SC4 / OA-X jumping problem

Try it please. We think it will solve the problem for many customers.

 

Hi Joshua - the improvements are not specific to the AO-8; there are improvements for the SBIG w/AO (eg STXL/STX/STT more modern SBIGs with AO), SBIG w/AO Legacy (Old ST/STL), and DL Imaging (Aluma, StarChaser, etc).
You can always request a free trial, test it out for 30 days, and then upgrade if it works for you.

 

No, there is no option to do that.
It is an interesting suggestion.
Normally, I manually stop AO tracking before focusing.

 

I have put in a Feature Request for consideration.

 

Yes, that is correct.

You will need to experiment with these settings.

Some rough calculations:
Sidereal rate is 15.041 arcseconds per second.
Guide camera pixel size = 4.8um
Focal length CDK14 f/7.2 = 2560mm.
Guider camera has 0.7x reducer, so 2560 x 0.7 = 1792mm
Guider resolution = 4.8 / 1792 * 206 = 0.55 arcseconds per pixel.

Binning 2x2 = OK. 1.1 arcsecond per pixel resolution on your scope. Start with that.
Bin 3x3 = 1.65 might be better. See what works best.
If the seeing is bad (> 2-4 arcseconds, definitely increase to 3x3 or 4x4).

What is the guide rate on your mount? eg 1x sidereal rate?
Some of the PW L mounts default to 0.5x

Bump time - 10/100 = 0.1s x guide rate
Assuming guide rate = 1x sidereal
0.1 x 1 x 15.041 = 1.5 arcsecond bump.

Assuming guide rate = 0.5x sidereal
0.1 x 0.5 x 15.041 = 0.75 arcsecond bump.

So at 1x sidereal 0.1s bump is only ~1 pixel on the guider. That's might be too small.
Try 0.5s bump = 7.5 arcseconds, which is 4.5 to 7 pixels, which should fit in the track box.

Calibration time:
2s will only move the star 2 x 1 x 15.041 = 30 arcseconds on the guide sensor = 30/1.1 = 27 pixels at 2x2 binning.
Try a longer calibration time like 10s = 136 pixels.

Only a perfect system would be 100, 100.
If it was 100 vs 30, there is a problem.

 

I can get it below by changing 1s - change the value with the spinner arrows [^][v] or enter the number.

Or do you mean something else?

Verify that Options - Enable Auto-dark is checked (enabled) This should improve SNR.

Try to Decrease Max Move. It sets how far in pixels the AO can tilt.
See if it improves (decreases) RMS Wander (pixels).

Ok.
Upper winds or gusts can cause enough of a deviation that the AO correction is too much.

Try to Decrease Aggressivness.
AO will move an amount of pixels = (Agr / 10) x pixel correction needed.
eg If the star moved 6 pixels, AO is trying to move 10/10 * 6, which is too much on average.
See if it improves (decreases) RMS Wander (pixels).

Ok, that is good news.

So change the Max Move and Agressiveness, and lets see if that decreases the jumps.

Very nice! Thank you for this information.

 

We can reproduce the problem and are investigating it.
Some other discussion in this thread:
https://forum.diffractionlimited.com/threads/odd-aox-jumping-behavior.10661/#post-61997