Stefano Sposetti (1)

 

Stefano is based in Switzerland. He has dozens of photographs of satellites, asteroids, and comets on his web site. Stefano's site can be found here. These images are used with Stefano's permission, and the descriptions of the pictures are based on those on his web site.

A quick description of astronomical magnitude measurements. A person can see down to about magnitude 6 on a clear night with good seeing conditions. An increase in the magnitude number of 1, means the object is 2.5x fainter, since its a sort of logarithmic scale. A bright moon is about mag -9. the sun is about mag -29 !

Having had a good look at all these images, it amazes me just how much the satellites move around up there!

 

February 2004 update: Have a look at Stefano's link, and download the "Fireworks 1" and "Fireworks 2" mpg files. They are well worth looking at! Most spectacular, and a very nice bit of digital imagery.

 

 

Astra Fireworks! 7 Astra 1 satellites January 1998

January 10th 1998

This picture shows the track of seven Astra satellites over the time period of 12 hours and 40 minutes (!).

It is the result of the simple superposition of 368 120-seconds CCD images. The first picture began at 17h11m UT January 10th 1998 and the last picture ended at 05h51m UT of January 11th.

During this time the satellites described those fantastic loops. I took the pictures with a C8, f/6.3 and a Hi-SIS22 CCD camera, in 2x2 binning mode. The telescope was fixed in place, so you can can see the horizontally star trails (North is up, East is left). The field of view spans 12.8 x 10.5 arcminutes. The brightness of the satellites vary between mag 12 and 14.

   

18 consecutive nights photography

  

February 3rd 1998

The seven geostationary satellites Astra were the target for a continuous 18 night follow up (from February 3rd to the 21st 1998). We observed them with an earth-fixed 20 cm reflector telescope and a CCD camera.

Images 16, 17, and 18 show one of the satellites being moved east. (Ed: I think this one is Astra 1D, the trouble shooter of the fleet.)

This image can be seen full size on a separate page. The picture may take a while to download.
   

 

6 Astra satellites March 1998

March 8th 1998

This picture shows the track of now only six Astra geostationary satellites during 10 hours and 35 minutes. It is the result of the simple superposition of 308 120-seconds CCD images.

The first picture began at 18h22m UT March 8th and the last picture ended at 04h57m UT of March 9th 1998. During this time the satellites were moving from the left to the right side of the image describing those loops. At the beginning of the night some clouds covered the sky as one can see from the diminished brightness of the satellite trails.

For 54 minutes (from 22h28m UT to 23h22m UT) the satellites were eclipsed by the earth shadow: this is the cause of the interruptions in the middle of the trails. I took the pictures with a C8, f/6.3 and a Hi-SIS22 CCD camera, in 2x2 binning mode. The telescope was fixed. North is up, East is left. The field of view spans 11.8 x 8.1 arcminutes. The brightness of the satellites vary between magnitude 10 and 15.

 

All images are © Stefano Sposetti.

 

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