[AZ-Observing] Messier Marathon Site Horizon Profile
- From: Tom Polakis <tpolakis@xxxxxxx>
- To: AZ-Observing@xxxxxxxxxxxxx
- Date: Wed, 15 Feb 2012 10:23:05 -0500
While AJ Crayon was discussing the site of the upcoming Messier Marathon at the
last SAC meeting, I heard a voice come out of the crowd claim that the
mountains in the direction that M30 rises are 6 to 8 degrees tall. This
estimate sounded high by at least a factor of five, since a rise in 1000 feet
would have to be less than two miles away to be reach 6 degrees. And the
airfield site is as flat as a pancake for miles to the east. Since I didn't
know the real value, I kept my mouth shut.
There had to be some measurements out there, and who better to know them than
Mister GPS himself, Rick Tejera? Several years back, Rick did a survey of all
of the high points along the local horizon at the Salome Emergency Airfield
site. He recorded elevations and distances and then did the trig to put
together the altitude vs. azimuth table below. Since M30 rises at an azimuth
of roughly 120 degrees, it looks like the elevation of the horizon is 1 degree,
at worst. This horizon will have no effect on the visibility of M30 at dawn.
Even with an ideal horizon, you'd never see M30 through that first degree of
desert horizon crud, anyway.
Tom
Azimuth Altitude
2 1.07
21 0.31
45 0.52
49 0.83
70 0.19
75 0.82
78 0.40
80 0.70
81 0.22
117 0.41
122 1.07
135 0.64
161 0.25
167 1.10
178 0.70
189 1.02
212 0.40
226 0.79
231 0.71
235 1.15
253 0.61
255 1.19
261 0.76
266 0.15
271 0.66
276 1.10
284 0.16
288 0.92
294 0.01
300 1.09
301 0.62
311 1.89
314 1.74
315 1.54
335 0.23
345 0.82
349 0.33
354 1.14
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