Exploring Delphinus

1 September 2019, 21:30 – 01:00 BST

A cold night, and too breezy for imaging. Instead, for a change, I put the TV60 to use as an observing scope while the XT10 cooled to ambient temperature.

Transparency: not as good as 30 August
Seeing: Good to begin with, but worsened as the night progressed.

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TV60 + 24mm Panoptic (15x)
It’s a treat to just ramble along the Milky Way at this magnification, but the most noteworthy observations came when I added the OIII filter:

Veil Nebula, supernova remnant, Cygnus
Both arcs were visible (albeit faintly) in the same field of view. (This wasn't a surprise to me as I'd already tried this some years ago using the Ultrablock filter, although my notes from that time state that the western segment 6960 was only just on the threshold of visibility.) I think from a really dark site, Pickering’s/Fleming's Triangle might even be possible with this combination. Something to bear in mind perhaps the next time I take the TV60 on holiday.

NGC 7000, North America Nebula, Cygnus
Large and prominent at this magnification, and the OIII filter confirmed it as clearly nebulous in nature and not just a star-rich section of the Milky Way. The brightest section was the part adjoining the “Gulf of Mexico.” (Again, this replicated an observation made some years previously using the Ultrablock filter.)

NGC 281, Pac-man Nebula, Cassiopeia
Showed up well as an amorphous little glow, albeit devoid of detail.

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Other observations for the night were carried out with the XT10, using (unless otherwise stated) the 9mm Nagler (133x).

NGC 6716, open cluster, Sagittarius
Tight, boxy little cluster, shaped a bit like a backwards “2”.

Cr 394, open cluster, Sagittarius
Sprawling cluster, larger than 6716.

NGC 6818, Little Gem Nebula, Sagittarius
Tough to find (in a bright part of the sky with no naked eye stars nearby), but when I did track it down, it presented as a bright little disc, becoming even brighter with the Ultrablock filter (the OIII was still on the TV60). Prolonged examination revealed a dark core – a typical summer planetary. I also looked for the nearby Barnard’s Galaxy, but (as expected) it was hopelessly lost in the light pollution.

M75, globular cluster, Sagittarius
Grainy little fuzzball, washed out by light pollution. No stars resolved. Seemed quite small compared to other globulars, but perhaps I was only seeing the core region.

NGC 6934, globular cluster, Delphinus
Another grainy, unresolved glow. Appeared to have a slight bluish tinge. Bright field star to west.

Gamma Delphinus, double star
Impressively bright and close double star with an equally close (but fainter) pair of stars to the north. Reminiscent of Epsilon Lyrae.

NGC 7006, globular cluster, Delphinus
Faint round glow, brighter towards centre, but lacking the grainy appearance of the previous two globulars viewed tonight. Looked more like a comet than a globular cluster.

M72, globular cluster, Aquarius
Weak round glow, very faint for a Messier globular.

NGC 6891, planetary nebula, Delphinus
Very small disc of light, almost stellar (which explains why I overlooked it on 25 August). Needed the Nagler 5mm (240x) plus the Ultrablock to confirm its nature. Seemed slightly elongated at high magnification.

Couldn’t find NGC 6886 (I’m guessing it’s even tinier than 6891), but NGC 6905 (the Blue Flash Nebula) showed up well at 240x. Smoke ring of asymmetric brightness sitting in a triangle of stars.

NGC 185, galaxy, Cassiopeia
An exercise in frustration (the sky conditions didn’t really justify the amount of time I spent on this and 147), but eventually I located NGC 185 (one of M31’s outlying satellite galaxies). Soft round glow – very faint and featureless. No sign at all of NGC 147. Not a night for faint galaxies.

NGC 7293, Helix Nebula, Aquarius
A little more washed out by light pollution / poor transparency compared to Friday, but still impressive. With the Ultrablock I could make out several field stars surrounding the helix.