The Ring Nebula M57 in a wide field (19/4/2023)

A week ago on the 19th April we had a clear night and so I set up my Celestron NexStar 102 SLT on a HEQ-5 mount. The main purpose was for me to try do some photometry of Melotte 111 (also known as the Coma Star Cluster) but towards the end of the evening I pointed the scope at a couple of other easy targets and one of these was the Ring Nebula in Lyra (which was rising in the north east). This telescope is not ideal for taking images of this planetary nebula because it is relatively small in the 2.07x1.38 degree field but nevertheless I thought I would have a go. The moon on this night was one day before new and astronomical twilight ended at 21:20 UT (22:20 BST).

 

 

M57 is the tiny blueish ellipse near the center of the field (you can click on this image to see it full size). M57 sits between two prominent stars in Lyra - beta and gamma. Beta Lyrae or Sheliak is the brightest star on this image and is to the upper right. North is up, East is to the left. The two stars of similar brightness at the bottom right are nu 1 and 2. I used Astrometry.net to plate solve this image.

This image consists of 10x30s frames at ISO 3200 taken on a Nikon D90 at prime focus (the first frame was taken at 22:42 UT and the last at 22:49). I processed these images in DeepSkyStacker (4.2.6) just using the light frames and some flat frames. The resulting image has been binned x2 and processed in Photoshop. The picture below is a crop of the original unbinned image:-

 

This shows the nebula more clearly and I liked the nice blue colour with a hint of red around the edges. The shell of gas is emitted by a dying star which isn't detected here but can be seen on deeper images. I have imaged this nebula before in 2018 using my 5.5" Orion OMC-140 Maksutov Cassegrain and I reproduced this image here below:-

Here you can see the central star as this is a deeper image (8 minutes on a 5.5 inch as opposed to 5 minutes on a 4 inch) however I think the colour on my lastest image is more accurate.

All text and images © Duncan Hale-Sutton 2023