Dealing with Light Pollution

or What to Do When your Sky at Night is Full of Light.

I live near in a Metro Area, the sky is awash in Streetlights,
Driveway Lights, Headlights, and every other conceivable light you can
imagine. (Except neon gets a pass, for nostalgic reasons if nothing
else.)

What I was wondering, other than traveling out to the 'dark country',
is what might the intrepid home astronomer (amateur) do to help his
favorable light gathering.

Has any one had any success with a shroud, as in a larger tube,
seemingly coal black on the inner surface, that extends out past the
telescope's body a ways. light in construction, and hopefully stiff in
materials, it might help with some of the local scatter.

I already know I'm crazy, but how crazy am I?


TBerk

TBerk wrote in news:9c402eb2-6320-405a-b90b-
:

or What to Do When your Sky at Night is Full of Light.

I live near in a Metro Area, the sky is awash in Streetlights,
Driveway Lights, Headlights, and every other conceivable light you can
imagine. (Except neon gets a pass, for nostalgic reasons if nothing
else.)

What I was wondering, other than traveling out to the 'dark country',
is what might the intrepid home astronomer (amateur) do to help his
favorable light gathering.

Has any one had any success with a shroud, as in a larger tube,
seemingly coal black on the inner surface, that extends out past the
telescope's body a ways. light in construction, and hopefully stiff in
materials, it might help with some of the local scatter.

I already know I'm crazy, but how crazy am I?


TBerk





http://www.astronomy.com/asy/default.aspx?c=a&id=4735


Be sure to optimize the telescope you own, no matter the size or type.
One of the most effective ways to improve the view is to add a tube
extension in front of the telescope. Not only will the extension slow the
onset of dew on a refractor's lens or catadioptric's corrector plate, it
also blocks stray side light. This is especially important with Newtonian
reflectors, where the focuser is often so close to the front of the tube
that side light can shine over the edge and right into the focuser.
Extending the tube at least one diameter in front of the focuser will
eliminate the problem and improve contrast noticeably. Be sure to paint
the inside of the extension flat black.

TBerk wrote:

or What to Do When your Sky at Night is Full of Light.

I live near in a Metro Area, the sky is awash in Streetlights,
Driveway Lights, Headlights, and every other conceivable light you can
imagine. (Except neon gets a pass, for nostalgic reasons if nothing
else.)

What I was wondering, other than traveling out to the 'dark country',
is what might the intrepid home astronomer (amateur) do to help his
favorable light gathering.

Has any one had any success with a shroud, as in a larger tube,
seemingly coal black on the inner surface, that extends out past the
telescope's body a ways. light in construction, and hopefully stiff in
materials, it might help with some of the local scatter.

I already know I'm crazy, but how crazy am I?

TBerk

The White Eye is going to have his lights. After the Apocylypse things may

change but you wont care -

It was so dark and clear at 11pm, last night, that I could see the
Pleiades on the horizon, rising like fierce, blue diodes, just above
the freshly ploughed fields, right through the net curtains of our
bedroom window, as we went to bed. Thank goodness I wasn't dark
adapted or I could have been badly dazzled!

Later, my wife complained she couldn't sleep because Sirius was
shining through the 6' thick hedge onto the closed curtains. She
thought somebody was outside with a torch.

Some pray for dark skies. Others have it thrust upon them.

On 9/4/2010 7:34 PM, TBerk wrote:
or What to Do When your Sky at Night is Full of Light.

I live near in a Metro Area, the sky is awash in Streetlights,
Driveway Lights, Headlights, and every other conceivable light you can
imagine. (Except neon gets a pass, for nostalgic reasons if nothing
else.)

What I was wondering, other than traveling out to the 'dark country',
is what might the intrepid home astronomer (amateur) do to help his
favorable light gathering.

Has any one had any success with a shroud, as in a larger tube,
seemingly coal black on the inner surface, that extends out past the
telescope's body a ways. light in construction, and hopefully stiff in
materials, it might help with some of the local scatter.

I already know I'm crazy, but how crazy am I?


TBerk




People are viewing and broadcasting regularly from light polluted
urban areas.

http://www.nightskiesnetwork.com/

Be aware they are using video cameras. Diehard visual observers may be
offended.

LdB

On Sep 5, 6:26*pm, Chris L Peterson wrote:

Tell me about it! We narrowly escaped disaster just last week when the
light of Jupiter, focused by a window ornament, set the couch on fire.
What SPF do you find best for protection from the Milky Way? We've found
that SPF 30 is usually sufficient.

SPF30? I wish! I warm up in welding goggles, a leather apron and a
baseball hat to block extraneous glare from overhead. Being so far
north helps to keep down radiation burns from M1. Twenty minutes
outside is about the safe limit for us though. I tried cooking foil on
the cap but it soon became too hot to touch and fogged the film in my
camera.

On Sep 5, 9:26*am, Chris L Peterson wrote:

Tell me about it! We narrowly escaped disaster just last week when the
light of Jupiter, focused by a window ornament, set the couch on fire...

