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  #21  
Old 13-01-2008, 08:12 AM
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Ingo,

If your using raw processing the extra noise you might be seeing is because of the 14-bit versus 12-bit. In the 40D the signal (and hence noise) will be amplified roughly 4x more than the D50 because of the 14-bit versus 12-bit raws. The thing that is important is Signal to Noise, so more noise is OK as long as you have more signal (i.e sensitivity).

Terry
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  #22  
Old 04-02-2008, 06:20 AM
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Hi,

Last week I bought a Canon 40D to replace my modified 350D.
At first I was a bit disappointed with the results, but it turned out that processing is a bit different. I'm using ImagesPlus to shoot and process the images.
Yesterday I made the first pictures with the still unmodified camera, the results can be found at:
http://www.astropix.nl/images/M45/M45.html due to clouds I didn't get more than 5 exposures of 300seconds at 400 ISO. In processing I used proper dark, bias and flat frames.
I'm satisfied with this first result, dark current is defenitely lower compared to the 350D, the amp glow is gone completely.

Next Saturday I will modify the 40D , the Baader filter is waiting in its box...

Regards,
Albert van Duin
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  #23  
Old 04-02-2008, 06:26 AM
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iceman (Mike)
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Beautiful results, Albert. Excellent nebulosity for only 5 x 5min exposures, especially for only 400ISO.

Are your skies very dark?

A modded 40D - ah, I'd love to have one those. Good luck with the modding!
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  #24  
Old 04-02-2008, 06:32 AM
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Hi Mike,

Thanks!
No, my sky is not very dark. In the direction of M45 during that shot around mag 5.5 I guess. I think the 40D is a big improvement due to the absence of amp glow.

I still think a lot about the Queensland Astrofest 2006, those were dark skies!

Regards,
Albert
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  #25  
Old 04-02-2008, 02:26 PM
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Question. Would it be better to use the ISO800 NR on, or off and leave any software NR to processing software? I always thought it might be best to get images as raw and unprocessed as possible from the camera, then do the dark subtraction and flatfielding, and any noise reduction in your favourite astro processing software (in my case Iris as its free and works ok)
Scott
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  #26  
Old 04-02-2008, 07:43 PM
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Albert,

Wow! You'll definitely have travel back to Oz soon and bring your ASA

Terry
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  #27  
Old 05-02-2008, 06:00 AM
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Quote:
Originally Posted by tornado33 View Post
Question. Would it be better to use the ISO800 NR on, or off and leave any software NR to processing software? I always thought it might be best to get images as raw and unprocessed as possible from the camera, then do the dark subtraction and flatfielding, and any noise reduction in your favourite astro processing software (in my case Iris as its free and works ok)
Scott
Hi Scott,

I would defenitely switch the automatic NR off and make separate dark and bias frames (and flats as well). Iris is a fine software package and you should be able to get good results, but nowadays I am lazy and use ImagesPlus. It makes life very easy.

Albert
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  #28  
Old 05-02-2008, 06:03 AM
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Originally Posted by CometGuy View Post
Albert,

Wow! You'll definitely have travel back to Oz soon and bring your ASA

Terry
Hi Terry,

I would like to visit Astrofest again with my ASA.
Maybe in a few years time!

This evening I made an image of the new comet 2008 C1 (Chen-Gao)
You can view it at:
http://www.astropix.nl/ChenGao-CombineFilesExcAvgDDPPS2srgb.jpg

6 x 3 minute exposures with an ASA 8" F/2.75 and a modified Canon 350D
Images acquired between 18:47 and 19:07 UT on February 4, 2008
A lot of gradients due to soccer field lighting 200 m from my observatory

Albert
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  #29  
Old 25-07-2008, 09:05 AM
cfranks (Charles)
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Finally getting round to setting up my 40D to take 'back-yard' pics and my research about in-camera NR found it only applies to Jpeg images. RAW is untouched. I will have to take Dark and Light frames at each session. Dark frames I think I can cope with but what is a recommended way to take Light frames?

Thx.
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  #30  
Old 25-07-2008, 09:21 AM
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Light frames are your actual real exposures.

Do you mean flats?
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  #31  
Old 25-07-2008, 09:38 AM
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Shows my inexperience.

Flats I meant.
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  #32  
Old 25-07-2008, 09:54 AM
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Do a search on flats - there's been a lot of discussion on how to take them etc.
The best way to take them is to use a lightbox. Then you can take them at any time of the night.
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  #33  
Old 25-07-2008, 01:37 PM
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Ingo, I don't know how long you have been using your camera for astro work, but give your self some time before you kill it, a good six months of trying, testing, you name it, and then if not happy, bury it.

Leon
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  #34  
Old 25-07-2008, 03:57 PM
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My 40D is back in it's box - battery and memory card out (of cause).

My Atlux is assembled and in the spare bedroom, with the old CG5.

My 10" newt is still in pieces waiting on me to get around to rebuilding it.

Life .... it's got a habit of getting in the way .... plenty of things to do to get my astronomy and imaging up and running again ....not likely until late August or September.
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  #35  
Old 25-07-2008, 04:08 PM
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Ingo, I've found that too little exposure will result in noisier images.
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  #36  
Old 31-07-2008, 07:14 PM
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Anything less that 10sec with my 350D produces noisier results...

If anyone is interested, I could do some direct comparison images... I have a D50/D80 and a 300D/350D

300D ~ D50 are both 6mp cameras with a crop sensor.. perhaps the closest comparable test I can do... Otherwise the 350D (8mp) vs D80 (10mp)
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  #37  
Old 31-07-2008, 07:38 PM
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Ian, thats soooo lame.
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  #38  
Old 01-08-2008, 01:27 PM
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Ian, thats soooo lame.
Yep .... but got lots to look forward to when I get my astro-act together and restart.

Can't believe it's been two weeks and no horrible bright outside light on at night (cf crazy neighbour) .... the threat to take him to court and involve the cops (harrassment) must have done the trick.

Considering putting a permanent pedestal in the backyard onto which to install the Atlux head (when viewing / imaging) rather than laying a flat slab of concrete on which to set up the tripod (my back yard is not flat (is 1:20 slope).
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