67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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The "Lunar X" (Werner X), will be observable from North America starting Friday Night, August 8, approx. 2306 UT. Good luck viewing and photographing the "X-shaped" lunar illumination near the terminator!
Dana T
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"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
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PhilH
sage
Reged: 01/27/05
Posts: 237
Loc: Long Island, NY
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Hi Dana,
I was just passing through when I saw this notice and thought I'd give it a look. The seeing was quite unsteady and the Moon low, but still, not too bad for a first-timer.
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Phil Harrington
"Binocular Universe" Columnist, Astronomy magazine
Author: Star Ware || Star Watch || Touring the Universe through Binoculars || et al...
http://www.philharrington.net
http://www.observingsites.com
"Two eyes are better than one!"
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Tommy5
Pooh-Bah
Reged: 03/28/04
Posts: 1436
Loc: Chicagoland
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Nice capture Phil, i saw this event tonight as well thanks for posting.
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dmdouglass
member
Reged: 12/23/07
Posts: 91
Loc: Tempe, AZ
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Phil, many thanks. I was trying to find a reference as to the location of this object, and you came through perfect.
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David M. Douglass
Tempe, Arizona
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PhilH
sage
Reged: 01/27/05
Posts: 237
Loc: Long Island, NY
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Thanks, Tommy and David. First time I've been able to see it, although I have heard about it previously.
I wonder if Dana might discuss the source of the visibility timetable. I understand it's based on the terminator's precise lunar longitude, but my question is, what program/web site did you use to come up with your original post?
Thanks!
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Phil Harrington
"Binocular Universe" Columnist, Astronomy magazine
Author: Star Ware || Star Watch || Touring the Universe through Binoculars || et al...
http://www.philharrington.net
http://www.observingsites.com
"Two eyes are better than one!"
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Jim Mosher
sage
Reged: 05/22/06
Posts: 254
Loc: Newport Beach, CA
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Phil,
According to the information collected on the-Moon Wiki, the appearance of the X is controlled by the Sun's altitude over a point on the Moon's surface at about 0.9° east longitude and 25.2° south latitude. Various observers have reported seeing a "perfect" X when the Sun's altitude above the horizon (at that point on the Moon) is anywhere from about -2° to 0°. At the time of your photo, the Sun was at an altitude of -0.06°, which I guess the more expert observers would regard as near where the X starts to merge with its surroundings. You can see examples of what the X looks like at several sun angles on the Wiki page and elsewhere.
I don't know the exact source of Dana's predictions, but there is a quite suitable Moon Event Predictor in the freeware LTVT software. Simply go to the "Sun Altitude" mode, enter 0.9 for the target longitude, -25.2 for the target latitude and -1 for the target sun angle, or better ask the software to calculate the altitude (-0.06) and azimuth (89.96) of the Sun at the time of you observation. "Filter" the output, if you wish, to suppress the events with the opposite solar azimuth (that is, sunset, rather than sunrise, events).
The next repetition of the -0.06° lighting shown in your photo (it is visible somewhere on Earth every month) will be on September 7 at 11:51 UT. Weather permitting, the next repetition visible from Long Island, NY will be on October 6 at 23:37 UT, with the Moon 20° above your horizon (very slightly better than last night). An hour earlier that evening, at sunset, you should be able to see the Lunar X illuminated at the slightly more "perfect" sun angle of -0.6°. Dana seems to be giving the times when the sun angle is a still more perfect -1.0° (which, in October, as it did this month, will occur before sunset from your location).
-- Jim
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Tom and Beth
sage
Reged: 01/08/07
Posts: 494
Loc: Tucson, AZ
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By the way, you don't HAVE to have dark skies in order to observe this phenomenon. Yesterday's event was at 4 in the afternoon (Tucson, AZ) and easily visible even in the finder.
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desertstars
Deja moo
Reged: 11/05/03
Posts: 30411
Loc: Tucson, AZ
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Quote:
By the way, you don't HAVE to have dark skies in order to observe this phenomenon. Yesterday's event was at 4 in the afternoon (Tucson, AZ) and easily visible even in the finder.
You saw the Moon yesterday?
From Tucson???
I must live in the wrong part of town... 
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Tom W.
SVP8 'She turned me into a 3-legged Newt' EQ
Ralph, the All-Purpose 102mm Refractor
Under the Desert Stars
All truths are easy to understand once they are discovered; the point is to discover them. - Galileo Galilei
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Tom and Beth
sage
Reged: 01/08/07
Posts: 494
Loc: Tucson, AZ
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Quote:
Quote:
By the way, you don't HAVE to have dark skies in order to observe this phenomenon. Yesterday's event was at 4 in the afternoon (Tucson, AZ) and easily visible even in the finder.
