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Details for Benchmark: EW7221

N 34° 13.355 W 118° 03.755 (NAD 83)

Altitude: 5655

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

Location:
In LOS ANGELES county, CA View Original Datasheet
Designation:
MT WILSON E 10A
Marker Type:
survey disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

Reference Points

Must Read!

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She's still there! Worth the trip.

[Photos:]
photo

An early morning hike got me here just after sunrise.

[Photos:]
photoWilson benchmark

Good hike.

Found after reaching the peak. Hiked up from the Mt Wilson trail head and ended up doing a 14 mile hike. The views are amazing and the Benchmark is in great condition.

[Photos:]
photo

Found while completing peak 1 of the six pack of peaks challenge.

[Photos:]
photoP2141421.25

Drove up to Mount Wilson because Switzer Falls was full.... Spotted this while trying to get coverage for my iPhone Geocaching

Easy one at the top.

[Photos:]
photoIMG_1180[1]

No problems locating this BM after a long hike up Mt. Wilson from Chantry Flats through Sturtevant Camp. Pretty much ran right into it on accident, and snapped a pic in case it was a listed BM.

[Photos:]
photoEW7221

Found this benchmark while hiking the loop trail from Chantry Flats with my son

Found this one at the beginning of our hike on the Mt Wilson Trail.

Found it on my hike to Mount Wilson.

[Photos:]
photoMount Wilson

An easy find at dusk after a long loop hike from Mt. Wilson. We enjoyed watching the stars come out after spotting it in good condition.

[Photos:]
photoMt Wilson Parking Lot Benchmark - EW7221

Out with the family, enjoying picnic lunch for Father's Day. Stumbled, literally, on this one by happenstance. Glad to see it was in the database.

[Photos:]
photoE 10A Survey Disk

Jack Bilheimer and Donald Shade hiked from Altadena to Mt. Wilson on March 10th, 2008. 18 miles roundtrip in 9 hours.

[Photos:]
photoMt Wilson E10A
Mt Wilson E10A on March 10, 2008

Found while visiting Mount Wilson after Drum Corps Finals in 2007. Beautiful area.

Out for a walk on the observatory grounds with my visiting parents and doing a bit of benchmarking along the way. Found this mark in good condition. Also located a RM about 75 feet at 288 degrees true (distance not measured) located in a well about .5 feet below the ground surface under an iron cover marked County Engineer Monument and stamped Mt Wilson E10A RM 1 1971 RE 7078.

[Photos:]
photoEW7221
Close-up of the mark.
photoEW7221 Location
The area around the mark.
photoEW7221 RM 1
N34 13.359 W118 03.770
Close-up of RM1. Don't know why the picture colored this way.
photoEW7221 RM1 Location
The location of the RM.
photoEW7221 RM1 Area
The area around RM1 looking towards EW7221.
photoEW7221 RM1 Cover
Cover over the RM.

Stumbled across this accidentally, glad to see it was logable.

No longer covered in pink paint. Just looks like a normal benchmark now. Easy find while stopping to eat lunch.

[Photos:]
photoMt Wilson E10A.jpg
Mt Wilson E10A

This was hard to miss today. They have outlined it with the pink paint. Just 15' away was a Horizontal Control Mark.

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photoMt Wilson E10A
photoHorizontal Control Mark TLRS-90

Visiting Mt. Wilson while at the Michelson Interferometry Summer Workshop and located this benchmark along with one heck of a HUGE pinecone! WOOT!

I thought I upload the picture I took of the benchmark and you can see how much it has changed from it's shinny self to a kind of greenish tarnish in the past year and half. Whoa... that's some change.

[Photos:]
photoBenchmark has weathered just a bit in the past 1.5
Check with the picture from 2004

Noticed in parking lot at Mt. Wilson.

Climbed up from Sierra Madre today and stumbled on this benchmark while taking in the view. It's very near the upper trailhead of the Mt. Wilson Trail. Nice to hike 7.5 miles one way, gain 4500 feet and find a benchmark to log!

[Photos:]
photoMt Wilson Benchmark
Very bright and shiny for a 33 year old benchmark.

Just learning about these things. I have been photographing the ones I come across, now I am trying to figure out which ones they are. This one was relatively easy.
ucspots

[Photos:]
photoMt. Wilson
This disk is in great condition. Very bright and visible. It's a favorite.

