top of page
  • Writer's pictureDale Hill

There's a NASA Control on Cuyamaca!

Updated: Mar 10, 2021

Perhaps one of the coolest survey marks (also referred to as a 'control') that I've found so far is the NASA-Goddard Space Flight Center disc I found today on Cuyamaca Peak. It is referenced in the datasheet during a 2008 recovery (although it's clearly been there much longer than that). Once I started to learn more about survey markers, it's been on my list to go back to Cuyamaca just to find this one.

When I reached the summit of Cuyamaca last year, the weather was pretty bad, I knew nothing of NGS datasheets or of the presence of other survey marks. I was happy to find Reference Mark 3 at the top, get my pictures, and head back down the mountain to get out of the rain.

This time around I was better prepared to hunt down more markers, I ended up finding four markers and a suspicious hole in the rock (more on that later). I missed one that SHOULD have been easy to find (I think it was buried in the snow 🤷🏻‍♂️) and several Brass Plugs mounted flush in various rock outcroppings that I wasn't too interested in looking for in these conditions.

From prior research, I knew that the Cuyamaca Azimuth Mark was located on Stonewall Peak and I'd have to make a separate trip back to Stonewall to find it. The image below an excerpt from the NGS Datasheet for Station DC1974, the Cuyamaca RESET with notations of what I found today (click here for the full datasheet)

DC1974 Cuyamaca RESET Extract from NGS Datasheet

Here's the recap of the day's efforts, clicking on a heading will take you directly to that section of this post.

  1. DC1974 Cuyamaca Reset

  2. CE9236 Cuyamaca Reference Mark (1) 1923

  3. CE9238 Cuyamaca Reference Mark 3 1954 *

  4. (No PID) Cuyamaca 2 1981 - NASA-GSFC

  1. DC1973 Cuyamaca Lookout Tower

  1. CE9239 Cuyamaca RP N Brass Plug

  2. CE9240 Cuyamaca RP NE Brass Plug

  3. CE9241 Cuyamaca RP NW Brass Plug

  4. CE9242 Cuyamaca RP S Brass Plug

  5. DC1975 Cuyamaca ECC 1939

  6. CE9243 Cuyamaca ECC RM 1

  7. CE9235 Cuyamaca Reference Cross

  8. CE9237 Cuyamaca Reference Mark 2 1935

  9. DC1971 Cuyamaca Azimuth Mark †

  10. CE9233 Cuyamaca Azimuth Reference Mark 1

  11. CE9234 Cuyamaca Azimuth Reference Mark 2


  1. * Previously identified on March 8, 2020

  2. Azimuth and Azimuth RMs located on Stonewall Peak - didn't attempt today.

Today's Recoveries

"Ground Control to Major Tom..."

What's a NASA-GSFC disc doing on Cuyamaca Peak?

With strains of David Bowie playing in my head, this was my "Find of the Day", the NASA - Goddard Space Flight Center Cuyamaca 2 disc.

As I mentioned above, I'd read about this disc in the datasheet but since it's not a cataloged USGS mark, there were no coordinates and no azimuth pointing to its location.

I’d seen other hikers post pictures of the NASA disc but location details were scarce and I couldn’t find a reference to it in any database. Basically, I just wandered around the summit/tower area until I found it. It falls into that “Cool” category because,’s a NASA disc! LOL. Researching deeper into the NASA monument program is on my “to do” list.

Preliminary research into the Greenbelt Maryland facility and survey monuments led me to the Goddard Geophysical and Astronomical Observatory monuments page that talks about the monuments that are on-site at their facility, but really doesn't address other monuments. I've sent out a few emails and have been poking around the website to see what I can find out.

I now return you to our regularly scheduled list of marks...

After locating the NASA disc, my next objective was to find the RESET of the original Cuyamaca Station, I knew from the data sheets that the disc itself was gone and the marking was going to be a cross cut in the top of the remaining survey marker stem that held the RESET disc. Looking for nails, bolts, or broken stems is a bit more challenging as they are much easier hidden by dirt, snow, debris, and therefore easier to miss, so I was happy to locate this one.

Ideally, the easiest way to find ALL the other reference objects for a primary Station is to locate the station first. As you can see from the excerpt of the datasheet above, if you know the location of the station, then you can use the distances and Geodetic Azimuth to pinpoint where any of the remaining marks are.

The Geodetic Azimuth (Geod. Az) on the datasheet is a single number presented in the following sequence "dddmmss.s" (degrees, minutes, and seconds). As used on the datasheets, this geodetic azimuth is an angle between 0° and 360° measured clockwise from North of the Station. Reference objects on the datasheet are listed in the order they are encountered as you work your way around the compass.

