SGP able to select guide star magnitude?


I’m new to SGP and wanted to know if there is a way to allow selection of the guide star based on a range of magnitudes (adu). The reason I ask this is that in the two or three sessions that I have used SGP it always seems to pick the brightest star in the fov. This of course saturates, but phd2 still seems to guide ok. Stars with the IF ONAG and 10u mount are round…Just curious. Thanks…Gunny


Someone please correct me if I am wrong. I believe that PHD or whichever guide program you select in SGP decides which star to select. Check the PHD options to see if it offers options on max guide star signal to noise ratio.



That’s right, PHD2 does the guide star selection. It would be great if you could post your question on the PHD2 forum. Please include a FITS file from the guide camera (in PHD2: menu => File => Save Image) for which PHD2 chose the saturated star. Also please include the PHD2 debug log from the session.


Thank you fellas,

Unfortunately weather is again plaguing my efforts here in the Midwest. B4 SGP, I would just use PHD2 and manually select a star that would not saturate. All worked beautifully. With SGP, it will be a little more challenging, but I’m confident it will work. The rub comes in due to the IF ONAG. Gaston recommended that my exposure time be set at 15 sec. with zero hysteresis. This provides minimal mount corrections and works well with manual star selection in PHD2. By automating the process, things get a little more complicated.

I will follow Andy’s suggestion and take this over to the PHD2 forum. The whole reason I purchased SGP was to be able to use PHD2. After I bought it, I’m realizing why so many are dropping the programs like maxim, tsx, and ccdap. For me, SGP opens up new fronts in ease of operation and a multitude of options. Even with the saturation problems, my stars are round, but that may be due to where I was imaging at the time.

I’m in hopes that the SGP developers will come up with a modelling program such as ModelMaker or t point that can be incorporated in SGP. Thanks for the help…Gunny