Dabbling in astrophotography without HDR-capable software is like baking a cake using a firelighter. Fortunately, a new version of Luminance HDR embraces the full dynamic range of the deep space scenery.

Newly released Luminance HDR 2.4.0 features a FITS importer accessible from the Tools menu. The importer suggests a slightly unorthodox workflow:

load three FITS pictures taken for different wavelengths as R, G, and B channels;

let Luminance HDR merge them;

use a color mixer to tint each source image/channel and preview your changes;

build the final HDR file and do the usual LDR tweaking.

You can also drop two more images into the channels mix: one for the Luminosity channel, and one taken in 656,28nm wavelength (H-alpha). The latter could be of interest for e.g. Canon EOS 60Da users (or, should we say, PR victims?).

While FITS support in Luminance HDR makes a perfect sense, once you try the actual implementation, you'll see that it still needs more work, especially in the usability department:

Of course, there just should be some way to tint each source image to produce a colorful HDR rendering, but color mixer might be a bit of an overkill.

be some way to tint each source image to produce a colorful HDR rendering, but color mixer might be a bit of an overkill. Actual color mixer UI eats screen estate like a flock of hungry langoliers; something vaguely GIMP/Photoshop-like would be more UI-frugal.

As the result, the HDR preview is way too small to make any sensible decision on mixing colors.

Moreover, the HDR preview at the color mixer stage is often completely/mostly black no matter how much you raise exposure, but at the same time, LDRs often end up looking so wrong that you have to rebuild your HDR just to tweak color mixer settings (this is all based on trying FITS images from the Chandra X-Ray archive).

Also, even moderately-sized FITS files easily crash Luminance HDR. Hopefully, this is just the beginning, and the next release will be a lot more forgiving.

The other major changes are auto antighosting, as well as optional exporting of 32bit float TIFF files (GIMP from Git master doesn't read those yet, but handles 16bit ones just fine).

If you feel like building Luminance HDR from source code you'll need Qt5 development tools, as well as LibRaw and LittleCMS v2. If you are a Windows or Mac user, you'll find download links in the release announcement.