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Re: [APML] Trouble with ST-4 & LX-200



 
----- Original Message -----
 
I am embarrased to admit, I don't know what the settings (C1 and C2) were/are. 
I am strongly considering replacing the relays just in case.  I bought the ST-4 used, but it appears in pristine shape, and responds like it should except for that little problem of not tracking. 
 
Frank I'd work with those settings before I did the relays. Try a C3 for both RA and DEC and also use 10 for the SA. The suggestion to work in straight-through mode instead of OAG is also a good idea to start with. If you still get an immediate tracking error after all these and you are sure you are at critical focus, then you might look at the relays.
Bobby Middleton 
 
----- Original Message -----
Sent: Saturday, July 13, 2002 12:48 PM
Subject: Re: [APML] Trouble with ST-4 & LX-200

Hi Frank,
 
You didn't mention your calibration settings (C1 and C2) or the results of running the calibration. And on a long FL scope it's usually a good idea to set the scintillation adjust (SA) to 8 or more to essentially shut that feature off. Have you read APML member Jim Janusz's ST4 article? It's at: http://www.astrocruise.com/st4tips.htm
 
Jim's article is located at several websites, but I refer you to Philip Perkins site because he has an additional article about using the ST4 with a 10" LX200: http://www.astrocruise.com/guide.htm
 
 
----- Original Message -----
Sent: Saturday, July 13, 2002 12:16 PM
Subject: [APML] Trouble with ST-4 & LX-200

I've had this ST-4 for a few years, tried to get it to work with my LX-50.  No such luck, and I didn't have the patience then to do much about it.  About a year ago, I got rid of the LX-50 in favor of a 10" LX-200.  Same thing, didn't have much time to play, so I just set it aside.  Now, I finally have the time to try to get to know the thing better, and I'm having a real hard time getting it to work.
 
I hook the ST-4 to my laptop to try to focus it better.  I have it focused in what I believe to be the best focus I can possibly have it in.  On the screen, I see a nice round dot in the x-hairs.  If I move the head outward or inward, it get distorted, so I am fairly confident it's in focus.  I have even verified this with a ronchi focuser. 
 
Now, if I don't do anything, the acuracy of the scope is pretty good.  In fact, the other night, I forgot to hook the CCD cable into the LX-200, and it worked like a champ, thinking I had it working, the guide star barely moved except for some basic turbulence, which corrected by the next cycle.  This got me through a 1-hour exposure of M8.  I then realized what was going on, and connected the ST4 to the LX200, and as soon as I set it to guide, it just goes out of control.  What I mean by that is, on the photo, it looks like a zig-zag line.  If I use the CCDTrack software, I get similar results, only I can actually watch it lose the guide star.  How is it that I can see the thing clear as a bell, yet the guide software and/or the ST4 in standalone mode just act like it has no idea where the star is, and goes off in some random direction? 
 
Again, keep in mind that I am new to the ST-4, and have never really had it work completely.  I know I have good polar alignment, and I am almost positive it's focused as best as possible.  I have tried re-doing the dark frame several times, and I have made sure that the guide star was around 50,50, and the star brightness was between 30 and 60.  I have not really done much with the settings on the ST-4 other than the brightness (b=3), and FL=L (long focal length). 
 
I apologize for those who are members of both MAPUG and APML, as I have posted this message to both lists.  I am just getting frustrated with this thing after two telescopes and several unsuccessful nights of even getting a decent track.  Any help would be greatly appreciated. 
 
Frank Schwartz