Salisbury Plain - last weekend

[gliderpilot]

14 November 2009

Tilshead Salisbury Plain

2030-2300

8.5” Dobsonian and 15x50 IS binoculars

Mark Radice & Jon Gale, Salisbury Plain Observing Group

Our third SPOG observing session was scheduled for the Friday but was postponed to allow the high winds and rain to pass. Jon Gale had prepared a list of “hidden treasures” for us to follow, some I had seen and some would be new so I was looking forward to an observing challenge.

The first one to arrive, I setup the scope under dark, clear skies that had been washed clean following the recent rain. First thing in the scope while my eyes adapted to the dark was Jupiter, now getting quite low against the horizon. Four moons were visible but the disc was featureless, other than the two equatorial bands and fringed by red and blue atmospheric refraction.

I also tried for the Helix Nebula but the low level murk defeated me again – the Helix is supplanting the Veil Nebula as my new nemesis!

Jon had arrived at this point so while he set up the 6-inch newtonian, I star hopped to M74, a large spiral galaxy in Pisces that is notorious for its low surface brightness. Although it was readily found, it appears as an extremely dim glow with none of the spiral details of, say M31 or M33. I stupidly forgot to check to see if it was visible in the binoculars and will need to check next time it is clear. Luckily Steve O’Meara’s sketch in his Messier book, made over several nights from 7,000’ in Hawaii, shows only vague hints of spiral structure so I don’t feel too bad!

I had recently noticed a “nebulous patch” with the naked eye, midway between Triangularum and Andromeda. A reference to the Pocket Sky Atlas showed this to be NGC 752. This rich open cluster is quite magnificent in the binoculars with a bright arc of stars wrapped around the southern edge and well worth a sketch next clear night.

The scope was then moved across to M33 which is becoming an autumn favourite now that I have upgraded from a 4-inch refractor to a homemade 8.5-inch dobsonian. Faint mottling and hints of the spiral structure can be seen. I think that I need to really sit down and study this for an hour or two to see what details can be picked up with a variety of magnifications.

Next object on Jon’s list was NGC 891, an edge on galaxy midway between Perseus and Andromeda. Although I had seen NGC 891 before, my notes show that I had attempted to observe this on several nights but had been defeated by moon glow, cirrus, dew and anything that dimmed the sky even a fraction. This time, I found it to be a real swine to star hop to as there is practically no stars to use as a reference. I tried moving from Gamma And and got lost so I tried again from Algol via M34 and got lost again. Unfortunately it also began to cloud over at this point so I performed the classic act of checking the star atlas and wondering why it didn’t match the finder scope before realising that the stars were fading away!

The last patch of sky to be clouded over was Gemini so a quick look at Castor showed a much fainter secondary star confirming its double nature.

A quick brew from the thermos and the sky cleared quite suddenly again. Having got frustrated with NGC 891 and preparing to accept a temporary truce, I moved on to the next objects on the list: NGC 1528 and 1545, both open clusters in Perseus. I had stumbled across NGC 1528 through the binos while exploring Perseus during the Comet Holmes outburst. I did have that 10 seconds of elation before realising that the chances of two bright comets in a few degrees of sky was quite slim, a logic that was confirmed by the star atlas.

NGC 1528 is quite stunning in both the binoculars and the telescope especially as it is set against a rich part of the sky with many background stars. NGC 1545, however, is quite disappointing. It features a group of ~10 or so stars forming a crude pentagram however it is so sparse that it would be easy to scan right over it – especially with NGC 1528 immediately alongside.

Unfortunately the skies really did cloud over at this point and even a second brew from the thermos failed to make them clear. I guess Jon and I were lucky to have even two hours of observing when last weekend’s forecast is considered. NGC 891 and the Pacman Nebula would have to wait for the next clear moonless night.

Clear skies,

Mark

[arad85]

Sounds like you had a good couple of hours Mark