Documented History (by the NGS)

01/01/1971 by CA-037 (MONUMENTED)
DESCRIBED BY LOS ANGELES COUNTY CALIFORNIA 1971 THE STATION IS IN LOS ANGELES COUNTY ATOP MOUNT WILSON IN AN AREA DESIGNATED AS SIGNAL POINT AND MORE PARTICULARLY AT THE MOST SOUTHEASTERLY CORNER OF A LARGE PARKING AREA FOR A PRIVATE PARK KNOWN AS SKYLINE PARK WHICH IS OPERATED BY METROMEDIA CORPORATION. TO REACH THE STATION FROM FOOTHILL BLVD AND ANGELES CREST HIGHWAY, DRIVE ON ANGELES CREST HWY ABOUT 14 MILES TO RED BOX RANGER STATION AND MT WILSON RD. TURN ONTO MT WILSON RD AND DRIVE ABOUT 4 MILES TO THE TOP AND THE ENTRANCE TO SKYLINE PARK. ENTER GATE AND DRIVE SOUTHEASTERLY 0.4 MILES TO SIGNAL POINT. FIND STATION AT THE MOST SOUTHEASTERLY CORNER OF A LARGE PARKING AREA. STATION MARK IS A LOS ANGELES COUNTY SURVEY SYSTEM 4 INCH BRASS DISC STAMPED---MOUNT WILSON E-10 A 1971 RE 7078---SET IN AN 8 INCH BY 8 INCH CONCRETE MONUMENT FLUSH WITH THE GROUND SURFACE. THERE IS NO SUBSURFACE MARK.
11/05/1982 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1982 (CLN) THE STATION, IS 7 MILES (11.3 KM) NORTHEAST OF PASADENA, 0.5 MILE (0.8 KM) SOUTHWEST OF MOUNT WILSON OBSERVATORY BUILDINGS AND 0.5 MILE (0.8 KM) SOUTHEAST OF THE CENTER OF THE MOUNT WILSON TELEVISION ANTENNA SYSTEMS. THE STATION IS LOCATED ON TOP OF MOUNT WILSON IN THE AREA DESIGNATED SIGNAL POINT AND AT THE SOUHTEAST CORNER OF A LARGE BLACKTOPPED AND GRAVELED PARKING LOT OPERATED BY THE METROMEDIA CORPORATION. TO REACH THE STATION FROM THE JUNCTION OF INTERSTATE HIGHWAY 210 AND STATE HIGHWAY 2 AT LA CANADA, DRIVE NORTH AND NORTHEAST ON THE STATE HIGHWAY FOR 13.7 MILES (22.0 KM) TO WEST FORK DIVIDE AND THE RED BOX RANGER STATION ON THE RIGHT. TURN RIGHT AND DRIVE SOUTH AND SOUTHEAST UP THE WINDING BLACKTOPPED ROAD FOR 4.5 MILES (7.2 KM) TO LOCKED ENTRANCE GATE INTO SKYLINE PARK. PASS THROUGH GATE AND DRIVE 0.15 MILE (0.24 KM) TO A LARGE PARKING LOT. BEAR RIGHT AND DRIVE SOUTHEAST TO THE SOUTHEAST CORNER OF THE PARKING LOT TO THE STATION, A DISTANCE OF 0.1 MILE. (0.2 KM) NOTE, LOS ANGELES COUNTY FIREKEY OR CALIFORNIA EDISON ELECTRIC COMPANY KEY WILL FIT GATE. PARK IS ATTENDED AFTER APRIL 1 OF EACH YEAR. A LOS ANGELES COUNTY SURVEY CONTROL TRIANGULATION DISK THAT IS 10 CM (4 INCHES) IN DIAMETER AND SET IN THE TOP OF A CONCRETE CYLINDER. THE STATION IS STAMPED,--MT WILSON E-10 A 1971 R.E. 7078--, SET INTO THE TOP OF A ROUND CONCRETE MONUMENT, 7.0 INCHES, 18.0 CM IN DIAMETER, PROJECTING 2 INCHES, 2.0 CM ABOVE THE GROUND. LOCATED 2.5 METERS (8.2 FT) FROM A NORTH-SOUTH CHAIN-LINK FENCE, 10.2 METERS (33.5 FT) SOUTH FROM A BRASS MEMORIAL TO B.D. WILSON, PIONEER TRAPPER, 0.8 METER (2.6 FT) SOUTHWEST FROM A ALUMINUM FLAG POLE AND 3.7 METERS (12.1 FT) SOUTHEAST FROM SOUTHEAST CORNER OF FENCED PARKING LOT.

Control Text

  • The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in June 1996. 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 NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.)
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The geoid height was determined by GEOID99.

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