Kevin Apertura 8" Dob, Pentax K-5 My Photography Website -- My Flickr
Orion ED80 - AT Voyager with TNT,pier ext.,Vixon steel tray and Manny's mod.
Omni 120 cg4 with Orion pier ext. and RA drive, Binotron-27 (25mm & 17mm Sterlings)
Orion XT10(Original F/5) SkyStopper Equatorial Platform
Jason Constellation Model 311(Modified with 1.25"Crawford Machine focuser & rings)
Quote:I like it. Nice job Kevin! Not quite sure what to make of the variance in colour from the google overlay as 3 of the 4 sites I might normally visit show as darker in your version. Talking about Ontario,Canada about 300 miles north of Toronto, 150 miles East of Toronto and the north shore of lake Erie. Eric
Teeter 15" Dob ReflectorSky Watcher Pro 120 ED RefractorCelestron AVX Equatorial MountExplore Scientific 82 deg N2 eyepiecesBinotron Binoviewer... Yeah Baby!Love my eyepatch when not binoviewing!
150mm MCT f/13, 31% CO
"People say I'm in denial. I disagree."
WO Megrez 90mm, Porta II
SW 200mm, SW 100mm ED, EQ5
Nikon Action EX 8x40, Fujinon Polaris 10x50
Garrett Signature 15x70
George N Obsession 20 Optical Guidance Systems 10" F/9 R-C Cass 6" F/5 & 8" F/8 home-made Newts Explore Scientific 127mm ED MI-250 mount Denk II bino-viewer, with PowerX and Newt reducer, Member, International Dark-Sky Association
Quote:Would their be any reason why the light pollution map wouldn't show up on an IPad? I can get the map ( underlay) to show up fine but no light pollution map.Any thoughts? Or is this something you already are aware of? I would love to take a look at your maps!
14" Strut; 10"XT; 102ES; 22 in Process; 3.5,5,7,10,14,20mm Pentax XW; 17.3 & 12mm Delos; 27mm Panoptic; 20&24mm ES 68; 24mm ES 82; 30mm ES 82; 6&10mm BCO;
Quote:In fact, it might be good to intentionally use a number of levels that clearly distinguishes this from the Bortle scale, to prevent further confusion.
First and foremost observing love: naked eye.
Last but not least, telescopes.
And I sometimes dabble with cameras.
Quote:Kevin, have you discussed using Dave Lorenz' maps with him?
Quote:The only way to see how dark a site truly is, is to visit there on a good night.
Quote:Quote:Kevin, have you discussed using Dave Lorenz' maps with him? I have attempted to but I got no reply. But since he has the PNG images available for download on his website, I don't think he would have a problem with it. I made sure to give him credit.
Quote:Quote:In fact, it might be good to intentionally use a number of levels that clearly distinguishes this from the Bortle scale, to prevent further confusion. Attempting to mimic the Bortle scale would simply increase confusion.
Quote:I deeply regret the original publication of the correlation by the North Virginia Astronomy Club, although their intentions were entirely legitimate. And its propagation through Wikipedia is even more unfortunate. However, the cat's out of the bag now; the harm cannot be undone.
Quote:Quote:Would their be any reason why the light pollution map wouldn't show up on an IPad? I can get the map ( underlay) to show up fine but no light pollution map.Any thoughts? Or is this something you already are aware of? I would love to take a look at your maps! Sorry I didn't really optimize the website for mobile devices. I don't have an Ipad to test with either. Maybe someday I'll learn how to build an app though.
Quote:The Wikipedia entry for "Bortle Scale" is now fixed.
Quote:Quote:The Wikipedia entry for "Bortle Scale" is now fixed. Wow, that's pretty drastic! I did add a caveat to that article, but I'm reluctant to remove information even if it's only approximately correct.
Quote:Quote:Quote:The Wikipedia entry for "Bortle Scale" is now fixed. Wow, that's pretty drastic! I did add a caveat to that article, but I'm reluctant to remove information even if it's only approximately correct. Given John Bortle's own statements that he was *not* involved, and that there would be considerable differences between the two, and that the Bortle Dark Sky Scale is intended for use for on-site evaluation, not for use in creating maps (and your own respected expression of deep regret), it seems perfectly appropriate to me.
Quote:Please let me know how you like the website and if you have any suggestions to make it better.
Quote:My first suggestion is to use the 255 grayscale map to create a new color mapping. It uses 7 colors:clear - no light pollution, natural pristine skies (e.g. 22 magsas)gray - 0-1 magsas brighter than natural, pristine skies (21-22)blue - 1-2 magsas brighter (20-21)green - 2-3 magsas brighter (19-20)orange - 3-4 magsas brighter (18-19)yellow - 4-5 magsas brighter (17-18)white - 5+ magsas brighter (17+)
Quote:But it might be worthwhile to more finely establish the divisions for the darker levels (due to the usually gentler brightness gradient), *if* the data permit this by not having significant error or noise.
Quote:A standard baseline for a pristine sky is a given, which presupposes a reasonably clean and dry airmass. For another, the mean air glow brightness by latitude should be established (it does brighten toward the poles.)
LP* MPSAS Color code0.00 -0.01 22.0 black/clear0.01 -0.11 22.0 to 21.9 gray0.1 to 0.3 21.9 to 21.7 blue0.3 to 1.0 21.7 to 21.3 green1.0 to 3.0 21.3 to 20.5 yellow3.0 to 9.0 20.5 to 19.5 orange9.0 to 27.0 19.5 to 18.4 red27.0+ 18.4- white
clear/black - natural pristine skies with no light pollutiongray - 0-1 mag of LP, with 4 shades to indicate 0.25mag contoursblue - 1-2 mag of LPgreen - 2-3 mag of LPyellow - 3-4 mag of LPwhite - 4+ mag of LPwith contour lines at 0.25 mag intervals.
Quote:Lee,I feel that the regime of the darker skies needs to be more finely differentiated than the more light polluted regime, because the contrast index is logarithmic, and the natural sky glow is a bias toward which the contrast index effectively converges asymptotically.Think of it this way. When you go from 3 to 4 magnitudes (delta = 1mag.) of man-made light on top of a dark, 22 MPSAS sky, the difference in the view is not really large. But go from 1 to 2 magnitudes (delta again 1 mag.) of light on top of that same dark sky, and the difference is much more profound. And from 0 to 1 magnitude (the same 1 mag. delta) of artificial light would be the proverbial night and day difference!This is why the scale currently in use is more compressed toward the bright end and expanded toward the faint end. One could work out the basis of this by plotting the contrast index defined by the ratio of artificial to natural sky glow on a logarithmic scale. Or something like that; I've not worked on this problem myself.
SB OB (OB=Object brightness)19 2320 2421 2522 26
SB OB (OB = object brightness)19 2320 2621 2922 32
19 2320 2321 2422 25