The Bubble, Cave and Lobster Claw Nebulas

This is a rich region for star clusters and nebulas on the Cassiopeia-Cepheus border: The bright open star cluster Messier 52 is at upper left, and below it is the Bubble Nebula, NGC 7635. Below the Bubble is the aptly named Lobster Claw Nebula, Sharpless 2-157 showing subtle shades of red and pink. The small bright nebula to the right of the Bubble is the unnamed NGC 7538. The large nebula at upper left is the Cave Nebula, Sharpless 2-155. However, the entire field is filled with faint nebulosity as well as small intense red patches. A small yellowish star cluster at lower right is NGC 7419. This is a stack of 10 x 8-minute exposures through the William Optics RedCat 51mm f/4.9 astrographic refractor with the red-sensitive Canon EOS Ra camera at ISO 800, and blended with a stack of 4 x 15-minute exposures through the Optolong L-Enhance narrowband filter, with the EOS Ra at ISO 3200, to make up for the nearly 3 stops loss of light from the filter. But it really pops out all the faint nebulosity. This was the first use of the add-on filter drawer from Starizona, which facilitates adding and removing a 48mm filter into the light path without having to remove the camera and risk field rotation. It worked very well. Guiding was with the Lacerta MGEN 3 stand-alone autoguider, which also controlled the camera shutter and applied dithering of 10 pixels between each frame to reduce thermal noise without having to apply LENR in camera or dark frames. However, the temperature was -16° C this night so thermal noise was likely low anyway! But the dithering doesn’t hurt! All images were stacked, aligned and mean combined in Photoshop with the filtered set blended with a Lighten blend mode. Taken from home November 12, 2020, using the Astro-Physics Mach1 mount.