Question about my declination graph...
Posted 19 January 2011 - 04:58 PM
and an 80mm short tube guide scope. I used ASPA and did a drift alignment using
PHD software. Everything is balanced so the mount was East heavy in RA and scope
heavy in Dec. My Declination graph show the Declination line steadily climbs.
The RA looks good. Is this a result of polar alignment that is off? I'm hoping this is a basic problem that I am overlooking...Any
comments or suggestions is appreciated.
Posted 19 January 2011 - 05:30 PM
Sounds like PHD cant throw enough correction at the mount to bring it back in.
Did you turn DEC guiding back on after PHD drift aligning?
Posted 19 January 2011 - 05:43 PM
Posted 19 January 2011 - 05:57 PM
I would PHD polar align first. I dont know how ASPA works, but if it involves moving the physical azimuth or altitude knobs on the mount, skip it. Even it if does not i would try skipping it for your next experiment tonight.
Once you know your mound it physically polar aligned. Reboot the mount and do you normal 2/3 star alignment to find things in the sky.
It takes time and patience... hang in there!
Posted 19 January 2011 - 08:42 PM
I set the autoguide rate on the hand control to RA 50 and DEC 99. I then redid the calibration and BAM!! No more climbing DEC graph. These full moon nights are good for something .
Posted 19 January 2011 - 09:55 PM
I am guiding via ASCOM drivers and using a USB to serial cable to plug into the hand controller.
I am just glad you found a flat line for DEC! Very Cool!
Can you describe the exact process you used?
Posted 20 January 2011 - 06:46 AM
Posted 20 January 2011 - 11:12 AM
Celestron Web Site
The way i understand sidereal rate is if it is 1 (full sidereal) then the mount should track the stars perfect.
So if your DEC is a little off you can increase the aggressiveness of PHD's correction pulse by putting the Autoguiding Rate for DEC to a higher percentage of sidereal.
Is this correct? Am i understanding Sidereal and Autoguide Rate correctly?
Will you need to tweak the Autoguiding Rate according to how well your mount is polar aligned? Or is this setting making up for the flaws in the mount gears/lube etc?
Hopefully it is the flaws in the scope and you never have to change it again.
Posted 20 January 2011 - 02:29 PM
I'm a simple man and I'm just glad I got this working. Now time to figure out the why.
Posted 20 January 2011 - 02:39 PM
Hopefully someone will confirm our understanding.