Em1 MkIII does good astrophotography

Started 2 months ago | Photos thread
OP Grimstod Regular Member • Posts: 196
Re: A spectacular image lies within the noise!

Pete Berry wrote:

Grimstod wrote:

sunnydayz wrote:

Grimstod wrote:

Testing out a new camera. This was taken last night(well this morning really) at Naylor Observatory. Bortle 5 sky. Using my own scope 80x522mm f6.3 and a new Em1 Mk3 which is on lone form Olympus. Think I will have to buy it now. 25x60s exposures. ISO1600 40 darks, 200 bias, 200 flats, 200 dark flats.

Not to C&C or anything because you've presented a beautiful image. Just wondering, when I open the image via the 'original size' link I can really zoom in and see red, blue and green noise and also vertical stripes in the image. I guess you must be stacking images to reduce noise, but how to approach tackling the 'artifacts' I mentioned?

Thanks.

I sorta underestimated this sensors ability to captures highlights. I should have taken longer exposures. I only did 60sec exposures. Ill do this agin soon with 2 or maybe even 5min subs. The pictures were very underexposed so longer exposure will fix that even if I cannot take as many. I was just using setting that I used on my old EM1.1 Its very easy to overexpose the core of the galaxy but as you can see is should have taken longer exposures.

Grimstod, this is a very nice, detailed capture with an excellent optic - no distortions corner to corner, excellent tracking, but with a heavy veil of noise when seen at 100%. I took the liberty of importing your full res. image into PS-10 and doing simple adjustments with levels: specifically, pushing in the black input level markedly up to 90 (from 0) while pulling back white input to 208 (from 256) where the white values begin to brighten, so no clipping of whites, but severly clipped blacks, which wipes out the huge amount of starfield black sky worm-like noise seen at 100%, while increasing contrast in the galaxy's spiral arms. Then an adjustment in color balance to subdue the yellow-reds. No NR used at all - you simply make the black sky black as it should be. A few of the very dimmest stars are lost, but star colors are accentuated.

I've used this technique for wide-field Milky Way, Southern Cross, etc. long exposure photography in the past.

Mod. of Grimstod's Andromeda Galaxy

Nice work Pete. I am aware of how to do this but just could not get myself to loose the outer edges of the galaxy. I am going to give this target another try though. This time I am going to double exposure length. This target is rather underexposed so double exposure time will get rid of all the noise.

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