Brian W
03-10-2008, 03:52 PM
Hi all, today I was comparing the messier M31, 32, 110 sketch with what i have been observing through my 8" reflector. There are many differences between his sketch and my observations.
Most of these differences can be attributed, undoubtedly, to the differences in the equipment used and his undoubtedly superior viewing skills. However there are two differences that puzzle me.
(1) his sketch shows an almost edge on view while what I see has a tilt that is moving towards 'face on'.
(2) his sketch shows a central bulge that is circular with almost equal amounts above and below the plain of M31 while I see the bulge more as a classical flying saucer half circle.
My questions are; (1) has M31 moved enough in the last 100+ years to account for the change in basic shape between my views and his or do I just need to improve my observing skills? (2) is the difference explained by the fact that he observed from Europe and I am near the equator?
Brian
Most of these differences can be attributed, undoubtedly, to the differences in the equipment used and his undoubtedly superior viewing skills. However there are two differences that puzzle me.
(1) his sketch shows an almost edge on view while what I see has a tilt that is moving towards 'face on'.
(2) his sketch shows a central bulge that is circular with almost equal amounts above and below the plain of M31 while I see the bulge more as a classical flying saucer half circle.
My questions are; (1) has M31 moved enough in the last 100+ years to account for the change in basic shape between my views and his or do I just need to improve my observing skills? (2) is the difference explained by the fact that he observed from Europe and I am near the equator?
Brian