"mas" - what is this unit?

[erick]

On this image:-

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

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

Thanks

[michaellxv]

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

[erick]

Ah yes, obvious now :ashamed: !!

Many thanks Michael.

[michaellxv]

actually it was just a lucky find :P but wikipedia is good like that.

[Robh]

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]

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

[Robh]

You are quite right. :thumbsup:
It should have been 1.1 billion kms. I inadvertently doubled it thinking I had the radius of the star.

Apologies, Rob

[Clayton]

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