Stars found


I have been able to get stars found to report anything but 0. Do I need to connect a focuser before it will report the number of stars in the image?



Is the lens cap on? :wink:


No Buzz , I did not forget to take the lens cover off

Please let me know how many stars you get get SGP to count in the attached image.




The HFR calculation works on any image taken by SGP. The focuser does not need to be connected. I did not see an attached image with your post. Perhaps you can put it in a drop box?



Here is the image again, I sent it to buzz.

What have I missed, I know that I need the stars found statistic to be something other than 0, correct? If that is so then how do I get it to report stars found other than 0.

The other problem I have is getting the image scale information that I input to be reported to the plate solver. Whats the secrect?




Nothing complex going on here. On the Camera tab define the pixel size for 1x1 binning:

SGP will automatically report this plate scale to the plate solving module being used.

With a frame you have taken being displayed, click the “star” icon and SGP will calculate the HFR of all the stars in the frame it can detect. The “minimum star size” setting (in the Focus Module) needs to be large enough to let the system find stars – start with a value of 12 or so and each time you decrement it, the number of stars displayed will decrease. You must have the Focus Control module displayed or the Auto Focus Options dialog box displayed to access the Min Star Size spin control.



Excuse me but how exactly do I do that




You open “Control Panel” (camera icon at top of screen) and select the Focus tab. There is a button to “Set” the auto focus options. That button opens the Auto Focus Options dialog box where you can specify the minimum star count.

You should also have the Focus Control module open:

View / Docking Modules / Focus Control

One thing to mention is that all beta releases of SGP assume you have extensive experience with the platform and, if not, the beta features may not be all that intuitive.



Sorry Ray - there is no image -

I had the same issues where the beta would not identify stars. It was down to exposure. I was using brief exposures, around 2 seconds and nothing was happening at any pixel scale. Previously I had no problems with a loose cluster but later on, when I pointed to a patch of sky where the stars were of lesser magnitude, it failed to detect any. On my f/8 system I have gone back to exposure times of about 6-10 seconds for Lum and 10-15 for RGB, 20 for narrowband. That setting seems to be more robust since SGP will reject very bright stars but the larger exposure always finds the more abundant dimmer stars for reliable detection. With the latest beta I am setting the min pixel count at 3. If you take an image, you hit the star icon at the top to give you a HFR calculation and then move the slider around. After a few seconds, it shows you the revised HFR calculation and the stars it chose. This is the trick. Before you go full steam ahead and do an imaging run, find the min pixel setting for your image and exposure times.

I did make a suggestion to Ken and Jared earlier that, like AF positions, relative AF exposures might be something to consider - where one puts in some standard set of AF exposures (in the filter tab table) and if you alter the AF exposure for one filter, the others are scaled proportionally.



Sorry about that image not opening, I have attached it to this email.

This is a 15 second exposure, I have the same results with a 5 minute exposure. I don’t know what slider your talking about.

I tried several images from different points of the sky all with the same result.

If it was a SNR problem shouldn’t SGP complain about not enough SNR.

I hope your able to glean something from the image.



Buzz I just figured out to share the image in drop box, It need to be converted to jpeg first, I hope , well any way here it is again.



OK Ray - Can you send me the actual FITS file - a screen grab does not preserve the image data. You can use dropbox or send directly to me at
chris at
I will load it into my SGP and see what it tells me.

The slider is in the focus tab - in the latest beta it has changed to a numerical entry call min star size.



Did you get me email with the attachment. It is getting late here, I’m on the west coast. I really need to know what to do next, I couldn’t do anything last night and I would rather not waste a second night just because I don’t know enough about the software to be able to focus the camera,

Please get back to me before 8:00 Pm Pacific time.

Thank you



I uninstalled and reinstalled, this time installing the latest beta. Now I get HFR and star counts. I played with nebulosity control a little and it had exactly the same affect that I was seeing, nothing happening when the star icon was pressed. I know that that was not the problem before because I tried different settings of that control and none of it worked.

Maybe a bad install??



Ray - you sent me a blank jpg of 350 bytes. I suggest you take a normal frame at the same binning and exposure as your AF frames and save as FITS, pop in a dropbox and send me the link.