For just a quick second there you had me going...

Someone once told me that I was gullible... and I believed him ;)

\Paul A

You're not crazy. For years, an "undisclosed" light rejection system was
used in Hubble when it was being used by the military. It was said to even
filter out sunlight when Hubble's position was within 1/4 deg of the sun.
I think the reason you haven't seen this in pro or amateur use is because
the technology hasn't been declassified. However, there is scattered
information here and there showing such a system existing capable of
filtering out ALL light pollution while leaving behind only starlight or the
chosen DSO. The keys are in the light rejection and tuning out of specific
wavelengths, then ignoring the unique wavelengths of space object light. A
VERY fine filter but there is a miniscule spectra shift between starlight
and Earth bound light because the former must cross the atmosphere, and this
is where the filter does its work.

maybe someday the technology will be released, but not at this time.

"TBerk" wrote in message
...
or What to Do When your Sky at Night is Full of Light.

I live near in a Metro Area, the sky is awash in Streetlights,
Driveway Lights, Headlights, and every other conceivable light you can
imagine. (Except neon gets a pass, for nostalgic reasons if nothing
else.)

What I was wondering, other than traveling out to the 'dark country',
is what might the intrepid home astronomer (amateur) do to help his
favorable light gathering.

Has any one had any success with a shroud, as in a larger tube,
seemingly coal black on the inner surface, that extends out past the
telescope's body a ways. light in construction, and hopefully stiff in
materials, it might help with some of the local scatter.

I already know I'm crazy, but how crazy am I?


TBerk

TBerk wrote:

What I was wondering, other than traveling out to the 'dark country',
is what might the intrepid home astronomer (amateur) do to help his
favorable light gathering.

Some ideas come to mind:
1) shield your observing spot from all light trespass
2) block all light from your observing eye excepting only that which
arrives via the eyepiece
3) use the highest magnification practical to maximize the darkness of
the telescopic field

For #1 the erection of opaque walls would be one possible approach.
For #2 one method would be to get a pair of safety goggles, cut out a
hole appropriate for the eyepiece, and paint the goggles black. For
#3 a certain amount of trial and error would likely be needed.

I already know I'm crazy, but how crazy am I?

Not likely any crazier than myself! I'm under magnitude 6.5 skies,
nevertheless I've used all three of the above mentioned suggestions --
and others geared more specifically toward dark sky use -- when
attempting visual observation of 'challenging' objects.

Sketcher,
To sketch is to see.

Chris.B"
Pleiades on the horizon... Thank goodness I wasn't dark
adapted or I could have been badly dazzled!

Some pray for dark skies. Others have it thrust upon them.

Chris L Peterson:
Tell me about it! We narrowly escaped disaster just last week when the
light of Jupiter, focused by a window ornament, set the couch on fire.
What SPF do you find best for protection from the Milky Way? We've found
that SPF 30 is usually sufficient.

Now _that_ is funny!

I was out myself last night. The clarity and darkness were stunning,
for Maryland. I saw the Pleiades as soon as they cleared the trees to
the east of me--not a usual thing. Hurricane Earl missed us by a
wide-enough margin, and it left behind a high pressure zone and
remarkably clear skies. They may last 'til Thursday, when I'm off to a
Pixinsight http://www.pixinsight.com seminar at the Adler Planetarium
in Chicago.

Sadly, however, my objective of a long night of astrophotography with
the 106mm refractor was not to be. I recently installed an SBIG
eight-position filter wheel (RGB, Lum, Clr, Ha, OIII, SII) on my
STL-11000. Unfortunately, I misplaced (or thought I misplaced) the .010
spacer washer that SBIG specified for the mounting plate on my camera
sample and I had a makeshift substitute in place. No good: focus was
still uneven across the field. At 03:00 I found the washer where I had
put it, in a carefully and copiously labeled little zip bag, placed
where I "couldn't" lose it. I brought the camera into the house and
installed the washer, but my back was killing me from a sprain of about
a week ago, and my lower jaw was paining me from dental-implant surgery
this past week, so I gave it up for the night. Furthermore, my newly
contrived OTA rear counterweight for my 150mm refractor, a 20-lb ankle
weight reduced to 14 lbs, had slipped a bit, interfering with the
focuser. More bad luck.

I believe that all is fixed, and the camera is reinstalled and ready
for tonight, which looks like it will be another unusual night. My only
question is whether the spacer that was designed for the camera as I
bought it will work now, as the new focuser includes an entirely new
front for the camera. I'm trusting that the aluminum castings are of
such high-precision that all will be well.

Before I quit last night I did what I never (hardly ever) do--I put an
actual eyepiece--I think that's what they're called--on the 150mm and
had a look at the Pleiades as well as Albireo and some obscure
clusters. Interesting, those eyepiece things. I'm told Galileo and
Newton both used them, but I don't see them catching on again in the
21st century; too hard to see most nebulae. Sorry I can't come up with
a joke about blinding red light from the North American Nebula last
night; it would pale next to the two Chris's.

Davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm