Re: having guiding problems

Joe Mize

Alan, you are an ol' warhorse, still using an ST-4 and film!!! Talk about being a rarity, I wonder how many out there are still
film based.

Looks like you're heading in the right direction, check your AP documentation and use the recomnded Guide speed settings, 1x. I
also was stuck in the 0.5x mode until Roland said to use 1x for guiding. It works.

Then go to the Backlash settings section and check what it should be, if I remember correctly mine says 0.3 in DEC, 0.0 in RA.
Since you have a newer AP1200 you my have a different setting recomendation in the documentaion. Once you've performed the
tests 'visually' confirming your star doesn't jump or hesitate when reversing direction then calibrate your ST-4.

Your ST-4 settings sound pretty good to me except for the Cal Time. But that's dependant upon your optics so try to get the
highest Cal Time without running the star off the chip in either direction. You may find one axis requires a longer drive time
than the other. Good Luck...joe :)

"May You Go Among The Imperishable Stars"

Joe Mize
StarFields Observatory
Chiefland, FL 29:24'33.4"N 82:51'37.7"W

------- Original Message -------
From : Alan Voetsch[mailto:alanv12952@...]
Sent : 12/9/2007 1:41:56 PM
To : ap-gto@...
Cc :
Subject : RE: [ap-gto] having guiding problems

Hey all,

Still getting familiar with the new 1200 which arrived in late Oct. Had a few
opportunites (weather has sucked since mid-Sept) to use the FS-102 for a few comet shots
and managed to do the meridian delay alignment routine. There were no problems during
this time, other than operator errors.

My 12" LX200 'R' OTA arrived about 10 days ago. At this point it is balanced in both
axis', and OTA is collimated. Last night had some clearing so i tried to image the HH. I
am shooting film (OM-1) at prime focus and using a standalone ST-4 (no computer in my
observatory) and Taurus Tracker III OAG to guide.

All attempts to guide failed until I did the calibration at 0.5 speed, and guiding at
0.25. These settings worked for about 90 minutes, then the guidestar was lost. Actually i
think it's more a case of the ST-4 moving the GS TOO much, until it's off the chip. I may
try .25 for both next chance I get.

I plan to check RA and Dec backlash to see if either of those are a problem. I did not
stay out in the observatory the whole time, but I did notice that there were some large
spikes where the correction indicated was 'E' for a couple times, then it would settle
down to 1-4.

This OAG and ST-4 have worked well with the previous scope, a stock 12" LX200 classic.

So, I'm hoping that someone who has used a similar setup may have some areas for me to
check. Like I say, I am used to setting the the ST-4's parameters for a fork mounted
LX200 and possibly I am using a setting incorrectly. Last night i used 5 second exposure,
boost of '2', average, no backlash adjustment, cal '3' both ways, scintillation '4', and
a correction after each exposure.

Any suggestions?



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