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Hi Astro AJ,
I think it will depend quite a bit on what you are observing and what the conditions are like.
One example is Mars at the moment. At best it is less than 30 degrees above the N horizon and the seeing will never be consistently good there -- indeed it will be rarely good let alone very good or excellent.
On an average night's seeing there will only be maybe 5 or so seconds out of 10 minutes when the seeing will settle to the point where most of the available detail will be apparent to the eye. If you are not at the eyepiece when that happens you miss out. In this situation it would be common for me to spend 20-odd minutes on Mars out of which perhaps 30-odd seconds will be truly worthwhile and your task in those 30 seconds will be to see and record in the brain-box or on paper as a sketch, as much as possible.
As for deep-sky observing, the seeing does play a role but not a big one -- transparency is more important and it does not vary from minute to minute so the view per-se won't change. But your eyes will. Move away from the scope and look at a map (even with a dim red light) or a lap-top or what-not and you loose _a degree_ of dark adaptation. Time spent at the eyepiece looking at a dark field will bring it back in. Also a lot of deep sky objects, particularly very faint galaxies or PNe are only one or so percent brighter than the native sky background. It will take time to notice them if they are really faint -- even if you do know precisely where to look. Time staring through the eyepiece does that.
My general routine (for what it is worth) if I am going through a list of galaxies or PNe, is that I will look at my paper list and find the catalogue number of the next object to look at. Then go to the laptop (with a _heavily reddened_ screen) and look it up on megastar and see the field and then superimpose a real-sky (DSS) image so I know what to look for and the star patterns. Go to the scope, dial it in on the Argo Navis and hit the slew button. Slew finished I look in the eyepiece and confirm (using star-patterns etc) I'm at the right location from the DSS/Megastar. All this takes maybe 90 secs to 2 mins.
Then I spend a _minimum_ of 3-5 minutes looking -- just looking and trying to see as much as possible. There might be three or four galaxies in the field -- hunt them! While this is going on my dark adaptation from looking at the screen is coming back to maximum.
After this time I whip out the Dictaphone and speak some notes on the galaxies in the field. What size are they? What PA? Distances from each other? Superimposed stars? Internal structure? Nucleus? Etc etc. This takes about another 3-5 minutes. Then move on to the next thing on the list.
Assuming there are no changes in eyepiece or identification/finding probs, an observation of a field takes about 8-10 minutes. The field might contain one object, or maybe 5. In this way I usually manage to get through about 15 objects per hour.
My observing is not always this "structured" though. I take little breaks, enjoy the naked-eye view of the sky etc. There are of course many, many occasions when I don't bother with a list and just look at favourites. But, I still spend a minimum 3 minutes each.
Longer at they eyepiece? Yep, you see more!
Best,
Les D
Contributing Editor
Australian Sky & Telescope
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