Probably a stupid question

[smulx]

I just got The Illustrated Guide to Astronomical Wonders and was taking a look through it, and noticed that the explanations for finding things use the cardinal directions. After I thought about it, this confused me a bit. If I'm looking at a star, which way is north of it? Is it directly above, or is it above but perpendicular to my line of sight? Or something else?

Seems like a stupid thing to ask, bit it just confused me.

[Revs]

Good question, I'm not sure. I say we sent someone with a compass to find out

[Merlin66]

The direction of "north" will vary with the position of the object in the sky. "North" is always towards the pole star. Google "ra and dec" or "astronomical coordinates"

Astronomical coordinate systems - Wikipedia, the free encyclopedia

[perrin6]

If you aren't using a motor drive, West is always the direction the star is moving in therefore North is 90 degrees clockwise from it. I use this to estimate the position angle of double stars. Thanks for that as that's another reason for me to be glad I have a dobsonian as I don't have to fiddle with a switch to turn a motor off to find out where North is, it's immediately obvious as soon as I look in the eyepiece !

Alan

[brantuk]

You will find you'll want to look South most of the time initially - same for all new scope owners. Cos that's where the ecliptic is (a line followed by the planets) and your first targets are bound to be planets.

So it's dead easy to remember that North is behind you, East is on the left, and West on the right. And tracking is done in Right Ascension from L to R.

East and West are simply reversed to the way they look on a map when you stand your scope facing South.

Of course - to polar align you'll want to swing the scope around to the North - the pole star is dead easy to spot on a clear night

[smulx]

I'm not sure if I'm just misinterpreting what you're saying, but I thought my question wasn't really related to N, E, S and W as shown by a compass. I'll copy an example from the book...

From m2 Alpheratz, which is the NE star star in the Great Square of Pegasus, hop 6.9o ENE to m3 and then 7.9o NE to m2 mirach.

So even if I was stood with a compass, obviously I'd easily know which way was NE in relation to the north pole, but I don't understand how this can also relate to moving from star to star which occupy the same tiny patch of sky.

Does that make sense? I don't know if I'm looking at it the wrong way.

[Merlin66]

If you're using a telescope - see Alan's #4 post....

If you're using binoculars then think about the relative star positions as you move the binos

[perrin6]

It just takes a bit of practice to get oriented. When facing South, the North East star of the square will be the top left one because East is left & North is up & behind you, (the last bit sounds confusing unless you imagine a grid of lines projected on the sky. Look up an imaginary vertical line & your eye moves overhead then behind you to the North, when facing South).

Alan

[brantuk]

If you have Stellarium then switching on the grid lines and cardinal points may help. You have a choice of alt/az grid or RA/Dec grid. Switch them all on if you really want to get confused lol

[MikeWilson]

If you have Stellarium then switching on the grid lines and cardinal points may help. You have a choice of alt/az grid or RA/Dec grid. Switch them all on if you really want to get confused lol

I always wondered why Stellarium allows you to switch them all on instead of either/or! When I first started Stellarium they were both on and I was pretty confused!

Also confusing is how Stellarium has a filter for "Nebulas" which isn't really nebulas at all but just the M & NGC catalogues. Should be called "Deep Sky Objects" or something....

[smulx]

Thanks everyone, I think I get it now.