Re: Notes on Magdalena, New Mexico, and the Route 60 Corridor


John W Briggs
 

It's a good thing to bring up the general issue of wind and dust.  Until one has a chance to live in the Southwest, it's easy to underestimate how significant the spring windy season is.  I moved here (NM) as a native of Massachusetts.  Likely the first seasonal thing one learns about here is the monsoon season that normally runs through the summer.  At Sunspot (originally a site of National Solar Observatory), a local joke was that the monsoons started immediately after the July 4th holiday weekend.  But it was amazing how often this seemed exactly true, at least while my family and I were there!

The effect of the monsoons is for an afternoon buildup of thunderstorms that often last through at least the first half of the night.  The second half, however, can be wonderfully clear.  Nevertheless, professional observatories in the Southwest, like Apache Point, typically schedule major engineering projects and other observing shut-downs during the monsoon season.

In the spring, however, the problem is the wind, and as far as I've learned, it's a problem everywhere in the Southwest.  In our experience so far here in Magdalena, the worse month is April.  This year, it seemed to start early and end late.  My impressions are very subjective of course.  But what is certainly true is that there's a regular annual season of high wind that's very significant to astronomers.  Professional observatories often have dust monitors that can trigger quick closings during "dust events."  The most serious issue can be windblown pine pollen that's potentially sticky on optics.  In turns of housecleaning, windblown dust pushing through door frames and windows can be a bit obnoxious, no denying it.  

But lest I sound too negative describing these issues, I think most of us living here will agree that we're very grateful for the overall astronomical advantages of the Southwest.  One should just be prepared for the details that come with a particular environment.  For example, we're very sensitive to seasonal issues when we plan our annual Enchanted Skies Start Party that's begun to attract repeat participants coming from as far away as Switzerland.  We would naturally not schedule that in either the monsoon or the windy seasons.  An operation running short-term rentals is not likely to get many astronomers renting in those seasons.

At the high altitude of Sunspot (over 9,000 feet), one advantage was that often it seemed the gypsum dust of nearby White Sands National Monument would not reach all the way up to the observatory during the windy times.  (But sometimes, on the other hand, it sure would!)

A final class of environmental issues that may catch newcomers off-guard is how very serious moths and ladybugs can be getting into scientific equipment in huge clumps at some locations.  These insects were awful pests at Sunspot and Apache Point.  At the lower altitude of Magdalena (6,500 feet), they don't seem such a problem.  Not yet in my experience here, anyway!

Finally, I attach following right below another message I recently sent out to local astronomers and interested community friends.  In the last month or so, we've been making a particular effort here to get all-sky and weather information for FOAH Observatory on the Internet.  It's not hard.  But it took enough work that I was glad being able to brag a bit in sharing it, as follows:            (--JWB.)

###

Check out this link to the weather station now running on the FOAH Observatory hilltop:


The wind is typically much more severe at the hilltop than it is in the Village to our south or even at our house at the bottom of the little hill.  The altitude at the hilltop is exactly 6500 feet or 1981 meters, per Google Earth.

The weather instrument is an Ambient WS-2902B and cost about $170, not counting the hardware to mount it securely about 7 feet above ground on the hill.  (I've been up there at times it seemed my F-350 pickup was gonna blow off!)

Links to our all-sky camera, now running regularly pretty well, are here:


The Clear Sky Chart specifically for FOAH Observatory is here:


FOAH has an assigned IAU observatory code, V23.  This allows computations of JPL ephemerides specifically for FOAH and is thus especially useful for pointing to near-Earth objects that may have significant horizontal parallax.  Enter V23 as necessary to define the site:


--JWB.



On Tue, Jun 2, 2020 at 11:30 AM maxeem <maxeem@...> wrote:

Then this may be another argument for why it may be better not to establish in Southwest NM. I watch the dust column index (personal health reasons) and SW New Mexico all the way up to Silver City gets hit when the winds blow it North. The forested area might be a breaker, leading to less obfuscation if you can get above the tree lines.

According to the measurements given anyway, dust will also get up to Albuquerque or further at times, but not as thick or as often? Haven't paid much attention to Texas but the times I've seen it it's largely in West TX blowing West-Southwest.

Just a fun and useful tool for gathering data from weather.gov

Maxeem


On 6/1/20 4:15 PM, David Oesper via groups.io wrote:

John,

I'm so glad you mentioned the importance of astronomical seeing in choosing a site. It certainly must be a key consideration. Is there a DIMM that is commercially available? If not, we may need to borrow one of yours (or make one ourselves) when we are ready to evaluate a site.

Thanks for the link to your poster paper!

To the group, here's some more information about astronomical seeing. Perhaps an oversimplification (John?), but it does give you a good introduction. For starters, you want to be on the prevailing-wind side of any mountains or hills to avoid being on the receiving end of any topography-induced turbulence.

http://www.ifa.hawaii.edu/~meech/a281/handouts/seeing.pdf

Dave

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