[AZ-Observing] Re: SQM Readings
- From: "Jack Jones" <Telescoper@xxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>
- Date: Mon, 16 Apr 2007 00:50:14 -0700
It does kind of look like Joe is meaning either 7 out of 10 rating or
seeing/transparency 7/10, doesn't it, although I'm sure it's
seeing/trasparency he's listing. I would be interested in another set of
measurements with the spike of light there now, assuming it was not there when
he made the measurements in March. The shaft is very thin, but stuck up 20
degrees and illuminated a spot on clouds at about 30 degrees above the
horizon. I don't know how much of it diffuses to the rest of the sky or if
it's just localized affecting only the west part or none at all.
At Antenna site Friday the 13th it was more like 4/7 for me. Seeing was quite
poor. Plus the high-flying scrud began creeping in quite insidiously and you
don't realize it. I should have used the light spike as a transparency gauge.
I was observing galaxies in Hydra and moved over to Ursa Major quite late,
(coincidentally using my field copy of your book, I mean Chris' and your book)
and soon was saying " Whaddya mean a 13.5 mag star 2'.5 NNE? I don't see no...
uh-oh where'd the sky go?" The cloud spot should have tipped me off.
I say field copy of the book because I had to retire my first copy to preserve
it due to its getting a little loose in the binding. I don't know any other
book anyone had to buy again due to wear, except maybe the Bible or a
crossword puzzle dictionary. :-)
[Note: Referring to Observing Handbook and Catalog of Deep-Sky Objects,
Christian B. Luginbuhl & Brian Skiff, c. 1989 Cambridge University Press]
Jack
----- Original Message -----
From: "Brian Skiff" <bas@xxxxxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Sunday, April 15, 2007 7:59 PM
Subject: [AZ-Observing] Re: SQM Readings
> The relatively bright readings at 2000 MST result from there
> still being a bit of twilight at that time. The gradual decline
> through the later evening hours comes mainly from the increasing
> galactic latitude at this time of year. If typical, it looks as
> though the Flatiron site is medium-dark, whereas the other two
> (Hovatter, KOFA) are as dark as you'll find anywhere, especially
> KOFA obviously. Nice to know that spot is as dark as it is
> despite the proximity of Yuma. Still only a 7/10 site? B-)
>
>
> \Brian
> --
--
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