Call (802) 651-4100

Mark's AP Corner - 03/18/2012 - NGC2244/46 - The Rosette Nebula

NGC2244/46 - The Rosette Nebula

NGC2244/46 - The Rosette Nebula

I had a chance to get set up for the night of 3/18 for about half the night. Clouds started to take over at around 11:30pm and I remained positive and stuck with it until 2:00am, at which point I could see flashes of lightning off in the distance. Time to pack up the lightning rods! Before that all happened, I was able to get some time on an object I hadn't imaged since February of 2011. I was hoping for at least 3 solid hours of shutter time on NGC2244. Unfortunately, for some reason, I was having guiding issues from the very beginning of the night. It's been a very long time since I've had any issues of any kind with autoguiding. Things sort of ironed themselves out over a period of time, but I ended up throwing out about half of the data I had captured due to trailing stars. I'm already on to solutions, and a new guide scope ships tomorrow.

I shot in ISO800 Sunday night because it was pretty hazy in Waterbury for most of the evening. As the sun was setting, I could see the low hanging reddish/brown through the valley that's a good indicator that there's going to be some interference, and I know from experience it's going to show up in the frames pretty easily. I used a short 30 second Custom White Balance (CWB) for all the frames in order to get a more isolated color balance on things and it seemed to work pretty well in dealing with sky glow. The CWB is a regular practice to deal with the night-to-night varying sky conditions. It's too bad I had to toss half of the frames out due to autoguiding issues...that was rough. You win some, you lose some in this hobby. Luckily all was not lost and it ended up being a worth while night.

Considering that I knew I had some usable frames from the Rosette last year, I decided to combine both nights and come up with an image of greater dynamic range. Last year's attempt was a little flat in terms of color, and I over-edited to make up for it. But seeing that it was generally good data, it could still be used with the new stuff from Sunday night. On Monday, I combined the files in a folder, moved them over to another machine, loaded up all of the noise calibration frames for both ISO settings, started the process, and walked downtown to go eat lunch as I knew I wouldn't be looking at a workable image for about 45 minutes.

When I got back, I saw the screen and was immediately pleased with the straight-out-of Deep Sky Stacker initial image. I started with boosting the saturation and fine tuned the histogram to properly balance the RGB levels and was looking at a decent image for the two nights. After levels, and shifting the output midpoint ever so slightly with CS4, I opened the image in Nebulosity 2 for very minor star sharpening. Not too much, or it makes dark circles around every star. There's a very comprehensive plugin within Neb2 that's called GREYCstoration, and with some adjustments, you can coax some details out of the information there that otherwise wouldn't have been quite so 'defined'. Instead of the eye wandering, being attracted to noise from the camera, it tends to move more seamlessly from detail to detail with only a minimal amount of information missing. Without it, noise replaces those details and the eye tends to gravitate towards the noise and the image looks too busy. It's a powerful yet delicate plugin to use that can either make an image look twice as good, or over average the details and then it looks like you're peering through a frosted glass shower door. I try and keep on the lighter side of averaging and let the eye make the choice between what's noise and what's part of the object. This was a short edit by normal standards, which mainly has to deal with getting good data when things are actually going right.

All of the images in this article were taken by Mark Byland and are his property. Please do not copy or distribute these images without his sole permission.

Leave a Reply