Hi JOe--I should have pointed you in the direction of Chuck Vaughn when
you mentioned your problems the other night.
See:http://www.aa6g.org/Astronomy/articles.html
Apparently he not longer has up his modification article on how to
replace the relays with transistors, but his symptom description should
help you I think. You might also drop Chuck a note, although he's probably
out imaging this weekend.
Good luck--Steve
Joseph/Leslie Schaefer wrote:
Hi
Bobby, Your
suggestion of sticking relays is interesting to me. Over the last two nights
(once each night) I experienced a problem with my ST-4 receiving an E in
RA and driving the star until I press the interrupt button . I can restart
the tracking and it runs fine, but by the time I catch it the system as
driven the star to far. The first time it happened was 85 minutes into
a 120 minute exposure. (I wasn't to happy as I saw my image go down to
drain) and last night it was 25 minutes into the exposure. The tracking
before and after the malfunction was good (A1-A4).
I first suspected moisture in the CCD head but it guide fine after I restart
it. I was wandering
if anyone else has seen this phenomenon. I equipment
is a MI-250 mount, Celestron C11 with GEG. I am also using a ST-4 focal
reducer.BTW, Thanks for the relay
information.Joe
Schaeferwww.starfillednights.com
----- Original Message -----
Sent: Saturday, July 13, 2002 2:10
PM
Subject: Re: [APML] Trouble with ST-4
& LX-200
The best I remember I used 3 or
4 for Calibratrion settings and always used SA=10 with my 10" LX200. I
also used FL= S. That doesn't make sense because 2500mm is definately long
focal length but FL=S always worked for me.Another
possibility is sticking relays. When I get occassional unexplained tracking
errors I'll change relays and that has always stopped the problem. Perhaps
your relays are staying stuck all the time. Here's a link to the relays:www.digikey.comAromat
DS2E-M-DC12V ; Digikey Part # 255-1071-NDI can get you a
pic of the inside of the st-4 if needed.Bobby Middleton
----- Original Message -----
Sent: Saturday, July 13, 2002 11:48
AM
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 John
Boudreau
jeboud@attbi.com
http://home.attbi.com/~jeboud/astro.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
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