Imaging the Winter night sky


Really clear nights with stable atmosphere have been few and far between of late. Add to that the winter rarely grants us too many nights at best and it makes a recent Saturday night a rare event.

With the Southern Cross, Coal Sack, and Eta Carina all very low in the night sky it was a pleasant surprise to see stars right down to the horizon and still maintain clarity. Overhead Scorpio & Sagittarius are passing through the zenith and with Jupiter directly overhead saw me shooting a series of RAW & Jpeg images.

I’ve been slowly processing the images over the past week using a variety of tools. Namely, DeepSky Stacker, Sequator, Siril for image stacking with RawTherapee, Lightroom (trial version), Gimp and Photoscape for various parts of the image editing process. Not being well versed using Gimp produced quite the learning curve, but as I use this application more frequently I’m beginning to come to grips with it. Long time photoshop users will no doubt find Gimp very familiar.

The reason for the amount of differing image tools varies on what the end result  is expected to be. Processing the RAW files takes a different set of tools to get the most from the images and the same can be said for  processing of the Jpegs. I find that some tools are better for each of the different filetypes. There are those who will use the same tools no matter what they are processing and that is fine as well. Using free image processing tools is what we are concentrating on in this series of images and is in keeping with the Frugal Photographer ethos.

If you have access to the paid packages and you are comfortable paying  what in my view is some pretty hefty pricing then go for it, there is no right or wrong method, merely what suits your desired outcome and affordability criteria.

25 x 10 sec f4 @ ISO 1600 Jpeg files Stacked in DSS and processed in Raw therapee & Photoscape.

25 x 10 sec f4 @1600 ISO CR2 Raw files Stacked in Siril and processed with Gimp & Photoscape

 

25 x 10 sec f4 @ ISO 1600. Stacked in Sequator and processed with Gimp & Photoscape.

20 x 10 sec f4 @ ISO 1600 CR2 RAW Files stacked with Siril and processed with Gimp & Photoscape

20 x 10 sec f4 @ ISO 1600 Jpeg Files stacked with Siril and processed with Gimp & Photoscape

One of the most noticeable things when processing these images is just how much data is available in the stacked Jpeg files. The camera does a good job of color correction, distortion correction and overall detail balance in the image. This makes stacking and final processing a good deal faster than processing the RAW files.

I still feel that visually the RAW images are a little more refined but lack the visual impact of the final Jpeg edits. I have no doubt that I could with time and practice match the appearance of the Jpegs if I were to push the RAW file processing somewhat more intensely. However unless you are intending to print these images at A3 or above I have no problem with printing the Jpegs at A4 or A3 without needing to further process the RAW based images.

This is something I noticed markedly with my Fuji XA2 when using it for astrophotography. Stacked Jpeg images from the XA2 were spectacular and lacked nothing for detail, color & contrast. Given how good Fuji Jpeg files are this really comes as no surprise and while RAW files do hold a huge amount of data I suggest you ignore stacked Jpegs at your peril, you may just be missing  an important part of your astrophotography process.

I cannot however say the same when it comes to the images from my 700D. Thats not the cameras fault but rather the 18-55 STM lens while sharp over the center 50% of the lens is woeful around the periphery as can be seen by the elongated star images in the outer portion of the images. Not a good lens for this type of work. It is at best adequate and if you like me haven’t anything better then it does suffice, and in reality I shouldn’t grumble too much.

I only have to step back 30 years to remind myself that I would never have dreamed I could take images such as those above with what is a pretty standard entry level camera and kit lens. We have certainly come a long way in the past few decades.

Happy Snappin’

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