Southern Cross Star Field and LMC widefield

[gregbradley]

These are the last of the recent widefield lens series I have done. I recently got an intervalometer that works on my Sony s7r camera so next trip I'll do some more but mounted on a GEM and perhaps longer exposures/lower ISOs.


The Southern Cross star field. I like this one the best of the series.

http://www.pbase.com/gregbradley/image/161741221/large

http://www.pbase.com/gregbradley/image/161741221/original

The Large Magellanic Cloud

http://www.pbase.com/gregbradley/image/161741486/large

http://www.pbase.com/gregbradley/image/161741486/original

a7r, Polarie, Zeiss FE55 F1.8 at F4, several 30 seconds ISO3200,
Adobe Lightroom, PixInsight, Photoshop cc 2015.

Greg.

[DJT]

Hi Greg

Nice set but you have some horizontal banding artifacts going on here on both images. Difficult to see on the large and original but when you look at the thumbnails on your Pbase page its quite marked.

I think PI has a canon banding removal script/process if you want to have a fiddle

[Rod771]

Really nice, Greg! I really like the LMC shot , very good!

[gregbradley]

I noticed a stripe on an earlier image. I am not sure its an artifact though as this camera does not have a banding issue. I have never seen it do it regularly. Its possible but I think its more likely some either airglow or bushfire smoke in bands or perhaps a bit of thin cloud. Its not really regular or evenly spaced. I'll check the original RAWs again. I know some Canon cameras can have that issue but this is a Sony camera and the sensor is very very artifact free.

I checked the RAWs and there is definitely no banding. The little rivers of red may be air glow. I see it at my dark site a lot. I have done time lapses and you can see it dancing around like rivers in the sky. I think that may've been the weekend when that strong aurora was happening down south. Perhaps more airglow than normal. Its often green but sometimes its reddish.

I checked it out more. The slight banding (which is a bit clearer on the Eta Carina shot but its uneven. not level, varying widths, doesn't go full width of the image) is real not an artifact. I tried PI DBE, PS Carboni remove banding action - no effect. The Canon banding is even, regular and really is pattern noise of some type. This is irregular and uneven and is an air current of red airglow.

By the way what is the PI Canon banding removal process in PI called? I had a look and couldn't see one easily (PI uses big words).

Thanks for your response though. It made me check it out more as I wondered about the earlier image if it had banding.



Thanks Rod.

Greg.

[Ryderscope]

These are particularly attractive images Greg. Very nice composition. The capture and setting of the LMC image has worked very well.

[gregbradley]

Thanks Rodney. The LMC is several images stacked and then I layered in a the tree from a single image as it was blurred from stacking the tracked images. I used lighten blending mode and a hide all mask then brushed in the area of the tree.

Greg.

[RickS]

Very nice, Greg! I can't decide which I prefer. The LMC just hanging there like a jellyfish is very cool.

[Rod771]

"Canon Banding Reduction" Located in: Script / Utilities / Canon Banding Reduction.

I've used it a few times, Greg. Including my latest Helix post. The default setting of 1.0 seems to be a little too strong for my sensor, so I generally lower it to something around 0.3 or 0.4.

[gregbradley]

Thanks Rick. I plan to do another series next trip. I now have a wired intervalometer and also wifi remote control. It was cold when I took these - it was just after that big snow fall in NSW and there was still snow around.



Cheers Rod. I'll check it out.

[strongmanmike]

Lots of nice sharp stars again Greg :thumbsup: I like the LMC above the trees, different, looks cool.

Mike

[Shiraz]

I like the cross - looks beautiful against the carpet of stars. That lens seems to be pretty good!

[gregbradley]

Cheers Mike.



Thanks Ray.

Yes it is an excellent lens.

Greg.

[E_ri_k]

Nice Gerg, so many stars! I love the trees along the bottom of the LMC.
Erik

[Phoenix]

Both very nice - I particularly like the LMC image.

Cheers Steve

[gregbradley]

Thanks Erik. I knew I would get an image one day with that dead tree in it!



Thanks Steve.

Greg.

[marco]

Nice chunk of southern milky way Greg, I really appreciate these wide field images of the sky, more please :thumbsup:

Clear skies
Marco

[Paul Haese]

I agree with Marco. This size wide field looks great. I like the subtle detailing. Maybe just a little too blue I think. I could be wrong but I think there is more yellow stars in this region. Still a very nice image in any case. :thumbsup:

[Bassnut]

mmm, excellent detail, but the background is so high grey and brown dominate. A bit of level/curving bought out hidden colour and more contrast made it pop.

[gregbradley]

Thanks Marco. Its handy when its not really viable to set up all the gear.



Thanks Paul.



Thanks Fred. I'll check it out.

Greg.

[SimmoW]

Lovely Greg! That Southern Cross area shot is very nice.

Stay tuned for some of my own widefield shots taken with the A7s, I finally worked out a convenient way to mount the cam inverted beneath the scope after all this time, loving the 85mm and 200mm f/l's

[gregbradley]

Thanks Simon. I have been reading threads about the star eating spatial filtering that Sony uses on its RAWs (like Nikon uses but they toned it down so doesn't eat stars anymore). It kicks in when you use bulb. These images were 30 seconds so no star eater. The earlier images I posted were 60 seconds so they would have been affected. I think it may be an overblown issue but worth checking. I saw one image online with dark holes in the centre of stars.

I use a Losmandy D mount clamping bracket to mount my camera and also on the dovetail that sticks out the front of a scope. Or on top if the scope has a rail on top (both mine do). You can slide it that way which you need to do it using widefield lenses otherwise the scope is shown in the image!

Greg.