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Celestron Ultima 100
I recently bought a fixed eyepiece for a Celestron Ultima 100 . The
eyepiece is a standard 1.25" Plossl which I believed would fit the Celestron. When I tried to fit it to the telescope I discovered it is very slightly too big to fit into the mount. My local Celestron dealer said he has heard of this before but doesn't know if there is a special adapter for these eyepieces. Yet on some forums on line I hear people have used fixed lenses in their Celestrons before. Having measured the sizes I would say a simple 35 mm to 30 mm adapter ring would do the job very well. Has anyone here had this problem? Is there a special adapter I can buy somewhere? Or perhaps someone has discovered their own personal work around for this problem? I'd appreciate any help. Thank you. omega |
#2
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Celestron Ultima 100
On 01/05/2011 12:36, Omega wrote:
I recently bought a fixed eyepiece for a Celestron Ultima 100 . The eyepiece is a standard 1.25" Plossl which I believed would fit the Celestron. When I tried to fit it to the telescope I discovered it is very slightly too big to fit into the mount. My local Celestron dealer said he has heard of this before but doesn't know if there is a special adapter for these eyepieces. Yet on some forums on line I hear people have used fixed lenses in their Celestrons before. Having measured the sizes I would say a simple 35 mm to 30 mm adapter ring would do the job very well. Has anyone here had this problem? Is there a special adapter I can buy somewhere? An adaptor will only work if the scope has enough back focus to allow the image to be focussed. You should be able to test if this is physically possible by holding the new eyepiece up against the hole and looking at a distant object with it. If you can still obtain focus at infinity then an adaptor is possible. Test this before investing any money in obtaining an adaptor... You might be able to bodge something out of plastic plumbing parts for a quick test of concept. Or perhaps someone has discovered their own personal work around for this problem? I'd appreciate any help. I don't know it they do one, but SRB-Griturn have always been a good source of awkward threaded photographic adaptors, fliters connectors and are usually game to make custom things that might be popular. http://www.srb-griturn.com/ Mostly photographic, but they are sympathetic to astronomers requests. Regards, Martin Brown |
#3
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Celestron Ultima 100
Thank you Martin. I have unscrewed the barrel from the eyepiece and then
the eyepiece will sit in the mount albeit loosely. It focuses perfectly while I hold it down with room to spare for a thin 'ish adapter if I can find one. Obviously I can 'make' it sit in the mount more secure with perhaps a few twists of tape but I'd like to see a proper job with an adapter when I start swapping lenses in the dark. I'll try get hold of your firm after the holiday. omega "Martin Brown" wrote in message ... On 01/05/2011 12:36, Omega wrote: I recently bought a fixed eyepiece for a Celestron Ultima 100 . The eyepiece is a standard 1.25" Plossl which I believed would fit the Celestron. When I tried to fit it to the telescope I discovered it is very slightly too big to fit into the mount. My local Celestron dealer said he has heard of this before but doesn't know if there is a special adapter for these eyepieces. Yet on some forums on line I hear people have used fixed lenses in their Celestrons before. Having measured the sizes I would say a simple 35 mm to 30 mm adapter ring would do the job very well. Has anyone here had this problem? Is there a special adapter I can buy somewhere? An adaptor will only work if the scope has enough back focus to allow the image to be focussed. You should be able to test if this is physically possible by holding the new eyepiece up against the hole and looking at a distant object with it. If you can still obtain focus at infinity then an adaptor is possible. Test this before investing any money in obtaining an adaptor... You might be able to bodge something out of plastic plumbing parts for a quick test of concept. Or perhaps someone has discovered their own personal work around for this problem? I'd appreciate any help. I don't know it they do one, but SRB-Griturn have always been a good source of awkward threaded photographic adaptors, fliters connectors and are usually game to make custom things that might be popular. http://www.srb-griturn.com/ Mostly photographic, but they are sympathetic to astronomers requests. Regards, Martin Brown |
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Celestron Ultima 100
On 01/05/2011 17:59, Omega wrote:
Thank you Martin. I have unscrewed the barrel from the eyepiece and then the eyepiece will sit in the mount albeit loosely. It focuses perfectly while I hold it down with room to spare for a thin 'ish adapter if I can find one. Obviously I can 'make' it sit in the mount more secure with perhaps a few twists of tape but I'd like to see a proper job with an adapter when I start swapping lenses in the dark. I'll try get hold of your firm after the holiday. The other option is to find your local model engineering club and talk nicely to them. Someone with a lathe might be prepared to make you a one off for the cost of materials and a nominal charge. You might even find a standard stock aluminium tube of the right diameter on eBay. Regards, Martin Brown |
