History Of the Observatory eyepiece.

I found some interesting information on the Siebert Optics site in the Observatory series eyepiece page. I have one of these eyepieces and was interested to find out how they were conceived. It was interesting to find out they started out as a project at the request of some historic Observatories to relieve a problem these scopes have with small true FOV because of their scopes large size. One of the observatories was using a 2" 55mm and getting a .15 deg of sky. It would seem they wanted to get a .25 deg minimum and needed an eyepiece with a 116mm FL. and in the 5" dia. You can find the page by typing "Observatory eyepieces" in a google search and the page will come up second. The information is all the way at the bottom of the page.

Manuel,
Which one do you have, how do you like it and why and what scope is it used in now, if you please!

I remember seeing a couple of 4" eyepieces while down at the WSP, here in South Florida...

They were definitely "special" eyepieces... and I wonder "are these the largest ones, or is there anything larger than these?"

It's gotta be impressive to look through these eyepieces... (I would suppose) or because the large telescopes they would go into, they would end up being like .965" or 1.25" eyepieces for ours, mere mortals?


Has anybody here viewed through some of these "LARGE" eyepieces? what was the experience like?



Clear skies! 8)

A fellow who lives about 20 minutes from me has an ATM 11" refractor with a D & G Optical objective lens. (His roll-off observatory is the largest I've ever seen.) He owns two 4" eyepieces. IIRC, they are a 75mm Pentax and a 90mm Zeiss. It's a rather interesting experience to look through these monsters.

Dave Mitsky