Quote:
Originally Posted by LewisM
This would mean that SIMBAD, Caltech et al are all wrong, as I got my figures from the official database. If they say the angular dimension translates to 5° x 3.5°, I think they have a better astrophysics knowledge than all of us here. The Messier catalogue dimensions in arc min are more than enough - just divide them by 60 to get degrees and you see there is simply no way the SMC subtends 2° apparent.
The SMC isn't circular - far from it (thus the 5x3.5). If you interpolate that a bit, an approximate 4° circle is produced - FAR from ideal since the shape is more elliptical.
You simply cannot use sin, cos or tan trigonometrically outside of a right angle triangle, so you need to use 3500 LY as the radius (you cannot use a 7000 LY diameter), as the RA triangle is opp 3500, adj 200,000.
But anyway. I'll stick with Messier, NASA, Caltech, Wiki and even Colin  |
Thanks Lewis
Angular dimension is there for all to see. Error must be in stated diameter or distance as stated in ly not in angular size as seen from Earth. For a three dimensional object the maximum length as seen from any angle cannot exceed root 3 x maximum side length. Even if SMC was a cube of side length 7000 ly it should have no more than 3.5 degrees angular at dimension as seen from Earth. If it is a sphere of diameter 7000 ly then it should be no more than 2 degrees at maximum. An ellipse or circle cannot exceed that.
No argument with what can be observed ie angular size, only with what is inferred ie distance or diameter in ly. Quoting Caltech etc on angular dimension does not prove actual diameters in ly.
Don't forget NASA sent Hubb lie into orbit with a spherical mirror by accident.
Cheers
Jim