ED80 Flat Mask (Dew Shield Cap)

thingiverse

# 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 the mask. This mask can then be directly inserted into the end of the dew shield of the telescope tube, where it will sit. # Why would I make this? Rubber bands cannot launch themselves into the cactus plant you have nearby. Clean fabric cannot wrinkle up or drop to the ground and land in the inconveniently placed mud. Things are good. # How to Use The two halves are designed to lock together with friction when a piece of cloth is placed between them. Depending on your printer, your consumables, and your settings, you may find that you need to sand the edges back slightly before the pieces can click together. This is particularly true if you get "elephant footing" where your first layer squishes and flares outwards. 1. Print the two pieces. 1. Get some white, slightly stretchy cloth. 1. Stretch the cloth over one half. 1. Press the other half on top of the stretched cloth. 1. Optionally trim the stretched cloth (though if you trim too much, it might make it difficult to put it back in again later on after taking it out to wash). --- Clear skies!