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RE: (meteorobs) Question about Re"best" Perseids observing site
Many factors come into play for determining the best location to view a meteor shower. For this years Perseids, only the third peak at 08:30UT Aug 13 will be favorable for the US. The early and classic peaks at 20:15UT and 22:30UT Aug 12, respectively will occur during daylight here.
Of course, observing the Perseids can and should be done anytime around these or between these peaks to validate activity. For latitudes north of about 30°N, Perseid activity can be followed all night Aug 12-13 because the radiant will be above the NE horizon, albeit very low if you are closer to the southern bounds of latitude. Going north helps, to a degree, especially if you will observe earlier in the evening, because the relative altitude of the radiant will be improved. However, the summer twilight begins to affect you more and more, cutting down the dark hours available for observing. North of about 53° it starts to interfere at the peak time of the third peak in the central part of North America.
Overall, the most favorable locations in North America (from the respect of radiant altitude and twilight) will be in the Great Lakes region. The radiant altitude will exceed 60° at the time of the third peak (4:30am EDT Aug 13) there. Further east, in NY and New England twilight will have begun at the peak time. Radiant altitude will decrease as you head SW, with the worst location being San Diego, CA - a radiant height of only 35° at the peak time.
Of course, climactic conditions play an even more significant role. The dry SW US is a much more favorable location for clear skies than the humid NE! So, finding the best spot involves optimization of radiant height and probability of clear skies. Unless you get lucky with the passage of a cold front in the Northeast, the Southwestern US should be the best place to be.
In regards to the best location in Texas for the third peak (3:30am CDT Aug 13) - NE Texas is best for radiant altitude - 48° at Texarkana vs. 40° at El Paso in the SW. But I would expect much more transparent skies with greater probability of seeing meteors in the dry western part of the state. There may be an advantage to going to Amarillo in the NW because you would gain several degrees of radiant altitude, but will the dry conditions like around El Paso prevail so far north? The difference in hourly rate between a 40° radiant height and 48° is only 15%. Is that worth the risk of getting clouded out?
Mike Linnolt
--- Ed Cannon <ecannon@mail.utexasdot edu> wrote:
> A general question was forwarded to me: "Where's the
> best place
> ... for watching Perseids?" I want to ask this list
> how to balance
> two specific considerations: altitude of the
> radiant versus
> beginning of morning twilight. For example, Fargo,
> North Dakota,
> is about 20 degrees north of Brownsville, Texas, and
> so is better
> with respect to the altitude of the radiant.
> However, morning
> twilight begins 80 minutes earlier in Fargo than it
> does in
> Brownsville. Which would be the better location for
> observing
> Perseids?
>
> (Now I'll disclose that the question really was more
> specific:
> "What's the best place *in Texas* for watching
> Perseids?" But I
> thought comparing Fargo and Brownsville might help
> me get a better
> grasp of comparing two sites with respect to effects
> of difference
> in latitude. Within Texas the two to compare would
> be Dalhart and
> Brownsville. Another pair to consider would be east
> versus west:
> Beaumont versus El Paso, roughly 10 degrees apart in
> longitude.)
>
> With respect to elevation above sea level and
> general climate, I'm
> pretty sure that Dalhart and El Paso -- both being
> dry places
> roughly 1200 meters [4000 feet] above sea level --
> are preferred
> areas. Thank you very much for any insights!
>
> Ed Cannon - ecannon @ mail.utexasdot edu - Austin,
> Texas, USA
>
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