Hi Ben,
Quote:
Originally Posted by Benjamin
Love the detail in these observations. Again a bit of a newbie question but how do you measure the PA (or determine where the NCP is?) through the eyepiece? Watching the stars drift could give the East West orientation of things I guess or is it more down to experience?
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Back in the "olden days" using a GEM on my old 31cm or 25cm, I'd give the Dec slow motion a little twiddle either way and that would tell you north & south, and it is easy to work out from there.
Really is it too fiddly to do with a dobson mounted newtonian. I work in the field with the planetarium software Megastar on my laptop. After identifying the galaxy I will look for a couple of stars (that obviously make a line) in the field, then refer to the map and see what way they point, then use this as a reference to determine approximately where north is in the field, and then guesstimate the P.A (if any). With my old GEM, I could reliably estimate PA to within 15 degrees. Using my present 46cm, it is really a guesstimate from either 0, 30, 45, 60, 90, 120, 135, 150 degrees.
Best,
L.