Taylor Observatory-Norton Planetarium is 100 mi N of SF in a Bortle 3-4 area. The observatory, since 1978, is owned by the local K-12 public schools. As members of Friends of Taylor, our goal is to raise awareness of astronomy for youngsters. Thus we do fund raising, run monthly public night programs (talk, planetarium show and viewing) and participate in a "2nd Saturday Science" event in which a visiting school class members look at the Sun through a Coronado PST.
The observatory dome has a 16 inch SCT (Meade LX-200) that is rather poor for public viewing. Just the same, returning adults still savor their experience, for some many years ago, of climbing the ladder and peering through the telescope.Young children are still awed by the experience of their first view of the moon, Jupiter or whatever. Eventual replacement is under consideration. Formerly, 6” Orion dobs were used outside, but these are problematic for several reasons – mirror size, difficulty in locating targets, and lack of tracking. In addition to the Meade SCT in the dome, we’ll be using two recent gifts to the observatory, a 4˝” Meade SCT (GEM with GoTo and tracking), a 10-inch Meade Newtonian on a GEM with RA drive only; plus a new added scope if we wish.
Our goal is improved viewing of DSOs. The Meade 16 is not so satisfactory because of its high f value (10). Thus we have considered a dob, but anything is still in the mix. Funding is available at the multi- thousand $ level.
If a dob, what is an optimal mirror size, realizing most visitors view of only a few minutes? At whatever aperture is chosen, do we stick with the “standard” (low cost) Orion, or go for something perhaps lighter and custom built – Teeter, Obsession etc. We have a slight leaning toward maybe a 14-inch diameter dob – perhaps giving a 6-fold light transmission improvement over the Meade 16 SCT. The new scope should have tracking and GoTo so that the duties of the assistants are lessened. In general we won’t transport this scope away from the observatory, so portability has reduced importance. Still, it might be nice, very occasionally, to use it for school science nights. For the Orion, we have some concerns about mirror quality from posts in various forums and maybe a little concern about weight. But the new equipment would not have to be a dob if something else if preferable.
If necessary, we could comfortably afford $10,000 or more, but we’re hoping not to. We are aware also that having too large a scope makes it like a museum piece for visitors, so we wouldn’t want to use only many-thousand $ scopes for viewing.
Our “group of 5” in Friends of Taylor has 4 reasonably knowledgeable astronomers including a PhD physicist with an undergrad physics-astronomy degree and just starting photography, a very smart recent HS graduate from our high-school public service program who is a solar system expert who has lectured widely in N. Cal., a Phd Chemist/spectroscopist and amateur astronomer, and a former director of a major Midwest lighthouse museum who has recently constructed an 8” Newtonian in a “Steampunk” woodwork style with dob mount. Our 5th member is an attorney/financial officer, who has two school age daughters interested in astronomy. So we are very “hands-on;" four of us have our own scopes at home, and 3 of us are in a Messier competition this year using our home telescopes.