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What unit of measure is mas?
Posted: 09.12.2008, 16:46
by jdavies
Just a noob question. Going through the Hipparcos data files I see that some fields have "mas" as their unit of measure. Fields like the Proper Motion for both the right ascension and the declination are measure in mas, as are some of the standard error measurements. What is a "mas"?
Thanks in advance!
- Jeff
Re: What unit of measure is mas?
Posted: 09.12.2008, 17:29
by granthutchison
Milli-arc seconds. A thousandth of a second of arc, which is one 3600th of a degree.
Grant
Re: What unit of measure is mas?
Posted: 09.12.2008, 23:19
by jdavies
Thank you!
Re: What unit of measure is mas?
Posted: 10.12.2008, 00:49
by julesstoop
Hmm?
Isn't one arc second 1/60 of a minute of arc, which makes a thousandth of a second of arc 1/60.000* of a minute?
(instead of 1/3.600**)
*60'000
**3'600
Edit: Sorry, only got to me now
1 arc second == 1/3600 of a degree.