My Backyard Observatory Skies
I am very lucky to leave in quite rural
area with excellent skies. I made several measurements of sky brightness
at my observatory, and it varies with weather (haze, or high thin cirrus
make it worse) and time of the night (many lights switch off after
midnight). Most recent measurement logged is 5/8/2018 11pm: at zenith
21.33 mag/sq.arc.sec (equivalent limiting magnitude 6.30!), angled
towards primary directions at 45 degrees: south 21.07 (6.16), east 21.13
(6.19), north 21.13 (6.19) and west 20.78 (6.00). To illustrate the
numerical data I made several wide-angle pictures of the night sky using
Canon T6s and 8mm lens (f/3, ISO 12,800 and 15 seconds
exposure). They were done on a good clear moonless night June 11 2018
starting at 11pm.
to the south from my observatory deck. Declination limit is about -32 degrees, and
light pollution in this direction is small, even close to the horizon, it gets a bit worse on the
western side since we are getting closer to Ithaca, which is west and north-west.
View to the north, including north-west and north-east. North itself is
quite OK, but two light domes are obvious: Ithaca at north-west (left),
about 12 miles away and Dryden (MUCH smaller, but also closer) to the
north-east, about 4 miles away. What is most important is that around and
above Polaris the sky is very good, therefore I can comfortably view about
half of the northern skies at any time, and all of it throughout the year.
Eastern view from the grass behind the south side of the observatory deck.
Only Dryden lights are visible on the north-east, the rest of the horizon is
excellent. My house lights are visible on the left.
South view from behind the observatory - you can see red light leaking out
through opened front doors on the left and weather station on the
north-western corner of the observatory deck. When observing from the deck
the weather station is exactly towards Ithaca, and it doesn't matter.
View to south-east from behind the observatory, my house visible on the
South-east view from the grass behind northern side of the observatory.