My 23" Dob needing TLC, NZ

[Finite]

Here's my monstrosity. It's been hidden away behind stack of furniture in the garage till recently. Was hard to get in the photo even with a bit of space around it, only recently it has re-emerged, with the removal of my parents furniture which I was storing for them while their house gets built.

Thought I'd share a pic of the scope. I've had a look at the focuser on it this morning, it is three inch in brass. I noticed it is enscribed with PH Dallmeyer, London. A search on the net shows he was born in the 1800's and moved into making telescopes and other optical equipment, but left his business in the late 1880's to travel, upon his Doctors advice for the sake of his health. He disappeared from a cruise ship off the coast of NZ. But the company continued and then also made military gunsights, of which I think this is likely a part. The viewfinder is also brass and the numbers on it show that it was a gunsight from the 2nd world war.

The maker of the primary mirror for this scope was Graham Loftus, and he was a pilot in WW2. I guess he still had contacts!

[Finite]

Here it is.:rolleyes:

I tried to add four pics, only the last one made an appearance.

[Finite]

The secondaries mirror face is 8 3/4" x 5 1/4" in itself.

[tim.stephens]

Did you have this for sale on trademe a while back? I seem to recall the blue-green paint and specs.

HUGE system. How difficult is it to move around? Do the mirrors need recoating or just cleaning?

Tim

[Finite]

Hi Tim, I bought it off trademe several months ago as a project. It was relatively local to me, and the advert heading read that it was a 23" mirror for sale, but the whole scope was there. It's actually a 24" mirror but has a chip in the perimeter. Still, I couldn't resist it.

The mirrors need re-coating as the silvering is deteriorating but they also need cleaning. It would still operate but I haven't tried it at all, - my understanding is a mirror of this aperture would still give dim images even if there were no silvering on at all. And I believe the turntable the mount sits on needs replacing (currently it is a sheet of chipboard, swollen in some places). When I bought it my parents were just several days away from moving to live with me so I put the scope in the garage (which for obvious reasons took three of us to manhandle into place) then the garage was filled with furniture around it. Even The mount was filled with boxes of books and things. Oh the tease of it all, I couldn't even pull the base off the mount to make a new turntable. All of which is why I record it in my signature etc as being a project. Re the blue-green paint, it certainly doesn't enhance its appearance. Would look great painted properly.

Recently and around the time I were looking to send the mirrors away for recoating I bought a 20" dob, much smaller and complete. Which sits in my hallway, making my wife like me lots :rolleyes: I've used it once so far, with dusty, slightly dirty, and uncollimated optics.

I will be selling the big big dob if the 20" one performs ok.

[AEAJR]

All I can say is WOW! That is a big telescope.

Incredible to think your OTHER smaller scope is a 20 inch.

Yes, if I had those my wife would be a bit upset too.

[Finite]

Hi Ed, yes it's been a talking point at home. On the plus side, at least I am in the country and could roll it in and out of the garage, which can be my observatory. That's how I used my previous scope, a 10" LX50 sct, once I'd made a trolley for it.

[mental4astro]

Oh, juicy stuff! :)

Any idea on the focal length of the wee beastie?

Alex.

[Finite]

Focal ratio F/5.25 is what I were told. The FL on that would make it 3065mm. But I calculated on the mirror being a 23" whereas it is actually a 24" so I must re-address. Am running out the door right now though to an appt.

[tim.stephens]

Ah so you were the one who nabbed it! Glad to see it go to a good home. Was considering it but given my itinerant life at the moment, couldn't justify the space needed.

Good luck with the repairs and keep us posted on progress!

Tim

[Finite]

Keep an eye out Tim! I'm likely offering it up for sale, once I'm satisfied with the new scope.

[dannat]

old melbourne observatory has a dallmeyer refractor, a 4" photo-heliograph for taking solar pics, it was moved out in 1874 for the transit on venus in that year, there were 5-6 commissioned by the English at this time. it is in fact privately owned now but still in use at mebourne obsertavory for visual viewing [has a PST back on it]
think its the only version left in working condition, not sure if i have a pic, cost 364 pounds at the time

[tim.stephens]

Haha thanks John but dont have the space currently.

Tim

[Finite]

Aha Tim, then you could use it as a spare bedroom...😊

[Finite]

Wow, interesting,- thanks for that, and what a great old instrument that would be. Worth a bit more now I expect...!

I'd read Dallmeyers company made high end equipment.