Orpington Astronomical Society

Astronomy => Alerts! Questions? Discussions... => Topic started by: mickw on Jan 21, 2012, 09:10:37

Title: Star count 2012 - Friday 20 - Friday 27 January
Post by: mickw on Jan 21, 2012, 09:10:37
The Campaign to Protect Rural England is doing another sky survey to assess light pollution - Assuming you can actually see the sky  :-?

What it's about (http://www.cpre.org.uk/what-we-do/countryside/dark-skies/update/item/2666-star-count-2012?dm_i=6A4,O6TM,41UQDI,1YBB9,1)

Cut to the survey (https://www.surveymonkey.com/s/starcount-2012?dm_i=6A4,O6TM,41UQDI,1YBKZ,1)
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: Rick on Jan 21, 2012, 14:52:35
It's this week, so if you get a chance, go out, count, and get some data in, please!
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: mickw on Jan 23, 2012, 20:43:43
Grand total of 9  :(
SQM 17.9
Dulwich
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: MarkS on Jan 23, 2012, 21:18:42
9:15pm
22 stars (excluding the 3 belt stars)
SQM 20.62
High Halden
The sky is continually improving, so I'll try again later

Mick, you've got all this to look forward to!!

[Later edit:  The SQM later improved to 20.65 but I couldn't see any more stars.  Filled out the CPRE survey.]
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: Rick on Jan 23, 2012, 22:39:42
Trinity School, Croydon, 21:50. Grand total of... five. Including the belt stars.

My garden, Orpington, 22:10. Grand total of... eleven, likewise.
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: mickw on Jan 24, 2012, 11:45:43
QuoteMick, you've got all this to look forward to!!

:D
Title: Last Night Skies..
Post by: JohnP on Jan 27, 2012, 09:17:09
Mark - did you get a chance to take any sky quality readings last night? Just curious as I was walking back from Indian around 10'ish & although blustery the sky looked very good (at least for Bromley) - I counted at least 7 stars in Orion....

John.
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: Rick on Jan 27, 2012, 09:19:54
Bother.  :bug: Clean forgot to count the stars after the meeting last night.  :bug:
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: Rocket Pooch on Jan 27, 2012, 09:28:43
Well when I got home at 11pm it was fantastically clear and there were tons of stars all over the place, probably the best night I've seen for ages.
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: MarkS on Jan 27, 2012, 09:30:06
I did so in the lower car park at High Elms (the one away from the lights).
15 stars (excluding the belt)
SQM reading 19.45
Time 10:20pm

The SQM reading translates into a naked eye limiting magnitude of around 5.1
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: MarkS on Jan 27, 2012, 09:41:02

I also stopped at a car park in Ashford town centre last night.  I was surprised at how dark the sky was and how many stars were visible from a town centre.  However, it was 12:45am and too late to count Orion.  I also couldn't get an SQM reading because it was impossible to shield the meter from nearby street lights and car park lights.
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: MarkS on Jan 27, 2012, 15:25:42

Remember, the count should not include the 4 "corner" stars nor the 3 belt stars:

"We are asking people to count stars within the constellation of Orion, which will be visible in the southern sky (the same direction that household satellite dishes face). The main area of the constellation is bounded by four bright stars. The star count should not include these four corner stars – only those within this rectangular boundary – but do include the stars in the middle known as Orion's three-star belt."
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: Rick on Jan 27, 2012, 16:30:31
Quote from: MarkS on Jan 27, 2012, 15:25:42
"We are asking people to count stars within the constellation of Orion, which will be visible in the southern sky (the same direction that household satellite dishes face). The main area of the constellation is bounded by four bright stars. The star count should not include these four corner stars – only those within this rectangular boundary – but do include the stars in the middle known as Orion's three-star belt."

Poorly worded, that, particularly as the main graphic does not mention excluding the belt stars.  :unwell:  I expect their results will contain a large proportion of counts which have included the belt stars.  :bug:
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: MarkS on Jan 27, 2012, 23:24:22

Quote from: Rick
I expect their results will contain a large proportion of counts which have included the belt stars.

Yep - I'm afraid you're probably right. 

Mark
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: mickw on Jan 28, 2012, 09:56:27
I don't think it will affect the results from the M25 area a great deal  :(
Title: Re: Star count 2012 - Friday 20 - Friday 27 January
Post by: Rick on Jan 28, 2012, 11:38:11
Quote from: mickw on Jan 28, 2012, 09:56:27I don't think it will affect the results from the M25 area a great deal  :(

Aye, sadly, given they're most likely in single figures even if you do count the belt stars...