Re: Curious GOTO issue on M objects...


Just a note to Howard, Roland and Daniel that the problem was indeed the battery. I changed it for a new one and uploaded the database again - everything is now working perfectly again!

Many thanks for the suggestions and assistance...


-------------- Original message ----------------------
From: chris1011@...
In a message dated 7/27/2007 1:26:11 AM Central Daylight Time,
cford81@... writes:

1) I have noticed a rather curious problem with the GOTO. The scope tracks
in sidereal perfectly. I can use the GOTO to slew to any solar system object
or any star perfectly so the mount must know the scope is on the correct side
and correctly polar aligned etc... Everything seems spot on.... except when
I go to a Messier object such as M13 or M27 I get a message stating that the
objects are below the horizon... (On a summer evening!) Other M objects that
the mount thinks are above the horizon are not correctly pointed to...

You may need to check the location that is in your new used keypad. The
location (or perhaps time also) might be for another part of the country, and
may be why the object is below the horizon. Another possibility is that the
keypad was dropped by the previous owner, and this might have momentarily
dislodged the internal memory battery, which subsequently scrambles the data in
Messier and NGC catalogs (stars are not affected). You can easily verify this
by entering a known object like M1, then press the > button to access the data
for that object (do not press the GoTo button) and then press the < button to
access the RA/Dec co-ordinates for that object. The display will show the
co-ordinates and you can then verify that they are correct or not. If not, then
you must go to the AP website and download the database. You will need the
proper chip in your servodrive to do that (hint: use your new mount if the older
used mount servo has the wrong chip).

(2) Though I have not tried it, (for fear of confusing the above problem)
would switching the newer keypad that came with the GTCOP3 on my AP1200 be
interchangeable on an older GTCOP2? Has anyone switched a keypad between
multiple mounts with different generation controllers?
You can always switch keypads between mounts. You should keep the servo
drives with the original mount because each servodrive will have in its memory
PEM error data saved, so if you switch the servodrives, you will lose the
starting points for the worm cycles of each mount and you will need to record
again for each mount. You will also lose the park positions for each mount.

Bottom line: you can always switch keypads - no problem. You should not ever
switch servos unless absolutely necessary - but then remember that all saved
data of the PEM and park functions are lost.

Roland Christen

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