Starship Asterisk*

[quote="AlexFR"]Hello and thank you for your nice comments,

The individual frames were taken the night between the 24th and 25th of January but the star trail was made the 26th January.

Here is the time lapse of this star trail : http://www.flickr.com/photos/santerne/6759626677/in/photostream/

cheers

Alex[/quote]

Thank you Alex for that clarification. :)

Hello and thank you for your nice comments,

The individual frames were taken the night between the 24th and 25th of January but the star trail was made the 26th January.

Here is the time lapse of this star trail : http://www.flickr.com/photos/santerne/6759626677/in/photostream/

cheers

Alex

In the explanation it states the image was taken "about 4 hours on the night of January 24", which could therefore be partly or all in the early hours of January 25. However, in the information brought up through the "the image is" link it states "This photo was taken on January 26, 2012". I wonder what is the correct date :?:

I really liked this APOD, the way the photo shows both North & South views is really brilliant and something I haven't seen before. Very very nice!

damn hot pixels!

[quote="Chris Peterson"][quote="moconnor6"]So I have what I would call a "newbie" question. Is the length of all of the arcs exactly the same?
I understand that they are formed by the earth's rotation, but the entire earth is moving, too, as so are the stars. I assume that they are not necessarily moving in the exact same direction. Some stars may be moving to the left, others to the right, others up or down. Are the distances involved so great that all of the arcs are parallel to each other and are the exact same length?[/quote]
Any shifts induced by the motion of the Earth in its orbit, or by the proper motion of the stars, are unmeasurably small over the few hours an image like this requires. So the arcs are all parallel (concentric might be a better word), and all have the same angular length (naturally, stars closer to the pole generate shorter arcs in terms of their actual path length).[/quote]
Fascinating stuff. Thanks, Chris.

[quote="moconnor6"]So I have what I would call a "newbie" question. Is the length of all of the arcs exactly the same?
I understand that they are formed by the earth's rotation, but the entire earth is moving, too, as so are the stars. I assume that they are not necessarily moving in the exact same direction. Some stars may be moving to the left, others to the right, others up or down. Are the distances involved so great that all of the arcs are parallel to each other and are the exact same length?[/quote]
Any shifts induced by the motion of the Earth in its orbit, or by the proper motion of the stars, are unmeasurably small over the few hours an image like this requires. So the arcs are all parallel (concentric might be a better word), and all have the same angular length (naturally, stars closer to the pole generate shorter arcs in terms of their actual path length).

So I have what I would call a "newbie" question. Is the length of all of the arcs exactly the same?
I understand that they are formed by the earth's rotation, but the entire earth is moving, too, as so are the stars. I assume that they are not necessarily moving in the exact same direction. Some stars may be moving to the left, others to the right, others up or down. Are the distances involved so great that all of the arcs are parallel to each other and are the exact same length?

I am soooooo dizzy!!!

:---[===] *

The star trails seen in the ESO mirror also appear to contain auroral rings perhaps? The ring is more or less complete and seems to show the southern horizon which is a dark circle. I believe it was quite likely aurora on Jan 24 did occur.

[url=http://apod.nasa.gov/apod/ap120202.html][img]http://apod.nasa.gov/apod/calendar/S_120202.jpg[/img] [size=150]La Silla Star Trails North and South[/size][/url]

[b] Explanation: [/b] Fix your camera to a tripod and you can record graceful [url=http://www.astropix.com/HTML/I_ASTROP/TRIPOD/TRIPOD2.HTM]trails traced by the stars[/url] as planet Earth [url=http://apod.nasa.gov/apod/ap070519.html]rotates on its axis[/url]. If the tripod is set up at ESO's [url=http://www.eso.org/public/teles-instr/lasilla.html]La Silla Observatory[/url], high in the [url=http://apod.nasa.gov/apod/ap110811.html]Atacama desert[/url] of Chile, your star trails would look something like this. Spanning about 4 hours on the night of January 24, [url=http://www.flickr.com/photos/santerne/6762995775/in/photostream/]the image is[/url] actually a composite of 250 consecutive 1-minute exposures, looking toward the north. The [url=http://apod.nasa.gov/apod/ap101224.html]North Celestial Pole[/url], at the center of the star trail arcs, is just below the horizon in this southern hemisphere perspective. In the foreground, the polished 15-meter diameter dish antenna of the [url=http://www.eso.org/public/images/esopia00049teles/]Swedish-ESO Submillimeter Telescope[/url] (now decommissioned) shows star trails toward the south by reflection. Sweeping around the [url=http://apod.nasa.gov/apod/ap061202.html]South Celestial Pole[/url], the distorted arcs of those stars appear underneath the southern horizon in the focusing dish's inverted view. Right of the dish is the dome of the observatory's 3.6 meter telescope, home to the planet hunting [url=http://www.eso.org/sci/facilities/lasilla/instruments/harps/]HARPS[/url] spectrograph.

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