Though telescopes have a long history they were only produced in quantities to be widely available in the late 18th century.
Problems of lens polishing, lens composition, and manufacturing were slowly overcome and the telescope became a vital element of seafaring equipment. Superior optics meant that navigation hazards could be identified at longer distance, and in time of war and piracy it meant that approaching vessels could be recognized at longer distances. It also made the use of communications by signal flags practical.
Early telescope construction consisted of barrels constructed of leather, vellum, or wood with the lenses held in place by brass fittings. The one pictured below and found in the National Maritime Museum, Greenwich, London dates from 1775 and is made of mahogany. It measures 35″ closed and when open is 44″ long. The opening holding the objective lens is 66mm, about 2.5″, in diameter. Hardly something you’d want to climb into the rigging holding.
As the science of metallurgy advanced, the telescope barrels of brass became more common. This next telescope, also from the National Maritime Museum, dates from about 1800 and is leather-covered brass some 25″ long when closed and 29″ long when opened. The end holding the objective lens is 44mm or about 1.7″ in diameter.
In the case of the brass telescope, the handiness of lopping some 15 inches off the extended length is a radically reduced field of vision.
Another interesting innovation was the development of the night telescope, or night glass. Using a conventional telescope at night is difficult because the relatively small objective lens did not permit a lot of light to enter the tube and interior lenses which were required to correct the inverted image produced by a simple refracting telescope absorbed part of that light. The result was a telescope with a fairly large objective lens but which produced an image that was inverted,
The below example of a night telescope dates from 1810, it has a leather tube with brass fitting. It measures 28″ long closed and 34″ when extended. The end holding the objective lens is 82mm, or nearly 3.25″.
Age Of Sail 
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I am a collector of British naval telescopes. I am looking for some source that references standard Admiralty patterns for manufacturers to use strting from the 1880’s onward. I would appreciate any suggestions
I’d suggest checking with the people at http://groups.yahoo.com/group/RoyalNavy_from_1789/ there are a lot of experts on the RN on the list, something which I don’t claim to be
I have a friend with an amazing collection. The store won’t be open until 1/10/10, but you can get a look at what he has online in the museum. It’s a gorgeous site. http://www.opticaliamuseum.com
I am trying to find some information on two telescopes we have .
First is a W.Watson & son –1916 ,No 5278
sighting telescope No4 Mk III with the
Goverment arrow . ex father-in-law .
The 2nd is a H . Hughes & sons Naval telescope of
my grandfathers No 417a/3969
I also have a H . Hughes & sons brass and leather naval telescope that beldonged to my grandfather. Unfortunately the lens at the end is missing. I would love to know what it looked like as I am thinking of looking for a specialist who could replace it.
Mine is engraves: H.(enry) Hughes and Son, 59, Fenchurch St., London. That was the makers address between 1879-1941.
Does anyone have information on the “Come Up” telescope that Jack Aubrey employs from the upper yards to determine if he is overtaking a prize? I cannot cite the volume in O’Brian’s series where this event took place, but the scope had two (2) images side by side of the chase. If one were overtaking, one of the images would superimpose (?) over the other or some such optical magic.
Google, Wiki, ePay, and Amazon have not been able to help me in finding information or sources about this fascinating piece of equipment.
Thank you
“What a fascinating modern world we live in!”
agreed! I also found a reference to this in Alaric Bond’s “The Jackass Frigate” and I can’t find any explanation or description of it… in fact the only reason I found this page is that it came back as a hit on “come up glass”!
http://www.tandfonline.com/doi/abs/10.1080/14786440508562460?journalCode=tphm12
” invented by the late Mr Ramsden It consists in applying a micrometer to a refracting telescope of about two feel long or to a day and night telescope”
naturally like your web site however you need to test the spelling on several of your posts. A number of them are rife with spelling problems and I in finding it very bothersome to inform the reality on the other hand I’ll certainly come again again.
Jack Aubrey’s ‘Night Glass’ seems to have been a conventional telescope but with one or more of the internal lenses missing so that more light enters- hence better night vision- but at the cost of making do with an inverted image.
hello
frith naval telescope is from ?
Anthony Ashmore is referring to a review in The Philosophical Magazine v22 issue 88, starting on page 319. It takes some work, but you can find the full PDF for this issue on google books.
I am interested in information on a lot of recently purchased antique telescope eyepiece tubes, which are all marked U.S. Navy. Almost all of the tubes are marked 12.5X and appear to be from Officer of the Watch type telescopes that have not been a focus of my collection. Additional research on the manufactures suggested almost all may be from actual civil war telescopes. Most specifically, A. Bardou appears to have changed to Bardou & Sons prior to the civil war.
The manufactures were:
Queen & Co. (2 scopes)
A. Bardou Paris (8)
Bardou & Sons Paris (3)
Dubois & Co. Paris (3)
Perhaps most interestingly one scope is labeled only Sig. Dept. U.S.A. This scope has a complete eyepiece lens set and two additional draws. It appears to be of high quality as the two large tubes are perforated and the internal threads are set down inside the telescope.
Other than that, there are no objective lenses and only a few battered partial main tubes, but I am hesitant to start stripping the scopes for lenses until I determine if they have historic value.
If you (or anyone you know of) might address this issue, I could use some guidance.
Hello! Can someone advise, please? In the 1950’s, when I was in my early teens, an uncle on his deathbed sent me a brass telescope via my parents. I was told that it was “a night glass from the HMS Iron Duke”. I still have the telescope, in full working condition. Only the lens cap is damaged.
Can anyone shed any light? Is it likely to be the real thing, or fake? I can discover no connection between my uncle and the navy. My interest is aroused just now by the WW1 publicity.
Thanks! Chris Marples
You need to get a professional appraisal. The UK’s National Maritime Museum in Greenwich would be where I would start.
Thanks Bill, good idea.
Hello, I’m trying to find out (or make a reasonable guess at) what sort of telescope Joseph Banks would have had with him when he was sailing with Cook in 1770. He was a very rich man, so would presumably have bought the very best for the purpose, available at the time. Possibly a Dollond day and night? What sort of magnification would it have had?
Thanks, Edwin Ride
I caught a name on the side bar and thought I would let you know that I have all of the Ramage books and have loved every one of them. It has inspired me to write myself, thats another story. Reserching for my book and came accross your site thanks for the information.
chris
I am writing about the Admiralty Shutter Telegraph system of ca 1800 and am surprised that a telescope could distinguish the positions of shutters some 10-15 miles away. Do you know, please, the magnifying power of a naval telescope of that period?
really sorry, but i don’t but according to this an other sources they were between 12x and 30x, with 30x being the absolute maximum. https://www.college-optometrists.org/the-college/museum/online-exhibitions/virtual-observatory-gallery/telescopes-part-1-.html
Click to access Binoculars-and-Telescopes-Proceedings-8129.pdf
I am trying to find info on telescope by Wm Chalmers, Glascow, 1899. Tom
I am trying to find info about a telescope I have of Bardou & Sons used by a captain of Scotland in Hong Kong 1850. Does anyone know how much this is?