#5
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Celestron Ultima 100
On 02/05/2011 11:10, Martin Brown wrote:
On 01/05/2011 17:59, Omega wrote: Thank you Martin. I have unscrewed the barrel from the eyepiece and then the eyepiece will sit in the mount albeit loosely. It focuses perfectly while I hold it down with room to spare for a thin 'ish adapter if I can find one. Obviously I can 'make' it sit in the mount more secure with perhaps a few twists of tape but I'd like to see a proper job with an adapter when I start swapping lenses in the dark. I'll try get hold of your firm after the holiday. The other option is to find your local model engineering club and talk nicely to them. Someone with a lathe might be prepared to make you a one off for the cost of materials and a nominal charge. You might even find a standard stock aluminium tube of the right diameter on eBay. Just remembered a couple of other places that might be worth a try for small engineering bits so will tack them onto this thread: AWR Technology (Astroparts) http://www.awrtech.co.uk/awr_info.htm BC&F AstroEngineering http://www.astro-engineering.com/cat...ors/index.html Hope you can find the right bit! Regards, Martin Brown |
#6
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Celestron Ultima 100
"Martin Brown" wrote in message ... On 02/05/2011 11:10, Martin Brown wrote: On 01/05/2011 17:59, Omega wrote: Thank you Martin. I have unscrewed the barrel from the eyepiece and then the eyepiece will sit in the mount albeit loosely. It focuses perfectly while I hold it down with room to spare for a thin 'ish adapter if I can find one. Obviously I can 'make' it sit in the mount more secure with perhaps a few twists of tape but I'd like to see a proper job with an adapter when I start swapping lenses in the dark. I'll try get hold of your firm after the holiday. The other option is to find your local model engineering club and talk nicely to them. Someone with a lathe might be prepared to make you a one off for the cost of materials and a nominal charge. You might even find a standard stock aluminium tube of the right diameter on eBay. Just remembered a couple of other places that might be worth a try for small engineering bits so will tack them onto this thread: AWR Technology (Astroparts) http://www.awrtech.co.uk/awr_info.htm BC&F AstroEngineering http://www.astro-engineering.com/cat...ors/index.html Hope you can find the right bit! Regards, Martin Brown I've sent an email off to AE as they look quite promising and also mailed one or two others. Will let you know if I get a part or not, in due course. Thanks for the links. omega |
#7
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Celestron Ultima 100
"Martin Brown" wrote in message ... On 02/05/2011 11:10, Martin Brown wrote: On 01/05/2011 17:59, Omega wrote: Thank you Martin. I have unscrewed the barrel from the eyepiece and then the eyepiece will sit in the mount albeit loosely. It focuses perfectly while I hold it down with room to spare for a thin 'ish adapter if I can find one. Obviously I can 'make' it sit in the mount more secure with perhaps a few twists of tape but I'd like to see a proper job with an adapter when I start swapping lenses in the dark. I'll try get hold of your firm after the holiday. The other option is to find your local model engineering club and talk nicely to them. Someone with a lathe might be prepared to make you a one off for the cost of materials and a nominal charge. You might even find a standard stock aluminium tube of the right diameter on eBay. Just remembered a couple of other places that might be worth a try for small engineering bits so will tack them onto this thread: AWR Technology (Astroparts) http://www.awrtech.co.uk/awr_info.htm BC&F AstroEngineering http://www.astro-engineering.com/cat...ors/index.html Hope you can find the right bit! Regards, Martin Brown Several of my enquiries drew a blank with most correspondents never heard of such an adapter. The firm you mentioned in your first reply say on their site, they will make to spec' but I noted their start price was £50 plus VAT then postage. I have been in touch also with the Celestron importers and they say my particular model was never intended for fixed eyepieces. One dealer though informed me that Acuter fixed lenses will fit as they share the same size collar as the Celestron zoom lenses for the Ultima. But again, I discovered they are twice as dear as a good quality Plossl from Ebay. So I've hung my holsters up on this one for the time being at least. As a matter of interest, the new Celestron 'Regal' range will take a common Plossl 1.25" fixed lens. Great I hear you all say but they are LOT of money in the first place. Truthfully I'm happy with the clarity of the Ultima but I do love me gadgets and a couple of Plossls sounded great at the time. Thanks for the links, at least I'm a little wiser now. Omega |
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