Quote:
|
Originally Posted by janoskiss
Chris, each chart will show just a portion of the sky. You have a spherical coordinate system with right ascention in hours (0 to 24 corresponding to 0 to 360 degrees around the celestial equator) and declination (-90 to 90 degrees as measured from the cel. equator to cel. poles). The charts should have these marked from which you can figure out how they join up to cover the whole sky.
|
Thanks for your help everyone. I should have made my question a little clearer...
I can see how the maps fit together, but I'm not sure how to know which map will be needed for a particular section of sky on any given day/hour (or is that just too complicated?)
Is there anyway of knowing which one will be of use or that just something that has to come with time? (for instance is "0 hrs" directly above Greenwich at midnight - which would make 10 hrs directly above Melb at midnight during EST? ..... or something like that?)
I'm sure I could just get one out at random and back-track from there, but I like to know how things work.
Quote:
|
Originally Posted by janoskiss
You cannot have charts that are the "right way up" all the time because the sky is looks different at different times of the year and at different times during the night; e.g., right now, the Southern Cross is "upside down" after sunset but it is the "right way up" by dawn.
|
That's true, but if I'm not mistaken, charts that are flipped will more often look correct for anything in the northern sky? ie - I've never seen Orion the "right way up" before.
I'm sure I'll get used to flipping things in my head. I had the sudden realisation the other night that I was moving my telescope 'the opposite way' - ie I was compensating for things being reversed without being conscious of it.
