Thursday, November 16, 2017

checking visibility part 4

Chris jumped into the "best day to observe" thread. He said:
You could also add (or subtract) twelve hours to (from) the desired object's R.A. and then adjust the date to place the sun at the calculated R.A... Then revert to night time and adjust the hour to put the object on the meridian.
Ah. Is it that simple? By adding (or subtracting) 12 hours against the target RA, it puts the Sun opposite the target. And then the target will be high in the night sky.

This gets it near the meridian at midnight.

What a cool trick.


Not knowing the sky, in my head, in terms of celestial coordinates, I would still have to use software. And if you fire up Stellarium to do all this, then, well... you can just go to the object and figure it out that way... If Nick is after a calculation he can do in his head or do on a scrap of paper, I'm not sure it is possible now.

Ed has been alluding to this in a way in his comments that the "best night" is also impacted by other factors. The big one, for me, is moonlight. If you're going for dim fuzzies, you want maximum elevation on dark nights. The elevation is pretty easy to get. But then the lunar cycle comes into play...

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