M52 Area in Cassiopeia, taken August 15, 2007 from home. Stack of 3 x 4 minute exposures at ISO800 with Canon 20Da and 135mm L-lens at f/2.8. Field equals 7° bino field. Bubble Nebula (NGC 7635), NGC 7538, and Sh2-157 in field.
A collection of bright star clusters and colourful nebulas on the border of Cassiopeia and Cepheus. The prominent star cluster at left is Messier 52. The emission nebula to the lower right of it is NGC 7635, aka the Bubble Nebula; above and to the right of it is the small but intense nebula NGC 7538. At upper right of the frame is Sharpless 2-155, aka the Cave Nebula. The diffuse nebula at bottom is Sharpless 2-157, aka the Lobster Claw Nebula, with the small star cluster NGC 7510 near the end of one of its claws. The small star cluster at lower right made yellow by interstellar dust absorption is NGC 7419. This is a stack of 8 x 8-minute exposures through the Borg 77mm f/4 astrograph and with the Canon EOS Ra red-sensitive mirrorless camera, at ISO 800. Stacked, aligned and processed in Adobe Camera Raw and Photoshop 2020. No nebula or light pollution reduction filter was employed in taking the images. I shot this from home November 25, 2019 on a very fine if frosty autumn night. No special star masks were employed in processing to enhance star colours or process them separately.
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.
