Seagull Nebula and Thor's Helmet

[avandonk]

After months of cloud finally a clear night without an interfering Moon.

Details
Canon 5DH, Canon 300mm F2.8L, at f/3.6 with exterior aperture.
Hutech LPR filter.
Exposures 20X( 30s, 60s, 120s, 240s) at 1600ISO, fridge at -10C.
The usual HDR method

Large image 5.5MB

http://d1355990.i49.quadrahosting.co...0_12/seagn.jpg


I have made some modifications to the optic train with a noticeable improvement.
The image has only been very slightly cropped from the full frame notice how the corners and edges are quite good for colour and signal to noise.

I used to get a colour cast due to vignetting and incident angle of light on rear LPR filter. I have mounted an 82mm LPR filter in front of the lens this also acts as an aperture.

Bert

[h0ughy (David)]

great wide field Bert

[leon]

Love it Bert, nice and wide my favorite type of imaging, err, well it used to be.

Leon

[tornado33]

Great image there. A good idia using the filter external to the lens, which is an interference type filter, whose passband changes with fast F ratios. Also, only filtered light can now enter the lens.
Scott

[astroron (Ron)]

Very nice Birt, puts things in perspective.

[avandonk]

Originally Posted by tornado33

Great image there. A good idia using the filter external to the lens, which is an interference type filter, whose passband changes with fast F ratios. Also, only filtered light can now enter the lens.
Scott

You have hit the nail on the head Scott! Any light in your optic that is not contributing to the image will lower contrast and signal to noise.

Bert