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View Full Version here: : NGC 3766 and Omega Centauri in HDR

avandonk
15-03-2007, 02:01 PM
Tried collecting more data till the Moon came up. The focus is better and I have purposely left the faint background noise in. This noise would almost disappear with median stacking of multiple images.

NGC3766 1.1MB
http://members.optusnet.com.au/~trlee8/NGC3766.jpg

Omega Centauri 1.3MB
http://members.optusnet.com.au/~avandonk2/OC_hdr2.jpg


Details
Canon 5DH, TAL200k, Hutech focal reducer (7887) so FL 1790mm at F9, no filters. ICNR on.
Both these images were the result of using EasyHDR on a set of exposures for each, consisting of 1,2,4,8 and 16 minutes at an ISO of 200.

I used ImagesPlus to convert from RAW to TIFF and correct for flats. Then used digital development
to simultaneously get a set of five images with suitable brightness range.
Then used RegiStar to produce a set of aligned images of the same dimensions.
EasyHDR was then used to produce an LDR tiff and PhotoShop to adjust levels.

This is just testing to work out what would give the best results. I am sure like any method of image processing there is no correct answer.

Bert
h0ughy
15-03-2007, 02:09 PM
lots of lines and noise in them. what is the fuzzy line lower right in frame 1?
avandonk
15-03-2007, 02:18 PM
Its a reflection from the next door neighbours outside light from the front of the TAL200K as I don't have any sort of light or dew shield on it yet. That was the whole point hOughy these images show the brightest stars and the faint noise at the same time without anything being blown out or too dark. I can easily eliminate the faint noise with many methods. Thanks for noticing.

Bert
avandonk
15-03-2007, 02:58 PM
Here is an image of NGC3766 out of focus before I collimated the TAL200K as I had the mirror off for cleaning and flocking the main tube.
You should also be able to see what vignetting is!

No Homer jokes!
Bert
tornado33
15-03-2007, 04:06 PM
The Omega Centauri one shows great detail without burning out, and the 3766 shot shows great background detail.
Scott
h0ughy
15-03-2007, 04:34 PM
mmmmm doughnuts...... :D thanks for the reply Bert,
avandonk
15-03-2007, 04:43 PM
If you think about it Scott a 12 bit camera with exposures of five stops range to me means you can capture images with a dynamic range of 17 bits. The soft ware can handle up to 96 bits although it needs to be 'compressed' for display on an 8 bit LCD. The only limit now is the object and amount of sky glow and light pollution compared with the signal.
I will explore further.

Bert