After an extended layoff from astrophotography, the weather and the moon together cooperated for the last two nights to give me a small window to shoot the Rosette Nebula once again, this time using Optolong narrowband filters (6.5-nm bandwidth) for H-alpha, S-II, and O-III. I was able to grab 5.5 hours worth of 5-minute exposures, 22 for each filter, along with the usual dark, flat, dark flat, and bias calibration frames. This was the first image where I was able to use the new BlurXTerminator plugin for PixInsight from RC-Astro, and I have to say I was impressed with what it could do to sharpen the image.
I shot this image with the usual equipment–an ASI533MM Pro camera with the aforementioned filters through a Sky-Watcher Esprit 100ED apo refractor on an iOptron GEM45 mount. In addition to PixInsight and BlurXTerminator, I also used RC-Astro’s NoiseXTerminator and StarXTerminator. I prefer to strip the stars out before stretching and tweaking the nebula, and then stretch and add the stars back into the final image to avoid problems with star colors that can crop up in narrowband imaging. The whole image was processed using the false-color Hubble palette.