Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 10954
Loc: Los Angeles
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You're lucky. The other night at my home, AFTER moonset, and with no clouds, it was mag.16.8. I swear the sky was orange in some directions and blue in others.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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I agree--we need some comparisons.
Last night at my ranch 21:00 hrs. SQM 21.68 (best reading); 21.65 (avg of 6 determinations). I attribute the better reading to a patch of very heavy low clouds over the Casper, WY. light dome. My previous best was 21.61, and an average reading is about 21.58.
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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Bill-
Is this the voice of experience speaking? I'm wondering whether the Chaco Dark Sky Inititive affects the campground?
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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Quote:
Bill-
Is this the voice of experience speaking? I'm wondering whether the Chaco Dark Sky Inititive affects the campground?
Hi Rodger
Its my experience with campgrounds in general, not Chaco in particular. I've stopped camping in organized campgrounds years ago because of the problems with lights and fires, not to mention loud drunks who think that camping is an excuse for bad behavior.
Chaco may be different; be interested in your report.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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Bill-
Sorry for the delay in responding to your last post, but I've been traveling on business.
The Gallo campground is fairly "spartan" by the standard of most people, and the Chaco Dark sky initiative is taken seriously.
The website is: www.nps.gov/chcu/nightskyprogram.htm
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
Edited by RRaubach (04/04/06 01:54 AM)
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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The link is encouraging...its been many years since I have visited Chaco. I'll be very interested in your impressions of your stay.
Doesn't look like there is any light restrictions in the campground from what I can make out; also fires are not prohibited, just gathering firewood.
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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My primary reason for Chaco in the first place is to pick up a few southern declination globulars that aren't visible from my home site: Omega Centauri, in particular. It will probably be too late in the year for NGC 3201, though.
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
|
Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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FINALLY got a chance to observe last night. Again, the difference between the SQM readings and reality was demonstrated to me.
The meter had constant readings of 21.35-21.4 but my NELMs were about 5 with a noticeable overall haze (aerosols or dew or both). The Reno Nevada light dome which is 85 miles away was quite large which is another indication of transparency that I use for estimating. On a good night of transparency, it is quite low to the horizon and hard to see; last night it was quite obvious.
It was dry as far as dew when I started around 11 o'clock, temp about 43. When I quit at 1, the temp was 36 and dew was beginning to form.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 10954
Loc: Los Angeles
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Bill,
I've pointed out that the darkest readings would be under completely cloudy skies, so Darkness (as measured by an SQM) has to go hand-in-hand with Transparency (Clarity) to result in fantastic viewing conditions.
Other than the measurement of extinction (loss of visible magnitude with decreasing altitude), I know of no objective Transparency scale, though the Bortle Scale would suffice for a highly subjective scale.
But I agree with your comment. One of the best nights I've seen in years (resulting in fantastic views of very faint galaxies) was under skies measuring 21.35, while another night under 21.69 skies was nowhere near as transparent. It probably is relevant that the first night was at high altitude, while the the darker night was at low altitude.
Now, a night of 21.69 at high altitude.....that's in my dreams.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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Last night I finally had a break in the overall crummy weather. I wanted to evaluate my new W.O. 28 mm UWAN eyepiece, so I only set up my Takahashi TOA 130. I actuall had a great night, even with the smallest aperture I own. After observing Saturn, M41, M42, M37, and M104, iI realized that I had not yet taken a reading; WOW! My SQM reading, under totally clear skies: 21.78 (lowest of 5 readings), and 22.00 (highest of 5 readings!), with an average of 21.87!! My NELM was ~7.0 and seeing at 8 <1-10>.
I shoulda' had the TMB 203 out for a cruise!
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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When you get that observatory set up, you will always be ready with the 203 for those special nights....
It would be interesting to compare two meters side by side to see how close the readings come out. As I said before, comparing readings depends on a lot of uncontrolled variables. It would be like synchronizing watches and counting on the time to be the same two years later. The longer these meters are out there, the more I question the legitimacy of assuming my reading will be the same as yours under identical skies. or for that matter, whether I can count on my meter to give me the same readings over time.
We need an absolute calibration technique. This is the first rule in trusting instrumentation, something I am very familiar with after 25 years working in ultra precision technologies.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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Hey Bill-
I agree, since all of these isolated observations are meaningless in the absence of some sort of Quality Assurance program. I don't have the answer, though.
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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Amalia
Reged: 10/16/04
Posts: 5165
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Quote:
Figure 2 on the above page plots sky brightness at Mauna Kea over a decade and you can see the fluctuation that results from changing solar activity. Also, notice that the various plots and models are reflective of the lower limit of sky brightness in the V at about 22.0 mags./arcsec.^2.
Best regards,
Bill in Flagstaff
Yesterday evening I re-read the introduction to Stephen O'Meara's
"The Messier Objects". On pages 29/30 he explains the exactly
same relation between solar flux and the resulting mag/arcsec^2 in the
night. Truly interesting, and one more thing to consider! Now I
understand this better.
Thank you!
Amalia
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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Just returned for a week of observing with Ed Jones at New Mexico Skies. Every night was impressive with SQM readings of 21.6 to 21.85 and seeing at 1.25 to 0.6 arc seconds.
Had 30 inch telescope for 3 nights, 25 inch for a night and 6 inch Fuji binoculars and 5 inch f/5 refractor with OIII filter to observe large scale strucure such as the entire Veil and NA nebula in one FOV (separate views, of course.)
A little bit of heaven.....
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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Hi Bill;
I just returned last night from Chaco Canyon; overall it was a great experience. Skies were about equivalent to my home--maybe a 0.1 0.2 mag/arcsec^2 darker and with less "dome pollution" on the horizon. I have been recording 21.6x to 21.8x at the ranch; the Chaco sky was ~ 21.8x to 22.00, depending on the time.
There were NO rowdy campers, and campfires were prohibited. I observed from the visitor center parking lot, along with The Albuquerque Astronomical Society.
Had a great time! You must have had some fun, too!
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
|
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