Double Stars and Double Clusters

16 September 2018, 22:00 – 00:00 BST

First quarter moon adding to the light pollution in the south-west, but at least the seeing was good.

M15, globular cluster in Pegasus
Examined at all three available magnifications. The sky background was too bright to resolve stars at 50x; there was an improvement at 133x, but on this occasion the best view came at 240x – pleasing contrast, lots of faint stars resolved.

Veil Nebula, supernova remnant in Cygnus
Hindered a little bit by moonlight, but with the Ultrablock to filter most of it out, plenty of detail still visible. The nebula had a winding, braided structure. Brightness held up well at 133x with the two main arcs extending across several fields of view. Pickering’s Triangle suspected, but not confirmed – if so, it was right on the threshold of visibility.

A quick tour of the open clusters in northern Lacerta was a little disappointing. The sky was too bright to do justice to the 24mm Panoptic, and at 133x the field of view was too small to properly frame the clusters. For the most part, they just looked like sparse associations of bright stars.

A similar tour of the Cassiopeia clusters at 50x fared better due to the richer clusters and the darker background in that part of the sky. An intermediate magnification might help with some of these NGC clusters.

Eta Cassiopeiae, double star 
Looked very nice at 133x, with the secondary appearing to have an unusual purple hue.

Double Cluster in Perseus
The red giant stars stood out more at 133x, but the two clusters lose some of their impact at this magnification. However, higher magnifications might be useful for separating close pairs and picking out fainter cluster members at 240x.

The following observations were all carried out with the Ultrablock filter.

M76, planetary nebula in Perseus
Holds brightness very well all the way up to 240x. Bi-lobed, boxy shape, with the brighter lobe appearing almost rectangular. No colour apparent. Prolonged examination suggested one or two knots/condensations within the brighter lobe.

NGC 404 (Mirach’s Ghost), galaxy in Andromeda
Only a quick look, but this little galaxy showed up surprisingly well. It seemed the Ultrablock dimmed the glare from Mirach more than it dimmed 404, but I’ll have to try this again without the filter to verify.

NGC 604, emission nebula in M33, Triangulum Galaxy
Perhaps it stood out a little more through the filter, but the difference seemed marginal at best.

NGC 1491, emission nebula in Perseus
I actually meant to look for a different nebula, but this one stood out surprisingly well as an extended misty patch with a single reasonably bright star offset from the centre. Suggestion of mottled structure at higher magnification. Faded smoothly into the background sky, unlike some of the nebulae I’ve been looking at recently.