NavList:

I also have an updated model that has a way to set to your exact latitude and an easy way to set the LHA Aries. It is identified as Computer, Air Navigation, Celestial Azimuth, Type CP-300/U FSN 6605-557-0778. Also marked "U. S. Property."

It differs from the 2102-D in that the scale is slightly smaller, and the altitude scale goes down to minus ten degrees, in case you are shooting the sun from a high altidude B-52. Due to extenction, the only body that can be observed below a zero altitude is the sun and you hardly need a device to identify the  sun.)

gl

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Re the 2102D, batteries not required has a certain ring, slide ruless do too, even though I was never all that handy with the beasts. Otherwise, for those who view the old Rude, the following might be of interest. A similar seeming device, capable of 1 degree increments.  I have one picked up on ebay of amazon, don't recall which. It is named Computer, Celestial Type CPU 50A/P Mfr's Model: FAA-114B 6605-00-967-6692. The one I have was produced by Telex Communications Inc. The thing might be worth a look if any are floating around these days.