Quick naked-eye report, and a bit of darkness quality

[Captain Scarlet]

Lately, I’ve been given a SQM-L darkness quality meter, and have nipped outside every night it’s been clear since I got it, happily collecting data. On its Atlas 2015 simulation of darkness-at-zenith, lightpollutionmap.info shows my back garden as a 19.04, so I was quite pleased to note that at 2330, when the Moon was 4-5 degrees below the horizon and at 36% phase, my meter showed 19.13 over several readings. With my neighbour’s new searchlight just nearby too.

In due course I plan to see how well its readings correlate to Moon altitude and phase, and perhaps also take zenith shots with a DSLR out to see how a supposedly much more sophisticated metering system (is it?) compares.

Friday morning is my area’s refuse-collection day, so bins etc have to go out on Thursday evening. Normally, I take the other sort of bins out with me too if there are any gaps in the cloud, though inadvertently last night I forgot – it was naked eye only. Nonetheless I was pleased and surprised to find the whole of Orion reasonably well up in the South, first sighting this season, and thence the Hyades and Pleiades. I’m almost sure I detected through averted vision, M31. Trouble is I know exactly where M31 is, by loosely following the widest “arrow-pointer” of Cassiopeia, so it may well have been my mind playing tricks. I was also just about able to detect Eps UMi, the second star from Polaris in the Little Dipper, which is normally totally invisible to me. I've come to recognize and really like Mirfak and its streaked-out scatter of stars in Perseus - does this extended streak of stars count as an open cluster, notwithstanding it comprises the shoulder of the main asterism?

Anyway, a nice few minutes in spite of no optical equipment. Ideally on a night like that I'd grab-and-go my Mak 127 but I just can't handle the tiredness next morning on a "school night".

Cheers, Magnus

[Waddensky]

Thanks for sharing, very curious to see the results of your measurements. I take readings using my SQM-L for quite some time now on different observing sites. Very interesting to see day-to-day variations and the effect of moon phase and twilight.

Mirfak and its neighbouring stars are a real open cluster, also known als Alpha Persei Cluster, Melotte 20 or Collinder 39. A beautiful sight naked eye or using binoculars. Is about 550 light-years distant.

 

[Ludd]

I was out for about 45 minutes last night, also with no optical aid, and although there was a lot of twinkling, I thought the transparency was unusually good out in rural Buckinghamshire. 

It may of course be due to it being very high in the sky at the time, but I'd never seen quite so clearly with the naked eye how huge M31 is - it looked almost as if a chunk of the milky way had come loose and lodged in Andromeda.