You saw the Moon yesterday?
From Tucson???
I must live in the wrong part of town...
Not sure if you're on the wrong side of town, but I'm on the SE part of town North of the Fairgrounds.
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PhilH
sage
Reged: 01/27/05
Posts: 237
Loc: Long Island, NY
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Quote:
I don't know the exact source of Dana's predictions, but there is a quite suitable Moon Event Predictor in the freeware LTVT software.
Excellent, Jim! That's just what I was looking for. I just d/l'ed it and ran it through as you described to generate a list of coming appearances. Doing a quick check against another source, it appears to line up very well. I don't need predictions to the minute; I think to the nearest quarter hour should be fine.
Great tool you created there! Bravo! 
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Phil Harrington
"Binocular Universe" Columnist, Astronomy magazine
Author: Star Ware || Star Watch || Touring the Universe through Binoculars || et al...
http://www.philharrington.net
http://www.observingsites.com
"Two eyes are better than one!"
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67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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Phil,
I'm very pleased you finally captured it! I typically post predicted times where "sun alt" is 1.2 at crater Werner, as calculated by my spreadsheet program reworked from a BASIC program from George Rosenberg of ALPO.
Jim, thank you very much for the wiki note. That's the best info on the web right now concerning this optical event.
Dana T
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"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
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67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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Quote:
By the way, you don't HAVE to have dark skies in order to observe this phenomenon. Yesterday's event was at 4 in the afternoon (Tucson, AZ) and easily visible even in the finder.
You are correct, but it helps. Try imaging it in the daylight!
 
dt
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"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
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Dave Chapman
member
Reged: 01/27/07
Posts: 17
Loc: Halifax, Nova Scotia, Canada
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Nice observations and pictures, folks! A rough approximation for the event is when the selenographic colongitude equals 358 degrees. I consult the RASC Observer's Handbook which gives the s.c. at day 1.0 of each month, then count forward 12.2 degrees per day. For October 6, I calculate 22h 55m, but I would certainly start looking a couple of hours before that.
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Dave 17 of the Royal Astronomical Society of Daves
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67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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Thanks Dave!
Phil, Dave's the man on this subject. He had collected a lot of data on this a couple years ago.
I just try to keep the interest up and inform people who have never heard of it, because I'm STILL obsessed with it... (sad but true) HA-HA.
I only have one over on Dave, I saw it before he did!  LOL
dana t
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"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
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SaberScorpX
Post Laureate
Reged: 01/12/05
Posts: 4158
Loc: illinois, usa
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Great info Dave. I just happen to have the RASC Handbook in reach.
VMA concurs with a solar inclination of -1.3°. Three hours earlier
(terminator inside Werner's east wall) gives a colong of 356.4°.
I'll be watching for the exact VMA offset.
Dana: It's a worthy obsession. Thanks for keeping it alive here.
Saber Does The Stars at
www.astronomyblogs.com/member/saberscorpx/
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67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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Thanks Saber.
dt
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"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
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Ishtim
super member
Reged: 11/10/07
Posts: 180
Loc: N. Alabama, USA
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X marks the spot. 300D & 14" LX200 @ prime (cropped)
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67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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Nice job. I think you captured the Lunar "V" as well...
dt
--------------------
"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
Edited by 67champ (08/17/08 01:23 PM)
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PhilH
sage
Reged: 01/27/05
Posts: 237
Loc: Long Island, NY
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Quote:
Nice job. I think you captured the Lunar "V" as well...
Very cool! That's a new one on me. Just took a look at one of my shots and sure enough, it's there.
Okay, so tell me, *what* is it (the V)?
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Phil Harrington
"Binocular Universe" Columnist, Astronomy magazine
Author: Star Ware || Star Watch || Touring the Universe through Binoculars || et al...
http://www.philharrington.net
http://www.observingsites.com
"Two eyes are better than one!"
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67champ
sage
Reged: 07/03/06
Posts: 333
Loc: Ohio, USA
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Hi Phil,
Carol????? You know this don't you??? Isn't it "the horn(s)" something....? If no body ID's it tonight I'll look it up and post sometime Monday...
dt
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"To the Moon!"
Orion 127mm Mak-Cass
Meade 60mm Refractor
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