Reply To: Software for photometry (image calibration)

Forums Photometry Software for photometry (image calibration) Reply To: Software for photometry (image calibration)

Mr Ian David Sharp

I don’t know what stretching is.

Ah! then you have to learn about this!

Astronomical deep-sky images contain mostly black (or near black) sky. When you view an image un-stretched astronomical image you see virtually nothing – just a few pin pricks of light from the brightest stars. This is because most of the data is residing near the black-point of the ‘histogram’. But applying a non-linear stretch to the image, the data is spread more evenly across the histogram from the black point to the white point.

See my attached screen shot. The image on the right is a clone of the one on the left but I have applied a histogram stretch to the one on the right. Without this skill you will not be able to see your data properly, nor be able to check the calibration properly.

I feel you have learning curves all over the place! If you would like a Skype or Zoom (or similar) call I could share my screen and take you through a few things? Otherwise there will be a lot of back and forth with messages etc.

You can PM me here if you want to set something up…