If transit took 0.86s, why don't you see it in more than one frame at 15 fps ? Does the Sun fill your webcam image (or what % of the image/Sun)? If your webcam delivers 480 vertical pixels, and the Sun (apparent size 18 km at 2000 km range) fills the image, the distance between pixels is 36 m. So a smaller rocket (also moving 5 m during exposure) would not always be completely within a pixel, and then only reduce the image intensity to some 90%, not completely black, but it would of course look as big as one pixel. ----- Original Message ----- > It passed across the lower half of the Sun's disk at 18:30:26 gmt appearing > in one frame of AVI (1/2500th sec 15fps ) as a small blur traversing north > of the main sunspot cluster , presently visible. > > I was using a webcam / 200 mm zoom lens combination fitted with Baader solar ... > > I am however uncomfortable with the size of the target. > Last week I imaged a solar transit by a Cosmos rocket booster using the same > set-up.Again , the object seemed to be too large....so I have a couple of > questions. > ... > what causes this apparent magnification.....the booster is after all only > 10.4 metres in length and has a range of nearly 2000 km. > > Details from CalSky.com are as follows. > > 19h30m29.4s Resurs 1-3 Rocket > (23343 1994-74-B) Crosses the disk of Sun. Separation:0.25d > Angular Velocity:12.9'/s. Transit duration: 0.86s ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
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