Finding Neptune

5 September 2019, 21:30 – 00:15 BST

Conditions: a near first-quarter moon low in the southeast ruled out observations in that part of the sky. A few small clouds passing overhead, air cooling noticeably, otherwise good for observing.

Albireo, double star, Cygnus
At 92x in the 13mm Ethos this presented as a golden primary and pale blue secondary suspended in a sea of stars. This might be the most beautiful view I’ve ever had of Albireo – certainly one worth savouring.

NGC 7027, planetary nebula, Cygnus
Revisiting one of last year’s targets. In the Ethos it resembled a defocused star. At 240x with the OIII filter it was very bright with a tantalising hint of structure. Quite small.

NGC 7039, open cluster, Cygnus
Looks good in the Ethos. A rich band of stars framed by a rhombus of brighter stars. Not far from the North America Nebula.

NGC 7048, planetary nebula, Cygnus
Just visible without the filter at 92x as a faint smudge of light with a star to the west. In the OIII it appeared as an elongated cone of light with a star at the apex. Unusual shape for a planetary nebula, but I think the star probably caused it to appear more distorted than it really is.

NGC 7000, North America Nebula, Cygnus
With the Ethos and the OIII filter, the “gulf coast” region of the nebula was clearly visible as a milky glow, resembling a large question-mark melting into the starry background. I didn’t think I’d be able to see it as well as this in the XT10.

M2, globular cluster, Aquarius
At 240x, the asymmetry noted before appears to be caused by two wings of stars sweeping back towards the west. The foreground star on the eastern side of the cluster seems to sit in its own pool of darkness, adding to the asymmetry. The cluster resolved really well with averted vision.

M15, globular cluster, Pegasus
Also observed at 240x. Member stars brighter than those of M2. Long loose “tail” of stars to north. Bright, dense core. The (rare) opportunity to view these globulars multiple times over the course of a fortnight really makes a difference – the more you look at them, the more you see.

Neptune 
Helpfully very close (maybe a little too close) to 4th magnitude Phi Aquarii, so (unlike last year) very easy to find. Viewed at 240x (5mm Nagler) and 333x (9mm Nagler + 2.5x Powermate). I need to try this again when the seeing is better, but Neptune was a tiny blue-grey disk (like a defocused star), contrasting nicely with the orangey-red Phi Aquarii. No sign of Triton.

M30, globular cluster, Capricornus
Small condensed blur, very low in the sky (-23 degrees declination). Bright leading star to west. Amazingly, with averted vision I could begin to resolve the cluster despite its low altitude: the most prominent features were a straight line of stars to the north and another fainter one (not radial to the core) to the northwest, giving the cluster a very distinctive lopsided, spiky appearance.

Just for fun, I also viewed M57 and M27 at 333x. Despite being on the light-polluted side of the meridian the Ring Nebula looked rather impressive at this high magnification (like a black-and-white photo); the Dumbbell not so much (it's large enough already that it doesn't really benefit from the extra power). But it's good to know I can use this magnification on some deepsky objects.