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gregbradley
24-01-2015, 06:58 PM
I experimented with various exposure lengths and ISO's and decided the best results would come from building up signal (exposure time) rather than ramping up amplification (high ISO).

This is a single 10 minute exposure at ISO 200 Sony A7r.

http://www.pbase.com/image/158919897/large

Greg.

Bassnut
24-01-2015, 07:09 PM
Thats different, excellent Greg. Sort of racy compostition.

gregbradley
24-01-2015, 08:17 PM
Thanks Fred. It gets pretty low to see over the walls of my observatory now and it was getting pretty low here. One of the last opportunities to image it really.

Gre.

RickS
24-01-2015, 08:37 PM
Yes, nicely done, Greg.

graham.hobart
24-01-2015, 08:55 PM
That's actually quite a shot. Has motion in it. Beautiful.
Thanks for the look
Graham.

dvj
25-01-2015, 04:38 AM
Excellent shot Greg! Like zero gradient in that image. Was it corrected? how do you like the A7s?

j

gregbradley
25-01-2015, 07:04 AM
Cheers Rick.



Thanks Graham. That aspect did work out well.



I am very Trixie John! Yes its corrected.
I have an A7r which is the 36mp A7 model. Its much like a Nikon D800 but way smaller. Its actually a bit brighter than the D800 at ISO6400 for some reason. Not massively but noticeable. The noise pattern is better on the Nikon, colours and everything else except autofocus I prefer on the Sony.

Greg.

atalas
25-01-2015, 07:15 AM
Wow!thats a long tale....well done Greg.

gregbradley
25-01-2015, 08:20 AM
Yes its massive, isn't it.

Its somewhat of a visual object as well. Its now below the Pleiades and to the left of it. Last time I imaged it - 2 nights ago, it set around 11pm behind my rear mountains which take up about 15 degrees of my western horizon.

Greg.

Ross G
26-01-2015, 11:21 PM
Great photo Greg.

You have captured the long detail so well.

Ross.

ralph1
26-01-2015, 11:33 PM
:thumbsup:Very long tail; the stars are slightly red for my taste though. It would be pretty cool to take photos from the same location with the background in focus and combine them if it's possible.
Ralph

gregbradley
27-01-2015, 08:13 AM
Thanks Ross. It also took some tricky processing to bring it out more.



I may have a background shot I took as well. I'll have to check if I did that for this exposure. I know it did for some. There are quite a few yellowish stars that have a bit of a red ring. Probably some chromatic aberration of the lens. I can tone it down a tad but often in the sky there are patches of yellow stars. It probably is a tad red I agree. I was happy there was colour in the stars as that is the first thing that goes with high ISO shots compared to long exposure and low ISO. It preserves the colour.

Greg.

bwana
03-02-2015, 12:49 PM
Here's a comparison shot off the A7S:

https://lh4.googleusercontent.com/-VmBWv0j9gBY/VLiIOLE2VuI/AAAAAAAAbqQ/sgotPHiqkKQ/w1474-h682-no/Comet%2BLovejoy-PI.jpg
Canon 200mm f/2.8, Hutech HEUIB-II filter, full spectrum Sony A7S, Celestron AVX mount, 51x30sec @ ISO 3200, preprocessed in PixInsight, postprocessed in Lightroom

A few more shots at:
Comets & Asteroids (https://plus.google.com/photos/116260312230579398213/albums/5526527835851259537/6104779071973381858?pid=61047790719 73381858&oid=116260312230579398213)

Lovejoy was one of the best we've had in the northern hemisphere for a lot of years. You've had a few great ones more recently!

bwa