M45, Pleiades (7 Sisters)

Mar 2021

Imaging: ST120 achro, Canon 1000D 400ISO, no filter & LPRO
Subs: 182x120s NOFILTER + 103x120s LPRO (9.5h), bias, darks, and flats
Processing: PixInsight

(Additional notes below)



It is now galaxy season for astro photography. Unfortunately, all the available ones are either north or east where I have no visibility. Those will have to wait until later in April. Without anything to image, I decided to make my third attempt at M45, the Pleiades. This time I was hoping to capture the full nebulosity as I did it "right" this time with proper centering, guidng, many more hours of imaging, and full processing in PI. I started imaging without any filter as this is a broadband target. I got about 6h of data this way but I had a lot of trouble with gradients. For fun and giggles, I then collected an additional 3h of data using the LPRO filter to see how much of an effect that would have. It was unclear whether this would help or hurt as this cuts out a good chunk of signal which some experienced imagers claim is totally wrong for this type of target. In summary, I didn't see a significant difference between using no filter and using the LPRO on this target.

In the end, it is a better picture than my previous attempt but not by much. You can see the comparison on the Progress page. The background is much better and there is some more nebulosity. But I would have expected much more of an improvement going from 2.1 to 9.5 hours of integration.