Working with Star Tools – From Nikon D7100 to DSS to ST

[redarmy27]

Good morning everyone,

I’m relatively new to astrophotography but have been a photographer of terrestrial objects for a few years now. Even since I was a little boy, I’ve always been fascinated with astronomy and anything that is far above our heads. I decided to take the plunge into astrophotography and bought myself an Ioptron Skytracker.

So far I’ve managed to get some good shots of galaxies and even comet Lovejoy, but I feel I could improve my images with Star Tools. My images feel too blocky and over-processed.

The Orion Nebula:

http://www.captureminnesota.com/photos/1658443

Comet Lovejoy:

http://www.captureminnesota.com/photos/1655678

My normal routine is to shoot light frames, dark frames, and bias frames (all in raw: Nikon NEF) and then import them into my computer to be stacked with Deepskystacker (DSS). I made a discovery: DSS does not like the size of my NEF files. I tried numerous times to stack my shots, but it’d always run out of memory despite my computer being built for intense photo processing. I tried many different settings (and yes, I left the dreaded drizzle off!) with no avail until I did some research on the cameras other people were using. I discovered that since I use a Nikon D7100 24 MP camera shooting 6,000 x 4,000 size files, it was essentially slogging up DSS. I remedied this by first going to Lightroom, converting the files to a 16 bit Tiff, and then resizing to 85% of their size and then importing them into DSS.

From DSS, I then moved the image to Star Tools and failed miserably because the data was getting compromised. With the help of Ivo Jager (who’s been nothing but awesome in this), I discovered the conversion process was messing with the stretching and color balance of the files. So last night, I used a different converter (Nikon’s own converter/ resizer since Dcraw is a bit foreign to me despite my efforts), resized the NEF files to 16 bit Tif files at 85% of their size and created the following composition in DSS. I left as many addons and settings off in DSS as possible in the best effort to ensure that Star Tools has good virgin data to work with.

Would this file work? (Google drive of my latest Orion stacked image straight out of DSS)

https://drive.google.com/file/d/0B69PoC ... view?pli=1

I invite any of you to try with it and see if you’re successful as I’m pretty new at manipulating images in Star Tools. I’ve read the guides, but I’m not all that sure where to begin and I end up with some funky effects in the program. If you’re successful, I’d appreciate some guidance on the image as I’ve seen some great shots done around here. I’m used to working with Photoshop a bit, but I don’t feel as precise as I could be as if I were to be using Star Tools.

If the image is still over stretched and compromised prior to being processed, do you have any guidance? What can I do to convert the file better? If the data is good prior to stacking, what settings in DSS work the best? DSS has been a pain to work with at times, but I like it since it’s free and relatively easy to use. I guess the part that’s throwing me off is the resizing of the images to be compatible with stacking.

Any guidance on the best ways of getting my information stacked and then into Star Tools would be much appreciated. It’s a little overwhelming is all since I’m used to portraits and landscapes! Any tips or advice on how to transform the stacked image above into a great image would be wonderful. I’m eager to learn.

Thank you all very much in advance! I can’t wait to get better with my processing and my results!

All the best,

Jake

[admin]

Hi,

I had a look at the data. The data still appears stretched (but better than the data you previously shared with me). If you can't get DSS to stack your NEF files directly, your best bet is really to use dcraw. The Nikon file converter does all sorts of filtering and stretching to 'pretty' up your image for terrestrial use, but makes a number of things hard or impossible (including color calibration, detail recovery and deconvolution). Avoid!

Also in DSS, turn off RGB Channels Calibration and turn off Per Channel Background Calibration.

For dcraw, try

Code: Select all

dcraw -v -r 1 1 1 1 -4 -T -q 0 -k 0 -o 0 *.NEF

or

Code: Select all

dcraw -v -r 1 1 1 1 -4 -T -h -k 0 -o 0 *.NEF

for quarter resolution.

I'm not trying to be difficult! It's very important to get your data right before you start post-processing. This stuff is quite different from terrestrial photography...

[redarmy27]

No, I get it , I'm just having a bit of an issue trying to get dcraw to run on my pc at the moment. I moved the NEF files to the main directory (windows) and it continues to read "No such file or directory".

I'll keep putzing with it.

Any suggestions?

Jake

[admin]

No, I get it , I'm just having a bit of an issue trying to get dcraw to run on my pc at the moment. I moved the NEF files to the main directory (windows) and it continues to read "No such file or directory".

I'll keep putzing with it.

Any suggestions?

Jake

Sounds like it can't find dcraw.exe? (though it's been over a decade since I last used a Windows )