FreeLists / az-observing / [AZ-Observing] Re: R: 2008 All Arizona Messier Marathon - results

["AJ Crayon" <acrayon@xxxxxxx>]

Brian, nautical twilight for the MM, Saturday, April 5th was 19:44 MST, 
which is about 30 minutes earlier.  This means it would be about 7 deg above 
the horizon.  Still pretty low.

George Robinson's check list indicates M77 was viewed at 19:51, putting it 
about 5.6 deg above the horizon.  I say about because the mountains and 
elevation weren't taken into consideration for this measurement.

AJ Crayon
Phoenix, AZ

----- Original Message ----- 
From: "Brian Skiff" <bas@xxxxxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Friday, April 11, 2008 1:17 PM
Subject: [AZ-Observing] Re: R: 2008 All Arizona Messier Marathon - results


>     Since M77 has such a bright nucleus, it is probably recoverable
> in considerable twilight, especially with a well-aligned go-to mount.
> Don't know what the answer is, however.  How high up was it at -12 deg
> solar altitude (i.e. end of nautical twilight)?  The sky is
> probably plenty dark then for M77.
>
>     The bright twilight/low altitude observations more-or-less
> required by the MM, by the way, argues in favor of holding the Marathon
> as close as possible to the optimum date even with, say, 40% Moonlight.
> This is especially so given the horsepower brought to bear on the
> targets (per the rankings list).  As long as it's cloudfree,
> modest Moonlight is not a serious hindrance, and allows you an
> out if the weather's bad to hold it the next weekend (or whatever)
> without the Moon.
>
>
> \Brian
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