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Author
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Topic: Nothing to see here: Capturing secret satellites
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dom
Member Posts: 855
From:
Registered: Aug 2001
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posted 10-10-2010 04:20 PM
   
The Guardian newspaper's weekend magazine carried an interesting piece on photographs of "secret satellites". Secret projects are organised in such a way to maximise their own invisibility, but they have to happen somewhere. After driving overnight through subfreezing temperatures to the middle of the Nevada desert, and using long-range lens photography and astrophotography, Trevor Paglen has captured images and evidence of "black sites" -- bases for covert operations -- and secret spacecraft. Specks of light on the distant horizon, or a thin bright streak across the sky are telltale signs of covert military or intelligence activity. |
NovaRob
Member Posts: 242
From: Tucson, Arizona, USA
Registered: Nov 2008
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posted 10-11-2010 03:01 PM
One of the images is titled "Four Geostationary Satellites Above The Sierra Nevada", but shows what look to be standard star trails. If the satellites are geostationary, they shouldn't move in the sky, and would not produce trails. And the two trails that are visible from beginning to end are the same length, so wouldn't the two "satellites" need to be in the same orbit? This particular photo seems mis-titled, if not mis-represented. Other than that, it is a beautiful photo. |
hlbjr
Member Posts: 475
From: Delray Beach Florida USA
Registered: Mar 2006
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posted 10-12-2010 09:14 AM
The stars move in the sky relative to specific points on the earth due to the earth's rotation. Geostationary satellites are stationary relative to points on the earth. Hence the stars move but the satellites don't. |
Glint
Member Posts: 1040
From: New Windsor, Maryland USA
Registered: Jan 2004
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posted 10-12-2010 02:19 PM
quote:
Originally posted by NovaRob:
One of the images is titled "Four Geostationary Satellites Above The Sierra Nevada", but shows what look to be standard star trails...
I do see four "point" source objects viewed when zooming the image. Two are along the top edge, in the upper left corner, and over toward the right corner. Then there are two others. One is just left of the brightest star trail, and directly above it's lower end. The other is below the 2nd brightest star trail, forming a nearly equilateral triangle with its endpoints.However, given that geostationary objects are by definition spread over the equator, I would think that all four should be nearly co-linear when viewed from a given site. So perhaps the photographer is referring to some other artifacts in the image. Although the latitude of their subsatellite points is zero degrees, because of the parallax effect, geostationary satellites positioned near the meridian, as viewed from my location in Maryland, are always located linearly along a line coinciding with a Declination of -6 degrees. |
NovaRob
Member Posts: 242
From: Tucson, Arizona, USA
Registered: Nov 2008
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posted 10-12-2010 03:57 PM
Wow, you've got good eyes. I see the stationary points now, but I really had to search for them, even with your prompts. I don't know if that's what the caption refers to. Maybe the book clarifies it. (Upon zooming, I also see more than four trails, so I guess I misinterpreted the photo in my first comment.) |
Glint
Member Posts: 1040
From: New Windsor, Maryland USA
Registered: Jan 2004
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posted 10-12-2010 07:19 PM
About 10 years ago I had a web site with tips for observing satellites. Courtesy of the "Wayback" machine, here's the page for observing geostationary satellites. Great project for even small telescopes. | |
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