Reference Marks

There were three reference marks set on Cuyamaca, set in 1923, 1935, and 1954. Reference Mark 3 (the one I found last year) was really a no-brainer to locate, it's probably the most popular in summit pictures because it's where the summit use trail takes you. It's mounted in a concrete block that was once a footing for the lookout tower, and it's clearly stamped RM 3, which is probably good because its current location is not consistent with the distance and Geod. Az. given on the datasheet, probably having something to do with the destruction of the tower. RM 3 was set in 1954 because one of the legs of the Lookout Tower obscured the line of sight between the Station disc and RM 1 set in 1923.

In all the datasheet recovery notes, what I have determined to be Reference Mark 1, is simply referred to as "Reference Mark 1923" because that's all that stamped on it. However, if you look at the distance and Geod. Az. for RM 1 on the datasheet, it points directly to the 1923 disc and is within inches of the stated distance. Reading through the early recovery notes, it's easy to piece together that the 1923 mark and RM 1 are one-in-the-same.

Confirmed Lost/Destroyed Marks

The old lookout tower is really not hard to describe as lost/destroyed, it simply isn't there any longer, yet novice geocachers still occasionally report finding the tower mistakingly identifying one of the current radio towers.

However, if you read the description of the tower in the NGS datasheet (below), it's clear that it's gone as there is not currently a tower with a cabin and a wrap-around walkway. Too, the other giveaway is that Cuyamaca Reference Mark 3 1954 is set in the southeast pier of the "present" tower, that chunk of concrete sits all by itself and is one of the first and easiest reference marks that people find at the summit. So it's safe to say, this one is gone.

The description of the tower above was from a 1975 NGS Recovery of the station, For history buffs who are into Fire Lookout Towers, here are a couple of old photographs of the original Cuyamaca Towers (the description above identifies the 1960s tower). The first observation of the tower in 1936 would have been of the tower that was built during the '20s.

Unable to Locate

Other Reference Marks

I am hoping that locating RM 2 will be pretty easy and that it is still intact; since I have distance and direction information I should know pretty quickly, one way or the other if it still exists. The Reference Cross may be a little more challenging to find since it's not a standard disc but a cross cut in the face of a rock, these have a tendency to erode away over time. I did notice a rock with a lot of etching in it at the summit, but I dismissed it as more current vandalism than anything else. I'll have to go back to photograph it and possibly do a rubbing to see what it's all about.

Cuyamaca Eccentric Station

Current conditions at the summit prevented me from spending too much time looking for the remainder of the markers located at the summit. I know that the Eccentric station and its reference mark are located in thick brush and are close to the ground (and today) likely covered with snow. The Eccentric station has its own Permanent ID and reference mark, between the information and coordinates on that datasheet and the location information on the RESET datasheet, I expect it should be easy to find, the real issue will be just how thick the brush is surrounding it.

Original Brass Plugs/Copper Bolts

The series of Brass Plugs (or copper bolts depending on which accounts you read) are a little trickier to locate as they are ½" diameter and generally driven flush in the rock where they are mounted, THAT is going to be a fair-weather hunting expedition. In researching these plugs, there is a report that says one was lost in the construction of the tower, but the other three are still in place. The fact that any of these are still around is pretty amazing as they were the original Reference Marks set back in 1898!

Cuyamaca Azimuth

The Azimuth Mark and its Reference Marks are located on the summit of Stonewall Peak, I summited Stonewall last year as part of my San Diego 100 Peak Challenge, but I wasn't in the mode of looking for survey disks so I'll plan another trip back there soon to look for that one. I do know from reading the datasheets, that the Azimuth Mark itself is considered lost, apparently, when they built the stairs, handrail, monument, and viewing platform on Stonewall Peak, they built the monument right on top of the Azimuth disc. (Update 2/16: recovery at Stonewall Peak!)

The "Hole in the Rock"

Often, it's easy to see where a survey mark WAS by the hole left in the rock, so when I encountered this hole my first thought was "missing survey disc".

As it turns out the location of this particular hole doesn't jibe with any of the known markers so my thoughts are "Nope, not a missing Marker". Too, usually, the hole from a missing survey disc that was mounted in bedrock will be much smaller (the hole for the stem of the disc ¾" - 1"). Best guess, this hole was from some pipe or piece of a structure perhaps related to the old lookout tower.

Recent Posts

See All


bottom of page