Maxim guiding

[whzzz28 (Nathan)]

Trying to guide with Maxim so i can dither but not having much luck.

Everything appears to be working until it comes time to calibrate. At this point it doesn't seem to detect a star, or the star does not move.
The camera is an SX lodestar.

Attached is a screenshot of the movement (lack there of).
I let Maxim auto select a star and the little tracking pane sometimes does say "no stars found". Most of the time though it does not complain and the Guide Star X and Y values are filled.
Calibration fails every time though as the star does not move, or only moves 1-2pixels.
Increasing Cal Time does not help. I have confirmed a star is selected by manually clicking the star (and the Guide Star X and Y values do change).
I also confirmed scope control is working by moving the scope with the Obs control.

I am concerned about the image quality of the guide cam. It appears to be interlaced (lines). Progressive scan download is enabled and the image looks fine in PHD.
I am thinking this may be causing an issue as the stars do have black lines through them. Binning to 2x (which is what it is in the SS) does remove the lines, but guiding still doesn't work.

Any suggestions?


PHD guides fine with the camera as well.

[RickS (Rick)]

Nathan,

Maxim has a habit of trying to use hot pixels as guide stars and the Lodestars usually have quite a few. The fix for this is to take some bias and dark frames for the Lodestar and build a master bias and master dark (Maxim will scale dark frames for the guider, so just make your darks as long as your longest guide exposure is likely to be). Put the masters in your calibration directory and Maxim will automagically calibrate your guider frames.

I'm not sure if this is your only problem, but it's one you're going to run into anyway...

Cheers,
Rick.

[Poita (Peter)]

This guide should help you out:
http://rarcher.net/autoguiding.html

[pmrid (Peter)]

Nathan, under the Guide Tab, there is an Options tab on the right and in it, the options fr calibration. For a quich check to ake sure the guiding signals are actually making it to the mount, tick on the Simple Calibration tab. This will take a singl Dark exposure and apply it to future lights - Untill you switch off anyway. That should eliminate most of the dud pixels. Then, take an exposure, select a star and hit calibrate. If there is movement between guiding subs, then signals are getting through. If not, try anther star. If still no movement, check that your guide cable is well seated at both ends.

If you have a lot of backlash in either axis, this makes it hard for Maxim. But the solution depends on which axis is playin up. First things first. Try the above and go from there.
Peter

[troypiggo (Troy)]

I've recently been using full calibration for my guide cam (QHY5 not Lodestar) and it does clean up the image displayed. But keep in mind that the displayed image is stretched for viewing, and that may be why you're seeing "interlacing" exaggerated. If you manually play with the screen stretch, usually by moving the right slider to the right more, you can see a cleaner image.

That could be why the image appears cleaner in PHD. The data should be the same, just displayed more stretched in Maxim. Maxim uses the raw data, not the stretched screen display.

I also usually always manually select my guidestar instead of letting Maxim choose it automatically. I like control.

[Marke (Mark)]

If you just take a guide exposure you can click on any star in the field to guide off rather than letting it pick one its self.

[whzzz28 (Nathan)]

Thanks guys, ill give it a try again tonight with a dark frame and ill use Telescope for Autoguider output in case relays doesn't work for some reason.

Slowly getting it all down pat - figured out plate solving so pointing is now very accurate (don't know why it wouldn't work at Peter's place, works within 1-2seconds at home). Auto focus is sort of working, but offset values for filter wheel positions are giving me grief as well, although according to focus max the focuser position difference between each filter is minimal (~30 steps) so i probably don't need to do multiple focus points.

And it appears the issue i had with my M8 data at Peter's hasn't returned.

Now if only this wind would die down in Brisbane

[whzzz28 (Nathan)]

Originally Posted by Marke

If you just take a guide exposure you can click on any star in the field to guide off rather than letting it pick one its self.

I was doing this, but it still fails to move. There is no overlays to show you selected a star though, not sure if there should be or not. The X and Y position updates on the guide screen though.

[Marke (Mark)]

Check you have the right scope connection set in setup , I had an issue like this too and resetting defaults seemed to fix it.
When you select a star you will see its coordinates up date in the menu there wont be any overlay or other indication.

[whzzz28 (Nathan)]

Trying it again now.
It is guiding now, with Cal Time set to 20 for x and y.

I'll see how it goes tonight, given these craptacular wind gusts we are getting it should put it through its paces.

Thanks everyone.