I, too, have one of these compasses. It was made by Abrams (Instrument Co., I believe) during the latter part of World War II for use in Africa. I have discussed the compass with the present staff at Abrams, who remember manufacturing the unit on contract during the early 1940's.
They claim that the "date bar" is made for a specific year and must be replaced each year. I have not investigated mine further to determine how accurate it is today. I have hopes of using the sun compass to better locate true north during daylight as an aid in setting up a polar mount for a time-lapse video camera I use during solar eclipses. Good tracking over about four hours is needed. The right ascension axis elevation angle is easily set using a bubble level and precision protractor. The azimuth is not so easy, however. I have tried a precision compass, correcting for local deviation, but with only fair results. From a practical standpoint, there is little time to set up equipment for eclipse recording, and no time to use drift corrections to reset the polar axis. I wonder if the suncompass might be of use here. My compass includes an olive drab-painted, oak wood carrying case. I also have the complete (though small) operation and maintenance manual, a copy of which I have offered to Francois who recently raised this topic. Would anyone on the reflector care to comment on inaccuracies today resulting from not updating the date bar? -- Best wishes, Larry McDavid W6FUB Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland)
