Rosette Nebula and M45 From DSC

[julian]

DSC Blacklands Farm 21\1\2012

Canon modified 40D 100 to 400 lens set at 400mm F5.6
ISO 1600, Rosette Nebula 21 X 5min subs total 1hr 45min
M45 11 X 5min subs total  55min
PHD guiding with QHY5 , EQ6 pro mount

Not happy with these images as the stars are not round.
Just checked the internet and if I would have set the lens to F8 instead of 5.6
the stars may have turned out ok.
Never used this lens at   400mm on astro  photography before.
May have to get the large hammer out and fine tune the lens.



Link to original size   
http://farm8.staticflickr.com/7003/6751421073_5df7ea28bb_o.jpg



Link to original size    http://farm8.staticflickr.com/7018/6751421587_bb493f8e6a_o.jpg

[Mac]

very nice images,

Mac

[The Thing]

Nice shots Julian.

Try the lens at slightly less than 400mm as well as these sort of aberrations grow exponentially as you reach each extreme of a zoom range.

[MarkS]

Hi Julian,

A couple of good shots there.

It's a shame about the aberrations toward the corners but I've no doubt you'll experiment and find which settings (zoom and focal ratio) you need to get that back under control.  A star field really is the ultimate test of a lens!

From a processsing point of view, I find your background very black.  It makes me wonder if there might be some more faint data there, ready to come out, but was clipped by setting the black level too high. 

Mark

[Jim]

Nice one Julian.

[Mike]

Really nice Julian despite the aberrations. I agree with Mark that the background is too black.

[JohnP]

Look good Julian - Nice to see some images were captured as well. John

[Rocket Pooch]

Nice one Julian glad you toughed it out

[mickw]

Nice work Julian

I agree with Mark about the black, there's got to be more detail in the background ready to come out

[Fay]

well done Julian, you always stick with it. I love the bit about the hammer!!!!