The recent high pressure has led to increasingly murky nights and tonight was no exception. It looked ok as dark fell and there were no light domes visible so I set up. Unfortunately, this state of affairs didn’t last, as it got murkier and high clouds moved in, so it ended up being a much shorter session than intended.
I had intended to spend the session in Ursa Major but the combination of the ‘dob hole’ and high clouds prevented it.
Date: 25th April 2011
Conditions: Clear at first, slight breeze picked up later, slight haze, mild (11C, only needed a hoodie and observing vest on). No Moon. Conditions deteriorated badly less than an hour later, cutting the session short.
Transparency: III to V (started out okay but deteriorated badly)
NELM: started out as 6.0 but got worse thanks to increasing murk and light scatter.
Equipment: 12″ f/5 dob, 22mm Televue Panoptic (69x), 15mm Televue Plossl (101x), 11mm Televue Plossl (137x).
NGC 3726, galaxy in Ursa Major – Large, oval (not quite round) diffuse halo with a stellar core. Oriented north-south, with an 11th mag star on the northern end. 69x, 101x.
NGC 3675, galaxy in Ursa Major – Bright, almost edge-on. Elongated north-south. Brightens to an extended core. A scattering of mag 11/12 stars lies just to the west and a 12th mag star lies on the southern tip. 69x, 101x, 137x.
NGC 5466, globular cluster in Bootes – Faint and large. Dense. With averted vision some stars are resolved with others giving the whole thing a ‘granular’ appearance on a background glow. 69x.
|NGC 5466 in Bootes. Image from http://www.sdss.org/ in accordance with their image use policy (i.e. I haven’t just nicked it!)
NGC 5557, galaxy in Bootes – Fairly bright and round with a bright core. 69x, 137x.
By now, the conditions had deteriorated so much that, after just three quarters of an hour and a meagre four objects, I had to pack it in and call it a night. The sky just got murkier and, in the end, it was impossible to continue with any sensible deep sky observing. It was disappointing as I was hoping for two or three hours, but 45 minutes is better than nothing.
We’ll soon lose our dark skies for the summer as, from late May onwards, astronomical twilight lasts all night with no true darkness until late July/early August. I intend to carry on observing throughout, weather permitting, but I will go back to sketching the brighter stuff, something I have neglected recently as I have preferred to concentrate on seeing as much as possible because sketching is time-consuming so I get through fewer objects.
I’m off on a cruise on Friday, a four day trip on Royal Caribbean’s Vision of the Seas from Southampton to Copenhagen via Amsterdam. I am taking my binoculars so, if the sky is clear, I’ll do some binocular observing from any dark spots on the ship’s deck I can find. Unfortunately, cruise ships tend to be lit up from just aft of the bridge to the stern and from the waterline to the wheelhouse roof so I don’t have high expectations – either for darkness or clear skies! Hopefully by the time I get home next week, some thunderstorms and rain will have cleared out the atmosphere a bit.