Cannot find any stars for HFR measurement in image

I am using a Canon EOS 70D taking 20s exposures at 1600 ISO. I have SGP set to stretch with “Low” setting. However, when using Frame & Focus to capture an image … then previewing the image, only my auto focus target star shows up, even though there are numerous other stars in the frame. I used these exact camera settings in other apps with excellent results and can see the entire star field in the preview. The focus is very good after using Bahtinov mask.

I use three sequencing apps (APT, NINA & SGP) and try to use identical settings in all three. For example, when I take an image to use for plate solving, centering or auto focus, I shoot with my Canon EOS 70D DSLR … 20s at 1600 ISO and then do a basic stretch so I can see the star field.

Both APT & NINA can use the resulting image successfully to do a plate solve (ASTAP), a frame & center or as the starting image for an auto focus routine. However, SGP cannot seem to produce a usable image even from the identical settings.

In the link below I have provided several screen shots as well as my SGP log and sample images from the other apps.

In SGP, I was trying to capture an image to measure HFR for use in the auto focus step size formula. When I click the “Star” icon to display HFR readings, nothing happens and the image preview window says “No Stars”. And when I check the “save image to disk” box, SGP hangs. I must then kill SGP in the Task Manager (screen shot in the link).

I was anticipating your request for a copy of the image file, but I now have no way of saving it to share with you. I will share several screen shots and my log file.

I would very much appreciate some help getting this resolved. I love the functionality of SGP and if I can get it to work, it will become my GoTo sequencer for deep sky objects.

Thank you,


Link to Logs

Useful Info
OS: Windows 10 Pro - Build 1909
Ver: - Commercial License

Last night we had clear skies, so I ran a little test. Got my rig pointed and focused on Alioth in Ursa Major. Using 20s exposures at 1600 ISO with my Canon EOS 70D saving all in RAW format, I took three exposures with three different apps. The images taken with SGP are significantly different! I analyzed them in PixInsight and they are much dimmer and show very few stars. I have uploaded the sample images here:

Although I have scrubbed through the SGP settings several times, I MUST still have something wrong. I would very much appreciate some help getting them correct. As I have said, I really like the functionality of SGP and want to use it as my main seqencing app.

Thanks again,


I have again reviewed the PDF version of the user manual and carefully read pages 37-39. Following this guidance, I have configured my Canon EOS 70D as per the manual and am still having issues with Frame & Focus images.

I think I know what this is. You are only taking 1 second exposures :slight_smile:
It is to do with the mirror lockup setting. SGP can do a double take - which, when coupled with the mirrorlockup feature on the EOS triggers the mirror and then shortly afterwards does the exposure. If the mirrorlock settings are out of sync - then you get an exposure equal to the short delay. In your case, you set it up as 1 second (mirror settle time in the EOS settings)
Let’s say we choose to ignore mirror lockup (hardly relevant on long exposures). Disable it in the EOS menus and in SGP - change the 1 mirror settle time to ZERO.

Thanks Buzz … I will give it a test tonight.

I reset the Canon EOS camera settings in all my equipment profiles as follows:


I will apply these new profiles to all my saved sequences.

And when I checked the Mirror-Lock feature on the camera, it was already turned off.

I will post some images from tonight’s session here.