filters Filters don't fit eyepieces

[Jordan Konisky]

I have an Orion UBlock, a Lumicron Olll, and a Baader Neodymium filter, all 1.25.”  The Baader screws on nicely to all my Televue Plossyl and Delite EPs.  However, while, both the Orion and the Lumicron fit well to my 32 and 15mm Plossyl, neither screws on tightly to my 25mm Plossyl or my 18.2 or 7mm Delite).  All fit nicely to my 2X TeleVu Barlow. From several discussions on Cloudy Nights, it is apparent that that the issue of filter-fit mismatch is common.  My main telescope is a Sky Watcher Pro ED100 AP refractor which accommodates my 1.25” EPS via a 1.25 / 2” adapter.  My goal, then, is to make all my EP’s compatible with these filter types as well as to make the changing of filters more efficient.  I could sell off my Olll and UBlock filters and buy the comparable Baader filters and assuming they fit all my EP, live with the inefficiency of changing filters in the dark.  Or, I could acquire a 2” barrel extension to my 1.25/2” adapter and purchase 2” filters that would screw into the bottom of the extension barrel.  I could then easily switch back and forth between my 1.25” EPs.  In fact, extension barrels are cheap, so that I could even buy three of them, one each 2” filter.  Does this solution make sense?  Are there more reasonable solutions?

[rwilkey]

Hi Jordan, I know my 2" Lumicons can be a bit loose sometimes, but not in the sense that they will come apart.  Make sure you buy a 1.25-2" adaptor with a thread for filters, it is not always a given.  Also, do not see the sense of buying more than one adaptor as I usually stick to one filter whilst I search for a number of targets, not just the one.  If you are going to swap around a lot, a filter wheel would be a better solution. 

[Jordan Konisky]

Robin, Thanks so much for your suggestion.  I do have a 1.25-2" adapter with threads for a filter.  That would indeed work for most of my EPs.  However both my 1.25" 18.2mm and 7mm Televu Delites and my 1.25" Televu 2X Barlow extend out of the bottom of my adapter prohibiting the attachment of a filter to the adapter.  I suppose a solution here would be to screw in a 2" extension barrel onto the bottom of my adapter and then add the filter to the bottom of the extension barrel.  Plenty of room in my diagonal to accommodate the extension.  What do you think of this as a solution?  

[Ricochet]

5 hours ago, Jordan Konisky said:

 I suppose a solution here would be to screw in a 2" extension barrel onto the bottom of my adapter and then add the filter to the bottom of the extension barrel.

This is what I do with my dob. One extension barrel stays permanently attached to the bottom of the 1.25"-2" adaptor and then 2" filters are fitted to that if needed. If there is room in your diagonal to fit the extension plus filter(s) there shouldn't be a problem. Alternatively, if the diagonal nose piece is threaded you could attach the filters to that instead (but I guess it is more hassle to take the diagonal off than just the adaptor).

[Jordan Konisky]

Thanks everyone for your suggestions.  I guess I now have a solution.