November 21, 2024

Archives for November 10, 2021

NGC 7789 – Open Cluster in Cassiopeia

NGC 7789 – Open Cluster in Cassiopeia

Telescope: LXD75 SC8 @ f/6.3, LX65 mount, altaz mode

Camera: Baader modified Canon 600Da, interval timer

Filter: GSO IR Blocking Filter

Guide scope: None

Exposure: 38x10sec, ISO 1600, saved as RAW

Darks: Internal (Long Exposure Noise Reduction On)

Flats: 32×1/25sec, Tee shirt flats taken at dusk

Average Light Pollution: Red zone, Bortle 8, poor transparency, moonlight

Lensed Sky Quality Meter: 18.6

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: Deep Sky Stacker, Nebulosity, Photoshop

NGC7789 is a large and wonderfully rich open cluster located just west of Cassiopeia. It was discovered by Caroline Herschel in 1782 and is sometimes called Caroline’s Rose. It is a delicate object in small to moderate scopes, but blossoms into a rich field in large telescopes. When viewing this cluster I like to spend some time with the field. At first all I will see are the foreground stars and perhaps a soft glow in the background. As my eye adjusts, the first faint stars appear, and then it slowly blooms into a beautiful patch of stardust.

This is one of a series of images that I have been taking to explore using relatively simple equipment and techniques. This is the second time that I imaged this cluster using this system. The sky conditions were much better on this evening so I decided to give it another shot and I’m very happy with the results. Not bad for 10 second exposures with an altaz mount.

Caroline’s Rose is currently well placed in the northeast at sunset.