Changing background values on STi images. Causing guiding problems and star fades.

Has anyone tried 6.17 or 6.18 of Maxim yet? There was a possible fix for this problem but as others have seen the problem using other software I'm doubtful, but we still need to confirm it. I've just been really busy lately and have not had a chance to install the demo and test.

Thankfully I have an Orion SSAG on a guide scope as well on my imaging setup or I would be pretty much dead in the water. I have the STi on the SBIG OAG, I specifically bought it to get rid of flexure to enable me to do longer exposures for narrowband, but the bad subs don't allow that. In the winter I've had some success using the STi, also using the smallest track box size seems to help reduce the mount jumping some. It is quite frustrating to have invested a large sum of money in the OAG and STi a few years back and STILL can't make use of it. I'd like to just get a different guide camera but I don't feel right selling the STi to get funds to replace it knowing it can't be used.

The staff says they can't reproduce the problem in house, with this many of us having the problem I hope they see the need to concentrate some more on this.

 

Hi,

The new version of MaxIm DL (V6.18) has a change in shutter management that's worth trying. Please use Help | Check For Updates...

- Owen -

 

Thanks, I do plan on downloading the demo and trying it.

 

Well Tony, I do not want to hex things but I cannot reproduce the error I had with multi-star I have run multi-star for three nights without a problem. If it fails tonight, I will know why.

I watched the guiding windows in Maxim carefully last night and could see the bad frames. It was hot and they were frequent. The multi-star for some reason ignores them and seems to maybe drop making a correction and just tracks onward. Better no correction that one that makes the mount go crazy.

My stars are not perfectly round (.4-.6) but the eccentricity is inversely proportional to the star support in PI subframe selector. Another guide is how well the focuser works (FocusMax FWHM or whatever they call it).

Anyway, good luck and wish me luck that multi-star continues to work.

 

Jerry, are you running the STi off-axis or the FW8G? They both use the KAI-0340, but the supporting power & readout electronics may be different for each camera. That's our prime suspect at the moment. I ran the FW8G last night on some bright guide stars in Cygnus and got a good Veil, but I see the spiking or blooming on about 20% of guide images. Very consistent. Any less bright and the centroid disappears completely. Unfortunately I don't have a multi-star guiding option in my setup.

 

On the SBIG 8300M I have the option of OAG. There is a little prism in front of the filter wheel. This leads to a little 640x480 chip separate from the main KAF chip. I am not sure if this guide chip is the same one you have but it is flakey.

If you are using maxim to guide (and I guess you are since your are writing this stuff here), Maxim has the option for the multi-star well hidden: Maxim:Camera Control:Guide Tab:Options:Track Box Size pull down list.... (CIA could not have done better). I think this is an option to Maxim regardless of what camera set up you have as long as you have a separate guide chip.... it represents a mathematical solution on 8 or so stars I think rather than just one. The good thing is that it does not give a bogus offset if the screen goes blank once.... like whith a flaky chip.

This has been my Holy Grail for over a year now and I just hope it continues to work... now twilight in California and smoke seems to have cleared.

 

Do you see the flaring or spiking in the image with multi-star guiding? The theory is that multi-star guiding increases the signal to noise available to the guiding algorithm, which lets you pick up the multiple centroid signals better and thereby guide on fainter stars. But the electronics might be just as flaky underneath it all.

 

Interesting, the reported SNR is usually 200-300 while it is in double digits for single star. I do not see any spiking. I'll see what it looks like tonight. Sky seems to have cleared and the smoke blowing out.

 

Is anyone that is seeing this problem running version 6.18 of MDL?

 

Here is a multi-star autoguider image from the STT8300M with the filter wheel. Lotsa stars.... when it goes blank, it is just salt&pepper... last night I watched it while playing a little Call of Duty and there were 3 in one 1800s acquisition. On the guider graph they just show as no offset or correction (thank god).

 

Doug? Adam? Owen? Bill?
We could use your help!

 

Have you installed and tested with V6.18 yet? Are all your camera drivers up to date?

- Owen -

 

Drivers: SBIGUDrv.DLL Ver 4.99 Build 3 sbigu64.sys Ver 2.41.0.1338
Firmware: Version 2.58, Serial Number T13050394

Are these are the latest firmware and drivers? (It's what the "SBIG 64 Bit Driver Checker Utility" has installed on my system.)

I do not run Maxim V6.18 - perhaps one of the others on this thread can test it out and confirm the results.

 

What is the latest version? Of both the firmware and the drivers?

 

Doug is right. This is the latest version and it seems to have solved my problems with the chip. See the picture.

Last night a saw a few of these salt&pepper bad images. So i took out my iPhone and made a movie of the screen. Rather than send a movie, here are a series of screen shots. Before during and after. The system is using the multi-star guiding (thank-god). You will see the graph does not show a blip. You can see where it is with the times in the exposure window.

 

Hi Jerry, I'm a bit confused by your post. You said the latest version seemed to fix the problem with the chip, but you also say you are still getting the bad images?

What version of MaximDL are you using?

 

This salt&pepper is something hardware... probably the CCD chip in the SBIG 8300M and maybe other cameras.

I watch the remote in front of the TV at night and I'll see those bad frames every couple minutes. 5.18 seems much more stable with the multi-star guiding, so it "fixed" the problem insofar as multi-star does not produce a bogus correction that results in a bad image. See the graph of the tracking...looking stable. The single-star often will read the offset as something like 31 rather than a fraction of a pixel then throws in a major correction. The next frame is of course off because of the bogus correction.... its tracking will show a big jag of several pixels.

So if 5.18 keeps working automatically with ACP, I am a happy camper. It has been working automatically now for about a week. With 5.17 it never started up correctly on its own. So far this one is working. I do not need to know why.....