HELP !! Mount problems...

Hi all, this is somewhat of a cry for help, I've been trying to image with my cg5 goto mount for some time now without success with my C80ED refractor.
For visual work, this mount seems fine, with no movement of any star when centered in the field of view when to tracking with power on. Initially, I got some good shots, about 2 mins unguided before things went bad, I had a lot of streaking of stars in my shots. Here's what's been going on, thanks for reading.

I then proceded to clean the grease out of the declination motor, and put new high grade grease in. This went without a hitch, but there is no improvement in my shots, they are exactly the same as before, i'm sure i have'nt messed up there.

I've checked everything for the umpteenth time :evil: polar alignment, power supply, balance with the counterweight, level tripod etc. One thing is for certain...the RA drive is bang on, but the declination motor seems to be working against the movement of the stars....

Last night, I took a shot of the pleiades, the stars rising upwards and right in the east, here's what I got, the dec motor is funny...
s56.photobucket.com/albums/g172/Keithg1_...amp;imgAnch=imgAnch2

and in the west, i took a shot of a part of the milkyway for test setting in the west, the stars setting down and right...
s56.photobucket.com/albums/g172/Keithg1_...amp;imgAnch=imgAnch1

It looks like i'm in trouble, the dec motor seems to be running along perpendicular to the stars, but this was happening BEFORE I regreased that motor.

Any idea whats going on??? Is there something I'm not inputting into the hand controller perhaps, believe me I've spent mant hours looking into this, and no joy.
Thanks,
Keith..

Keith

Sorry to hear you're still having problems with your mount. Mine is still acting up and the only way for me was to autoguide.

Those shots look very similar to 1 minute shots from my asgt after I setup and polar align. Not sure about the trailing directions though. I'll do a similar test if the sky clears.

I've found that the only way that I get unguided exposures over about 30 seconds without trailing is to setup, do my align, followed by a drift align (which actually ends up pointing the mount quite a few degrees to the west of Polaris - I know that should make tracking worse, but in the case of my particular asgt it works better for some reason).

Have you tried to autoguide at all? The GPUSB seems to work well with the mount.

Cheers,

Trev

Keith, when tracking the stars, its only the RA axis that needs to move. IS there any way you can switch off the DEC axis and see what happens? If you polar alignment is bang on, you should see an improvement.

By the looks of the images, alignment is good and it certainly seems that the DEC axis is the one playing up. What settings are available for the motors? Can settings be set independently for each axis? Do you have any PEC programming available and switched on? Where you autoguiding at all?

Sorry for all the questions... This must be driving you nuts.

Dave

Have you tried to autoguide at all? The GPUSB seems to work well with the mount.

No Trevor, I don't have any experience with auto guiding, but it looks like i'll have to consider, or, sel this mount Thanks for your help.

IS there any way you can switch off the DEC axis and see what happens? If you polar alignment is bang on, you should see an improvement.

:idea: Yes! there is, all I have to do is unplug the cable from the dec port :idea: good idea! I'll try that.

By the looks of the images, alignment is good and it certainly seems that the DEC axis is the one playing up. What settings are available for the motors? Can settings be set independently for each axis? Do you have any PEC programming available and switched on? Where you autoguiding at all?

To be honest Dave, I'll have to have a look at the manual, as I am really only getting started, all I know about settings for each axes are anti backlash settings. Unfortunately, I don't have any PEC settings or autoguiding. I'll go to work.

Steep learning curve :arrow:

Keith..

Hi Keith,

I think that most people here (besides the uber rich Dave Mc) have mounts with significant tracking issues (from the point of view of astophotography) and auto guiding is the only way out.

Your photos seem to be consistant with a less than perfect polar alignment. So you may get some better photos by drift aligning, however you are still putting off the inevitable.

My Losmandy Gm-11 is not exactly a cheap mount, but I have to autoguide if I want to go much over a minute and a half.

So you are probably trying to fix a issue that is inherent in the mount you have (although the regreasing will help you get autoguiding working with less problems), autoguiding is what most people have to do.

Later,

Jed.

Hi Keith,
We all know the pain of trakcing issues, I had a serious issue up until recently which appeared a few months back after some work of the pillar (and it seems obvious now).
No matter what I did (like yourself) I just could not get rid of the drift during long exposures.
After a number of polar re-allignings and other things, I finally discovered that my spirit level was wrong !!! , the mount was not level and thats why I was getting constant tracking errors, so its worth checking your mounts level using a second spirit level to see where its at.

Like Dave said above, if you are using polar mode, the dec motor should ideally be off, the scope should not be engaging this motor.
Unplugging the dec cable might prevent the scope from initialising (at least in mine it does), so you may need to unplug the drive after you power the scope up and centered on your target object.

Can I ask how accurate are the GOTOs, if these are out then this will affect tracking for a given object.