Lightweight aluminum observing tripod. Astro party of C. V. Hodgson. Note remains of old observing stand to left

Assembling lightweight aluminum observing tripod. Astro party of C. V. Hodgson

Observing longitude with Bamberg broken telescope instrument. Astro party of George D. Cowie

Ed Brown's astro outfit. Astro party of E. J. Brown

World longitude network setup at Manila. Note radio gear to receive time ticks. Chronograph is drum-like instrument to right

Bamberg transit set up at Station NIU Hawaii. Astro party of E. J. Brown

Bamberg transit set up. Astro party of E. J. Brown. Part of World Longitude Campaign

Short wave radio recorder. Astro party of E. J. Brown. Part of World Longitude Campaign

E. J. Brown using Davidson meridian telescope. Astro party of E. J. Brown. Part of World Longitude Campaign

E. J. Brown at astro setup checking chronograph. Astro party of E. J. Brown

Early morning computing - verifying last night's work. Astro party of Ralph Pfau

Station NIU during reobservation of World Longitude stations. Looking for evidence of continental drift. Instruments too crude to measure small earth movements. Astro party of Joseph Lushene

Joseph Lushene operating long-wave radio receiver. Attempting to receive time ticks. Astro party of Joseph Lushene

Bamberg transit and equipment. Astro party of Charles Whitten

Chronograph drum without paper. Used to record time ticks during longitude observations. Astro party of Charles Whitten

Bamberg transit set up on Guatemala - El Salvador border. Border determined by C&GS. Astro party of Ralph W. Woodworth

At astro station on Honduras - Guatemala border. L. to R. - Honduras commissioner, Joseph Lushene, recorder. Recorder later died of malaria. Astro party of Joseph Lushene

Station Eskimo on Honduras - Guatemala border. Border determination a combination of astro and triangulation work. Astro party of Joseph Lushene

Guards accompanying Guatemala - Honduras boundary surveyors. Astro party of Joseph Lushene

Transportation by mules. Guatemala-Honduras boundary survey. Astro party of Joseph Lushene

Transportation by mules. Guatemala-Honduras boundary survey. Astro party of Joseph Lushene

Composite photo of many aspects of astro work. El Salvador - Guatemala boundary survey. Astro party of Ralph W. Woodworth

Ralph Woodworth at Bamberg broken telescope instrument. El Salvador - Guatemala boundary survey. Astro party of Ralph W. Woodworth

Installation at Station Observatorio. El Salvador - Guatemala boundary survey. Astro party of Ralph W. Woodworth

Installation at Station El Sitio. El Salvador - Guatemala boundary survey. Astro party of Ralph W. Woodworth

Lieutenant Eugene Taylor observing with Bamberg instrument. Astro party of Lieutenant Eugene Taylor

Vernon Burns setting up Wild T-4. Astro party of Lt.(j.g.) Albert Theberge

Astro setup in Mojave Desert. Richard Cohen preparing to record in truck. Astro party of Lt.(j.g.) Albert Theberge

Vernon Burns preparing Wild T-4 for observations. Astro party of Lt.(j.g.) Albert Theberge

Richard Maxey setting up Wild T-4. Astro party of Robert A. Pryce

Vernon Burns at twilight - determining initial azimuth. Astro party of Lt.(j.g.) Albert Theberge

A. E. Theberge discussing Wild T-4 with Afghani student. Astro party of Lt.(j.g.) Albert Theberge

A. E. Theberge discussing Wild T-4 with Afghani student. Astro party of Lt.(j.g.) Albert Theberge

Latitude observatory at Ukiah, California. International program to determine variation of latitude

Use of Navy Transit satellite receiver. Determining latitude and longitude simultaneously. Multiple passes over several hours to get good position

Texas Instruments TI4100 GPS receiver. Determining latitude and longitude simultaneously

Use of Texas Instruments TI4100 GPS receiver. Determining latitude and longitude simultaneously

Use of Navy Transit satellite receiver. Determining latitude and longitude simultaneously

Jasper Bilby with light reconnaissance buggy. Recon work on the 98th Meridian

500 lb. stone being lowered for Brown Valley Base. 98th Meridian survey. Jasper Bilby on right

Marking complete for Station Stephen East Base. 98th Meridian survey

Setting mark on Station Twin. Triangulation party of William M. Scaife

Setting mark near White Pass

Driving mark into the muskeg. Crew from PIONEER

Deep driven rods for bench marks. Crew from PATHFINDER

Digging a hole for a bench mark

Using gas drill to drill hole for bench mark

Mixing cement to set bench mark

Mark after being set in ground

Different types of bench marks