Triangulum Dust Clouds

I subscribed to Adam Block’s online tutorials and have been working my way through them. It’s a long, slow process. He’s incredibly thorough, sometimes painfully so, though I supposed that’s better than the opposite (skimming over things so fast you can’t follow along). So while I’m nowhere near finished with the tutorials, naturally I had to give some of the things I learned a try. Mostly this was along the lines of play with the settings for some of the processing to figure out what exactly it does. That’s slow and tedious, too, but it helps to realized that processing my images from an 85 mm focal length lens is going to be quite different than processing my images from a 250 mm focal length lens.

So, we’re back to Triangulum and the M33 region. I couldn’t help but notice that there were hints of dust clouds in the field. Years ago, I would have seen those faint smudges and concluded I had done a bad job calibrating the images and worked hard to “fix” that. I’ve come to realize that the “inky black” of space is only sort-of true. Alas, getting good images of that dust is hard and I have not succeeded here.

So here’s a do-over of the image processing from my last post. I started from the same initial RGB channel combination but then went down a slightly different path to my final images. Both have had the stars de-emphasized, which probably contributes to some of the apparent dust (i.e., it’s not completely real, it’s partially smudged stars). One has had the black point shifted so that the dust mostly disappears, the other plays games with emphasizing the stuff just above the black point to emphasize the dust.

This is 124 minutes at f/4. I’m slightly disappointed. I had seen an image in Sky & Telescope of the region from Pleiades to the California nebula which was an 85 mm (on a full frame sensor), 66 minutes at f/2.8 that has well-defined dusty lanes. That image did not specify the ISO setting, but starting around ISO 800+, most of the recent EOS line are effectively ISO-less. So I was expecting that my exposure would show similar definition. Of course, it’s not the same area of the sky, so maybe the dust is just dimmer here and I need more exposure. A lot more exposure.

The Rokinon 85mm isn’t really completely sharp at f/4. That could be a focus issue, though the stars seem pretty well focused in the images. I do have some chromatic aberration. I though I could take that out by realizing the RGB channels after the integration, but trying that didn’t show any reduction. Oh well. I’ll have to take more pictures.