Hi Phil, 4 seconds is a much too long duration for a satellite transit over the moon. It probably was a balloon, a bird or a high-flying aircraft. - Marco Verstuurd vanaf mijn iPad > Op 11 dec. 2017 om 22:37 heeft pstewart--- via Seesat-l <seesat-l_at_satobs.org> het volgende geschreven: > > 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 > (app.photoephemeris.com) 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 (not 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): - - > > Start: > > 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. > > > http://www.heavens-above.com/PassSummary.aspx?satid=25544&lat=38.9081&lng=-77.0361&loc=Downtown%2c+Washington%2c+DC%2c+USA&alt=23&tz=EST > _______________________________________________ > Seesat-l mailing list > http://mailman.satobs.org/mailman/listinfo/seesat-l _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Mon Dec 11 2017 - 16:35:12 UTC
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