Several years ago I had some experiences with afocal projection, in particular for taking pictures of the moon and the planets with my old 114 newton. A few months ago I motorized my Celestron C8. Since I have not a camera suitable for deep sky imaging (currently I use my C8 only for planetary imaging and visual observing), I experimented with afocal projection using a smartphone. I was quite skeptical about obtaining any interesting result. However, the seeing was bad for Mars and so I tried...
The obtained result have surprised me . Obviously it is far from the quality of the pictures that can be seen here taken with more "usual" methods, however I'm quite satisfied. In particular considering the usage of a smartphone and 8 seconds long shots (and a very simple eyepiece).
I don't know whether M42 is the only deep sky object that can be successfully photographed with this technique (given its brightness). May be also M27, do you have any suggestions?
Moreover I'm quite doubtful concerning the white balance level to set in the smartphone (in kelvin). What do you think is the correct value for deep sky imaging?
Here the image:
Afocal Projection with Smartphone, average of 14 frames
Smartphone: LG G4 (16 megapixel at F/1.8)
Eyepiece: Celestron SMA 25mm + Universal Cell Phone Adapter
Telescope: Celestron C8 (203 F10 SC Telescope) + 0.63x Focal reducer
Elaboration: GIMP, FastStone Image Viewer
2 frames 8sec ISO 400
7 frames 8sec ISO 800
5 frames 8sec ISO 1500
Edited by Maurizio, 21 November 2020 - 08:34 PM.