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Details for Benchmark: HS5122

N 37° 52.897 W 121° 54.891 (NAD 83)

Altitude: 0

Coordinates may not be exact. Altitude is UNKNOWN and location is ADJUSTED. (more info)

Location:
In CONTRA COSTA county, CA View Original Datasheet
Designation:
MOUNT DIABLO AVIATION BEACON
Marker Type:
NGS Benchmark
Setting:
setting not listed - see description
Stability:

Must Read!

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Found while visiting the visitor center during a geocaching hike.

Found it while thru hiking Mt Diablo Summit from South Gate via Summit Trail to Regency Gate via Middle Trail

Dipped TB72826 - Sam the Surveyor in Benchmark

More photos on AllTrails

[Photos:]
photoBM
photoBM with TB72826

Saw this one while on vacation. I don't have a photo of the beacon itself, I did see it and was within a couple of feet of it when I went into the tower.

Easily spotted while at the summit

This was interesting and unexpected. We saw this, and other benchmarks, at the summit of Mt. Diablo.

[Photos:]
photoHS5122 Aviation Beacon

Found while visiting Mt. Diablo summit.

[Photos:]
photoHS5122 Mt.Diablo Aviation Beacon

Geocaching with MelodiousMusicians, Annie Organ, MsAAH and hawalter today and we stopped to find this aviation beacon benchmark.

[Photos:]
photoHS5122

I found this benchmark while visiting Mt. Diablo.

[Photos:]
photoHS5122

There it is, now better placed "directly over" the Mount Diablo station as a very handy tower. Notes about this one pop up in that main one.

[Photos:]
photobeacon from the trail below

Discovered at the summit of Mt. Diablo.

[Photos:]
photoPlaque
photoBeacon

Going through my vacation notes and logging the bench marks

Gotta log a benchmark find on this one while up here.

Very cool!

Found this while out caching with my son.

[Photos:]
photoBecon

If the beacon was moved to the concrete tower, is it OK to log this? The majority thinks it is and so do I. Greetings from Switzerland!

[Photos:]
photoThe tower of power.

Day trip to the mountain. Spotted beacon. Hard to miss. Picture posted.

[Photos:]
photoMt Diablo aviation beacon

I probably would have blindly logged a find on this if I hadn't noticed Team Sagefox's 9/23/2008 log pointing out that the 1956 log reports that the beacon was removed in 1937, which means the station was destroyed, although for some reason the log doesn't use that word. This is confirmed by the adjusted coordinates, which point to the west end of the parking log -- as described in 1935 -- so over 200' from where the beacon is now. I was at the site today, and I couldn't find any trace of a tower ever being at the posted coordinates.

After doing some volunteer trail work this morning, my wife and I made it to the top of the mountain and spotted this benchmark!

[Photos:]
photoHS5122 Aviation Beacon

HockeyHiker19 and I had attended the [url=http://coord.info/GC4TYBP]Mount Diablo Trails[/url] CITO and wanted to make sure we made it to the top for these benchmarks.

[Photos:]
photoMt. Diablo aviation beacon

Found while attending the nearby CITO event. Beacon was visible and coords seemed to be accurate.

TFTFun!

[Photos:]
photoIMG_0872[1]

Benchmark still appears to be in the 1956 location! Great views on a gorgeous, clear winter day.

[Photos:]
photoIMG_0115

Pretty easy one. Found this as well as the nearby survey point. Great day for a hike to the top of Mt. Diablo!

[Photos:]
photoBeacon at top of structure

Wow, what a great day!!!

It started off EARLY with a fun gathering at the [url=http://coord.info/GC4494W]BUNDLE UP: BREAKFAST & GEOCOIN BONFIRE!!![/url] event. Then, the crew of [b][red]BooDogMama[/red][/b], [b][purple]Paracelsus[/purple][/b], [b][blue]Jimlips[/blue][/b], [b][orange]NightKnight[/orange][/b], and [b][green]I[/green][/b] was off to finish a Downtown Sacramento multicache! Somehow, we immediately transported ourselves through space and got to Mount Diablo right after the Sacramento cache Thank you SOOO much, [b][red]BooDogMama[/red][/b], for inviting me to tag along on your #3000 ! What an accomplishment![b][green] TNLNSL. TFTC!

~ecrane b#69
Davis, CA USA

Visited while geocaching and hiking in the area. Beacon tower is visible for miles and is in good shape. Beacon itself was not visible today. Coordinates are adequate, photo attached.

[Photos:]
phototower

Found with the lovely CarlottaP.

Oaknest and I hiked and drove around the area finding caches today. We also found this benchmark.

[Photos:]
photoMount Diablo, elevation 3846 ft.

wow a really cool benchmark wish i could see it on december 7

interesting notes on this one

The beacon is lit up annually on one day, the anniversary of the bombing of Pearl Harbor, Dec. 7. It would be cool to log this benchmark on that date and post a photo of the beacon light illuminated. Wished I'd thought of this two months ago.

