results are much better for precise pointing at both hemispheres than with a single model for both sides, so it is well worth the effort.
If you use the Reset button and then Alignment, the result is the same as with the Initial Alignment before. The model on this side of the pole will be deleted and the object will be the reference object for the next alignments on this side, setting only the Index errors IH, ID.
The Synchronize button does only touch these Index errors and does not change the other model parameters. You should use it after a Warm Restart (one time on each side) if you've a good model already, or if you want the best pointing in a certain area of the sky, f.i. to find a very faint object.
How to choose the stars? Imagine the selection of the stars span up an area of the sky that covers all that's within this area. Within this area the pointing will be improved. Don't use stars near the horizon or the pole. Doing the alignments this way (one star at one hour angle, the next object many hours in RA away, then some in between) should give good results (_on this side of the pole_). How much, depends on your setup. If the telescope is very well aligned even the first alignment will bring huge improvement, since the biggest error causes will be the Index errors. If the perpendicularity of you mount and the OTA is great in both axes, an alignment at the second, far away star will give a good estimate for the MA and ME terms and the third object (if it's hour angle is between the first two objects) should already be placed well in the eyepiece. In reality, one may need some more stars (at each side) to have the parameters converge nicely.
To have the two robotic telescopes pointing precisely over the whole sky at high magnification we had to select 8..10 objects on each side of the pole. In the field, where the biggest error usually will be polar misalignment, you may get sufficient pointing to find every object even with very few alignments (2..4) on each side. Regarding the object: They work at markers that are at a well-known position of the sky at a certain time. Their beauty can be enjoyed later, during the modeling it is pure astrometrics. You can do more then one alignment on the same object - if it moved some hours, or if you did a meridian flip (using it for the other model).
For a correct guiding is it necessary to fix the settings to photo ? Photo or All-Speeds mode, the AG port works in both settings. There may have been a problem in an earlier software version, but it works fine on the bench. BTW, with the latest HC software you can also check/set the mode under MENU -> HC -> Mode. > > and set the speed to guide ? This may depend on how the guiding setup works. The AG port is completely separated, guiders that connect to the AG port should work on all for speed settings of the HC or other software.
For software guiding, it depends. If the guiding software sends the normal move commands for guiding (:Me#, :Mw#, :Mn#, :Ms#) it has to definitely send a Rate Guiding command :RG# before and whenever something has changed. There are many ways to communicate with G2, but there are only two motors ... pushing the SPEED button on the HC sends the respective Rate command and this will interact with software using the same commands.
Guiding software that uses Precision Guiding commands should not be affected.
|Page last updated on May 12, 2016|
|This site is not for profit and sells nothing and asks for no money for any help it provides. This site is here to help fellow Gemini-2 and Gemini-1 owners. This Web Site is not associated with Losmandy-Hollywood General Machining Inc. or any of their employees and never has been. There is no guarantee that all the information is correct, but strives to provide the best information possible. The use of any information is at your own risk. The webmaster is an unpaid beta tester, and tries to work with other beta testers, and René the writer of the firmware.|
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Gemini-2 and Gemini is a registered trade names of Hollywood General Machining Inc.