Retrospective on HCRO in New Mexico

Dark Matters Astrophotography · May 6, 2026, 04:32 AM

The seeing in Pie Town is EXCELLENT most of the time. If you are deployed to other places in New Mexico like Rowe or Animas, then you are in for a treat if you move to Pie Town. The WORST nights in Pie Town are the same as the BEST times in Animas and Rowe. This is not very surprising though as the NASA VLA is not far from this location.

This is an interesting comment in that I didn’t know that optical seeing was a factor in radio astronomy. I always thought that its location was picked because it is relatively radio quiet in terms of local sources.

Bob Lockwood · May 6, 2026, 04:27 PM

Astrophotography Workshop Announced at Iconic Very Large Array - National Radio Astronomy Observatory

Wow, I wish I had known about this… I would probably have gone there just for the experience.

Back before COVID and the fires, Kitt Peak had an astrophotography course which I attended. And while I no doubt learned much more from sources other than the course, the experience of spending two nights at Kitt Peak and having a guided tour of the observatory was very worthwhile.

Arun H · May 6, 2026 at 01:29 PM

Thanks, Bill. This is very useful.

HCRO claims 275-300 clear nights a year. Is that reasonable or would you say what they get is less than that?

The 275 side I would say is probably the most accurate. It really depends on the intensity of the Monsoon Season, and the precursor to it. There is also this strange high cloud cover that does plague the area. It's clear, and the roof is open but you will get minor raccoon-eyes in the brightest of your stars at times due to a very very thin layer of really high clouds. This is less impactful to higher resolution systems, but folks with wide-field rigs have noted it quite prominently.

Tony Gondola · May 6, 2026 at 04:08 PM

This is an interesting comment in that I didn’t know that optical seeing was a factor in radio astronomy. I always thought that its location was picked because it is relatively radio quiet in terms of local sources.

The point was that government investments occurred in the area for the purposes of Astronomy. Usually, NASA is not going to drop that much gear to run at a crappy site. You overthought this one dude. The site is also used for outreach, astrophotography and other events of great interest to people. So it was only interesting to you because you did not bother to look into it at all and just rattled off some theory.

Arun H · May 6, 2026 at 05:00 PM

Wow, I wish I had known about this… I would probably have gone there just for the experience.

Back before COVID and the fires, Kitt Peak had an astrophotography course which I attended. And while I no doubt learned much more from sources other than the course, the experience of spending two nights at Kitt Peak and having a guided tour of the observatory was very worthwhile.

For sure! The size of the scopes they have there in the VLA are crazy. Gigantic scopes and lots of them. I guess they plan to redo the whole array design with even larger ones at some point. That is local (to Pie Town) rumors though. :)

It attracts a lot of people, as it is on the New Mexico Dark Sky Corridor. As is the site I mentioned (HCRO).

VLA belongs to NRAO, which is funded by NSF. NASA is not involved whatsoever. I know this because I was an NRAO scientist working at VLA’s operation center in Socorro. (NRAO headquarter is in Charlottesville, Virginia.)

The location was picked because it’s :

1. relatively radio quiet (for obvious reasons),

2. dry (so high frequency observations at 10-50 GHz can be more easily done without being affected by water vapor absorption),

3. and big and flat (so antennas can be easily deployed, moved, and stay connected over many miles).

Because of requirement #2, it is even slightly higher than Kitt Peak observatory. It is a very large flat area, so it is hard for low-altitude turbulence to develop. I guess this contributes to its good optical seeing.

I worked there for 2.5 years. I went to the VLA site to take astrophotos occasionally, with film at that time. Sitting next to the scope in the dark for hours for manual guiding while hearing packs of coyotes migrating through within distances of just 20-40 ft, was exciting the least to say (there are fences around me). Unfortunately I can’t confirm whether seeing is good there. Film on a small refractor does not have the resolution to tell good seeing from bad seeing.

Wei-Hao Wang · May 9, 2026 at 04:21 AM

Unfortunately I can’t confirm whether seeing is good there. Film on a small refractor does not have the resolution to tell good seeing from bad seeing.

On the topic of seeing in that general area, with HCRO being about 30 minutes farther to the northwest of the VLA site. I have a CDK14 at HCRO and started studying seeing analysis in early 2025 as part of my engagement in speckle interferometry of double stars. Due to that, I have been working with Greg to get the seeing monitors he has integrated into HCRO’s site-wide Alpaca ObservingConditions API. All HCRO users can use this in their respective imaging apps. Long term and seasonal tracking of nightly seeing data is the goal.

HCRO has two different seeing monitors: an Alcor System Cyclope and a Santa Barbara Scientific SM-3. Both sit adjacent to each other and both are the SIMM (Single Image Motion Monitor) type, where they stare at the NCP and analyze the seeing as it affects Polaris. That seeing is then scaled to zenith, as that is the normative reference point, using a turbulence-airmass scaling algorithm.

Getting seeing data (in units of arcsecond FWHM) into an ASCOM or Alpaca ObservingConditions ecosystem isn’t easy since the vendor-provided software for these seeing monitors makes little to no mechanism for that kind of integration in an architecturally stomachable manner. Both softwares’ primary outputs are periodic graph images and a CSV file of measurements. Not great.

I did discover that the software which operates the Alcor Cyclope has an undocumented TCP API, so I reached out to Alcor and got documentation on it. I used that info to create a Python-based bridge to it that exposes the seeing value on an Alpaca ObservingConditions API endpoint. The SBS SM-3 was still limited in its output. It uses a QHY camera so I took my experience programming for those and combined that with my seeing research to product a standalone replacement for the SBS app that outputs graphs and time-series telemetry, along with providing seeing data over an built-in Alpaca ObservingConditions API. Since HCRO’s Unihedron SQM unit was in a similar situation, with the Knightware SQMReaderPro app that ran it offering only a scripting interface, so I added support for that as well.

The seeing and SQM graphs on the HCRO telemetry page are from my app which also provides the the SkyQuality and StarFWHM properties in HCRO’s site-wide ObservingConditions endpoint (ran by the excellent Dark Dragons Draco system). The Cyclope’s own graphs are there for comparison. I also have this feeding an InfluxDB time-series database, which I graph here.

Tony Gondola · May 14, 2026, 12:18 AM

Dale Ghent · May 13, 2026, 07:07 PM

The seeing and SQM graphs on the HCRO telemetry page are from my app which also provides the the SkyQuality and StarFWHM properties in HCRO’s site-wide ObservingConditions endpoint (ran by the excellent Dark Dragons Draco system). The Cyclope’s own graphs are there for comparison. I also have this feeding an InfluxDB time-series database, which I graph here.

This exhibits what I see from most sites, a great deal of variablity.

Seeing is indeed quite variable, even on the “best” nights anywhere. It definitely never flatlines! The shoulder seasons of spring and fall, when the jet streams reconfigure themselves and seasonal weather patterns change over, tend the be the time of most tumult.

Time-series data collection began in last fall when I instrumented the Cyclope software, then transitioned to mine around March, so it’s still too early to discern long term patterns. What I have noticed is that the winter months saw longer periods of generally lower arcsecond FWHM compared to the preceding fall and current spring. Now, we still see periods of low seeing however the variability is greater. My next goal with the stats is to provide more long term analysis now that a body of real data is being built up.

The differences in global weather pattern changes on the regional scale will also be interesting to watch in the long term. We are entering (or have recently entered) a “super El Niño” year which definitely affects weather front activity throughout the US southwest. I have been able to match fronts and troughs on forecast maps that pass over the area reflected in the seeing data.