[Stonius (Markus)]

I'm curious about whether anyone makes a flat that can be inserted into the image train to create a precision mask for celestial objects - kind of like they do when studying the corona.


By way of example, on my microscope there is a scale that is inserted at the back of the eyepiece that allows you to judge the size of microorganisms. So I was thinking about something similar for telescopes



I imagine it must be possible with eyepiece projection, for example as it's the same principle. I'm guessing there is another plane of focus before the eyepiece where the scale is inserted, allowing it to be reproduced in focus at the eye. Maybe with a barlow it could work?



In the case of a deep sky setup, I'm not sure there are any focus planes before the sensor. The only way I can think to get a sharply defined dot is with dust on the sensor!


I'm thinking it could be interesting to capture faint moons of planets, or the homunculus, or even just using it as a technique to cut glare from stars ie Alnitak.


Is this just crazy-talk on my part, or is this possible? I'm aware of the occluding bars sometimes used by visual astronomers, but I'd be hoping to end up with a neater result than having bars running through my image.


Markus