John, Richard, or anyone else who can help. I have been holding off on writing this message until I had analyzed the situation to the best of my abilities.

Simply put, I can't autoguide when I use CCDAP3. I can manually select a guide star, calibrate and autoguide, but the minute I let CCDAP3 do it, autoguiding won't hold the guide star (keep it centered on the guider CCD). Last week the autoguiding was working with CCDAP3.

I have been racking my brain with this all weekend, reading through all the Bisque and CCDWare documentation to try and find the problem. Tonight I set up a imaging run on the "Running Chicken" nebula to test things. CCDAP3 slews to the object fine, plate solves OK, and selected a nice guide star. The funny thing is that it does not make any corrections, the guide star just slowly drifts away. So I bailed (aborted) the run. Then I manually selected the same guide star, calibrated, and turned on the autoguiding. Within three guider downloads, the guide star was locked in and autoguiding held the star until I turned it off an hour later. Then I captured the FOV in TheSky and fed that to CCDAP3 as the target. I ran it again with this target, and the same thing happened, the guide star just slowly wonders off as if the guider is not correcting.

If you need any files to help figure this out, please tell which ones you need and I will post them.
Telescope: Takahashi FCT-150
Mount: Paramount GT1100S
Camera: SBIG ST-8E with CFW-8 Filter wheel
Software: TheSky6 Pro latest update installed and CCDSoft5 also with the latest update.

This has got to be something stupid that I am doing because everthing was working fine last week.

Humbled and Respectfully yours.

Bill

Bill,

If you made any changes to the imaging train since you last initialized CCDAP you would likely see poor autoguiding results.

If you could post the CCDAP log for the imaging session we can see the actual events from the session and be able to make a more educated assessment.

Hi Bill,

Yes, please post your log file from the run that failed. It will help diagnose what may be happening.

Sorry Guys, I was working and just got home. Attached is the log file for the session I broke off. I will try to attach a second log that I let run for a while.

ccdap20080527_213406.log (5 KB, 118 downloads) Bad Autoguide #1

Here is the second log file with M16 as the target. This one failed the same way. After I aborted this run, I manually setup and calibrated on the same guide star. I was then able to complete fifteen 20 minute guided images of M16.

ccdap20080528_005357.log (8 KB, 120 downloads)

Hi Bill,

I have a few observations on your log file:

1. Your Minimum Move setting is 0.05 arcsec. This means that every guiding correction will produce a mount movement. At an image scale of 1.77"/pix., that small a correction will be basically chasing the seeing. A reasonable Min Move for your plate scale might be something like 0.55 arcsec. I would also increase my Maximum Move to something like 4 arc sec. At your max move of only 1.5 arcsec, the guidestar will never move 1 full pixel on the chip.

2. Your Target - M16 is setup for a PA of 172, but when you plate solve at 00:54:52, the PA is recorded as 92.7. This may be part of the problem if you are trying to use a guidestar at the 172 PA orientation. Also at 00:54:23 I see an uncorrected slew message. Are you using the Precision slew to target feature?

Without the precision slew to target set, you may have missed the guidestar altogether, indicated by the different X/Y values for the selected guidestar during the reacquire tries. A 14 sec exposure binned 2x2 through the clear filter should have produced a nice ADU count, but the peak value at 01:04:06 is only 6252. What was the mag of your guidestar for that session?

Without a rotator, how do you determine your camera orientation and set your framing for your target?

Hi Frank,

Thank you for taking time to have a look at my problem. Now on to answering your questions...

1. I just guessed at these setting since I didn't have any guidlines. I figured less was better than too much. I will change these settings and try another run.

2. No the Precision Slew feature was not selected. I will turn it on and try again.

3. I'm not sure of the guide star magnitude, maybe 8, I will pay closer attention on the next run. I was also puzzeled by this while it was happening, the guide frame was empty or just sampling background.

Good question. I have been carefully studying both the imager images and guider images, and noting the position of the stars. Then I setup my FOV indicator in TheSky to have the same PA.

Hi Bill,

If your guide frame was empty, then more then likely, you were not pointing accurately at your target coordinates. This would explain the difficulty in guiding as the program was either trying to guide on a hot pixel or a very noisy spot on the chip. A mag 8 star exposed for 14 seconds at 2x2 binning should have been well over 10,000 ADU.

A successful image link will provide you with the PA of your camera. It will also "snap" your FOVI to line up with the camera. This way you can easily see if there is a guidestar on your guider chip based on your framing requirements. If not, just move the FOVI around without rotating it and place a nice guidestar on the chip if you can. Then in CCDAP3, select the "Get" option and the coordinates will be placed in your target line. After you setup your other parameters, you are ready to Precision slew to the target and start taking images. good luck HTH .......

Bill,

It might be worth re-inititalizing CCDAP after a successful calibration in CCDSoft to make sure that CCDAP's guide algorithms are current.

I also noticed from your log that you are not using an autofocuser. I've found that regular automated focusing runs (every half hour or so depending on the temperature fluctuation)are a necessity with a refractor.

Forgive me if I'm stating the obvious, but the ADU values of your guide star seem quite low to me: 4340, 3283, 2446, and then 6252.
If it were my rig, I'd try to do a couple of test autoguider runs on a known bright star whose ADU value was 10,000 or so.

Also, as Wes Stauffer says above, make sure you run an autoguider calibration first, then Initialize AP3 without changing your autoguider binning mode.
Best of luck to you,
Don

This message has been edited. Last edited by: Don Scott,