Doh! RA confusion

[asteria]

Hi there - I've been trying to work this out in my mind - let's say an object is at RA 11H 30M, and another object is at RA 10H 30M. Is the second object considered to be east or west of the first (in terms of RA), or is the directional position described in some other way? For the sake of the question, let's assume the celestial latitude is roughly the same for both 'objects'.

Maybe I'm mixing up frames of reference here. Any helpful advice will be welcome.

Ed

[Talitha]

RA 10hr 30' is west of RA 11hr 30'.

The 10th hour of RA rose in the east an hour before the 11th hour did,

and will set in the west an hour earlier than the 11th hour will.

[ngc2403]

yeah that is correct,

the RA system is used to better relate the position in the sky with the time. however it is a difficiult thing to grasp and i don't want to confuse you, me and everyone else who might try to read my post on it

ally

p.s. 'frame of reference' have you been at the general relativity books?

[asteria]

Hi - thanks for the feedback - I posted some directions to M13 from pi Her in another thread and described it as "east" of the star, but afterwards thought that this couldn't be right. M13 is west of pi Her as it at RA 16H 45M (approx) and the star is at RA 17H 15M (approx). I used to have a lot of trouble finding M92 and M13 but now I've worked out this method it's much easier using a eq mount. Find pi Her - M92 is due north; M13 is due west.

OK - I think that's sorted it out!

Ed