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neB
20-10-2006, 04:11 PM
It makes good sense for star charts and other astro maps to have East and West swapped, but why is North always at the top?

Now, I don't turn my roadmaps around so I'm always travelling "up", but just about everytime I get a starchart (or moon map) out I face North, lift my chart skyward, only to find North now pointing South and have to turn the chart "upside-down" or chuck an about-face.

Am I the only one who does this!

Why is it so?

I do remember reading somewhere that NASA (or US DoD) forced this standard for moon maps during the Apollo program - but for star charts!

P.S. I had my old star-chart out last night - I got it in 1983 while studying first year Astronomy at Qld Uni - and noticed the price tag - $3.95.

Gas Giant
20-10-2006, 04:30 PM
Hi neB.
Are you using a whole sky planisphere? The way you generally use one for our latitudes is to hold it overhead, face south, with E on the planisphere to your left, and S in front. When you've identified a major constellation, such as Scorpius or Orion, face that part of the sky and orient the planisphere so it matches that part of the sky.

The Chandler version is excellent, in that it is double-sided, so that for the N part of the sky youi simply face N instead of south and use the other side.

For star charts used for finding Deep Sky Objects, just get the right chart for the area you are looking at; hopefully you can identify a at least a couple of stars then just orient the map accordingly.

That North is at the top is just a convention. If you were turn a globe of the world upside down it would be just as accurate.

My favourite star-hopping set of charts is the Herald-Bobroff Astrolatlas. It has one series of charts for looking at the northern constellations oriented so that you don't have to read the names of objects upside-down.

Hope this spiel helps.

rmcpb
20-10-2006, 08:18 PM
Have a look at Taki's site (http://www.asahi-net.or.jp/%7Ezs3t-tk/index.htm) it has some really great treasures especially the star charts. The mag 6 chart is orientated for the hemisphere and the 8.5 chart is just mind blowing considering the price - zip.