The focus module require stars not to be saturated, so as long as that is met then no issues.

What I would personally suggest is to use the recommended Unity settings 139/50/21for exposures between 120-240sec. Unity settings are considered a balance between SNR and Resolution.

When you're happy with the camera you can then try the optimal SNR settings which are 70/50/10 for 480-600secs.

Don't forget, you will need Bias, Darks and Flats at the same camera settings.

For focusing between filters you'll probably need to find a setting that allows focusing to be done quickly; 300/50/21 will get you to a few seconds exposure. Trial and error here is essential.

Thanks a lot for the proposed setting, will give it a try on next occasion!

One big issue is remaining, after some "research" on the internet, looks like I have a fair bit of amp-glowing with the ASI071 in combination with the Raspberry USB2 interface. Adjusting the bandwitdth (increasing to 100) seems to have a slightly reducing effect, but still it remains clearly visible (see attached example, with 1 and 8 seconds exposure (if I recall correctly, I set the offset at roughly 10% of the gain - could not find an entry in the FITS Header to doublecheck). The bandwitdth was left here at 40.

Is there any advice out there on this issue?

Update: Found on astrolumina homepage some advice on reduction of amp glow by lowering the USB traffic to a minimum of e.g. 1 - could the same approach be applied to the ASI071? I was trying in the indi controls to reduce the bandwidth below 40 - but that was not possible (not sure of this is actually the same parameter).

I have been collecting some information along the way for various ASI cameras as I don't have easy access to the settings in the ASCOM driver. Here are a couple settings the ZWO recommends for the ASI071 (ASCOM presets)

ASI071

Gain 50, Offset 12
- Dynamic range = 13.1 stops
- True gain = 1.5 e-/ADU

Gain 90, Offset 20 (Unity Gain)
- Dynamic range = 12.5 stops
- True gain = 1 e-/ADU

Gain 150, Offset 35
- Dynamic range = 11.8
- True gain = .5e-/ADU

I would suggest that anything you see below 30 seconds of exposure is not really representative of the sensor for long exposure. Spend an evening testing your rig on a variety of objects with Unity exposures up to 120-240sec. A dozen of each to give you some SNR to play with. Diligently acquire bias, flats and darks (even if you dont advocate using all types of calibration frames, it will expose a better understanding of how the camera works).

Then process your images like you mean it.

Quick question on the scale applied by the ASI ZWO indi driver for the gain and offset. In EKOS ASI071 Control settings I can shift the slider for the gain between 0 and 600. If I wanted to set the gain to 90, as suggested for the unity gain, is this 1:1 the same parameter value on EKOS?

If I may come back to this one, last night I got completely stuck. I am using an Apo with 500mm focal length (f/6.25), the ASI071MC as primary cam and attached the ASI120 to the OAG prism.

For the ASI071 let‘s assume I am using the unity gain setting, with gain = 90 and offset = 20. When running the solver and the focuser, what could be the ideal gain setting versus exposure (how about 1 sec)? I assume I would not change the offset.

For the ASI120, based on advise in another thread, I will set gain to 50% and set the offset to zero. For guiding (internal guider and phd2) based on these gain/offset settings, which exposure time (seconds?) is generally recommended - am I right that settings will somehow be different when using an OAG compared to a guide scope (e.g. higher gain)?

I am fully aware that „it all depends“ on specific situation, but I could just do with a good „starting point“...

Thanks a lot!!!

For guiding I think the camera settings all come down to matching a gain with the guide image interval. 1 sec is probably a good choice. I use the ASI 120 for guiding on a little 50mm f4 guide scope and keep it at its Unity setting. If you're struggling then maybe Bin the capture image and or create a master dark for subtraction.
For focusing with the ASI 071, as Jasem mentioned earlier in the thread, avoid saturating/saturated stars. At F6.25 you shouldn't have too many focus problems. The odd super bright one won't be selected for focusing so pay attention to the median brightest stars as focus candidates. The auto process works very nicely. You can always check with a Bahtinov mask as a confidence booster.

I wonder if the community can come up with a short guide for ASI users on INDI? It seems there is lots of information out there scattered all over the place which can be confusing and frustrating for new users. A short concise guide with the settings..etc would be really great! What do you guys think?

on another forum I asked about suggested ASI071 Pro gain/offset settings. Reply was:
"The offset for the Pro is now fixed in firmware and cannot be changed. I have heard that it has been fixed at 50.
When I first started using my original ASI071MC I used the unity gain, but I had to use very long exposures to get histograms like I was accustomed to seeing with my DSLR using an ISO of 800-1600. After researching the gain setting on the 071 I settled on gains of 200-300 as being roughly equivalent to ISO 800 on my DSLR. I eventually adopted a gain of 200 as being standard. "

This is very helpful. Tonight I applied unit gain with 2 and 3 minute exposure but images turned out very dark. Also running the focuser with 4x4 binning and for instance 10 sec exposure were not satisfying. For the solver, 2x2 binning and 10 sec exposure worked ok with unity gain setting. Will use try next time higher gain values as suggested.

As regards the ASI120 cam, used as guide cam, the 50% gain and zero offset settings worked pretty well. In Internal Guider, 1.5 sec exposure seem to score good results.

I ran unity gain@-10C on my newly acquired asi071 pro two nights ago on the leo triplet. 180s exposures worked out okay. I want to try the HDR setting (0 gain) next session. Helge, I was able to autofocus using a 3.0s exposure binned 2x2 and produced almost a dozen candidate stars to select upon. I used the same settings for solving at unity. I attached a screenshot....ekos gave my images a whacky iso value that I never asked to to assign to the filename. Im using a CLS filter and fitsviewer auto'd everything

On the asi120, mine gave me so many problems with dropped frames that it was almost torture to try to get 25 frames of Leo. I am a fan of the new SEP guiding mode. It seems to measure HFR of the fov to get a better guide star. I'm eyeing the asi290mini as a viable replacement to a camera that i've flashed and fought for a while.