When it rains, it pours, at least where my streams of conscious thought are concerned. Last week I posted about a shipwreck discovery off the coast of Namibia, where about 1,000 gold and silver coins were uncovered, along with 50 elephant tusks, copper ingots, 8 cannons and other items including two astrolabes.

Afterwards, friend and fellow Market Update writer, Lisa Bellavin, asked me to do a brief interview for Coin Chat Radio on the shipwreck, which we recorded earlier this week for broadcast through NumisMaster later today. If you'd like to hear it, just go to www.numismaster.com and click on Coin Chat Radio on the right-hand side of the top navigation bar. For the interview I did a bit more research, including some investigation into astrolabes, which I knew very little about.

At the National Maritime Museum and Royal Observatory website hosted in Greenwich, UK, I was able to learn quite a bit about the history and function of the astrolabe. One of the most enlightening things I discovered is that Mariner's Astrolabes, like the two uncovered in the Namibian shipwreck, are quite rare. Seems the NMM only has seven examples in their collection, of which only two are from the time period when these devices were actually used for sailing navigation. Mariner's Astrolabes were used for navigation most heavily from about 1500 to 1700 at the latest, when more accurate instruments such as the Backstaff and Davis Quadrant came into wider use.

But just how rare are Mariner's Astrolabes? Well, the most current bit of data on this turned up in yesterdays mail, when I opened a package from well known coin dealer, Daniel Frank Sedwick, good friend, well known author and long time Standard Catalog contributor from Winter Park, Florida. In the package was a catalog for Dan's upcoming Treasure Auction #3 set to close May 29th.

Treasure Auction #3 contains nearly 1200 lots of gold and silver cob and milled treasure coins primarily from the Spanish colonies, along with gold ingots, silver bars, and a vast array of artifacts including tableware of porcelain, greyware, silver, pewter and earthenware, plus a lovely Octant and, as luck would have it, a rare 16th Century bronze Mariner's Astrolabe. In the lot write-up Dan mentions that this is one of about 70 Mariner's Astrolabes currently know to exist. This example rests in a coral matrix and is estimated at $35,000 to $50,000.