Beginner pics!

[ebeyonder]

Hi all,

Tonight is the second time I did some imaging with the equipment I have collected. I imaged the pics from Cambridge, Massachusetts in the US. Any comments and suggestions would be greatly appreciated. I hope to learn as much as I can here so that when I return to Singapore later this year I can carry on where I left off!

I imaged M31 - about 20 images of about 300 sec exposures (or maybe 200 sec, cannot recall). I did the dark and light frames too. This was the best I could do with Photoshop:



Another version:



I am not sure why my image looks a bit grey? Or is this the normal colour? I shot everything in RAW this time.

I then tried to take M42 before it set. I only had a limited time because M42 is visible only for a short time from my balcony. I managed to catch it as it was setting behind some trees:



This is a single 30 sec shot.

I tried taking multiple shots, but the branch got in the way and combining the images gave a weird shadow where the branch is.

A crop of the shot above:



One thing I realise is that in the shots above, I can see tiny arrays... what are these, and how do I get rid of them?

Again, thanks for all your help... any comments and suggestions would be greatly appreciated!

[rcj]

good attempts on M31! however somehow the last two pictures don't seem to load, am interested to know what u mean by arrays?

[weixing]

Hi,

I imaged M31 - about 20 images of about 300 sec exposures (or maybe 200 sec, cannot recall).

Check your RAW files lor... it had the exposure time in it.

One thing I realise is that in the shots above, I can see tiny arrays... what are these, and how do I get rid of them?

Might be cause by the way you do the image processing. What camera did you use??

Anyway, the M31 was nice... way beter than my first DSO image...

Happy imaging and have a nice day.

[yybmage]

Wow!! Good control over your exposure and good job for the stacking!

[Bergkamp_]

nice! very gd for starting..

[ebeyonder]

Thanks for all the encouraging replies

By arrays I mean squarish things that appear. And these aren't just isolated specks like hot pixels or the like; these are repeated patterns, like those on a checkered shirt...

And also I used a Orion Starshoot Pro v2, taken with the included DL Maxim essentials, processed with Photoshop.

[rcj]

am able to see the pictures now....i see what u mean...yes, those are attributed to hot and cold pixel artifacts. Did u utilize any algorithm to remove the hot and cold pixels? If yes, at which part of the reduction process? It would be best to remove these pixels after doing dark and flat frame subtraction PER SUB-EXPOSURE separately, rather than removing it at the combined result. This is my guess though, cause I had similar artifacts before until the removal process was implemented per sub level.

[Airconvent]

Very good first effort ebeyonder!

[ebeyonder]

Remus, by removal of hot and cold pixels, do you mean the light and dark frame thing? If so, I did it for each sub-exposure before stacking them together...

[rcj]

Yihan,

The reduction process is a standard procedure for the preparation of images for eventual post processing and is followed by:

1) Dark frame subtraction from the Light frame
2) Flat frame subtraction from the dark-subtracted Light frame
3) Removal of hot/cold pixels from the flat-dark-subtracted Light frame - a.k.a Reduced frame.

only after step 3, is the resultant Reduced frame ready for stacking (combining).