Tips for Setting Up and Using Sitech.exe

Tips for Setting Up a GEM

posted Jun 15, 2009, 12:45 PM by James Roe

Below are excerpts from various emails and other sources that give tips for setting up a German Equatorial Mount (GEM) with Sitech.exe

From Dan Gray


Northern Hemisphere Setup

1. While using ServoConfig, Manually point the telescope toward the Western horizon.  Reset controller. Make sure pressing the up arrow moves the scope North and the encoder
counts increase. If this is not correct, change the direction using "Edit Parameters" button on ServoConfig.

2. Make sure that pressing the right button moves the telescope even more west (goes below horizon if still looking at the western horizon) and the encoder counts for AZ/RA increase. If this is not correct, change the direction using "Edit Parameters" button on ServoConfig and change the check mark on “Invert” motor and scope .directions or encoders as appropriate.

Southern Hemisphere Setup

1. While using ServoConfig, Manually point the telescope toward the Western horizon. Reset controller. Make sure pressing the up arrow moves the scope SOUTH. If this is not correct, change the direction using "Edit Parameters" button on ServoConfig. Also be sure to set the proper Latitude in the ServoConfig /AutoTracking tab.

2. Make sure that pressing the right button moves the telescope even more west (goes below horizon if still looking at the western horizon). If this is not correct, change the direction using "Edit Parameters" button on ServoConfig.

3. Exit ServoConfig, and call up SiTechExe (be sure lat and long are set correctly in the SiTechExe Configuration). If you are using SiTechEXE054H or later, everything should work just fine. If using an earlier version, you may get the “suspect bad GEM init” message.

4. Manually point to a star in the Western Horizon. Perform an offset sync. You may get a window "suspect bad GEM init". Click on the YES. Click on "Keep window up" once the SiTech init window appears. Make sure the button labeled "Looking West" is active.  Perform an offset init.

5. Now you should be able to GoTo and track properly while looking west.

6. Now, if you want to view on the East side, you will have to manually do a meridian flip. Center on a star, and perform a Synch again. You'll get the "Suspect bad init" again.  Go and say "Yes" Make sure the "Looking East" is active. Perform an Offset init. Now you can view on the east side all you want, and things should be fine.

From Bob Kirschenmann

First off, don't check any of those boxes on the second page in ServoConfig..SiTech takes over all that stuff with a gem when you check the type of scope in the config menu in SiTechExe.

Second, when you start your planetarium program and you aren't outside but want to fake it..pick a star that you know is up and roughtly point the scope in that place..do an offset init so the scope knows (or thinks it knows) where it is. Then the other parms you have entered in for a GEM will be active and you should get a flip when you reach the point close to the meridian that triggers the flip or on a goto if you call for a star on the other side of the meridian. Those two providing you have them checked on the config menu..otherwise the scope just stops tracking..if you have sound, it will announce you are approaching the meridian limit.

From Rich Bowden

All I've done with my CI700 is select GEM in the main page, as I have no scope encoders, unlike you. I have selected 'ignore' on main servo config.  I have 'invert' RA motor encoder selected as I'm in the Southern hem so you won't need this selected for you being in the Northern Hem.  I haven't selected equatorial mode.... this I think is where you are coming unstuck on the GEM flip.
 
On the 2nd page of servo config (auto tracking), I have nothing selected.... once again I don't have scope encoders here.
 
But maybe try your gotos without scope encoders and just use motor encoders.....

Start with the basics then work your way up with adding the scope encoders.... make sure your math is right and that both the RA- scope and motor encoders go up in the (+) together and down in the (-) together..  Same with your dec encoders.
 
Any way, just though I'd chime in as my CI700 mount is running well with firmware v35c and Sitech driver 54E,

From Bob Kirschenmann

When the scope does a meridian flip it moves the dec and the ra to point the OTA to north.  It waits until both are stopped and then reverses the ra and swings the dec to the west/east.  There are no hard stops on my mount, so it is free to go crazy if it wants and has once or twice when I had been playing with flips and had some init stars in the pxp file.
 
I meant to also state that if you have hard stops that can't be done away with, you should install a couple of micro switches to stop the motors before they cause the mount to crash into one of those stops.  Murphy will probably cause that to happen some dark night when you least expect it.
 
From Chuck Shaw

The fuzzy area for the meridian flip is how far PAST the meridian the mount will go before it does a flip.   If it cannot go past the meridian, set it to 00:00:00.  I can go about 15 deg past, so mine is set at 00:15:00.  The problem I have is when the scope is looking west (scope on east side, weights on west side).  I get mechanical interference if its aimed right at the zenith looking west.   So I LIKE for the mount to go past the zenith while looking east, so when it does its flip to where its looking west, its a bit past the zenith (i.e. a little further west)
 
Be sure you check "German Equatorial" in the Mount info tab in the config pages if it is a GEM, (else just check equatorial if its a fork or horseshoe, etc.)
 
Three ways to do a meridian flip.
 
1.  Command one (using features page "do gem flip" button.
 
2.  Allow the mount to do one while tracking (config tab, change config, mount info tab check gem auto flip track.  If you do not check that, the mount will simply stop tracking when it reaches the end of the fuzzy limit past the meridian (or AT the meridian if fuzzy limit is 00:00:00)
 
3.  Allow the mount to do a GEM flip if you slew to a target on the other side of the meridian (you need this checked to make the scripted PxP runs work, since it picks up stars on both sides of the meridian)
 
Bob described the motion the scope goes thu.  You can duplicate that using the handpad in slew mode if you want to while you are making sure your cables stay clear of everything.      I run my cables bundled in a plastic wire loom tube I got from AutoZone.    Makes it a LOT easier to avoid snagging stuff!
 


1-1 of 1