Results: Astrophotography with the D800E

Started Jul 20, 2012 | Discussions thread
RicksAstro
RicksAstro Veteran Member • Posts: 3,718
Re: Results: Astrophotography with the D800E

Very excellent images...makes me want to get out there with my D800E!

Here is a handy program that may help you:
http://www.rc-astro.com/resources/GradientXTerminator/

It's a Photoshop plug-in. You select what should be all the same color neutral background (basically de-select bright Deep Sky Objects and trees and even bright stars) and it removes the lens and sky gradients and you can have it neutralize the sky color as well. It works really well once you get used to how it works!

For selecting ISO, my method has always been to expose as long as I could without streaking and then set the ISO such that the histogram shows the sky background is just detached from the left side of the histogram, so you know you aren't clipping the sky background. Contrary to popular belief, you need all the dynamic range you can get with DSOs and stars and with these very low read noise cameras these days, it's better to use lower ISOs and stretch things a bit using curves than to use the higher ISOs.

I would definitely use good stacking software that supports TIFFs or NEFs. The D800E is so new that it may not be supported, although programs like Maxim DL can ofter open up the RAW file even un-demosaiced, which is ideal for calibration (dark frame subtraction, flat fielding...). You can also use a program like DCRAW in "document" mode to create 16 bit linear B&W TIFFs and then use software like maximDL or Nebulosity for calibrate, demosaic and stack them using floating point during the stacking process. You should not stack JPGs.

Good stacking software has options like Sigma combining where it throws away stray outlier pixels when stacking multiple images. I found with low thermal noise cameras, it was more valuable to take more images for Sigma stacking than it was to spend more time taking dark images. You ended up with higher S/N images overall even without dark frame subratction.

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Rick Krejci
http://www.ricksastro.com

AnakChan wrote:

Thanks to @Robin Casady, @JC1306, @bendak, @chili5555, @Astrophotographer 10, & @TheRidgeback for their guidance.

Here's the draft results of my 1st attempt at digital photoshoot with my D800E. I have done long exposure with film Astrophotography back in the 80's, and lunar photography with my older D-SLR, but this was my 1st time doing proper long exposure D-SLR and with a tracker.

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