Dusty Carina Repro new version at f/5

[avandonk]

As it says
Full res image here 4.5Mb
http://members.optusnet.com.au/~cheekyfish/carhdrD.jpg

Bert

[Omaroo]

Lots of stars, but they just look out of focus to my eyes Bert. :shrug: Maybe if you also presented it in intermediate sizes (say 1260px) it'd be sharper on our average monitors? Nice subtle colour in the nebulous regions. Pretty!

[avandonk]

Chris you are correct but the only way to view it is at full resolution on a 50 inch monitor!. I could fudge it. Just save it and view at what you think is OK. It is a very deep image at 300mm it will not show the clarity of a far longer focal length scope. But ihe field of view is rather wide. I have tried to get the dark dust to show up as well as everything else.

The HDR process does soften stars from the clearly defined circular objects only differing in size due to their apparent magnitude. This lens can produce perfect stars but there is no nebulosity.

When you can zoom back from an image produced by a long focal length telescope with only a few tight round stars and then see many tens of thousands of stars at the same apparent quality I will agrree with you. This image is over 16MB in JPG form and far better than this 4MB image.

Bert

[strongmanmike]

Have to agree with Chris Bert, the stars look like odd shapped donnuts, not sure if it is dust that you are showing over the FOV or if it is an illussion caused by the out of focus/abberated stars..? :shrug:

Do you stop the lens down? If not maybe you should try?

The FOV is excellent, having tight stars across the frame would make a world of difference I recon.

Mike

[avandonk]

Is this better? Same data, but I did not push as hard to get all faint data to show. The dust is it still there?

Full res 5MB
http://members.optusnet.com.au/~cheekyfish/carhdrD_02.jpg

I will try stopping down to get the star data. So you will all have to suffer another Carina image!

Thanks for the feedback folks. When you are too close to data you can lose objectivity and worse, complete sight of what you are trying to do.


Bert

[tornado33]

I love the colour balance and the dusty areas.
Thats a good idia using stopped down images for star data only and full aperature for nebula
Scott

[avandonk]

I did this with the lens stopped down to f/5. I have a feeling Mike Sid will say 'I told you so'.

Canon 5DH, Canon 300mm F2.8L at f/5. Hutech LPR filter.
Exposures 10x( 1m, 2m and 4m) at 800ISO. Fridge at -5.0C. The usual hdr method. I have not used any enhancement. I can see a slight improvement with hardly any loss of dim nebulosity.

Full frame 4MB
http://members.optusnet.com.au/~cheekyfish/carf5.jpg

Why I have been reluctant to stop down is that the iris blades cause unwanted diffraction spikes on the very bright stars. I actually used a baffle out of a refractor to stop the lens down by placing it inside the lens hood.

Bert

[strongmanmike]

Errr?...told you so? ;)

Diffraction spikes on a few stars look infinitely better than out of focus donnut stars. hat's the first stop after F2.8?..F3.5/4? maybe even they would be ok?

Looks much betterthan the first shot Bert :thumbsup:

Mike

[gregbradley]

Nice shot Bert.

I have taken some lens shots with an STL11 which is a similar sized chip to the 5D. I found I had to stop the lenses down a couple of stops to prevent coma which could get quite bad.

From digital astro yahoo group there were a few very knowledgeable people about lenses and they are often not that great fully opened up where the aberrations really start to show. There are some exceptions though.

The best lens shots I have seen were with Zeiss 300 F4 lenses. They seem to be really top end. Probably worth a lot of money too.

Greg.