Re: June 10, 2017 (UTC) moon crossing by possible satellite, viewed from Washington, DC

From: Thierry Legault via Seesat-l <>
Date: Mon, 11 Dec 2017 23:24:43 +0100
Phil, why don't you publish your video on Youtube?

Anyway, no satellite measures 15 arcsec even at 
zenith (except the ISS). And a Moon so low on the 
horizon means that the satellite would be very 
very far, so it would be an extremely huge 
satellite, probably bigger than the ISS itself.

What you have recorded is terrestrial: bird, bat, 
drone, plane, helicopter etc. They are much much 
more numerous than satellites and are often 
recorded by astronomers on lunar videos ;-)


At 22:37 11/12/2017, pstewart--- via Seesat-l wrote:
>Hi all, This is my first post here. I'm writing 
>to report a video sighting I made of something 
>crossing the moon that was not a plane and which 
>may have been a satellite. (I am assuming it was 
>extra-atmospheric, not a balloon floating by a 
>mile away or whatnot, for the purpose of this 
>post) I appreciate any help identifying it! IT 
>WAS - compact (such as a circle, a sphere, or a 
>cube is - with small perimeter-to-area ratio -- 
>at least as viewed at my camera's resolution) - 
>apparently symmetric (as seen from a distance), 
>or nearly symmetric (as seen magnified in an 
>image editor) - tiny in relative terms (about 16 
>x 12 arcseconds - estimated, see below) but: - 
>large in apparent (or angular) size for a 
>satellite . . . - e.g. it seemed comparable in 
>size to the ISS, _BUT_ _- _I believe the ISS did 
>not cross that part of the local sky that 
>evening, and that when it appeared, it crossed 
>in a different direction. I paste an extract 
>from Heavens Above's satellite pass calculator 
>for my location on that date at the end of the 
>present email, with URL to specify what I've fed 
>into it. IT CROSSED THE MOON - on June 9, 2017 
>local time (which is daylight savings, EDT) here 
>in Washington, DC at UTC minus 4:00 hours (it 
>occurs early June 10th UTC) - 
>Time:            June 10th,      01:01 
>UTC                         June 
>9th,        21:01 EDT (local time in Washington, 
>DC) - therefore crossing the moon at / 
>around             -           3.7 degrees 
>altitude             -           118.6 degrees 
>azimuth             -           (both positions 
>per Photographer's Ephemeris 
>( given camera's time 
>stamp) - as viewed from Washington, DC: Lat 
>38.92 N, Lon - 77.07 (W) - apparently from 
>southwest to northeast at a shallow incline and 
>quite slow-moving, in angular terms (i.e., from 
>my right to my left as I faced ESE). - following 
>a slope of -0.273 (precision unknown: my tripod 
>may have had a tilt on the order of a degree or 
>so), i.e. - at an angle of incline of 15 degrees 
>clockwise from "9 o'clock"; i.e. 195 degrees 
>clockwise from straight up i.e. from normal to 
>the Earth surface (I'm not sure of the last 
>digit down to the degree, since my tripod may 
>have some tilt I haven't accounted for) - giving 
>the appearance of rolling in the video, though 
>that seems likely to me to be a video processing 
>or aliasing artefact of some kind - giving NO 
>appearance of rolling upon inspection of still 
>screen caps of the image, its slightly 
>asymmetric (4 W x 3 H) profile keeping a roughly 
>constant attitude while it is visible ANGULAR 
>RATE OF TRAVEL ESTIMATE: Chord Described by the 
>Object's Transit of Moon: Chord's Length as 
>Proportion of Moon Diameter: 0.42 x moon 
>diameter (measured) Chord's Angular Length (from 
>estimated moon distance from Earth): 0.206 
>degrees Estimated Moon Distance used for the 
>above calculation: 250,000 miles (topocentric or 
>geocentric -- similar at this angle of viewing) 
>Duration of sighting: 4.0833… seconds (nnot sure 
>of the precision of this number: limited by 
>spatial & temporal resolution of video camera) 
>Angular Rate of Travel: 0.05 degrees / second (I 
