SharpCap Forums

After adjusting focus to best position, the images of brighter stars extend over many pixels. (I think this is called "blooming"). This occurs even when focus is good - e.g., the dimmer stars in the image are pin points. Is there a way to use SharpCap to prevent this?

Hi,

blooming is usually only a problem with CCD sensors, where excess charge accumulated in one pixel could spill over to adjacent ones. It's possible that this is what you are seeing, but if you are using a CMOS sensor then it's more likely that this is just the natural spread of light around a star (which is barely noticeable on dim stars) being quite signifiacnt on the brighest ones. The only real approach is to turn down the exposure to avoid letting the bright stars saturate, however that may conflict with getting a long enough exposure to see faint nebulosity

It may be that you can find processing tools in other software like PixInsight or AstroArt to help shrink stars, but SharpCap doesn't have a processing function for that.

thanks,

Robin

The is a third party script for Siril that has a star-reduction function. I've used it -- it's drawback is that it shrinks all stars an equal percentage. Sensor analysis may also help with this. Gain and exposure are your two best controls.... as a newbie myself, I'm realizing this is why this is as much art as science.