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Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
Is it just the normal 'twinkling' of the star?
I don't normally notice color variations in twinkling stars, but some old satellites have a very distinct color twinkling which I believe is due to diffraction in the solar cells (just like an oil slick).
Registered Member #10
Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424
... wrote ...
Is it just the normal 'twinkling' of the star?
Correct. You win. From the nursery rhyme "twinkle, twinkle little star..." It is simple twinkling of Alpha Centari, the 3rd brightest star. So what is "twinkling"? This photo suggests it is colour and intensity changes on a tens of millisecond scale. The Star was fairly low in the sky hence presumably greater atmospheric effect.
It was taken with a 180mm lens and the camera was moved manually in an arc on the tripod during a 5 second exposure. What you see here is perhaps 1-2 seconds of transit. So perhaps 1 pixel per millisecond on this 1000 pixel wide reduced image.
I took it with a view to seeing what the International Space Station might see for a light on earth as bright as a bright star with a camera swept across rather than tracked. This is for my project hoping to get the ISS to receive a morse code message from my world's brightest flashlight. My web site discussion and pics on it are here . Best to have further discussion on the "seen from space" topic here World's brightest flashlight thread though. Has anyone else taken a pic of this effect? If so start a new thread and leave a link to it here.
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Mystery Photos from TDU