>assume that is the correct precision for this 
>number) Direction of Crossing: 
>Southwest-to-Northeast, apparently (observer's 
>right to left when facing roughly ESE) APPARENT 
>(ANGULAR) SIZE ESTIMATE: On a 440 (Width) x 425 
>(Height) image of the moon (cropped w/in at 
>most, I estimate, +/- 2 pixels of exact size of 
>moon's edges on the image, for accuracy of 
>apparent diameter measure within +/- 4 pixels I 
>estimate), the object measures about 4 x 3 
>pixels, or 0.009 diameter D (so c. 1/100 D) in 
>Width dimension & 0.007 D in Height dimension. 
>This gives 15.9 arcseconds (Width) & 12.4 
>arcseconds (Height). Again I base this measure 
>on the estimate of the moon's distance at 
>250,000 miles. ALBEDO / FLASHING / PERIODICITY / 
>ETC.: I saw NO evidence of this object's 
>reflectivity at all either in the video or by 
>eye. I don't know what that signifies, but 
>Washington's sky is extremely light-polluted and 
>there was about average haze for this year's 
>sky--which I don't know how to quantify, but 
>which is pretty bad, and exacerbated by the low 
>altitude angle. Enhancing video by turning up 
>the brightness etc. didn't reveal any flashing 
>or continuous illumination coming from the 
>object, at least visible to the eye in noise. 
>EQUIPMENT: Panasonic HC-W580k camcorder with 50x 
>optical zoom, & up to 90x "intelligent" zoom. I 
>was using it somewhere low in the intelligent 
>zoom range, maybe 60x. Resolution: 1920 x 1080 
>Aperture: f4.2 (telephoto) Focal length: 103 mm 
>(telephoto) (equivalent to 1740 mm in a 35 mm 
>camera) Sensor: 1/5.8" MOS, 2.20 megapixels (in 
>video mode &16:9 aspect ratio as here) Format: 
>Progressive scan (?) in this recording Frame 
>Rate: 59.93 frames per second (from file 
>metadata) Encoding: h.264 Recording mode: 
>Intelligent Auto Plus (IA+), with contrast 
>turned up and white point biased towards red): 
>camera controls aperture, exposure, and focus. 
>Thank you for any help with this! I'm very 
>curious what appeared in my video, assuming it 
>can be individuated or characterized beyond what 
>I report here. Please let me know where I may 
>have made errors or not stated something 
>clearly. The video is available separately on 
>request. Best regards, Phil Stewart Appendix: 
>ISS in the Washington DC Sky on June 9th, 2017 
>(local) / June 10th, 2017 (UTC): 
>Date:                           June 9, 2017 
>(local time) / June 10, 2017 
>(UTC)                                     Pass 
>1:                       Pass 2: Brightness 
>(Mag):     -                                   - 
>Time               20:33:03 
>22:09:08             Alt.                  10 
>degrees                10 
>degrees             Az.                  NNW 
>                      SW Highest 
>Point                         Time 
>20:35:31                    22:12:30 
>Alt                   18 
>degrees                76 
>degrees             Az.                  NNE 
>                       SW 
>End             Time               20:37:58 
>               22:15:51             Alt. 
>          10 degrees                10 
>degrees             Az.                  ENE 
>                        SE Pass 
>Type:                daylight 
>    visible Three prior passes are reported on 
>Heaven's Above for this day, for the ISS; for 
>clarity I skip them here. Heaven's Above posts 
>the present date & UTC-5:00 at the upper right, 
>& I don't know if that pertains to this table 
>they generate or not. If so, it's in error & any 
>correction for UTC should be UTC-4:00 for June 
>9th evening (local time) / June 10th, 2017 
>(UTC). To make clear what Heavens Above's table 
>is being fed to generate these results, here is 
>the URL, embedding my approximate lat/lon 
>location etc. 
>Seesat-l mailing list

Thierry Legault

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Received on Mon Dec 11 2017 - 16:25:34 UTC

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