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Old 24-10-2011, 10:46 PM
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tilbrook@rbe.ne (Justin Tilbrook)
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When a Dob was a Dennett in the 1880's

Hi,
Here's my reconstruction of my great great grandfathers telescope, using the original mirror and one original eye piece.
Henry Hammond Tilbrook was the founder of our local newspaper the Nothern Argus, in 1860.
Henry was interested in all sciences, Astronomy, Geology etc.
He had two telescopes, an F/14 - 4" Solomons refractor, and F/9.4 - 9 .25" reflector which he constucted from a design by FC Dennett. This is the telescope I've reconstucted.
The plans for this scope came from the pages of the English mechanic. How do know he used these!
Because My brother owns the the EM from my great great grandfather. In the pages are his notes on constructing the telescope and mirror. Also, Henry also wrote letters to EM about constructing the scope. The EM was a bit like an Ice in space forum for the 1880's.
I've added some updates, a curved vein spider and light baffles, I wanted this scope to perform as well as it could.

Cheers,
Justin .
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  #2  
Old 25-10-2011, 08:15 AM
mercedes_sl1970
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Well done - looks like you have done a terrific job. How are the views?

Andrew
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  #3  
Old 25-10-2011, 11:01 AM
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GrahamL
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Thats a great and worthwhile project Justin

What do you know about how the mirror survived all these years waiting for another in the family to look to the sky ?
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  #4  
Old 25-10-2011, 06:08 PM
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tilbrook@rbe.ne (Justin Tilbrook)
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Hi,
Thanks for the kind words.
The view through the scope gives good contrast as you woulsd expect from a scope of this focal length and with light baffles. It suffers at high magnification though. I suspect that the figure on the mirror is not quite there.
In Henrys article he describes the view through it, and basically says the same as me.
The history of the mirror is quite intersting, it was used at the Northern Argus for many decades to mix ink on, remember seeing it as a young boy. I suspect the scope was dismantled by Henry because the original construction from deal board would have splt and cracked after a few years. Deal board is basically planks of timber about 10mm thick.
The other reason I know it's his mirror for sure, is in his letter to the English Mechanic, he described how he made the mirror and turned down the mirror blank on a peddle lathe. he says he left a step turned in the outer diam.
This step is still there!
My father sold the mirror to a chap called Lance Catford, he planned to use the mirror in his own scope. He had it recoated sometime in the early 1980's. Unfortunately Lance died before he finished, and to cut a long story short I evetually purchsed the mirror back in 2003 .
The scope has an interesting feature, that todays scopes could do with.
A fold out mirror cell, saves demounting the mirror for cleaning.
The other thing wou will notice, is the strange black tower on the base this has a pulley and chain setup. It's an early R.A. tracking system for alt az telescopes, again this is from EM.
Cheers,
Justin.
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  #5  
Old 26-10-2011, 04:07 PM
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torana68 (Roger)
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Amazing!
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Old 29-10-2011, 06:17 AM
Poita (Peter)
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Absolutely fascinating. They used the mirror to mix ink??
The fold out is a great idea as well.
Thanks for posting the articles as well, I love the sunspot drawings.
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  #7  
Old 29-10-2011, 12:28 PM
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tilbrook@rbe.ne (Justin Tilbrook)
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Hi, Peter.

I remember seeing it covered in ink, don't know why they did it.
If I had to guess, they were probably doing test mixes on it.

Thanks for the comments.

Justin.
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Old 31-10-2011, 12:39 PM
gary
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Hi Justin,

Absolutely fantastic!!!

Best Regards

Gary
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  #9  
Old 31-10-2011, 02:06 PM
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tilbrook@rbe.ne (Justin Tilbrook)
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Hi,
Thanks for the positive comments.
Thought I'd post the part on making the mount, it describes in the last part of the article how the R.A. motion control works.
Also a photo of my great great grandfather.
Cheers,
Justin.
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