I bought it used in 2000. It was pretty beat up. It had to be at least 5 years old. It was from the era when Discovery was primarily making Dobs for Orion and Celestron. The Sonotube Orion Dobs were made by Discovery, the 11 inch, 14 inch and 17.5 inch Celestron Sonotube Dobs were made by Discovery.
I have never heard or seen another one, a 12.5 inch F/4.06 Discovery. But earlier this year, I was talking to the guy that sold me the scope 20 years ago. He had bought another one 4 or 5 years ago.. Of course, Discovery was based in the Oceanside-Temecula area and this guy lives right there between the two cities.
In 2003, the PDHQ series had the birch base and large bearings but there was another series that included a 10 inch F/5.6 that used particle board.
The other scope in the photo is a Pirate Instruments 8 inch F/6. I was my first Dob,I bought that in 1999. It was very crude, single stalk secondary mount, bending was the only adjustment. The mirror cell doubled as a counter weight, it was three spokes made from cast lead. Pirate Instruments was the first incarnation of the Bill Larsen/Terry Ostahowski team that became Discovery.
Thanks for that interesting bit of history, Jon!