The camera is a Canon M running Magic Lantern. I am taking pictures with a Canon 200mm macro. Stars appear sharp and 1x. At about half full magnification on the display all stars including dim ones begin to show area. At full magnification all stars including dim ones show a definite circle. No stars are points.
My question is are there Magic Lantern settings that effect star sharpness or size on the M? I would like to adjust the image for the sharpest values. Thanks Dan
Please share untouched image. Which method was used to focus on stars?
Additional info, please: Filters attached? If a mount adapter was used: Type and type of lens attached?
Quote from: dansawyer on August 11, 2020, 02:30:49 AM
The camera is a Canon M running Magic Lantern. I am taking pictures with a Canon 200mm macro. Stars appear sharp and 1x. At about half full magnification on the display all stars including dim ones begin to show area. At full magnification all stars including dim ones show a definite circle. No stars are points.
My question is are there Magic Lantern settings that effect star sharpness or size on the M? I would like to adjust the image for the sharpest values. Thanks Dan
Like Walter said more info would be usefull.
In general getting stars sharp in camera is a science. Looking on a dim screen in x1 or x5 mode will not shown anything. You need to examine a image.
You could try to compile the astro module (no idea if it works on Canon M). The astro module has a star focus sharpness factor - or use the open source astrophotografy tool N.I.N.A https://nighttime-imaging.eu/ It might have a step learning curve, but it has solutions to all astrophotografy problems, including star focusing.
Thank you both. As follow up, after reading the comment I tried again. I carefully mounted the camera and very carefully focused a bright star at 10x. The camera is an M1, the lens is a Canon 200mm f4 macro. The mount is an Ioptron Pro. (I am really impressed with the performance)
I focused at f4 and then stopped down to f5.6. I set ISO to 800. That seemed to do the trick. Focusing was difficult and definitely touchy. The focus display definitely show halos on the stars. I was able to complete about 40 images of 50 seconds each.
I was centered on North American Nebula.
I looked for options to attach a file but could not find the command.
Sorry, still unable to follow.
With "mount" I don't mean your astronomical mount but the mount adapter (if any) between your EOS M and your lens. The only lens I could find meeting your description is this one, dating 1981:
https://global.canon/en/c-museum/product/nfd225.html
Have you tried to use another lens?
Why did you focus in f4 and stopping down after? To exclude focus shift I would recommend to focus with the aperture you are actually using for the shots.
Filter question unanswered.
You have to find a file/pic hoster and link file/pic here.
The issue was focusing. The lens is a Canon 200mm macro FD. The camera is a mirrorless M1. The adapter matches the FD to the M1.
The mount is a Ioptron tracker. It was reasonably aligned to CNP using the polar scope and a Polaris position app.
The system appears to focus beyond infinity. Using the 10x feature on the M1 I carefully focused on Deneb at f4. That was touchy, there was a definite halo on Deneb. I then stopped down to f5.6 and proceeded to take 40 50 second images. This was a test, no dark or bias images were used.
The result was actually very impressive for a first try. I stacked the images using siril. There were hot pixel track in the final image.
The M1 worked very well. I am looking for a how to to finish the color processing. The M1 raw image from the original question is answered. Thank you all. Dan
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