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Re: GMT from Lunar Photo
From: Antoine Couëtte
Date: 2022 Jan 11, 11:15 -0800

Re : http://fer3.com/arc/m2.aspx/GMT-from-Lunar-Photo-FrankReed-jan-2022-g51894

Frank,

The only "own" estimate I made was explained in my very first post., not really "glamour" as you can read it since I do not even know how to count pixels.:

Augmented D [of 32.6'] showing as 157 mm on my computer screen,

Given its position relatively to the Moon Horns, bottom right "bright spot" should yield a fairly resonable Lunar. It shows at 207.5 mm from the Far Limb on my

screen, hence at an angle of 0°43.119' from the far limb of the Moon. ". From this Far Limb value I "solved" Lunar # (1) for GMT(1) = 01h10m49s

Other than that, I treated the 1 o'clock star as an occultation, treated as Lunar (2) yielding GMT(2) =  01h11m34s . For the 12 o'clock star I used the pixel count from the 2.84' value indicated by Bill Ritchie and treated it as Lunar (3) yielding GMT(3) = 01h11m31s. Lunar (4) was simply a computation of the time of Emersion of the hidden star on the picture.

Like Bill, I think that my most reliable result is probably Lunar (3) since it does not rely on any scaling factor, of course assuming that the picture was taken "at" occultation time ....

Also, results (2) and (3) here-above showing only 3 seconds of time apart.

So if somebody can give me a FAR LIMB pixel count for the 4 o'clock star (HD 202284) I will gladly process it with such a value expected to be better than my own prehistoric 0°43.119' determination. Again, Thanks in advance.

Anyway, I have really enjoyed your puzzle a lot, since it put me back onto Lunars, including Occultations / Emersions. Fun !

Thanks again,

Antoine

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