Astro Meridian Mark?

[+julia51:)]

We have come upon the description for KX2201, Altoona Astro Meridian Mark, 1/1/1890 and are so curious about it. Can anyone explain an astro meridian mark? thanks so much. Hope to search for it soon.

[+Harry Dolphin]

Meridian markers mark a line true north. They come in pairs. (They seem to be near courthouses - at least the two pairs that I have found were.) 'Astro' might come form this station marking a point true north of STATION ALTOONA ASTRONOMIC. Which would be the other part to the pair. Altoona Astronomic seems to have been replaced by ALTOONA AST 2. Meaning that the original station has been replaced. From what little I have learnt. the '2' at the end of the station name means that the station was replaced, but there was no buried station to verify from. There are also two reference marks and an azimuth marker with their own PIDs to search for. Let us know how you make out!

[+julia51:)]

thank you, we've been so curious about this for so long, i don't know why we didn't think to ask here sooner! we'll be heading to altoona asap.

[mloser]

This one has been on my "to do" list for over a year, but I haven't mustered the energy for a trip to Altoona, since it is about 2 1/2 hours from me.

 

Harry is right--there WAS an ALTOONA AST station, described in 1941, but placed in 1890 according to the documentation. You can see the datasheet at KX0060. It was destroyed in 1984 and AST 2 was put in at that time. RM 2 remains from the 1941 mark and is stamped 1941 (and probably 1984 too). The astronomic station must have been pretty interesting. It was described as (bold text is mine):

 

KX0060'DESCRIBED BY COAST AND GEODETIC SURVEY 1941 (GWL)
KX0060'THE STATION (AN ASTRONOMICAL STATION OF THE U.S.C. AND G.S.) IS
KX0060'LOCATED ON THE E SIDE OF A LOW BARE HILL ABOUT 1-1/2 MILES N OF
KX0060'THE BUSINESS DISTRICT IN ALTOONA, ABOUT 100 YARDS W OF CHESTNUT
KX0060'STREET ON LAND OWNED BY THE PENNSYLVANIA RAILROAD COMPANY AND W
KX0060'OF THE RAILROAD SHOPS AND TRACKS.  IT IS 15 FEET SW OF A 2-FOOT
KX0060'COTTONWOOD TREE, WHICH IS THE LARGEST AND MOST NORTHEASTERLY ONE
KX0060'OF SEVERAL TREES AND ABOUT 100 YARDS E FROM THE HIGHEST POINT OF THE
KX0060'HILL.  THE MARK [b](SHAPED LIKE AN ARM CHAIR[/b]) IS A BLOCK OF SANDSTONE 5
KX0060'FEET LONG, 34 INCHES WIDE, 20 INCHES THICK, PROJECTING 30 INCHES
KX0060'AND RESTING ON A CONCRETE BED 16 INCHES THICK.  IN THE TOP IS A
KX0060'COPPER BOLT 3-1/2 INCHES LONG, 1 INCH IN DIAMETER WITH A CROSS CUT
KX0060'IN THE TOP.  INCISED ON THE S SIDE OF THE MARK IS U.S. COAST AND
KX0060'GEODETIC SURVEY LATITUDE 40 DEG 31 MIN 45.49 SEC LONGITUDE 78
KX0060'DEG 23 MIN 12.79 SEC 1890 ALTITUDE 1288.1 FEET.

 

No mention of what destroyed it but aerial photos show what looks like an old roadway to the northeast of the current one, so maybe it was shifted and the mark destroyed. An odd item is that the replacement mark is only a vertical mark instead of being used for horizontal control like the ALTOONA AST, which was also a first class vertical mark.

 

As for ALTOONA ASTRO MERIDIAN MARK, I am still not sure exactly what a meridian for an astronomic mark would have been but am guessing it was used to help align the instrument. It appears to be in a wooded area to the north of AST 2. The 1966 recovery of ALTOONA AST shows the meridian as being not found:

 

 KX0060'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1966 (RRG)
KX0060'THE STATION AND TWO REFERENCE MARKS, AZIMUTH MARK WERE ALL RECOVERED
KX0060'AND IN GOOD CONDITION.  DESCRIPTION IS ADEQUATE.  THE USC AND GS
KX0060'MERIDIAN MARK WAS SEARCHED FOR BUT NOT RECOVERED THIS DATE.  A POWER
KX0060'LINE POLE HAS BEEN ESTABLISHED IN THE VICINITY AND MARK MAY BE
KX0060'DESTROYED ARE COVERED.

 

The meridian will most likely be very difficult to locate--the description only relates it to ALTOONA AST and the distance is long--437 feet, as well as being down a steep bank (I think), across a road, and back up a bank into a wooded area--not easy to measure or even pace off. It is at ground level, in a wooded area so it will be covered with leaves, dirt and whatever else is there. There is no metal to use a detector on. About all you have to go on is GPS coords. I am not trying to scare you off. Just a heads up that for this one there are no real guidelines. Finding it is a shot in the dark, or the dark woods, as the case may be.

 

Matt

[+GEO*Trailblazer 1]

I guess my post earlier did not make it in.

 

Here is the list of Meridians.

LIST OF MERIDIANS

 

WIKI MERIDIANS OF LONGITUDE

 

WIKI LATITUDE

 

Most of the ones on the first list are NGS beenchmarks as well.

 

I use to have the list but lost all that data with a computer crash.

 

Time to start all over again.