"mas" - what is this unit?

erick (Eric) · #1 09-01-2010, 09:46 PM

On this image:-

http://antwrp.gsfc.nasa.gov/apod/ap100106.html

I'm not familiar with "mas" and cannot guess?

Thanks

michaellxv (Michael) · #2 09-01-2010, 09:50 PM

milliarcsecond http://en.wikipedia.org/wiki/Minute_of_arc

erick (Eric) · #3 09-01-2010, 09:55 PM

Ah yes, obvious now

!!

Many thanks Michael.

michaellxv (Michael) · #4 09-01-2010, 09:59 PM

actually it was just a lucky find

but wikipedia is good like that.

Robh (Rob) · #5 10-01-2010, 10:50 AM

The APOD info on Betelgeuse is a fascinating read.
Amazing they can image a disk let alone "see" any surface features.
According to the information given (angular diameter about 40 mas from the image, distance 600 light years), I calculate the diameter of the star as roughly 2.2 billion kms!

Thanks for posting,
Regards, Rob.

Clayton · #6 10-01-2010, 11:48 AM

Hmm? I get 1,100,475,270 kilometer

Robh (Rob) · #7 10-01-2010, 02:41 PM

Quote:

Originally Posted by Clayton

Hmm? I get 1,100,475,270 kilometer

You are quite right.

It should have been 1.1 billion kms. I inadvertently doubled it thinking I had the radius of the star.

Apologies, Rob

Clayton · #8 10-01-2010, 10:31 PM

No problems. My first answer was out by a factor of 10 as I had the decimal point in the wrong place