Primary Mirror info request

[markse68]

So I've caught the astronomy bug quite badly after the Tal-1m...

I saw this mirror on ebay and rather recklessly took a punt on it. It's a 12" mirror - the seller didn't have any information about it but it looked like a telescope primary- it had it's focal length written on the back anyway

I think it's a fair few years old and would love to know more about it if anyone recognises the style of inscription- if it's from a known maker?

It has inscribed on the back "R12/49" and I was wondering if that had any meaning- perhaps in relation to the figuring or a test result?

The plan is to build a dobsonian with it and get even better views of the moon and Jupiter  

Mark

[Demonperformer]

That looks like a reasonable purchase.

Could it be from a time when these things were made individually, by craftsmen who took pride in their work, and this was the 49th 12" mirror the maker had produced?

[Chriske]

Looking at the perimeter of that disk, it looks very like a Duran disk.
If it is then this mirror is an old one. Scott  discontinued making these disks along time ago.
And again if it is, I wonder why anyone would bother grinding the back also. Normally the back of a Duran disk is rather rough and at the same time shiny.
We made lots of telescopes with these disks during course. But in the '90 we started to use float instead.

[Peter Drew]

I agree that it looks like a Duran 50 disc or similar low expansion material. David Hinds used such discs and always ground the back surface. He also wrote the focal length and a serial number on it. These mirrors were supplied to many outlets so the additional inscriptions could be third party. If it is a David Hinds mirror you have done well!  😀

[Astrobits]

I too have a mirror ( 8 3/4" dia ) with very similar writing on it. I believe David Hinds used a 4 figure code which is present on your's and mine.

 

 

Nigel

[upahill]

1 hour ago, Astrobits said:

I too have a mirror ( 8 3/4" dia ) with very similar writing on it. I believe David Hinds used a 4 figure code which is present on your's and mine.

Nigel

Im no graphologist, but that is about as close a match as you're going to find 👍

Could the 49 relate to thickness in mm I wonder, seems strange to chop between metric/imperial though.

[CraigT82]

I have a fullerscope newt from the early 80s with inscriptions on the rear similar to yours. As I understand it mine is a B grade David Hind mirror, as noted by 3142B code,  the so the R number is probably a Fullerscope identifier.

[markse68]

Thanks for all the replies! Nigel and Craig there's definitely a family resemblance there so it's looking almost certainly to be a David Hinds mirror- which is great I think  and likely from a Fullerscope- did they have model names like R12, R3 etc? I'll do some more digging and contact the David Hinds webpage. 

I did find another picture on here of a Fullerscope D.Hinds mirror- looks to be similar layout though a different hand.

Mine lacks a grading letter but I chose to be optimistic and as 6" is the largest scope I've ever looked through I'm really excited and inspired to build something with this and have my mind blown

 

Mark