ED80 Flat Mask (Dew Shield Cap)

# What is This?

This is a "flat mask" built into a cap which is compatible in size for the dew shield of my Skywatcher ED80.


# What is it for?

Typically when capturing astrophotography images, a series of "flat" calibration images will be taken. Flats are used to capture images of any dust, vignetting, or other imperfections that exist within the imaging train of the telescope. These flat files can then be used to counteract the effects of these imperfections to create a better final image.

Capturing flats commonly involves stretching a piece of cloth over the end of the telescope, and pointing the telescope at the morning-lit sky. This can be done with a white t-shirt or a (clean!) white rag, and you can lock it in place with a rubber band or something similar.

I am clumsy and have high standards, so to do this a bit better, I have designed the flat mask you see here. The purpose of the flat mask is to trap a piece of stretched cloth between the front and back half of