Found while hiking to the Mt. Diablo Summit.

In town visiting for a few days and just had to visit the Summit of Mt. Diablo, doesn't get much easier finding Benchmarks when they are made so obvious as these.

[Photos:]
photoHS5122

Found 3/7/10 on a Mt. Diablo Hike

Found with no problems!

[Photos:]
photoHS5122

Heck I could have found this one from home on a clear night.

can't miss this one

Here's my MSN picture of the week...from the beacon.

[Photos:]
photoDSC04284

According to the recovery notes this beacon, if it is the same one as in the 1935 description has been moved and therefore is not the original benchmark station.

The 1935 description states that the beacon is on a tall tower built by Standard Oil and has SD on the sides of the tower. The current location does not fit that description. In addition, the 1956 recovery note gives supporting information that the original station is lost.

Great views!

The aviation beacon is still in place above the observation tower at the summit. Photos pending...

[Photos:]
photoAviation Beacon
The beacon has undergone some modification since WWII, but the benchmark is still intact with a bronze plaque sitting atop a 2-story concrete obelisk! If only all benchmarks were so easy to find? :-)
photoMount Diablo Summit
This is one way to prevent erosion, place the mountain inside a museum! Kinda like a "Dome of the Rock" benchmark.

Great views!

Part of a fun day on Mt. Diablo

Hiked some of the trail and drove to the top. Clear day to the east; I could see to the Sierras.

Found it while working on a multi-geocache GCMAF4. Thanks

Even went inside of it :-)

[Photos:]
photoBeacon and a Nazgul

Sagefox's later log appears to be correct. However I'd say there is room for doubt as the last recovery note doesn't make it clear that the station has been lost or re-monumented. I'm going with a note log on this one because my best guess is that the station is a goner.

[This entry was edited by Nazgul on Saturday, November 08, 2008 at 9:07:52 PM.]

[Photos:]
photoStone tower
photoBeacon, antennas and instruments

saw it.

Photo of beacon from the Devil's Pulpit.

[Photos:]
photoLooking up from the Devil's Pulpit

we found it..

Been there, done that.

[Photos:]
photoMOUNT DIABLO AVIATION BEACON

Yeah yeah yeah we saw it too...
You can see 360Degrees, S.F., Mt. St. Helena, Mt. Lassen, Yosemite(Half Dome).

Not as tough as Nano on High, so found it OK!

Yeah, Yeah, I saw this thing.

Rotating Beacon atop Stone Tower, Mt. Diablo

[Photos:]
photoRotating Beacon atop Stone Tower Mt. Diablo
Beacon atop stone tower on a very foggy day below 3800ft.

Up atop the mount caching with 4wheeler today.

Steel tower is gone but rotating beacon was relocated to top of stone observation tower,

[Photos:]
photoRotating beacon

The relocated beacon from 1956 is on the building and still in place.

Make note that this beacon is not in its original position as noted by the 1956 entry, and would not be used as a horizontal survey position. But, as this is benchmarking site and not NGS, I have logged this as found in the 1956 report.

[This entry was edited by CallawayMT on Sunday, March 14, 2004 at 8:26:14 AM.]

[Photos:]
photoMt. Diablo, CA - Aviation beacon on the building

Decent day, could see Mount Tamalpais sticking up above the Marin fog.

[Photos:]
photoMount Tamalpais from Diablo summit
Taken from near the aviation beacon.

Documented History (by the NGS)

Unknown by (MONUMENTED)
01/01/1935 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1935 IN 1935 DESCRIBED AS FOLLOWS--PROMINENT REVOLVING BEACON WEST OF PARKING SPACE AT SUMMIT OF MOUNT DIABLO, ABOUT 215 FEET WEST OF OBSERVATION PLATFORM, AND 65.51 METERS (214.9 FEET) IN AZIMUTH 81 DEG 08 MIN FROM STATION MOUNT DIABLO (SEE DESCRIPTION THEREOF). BEACON IS ON TALL STEEL TOWER INSTALLED BY STANDARD OIL COMPANY OF CALIFORNIA AND BEARS LETTERS SD VERTICALLY ON SIDES.
01/01/1956 by CGS (MONUMENTED)
RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1956 (WMG) THIS SITE WAS VISITED IN DECEMBER 1956 AND THE RANGER SAID THE AVIATION BEACON TOWER HAD BEEN REMOVED AROUND 1937. THE AVIATION BEACON ITSELF HAS BEEN RELOCATED DIRECTLY OVER STATION MT. DIABLO ON CONCRETE BLOCK HOUSE.

Control Text

  • The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in March 1994. The horizontal coordinates are valid at the epoch date displayed above. The epoch date for horizontal control is a decimal equivalence of Year/Month/Day.
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The geoid height was determined by GEOID99.

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