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DJT
08-04-2012, 05:31 PM
Hi
This is my first go at widefield so would appreciate some feedback to help me with the learning curve.

I am happy with this in that there is so much going on in the image but technically not so sure. I know there is more colour to bring out on the stars in the cross but maybe will try that on a reprocess.

This is 90 minutes of data at ISO 1600 in 10 minute subes with a 1:2 ratio for darks, Bias and Flats.

Canon D30, with a cheap and nasty 55mm lens at F6.3, (bought specifically for this as am normally Nikon for daytime but canon body only for astro) piggy-backed off an auto guided SWED100. CLS clip in filter used as image was taken at my light site (backyard in Sydney)

Thanks for looking

http://i1154.photobucket.com/albums/p523/aussiedave1/Deep%20Sky%20Imaging/southerncross0104121600v1applypsv16 bit180degree.png

TheDecepticon
08-04-2012, 05:57 PM
Not a bad effort. Nice vista. :)

The image in general lacks colour. It seems to be far too grey instead of the nice golden colour that can be seen in similar images. The image also suffers from some gradients that tend to pop out when you try to increase the saturation to boost the whole image. The stars could be worked on separately.

It's a long way up from here, but you are on the right track. :D

skysurfer
08-04-2012, 06:44 PM
This might be a result of the CLS filter. This 'golden color' is the wavelength around 590nm and is within the range from 510-610nm which is blocked by the filter. But the red nebulas (Eta Carinae and IC 2948) are well visible particularly when taken from Sydney where the sky is normally orange yellow. So a really nice pic taken at 1600 ASA with a 30d which has an older sensor than the 40d ! In general the image is well done !
Thanks to the CLS filter you actually can expose 10 minutes with even f/6.3 under the oragne-yellow Sydney skies ! Without it you can barely reach 2 minutes or the photo gets one yellow mess without stars.

You want the golden color ? Drive to the Blue Mountains / Katoomba and take the picture there and you'll need only 2 minutes per frame....

DJT
08-04-2012, 07:10 PM
Thanks for the feedback. After looking again I went straight back tpo PS and am fiddling around as I type. The original had very little processing done. There is a red gradient in the top left corner that crops up not only in this but other images, especially on longer exposures, which I think is caused by Amp glow as the sensor heats up. So will find a way to get the gradient removed. New to this so that will be fun.

Again, feedback valued.

As for dark sites..Looking forward to trying this again without a CLS somewhere a tad darker.

Ross G
09-04-2012, 12:33 AM
Nice shot David.

Lots of detail.

Try using In Camera Noise Reduction instead of seperate Darks. It takes a bit more time but I think the results are better.

Ross.

Dietmar
09-04-2012, 08:21 AM
splendid field of view!
that reminds me of my visit to chile last year. what I see in the image is pretty much what we saw bare eyed at paranal.
thanks for reminding me!

gregbradley
09-04-2012, 09:03 PM
Great start!

Overall a very pleasing image.

Greg.