Blue Tarantula?

[Buddman]

Hi all,

About a week ago I was trying out a new camera and for a test run I did Orion and Tarantula nebulas (nebulae?). I got good colour with M42 but Tarantula looks blue, I don't remember seeing it look like this with other peoples shots.

I've posted both images from the night. They have been stacked using DeepSkyStacker but the only processing is that I have increased the saturation. Was it holding it's breath, maybe I was:thumbsup:. Any ideas?

Both images were taken through an ED80 on a Canon 1000D. Tarantula was 7x5 min ISO 800 and 3 darks.

Adam

[Zuts]

Hi Adam,

Nice photo's. The Tarantula looks blue because unmodified DSLR's have a very poor Ha response. This is why people modify their cameras :)

Cheers
Paul

[JohnG]

As Paul has said, an umodded DSLR is poor with it's response to Ha light, the blue/green cast is caused by the camera picking up O111 and overpowering the red of Ha.

Cheers

John G

[AlexN]

Yep, the Orion image looks a bit blue too..

Heres 2 images of Orion I've taken, the first taken with my unmodified DSLR, the second taken with my CCD camera. you can see in my DSLR image, Orion is much more blue than in the CCD image.. Your images are pretty standard with reguard to unmodified DSLR astro images.. Theres not much you can do about it, short of modifying the camera.

Alex

[bojan]

Well guys...
To eye Tarantula definitely looks like greenish-bluish..
And so does M42.
I would not feel bad about unmodified camera at all.
People modify them because then they can pick up Ha, and there are objects there which do not radiate in anything else.
Universe looks very different in other parts of spectrum..

[Buddman]

Wow, I knew that the filter makes a difference but I didn't realise that it made that much difference, thanks Alex for the images.

I only just bought this camera so I am not going to consider modifying it until the 12 month warranty runs out at least. Does taking the existing filter out and replacing it make any difference to normal family snaps?

If I was to process these shots would it be possible to enhance the small amount of Ha data or am I hoping for a miracle?

Adam

[bojan]

No.. this kind of processing will just raise S/N (signal to noise) ratio. You can not create information which is not there..
My Canon is not modified, and it will stay that way for a long time.
Modification is somewhat expensive process.. if you do not dare to do it yourself.There is also a slight risk involved.
Modified camera can not use factory while balance table any more (I was wandering why no-one hacked that already?) so you have to use custom one (not hard, but still fiddly).
And, if someone is really THAT keen on IR photography, I think it would be better to to use dedicated B/W CCD camera with set of proper filters. Because the result ot this would be ~3x better photon sensitiovity, and
more accurate color calibration.. important for photometry.

[Hagar]

The red colour can be lifted a little but you must then endure the problems of a red colour cast over the entire image including all your stars.
An unmodified camera is still one of the best and easiest to use image capture devices available today. Your camera will make the best learning instrument you will ever get and will produce stunning images without modifying it.
Remember the images you take are taken to please you and a small change in colour is of no real consiquence in a well framed, tracked and focused image.

[Buddman]

Thanks for the advice,

I thought about it all for a while and I came to the same conclusion. If I get that serious I will look at a CCD camera with filters. If I did get my camera modded It would stop working in the next week with my luck anyway.

Thanks again for the advice and help.

Adam