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Re: [APML] ST-4 HELP (!!!!) needed...
John Lanoue wrote:
>
> Greetings,
>
> I missed out on 5 good hours of imaging last night because my st-4 wouldn't
> calibrate and I'm wondering if anyone else has seen this problem. This may
> be a continuation of my 'aurora' problems from two weeks back, I don't know.
>
> Problem:
> The ST-4, when calibrating (depending on the orientation of the CCD head)
> will do the following four movements, increase x by C0 seconds, decrease x
> by C0 seconds, increase y by C1 seconds and decrease y by C1 seconds, for
> shorthand sake, I'll call these four steps +x, -x, +y and -y. I have the
> head oriented such that x corresponds to RA and y corresponds to Dec. What
> I'm seeing is the +y step results in no change in y (on the ST-4 readout)
> and the -y step results in y incrementing (like you would expect it to do in
> the +y step).
To summarise then, during the calibrate mode there is no movement in a
single direction (depending on orientation of the CCD head) but the
reverse seems to work. This imediate points a fickle finger at one of
the following:
1) Cable
2) Internal relay in the ST-4 (most likely I would think)
>
> That's the jist of the problem, but here's more...
>
> Using the lx200 hand controller, in guide mode, I can move the scope in x
> and y (such that the display increments and decrements on the st-4).
Just proves the mount is working ....
> So I
> believe that eliminates the lx200 drive as the source of the problem. Also,
> it doesn't matter what I increase C1 to, on my scope, a value of C0=C1=3 has
> worked fine in the past (I'm guiding at prime focus of a 12" lx200), I upped
> C1 to 10 seconds and it made no difference in the third step, the +y step
> still resulted in zero movement. Also, during the failed third step, the
> scope is making no noise, and I've always been able to tell when it's moving
> in declination. I can clearly hear it moving when it's doing the -y step
> (which turns out moving the scope in the +y direction). And finally, not
> that it matters for calibration, but I set SA to 10 to turn it off. Also,
> my drive has a bit of backlash, what lx200 doesn't? However, it's never
> been a problem, but regardless, I messed around with H1 (hysterisis-y) and
> it made no difference.
So what happens if you try to manually move the scope using the
appropriate buttons on the ST-4 ? Particularly the +y movement
???????????????????????????????????????????????????????
My guess is that is won't move ?
> Oh, one last thing... (I know, I sound like columbo), if I disconnect the
> ST-4 from the lx200 control panel during calibration and using the audible
> clues of the st-4, manually press the N/S/E/W keys to emulate the
> calibration sequence, then believe it or not, the calibration succeeds and I
> can track. What this points out is that in track mode, it appears that the
> st-4 can issue declination corrections (declination=y). I say appears
> because I have a pretty good polar alignment, so its possible that no
> corrections were needed.
I think this doesn't help much .....
> I can't help but think this is a cabling issue... anyone out there seen this
> or want to take a guess? If you want to contact me off list and/or speak
> over the phone, that would be great. I would love to get out tonight if
> possible.
John, its trivial to open up the ST-4 and locate the relays inside.
There should be 5 IIRC. The *extra* relay is for the alarm. So you could
easily swap relay's around and see if that rectifies the problem or
"moves" it to another axis. if it does then the relay is the culprit and
it can be replaced with the alarm relay. I am not familar with the LX
wiring so cannot comment on it. Someone else can probably provide some
help there.
Hoe this helps ?
Regards
Bill
--
William R. Mattil |
wrmattil@ix.netcom.com | http://celestial-images.com
(972) 399-4106 |
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