Where to put a moon filter !

[Sirius Starwatcher]

I may be a liitle slow here but please bear with me.

Rather than buy 5 moon filters and ND filters for each EP. ( I like to use every bit of kit I've bought) can the filter be placed elsewhere in the optic train so I can get maximum benefit without having to put the filters on each EP. If so wheres the best position please. I don't mean both filters at the same time.

[Cornelius Varley]

Hold the filter above the eyepiece.

[NGC 1502]

Yes, the filter can go elsewhere in the optical train other than the eyepiece.

But you have to be careful - you could get one 2" filter and screw that onto the inner end of your 2" to 1.25" adapter (many adapters are threaded for that, but not all) but it's possible that your eyepiece barrel may contact the filter before it's fully inserted.    You could use parfocal rings to stop full insertion, but that's a bit of a pain buying and fitting them to all eyepieces.

The above works fine with a scope that takes a star diagonal, the filter fits the nosepiece of the diagonal, lets you change eyepieces with the filter left in place.

The simple, if slow, solution is to remove and refit the filter when you change eyepieces......

There are probably other ideas, so see what others say.

Regards, Ed.

[John]

My suggestion would be to keep it in your accessories case but thats because I don't feel they are needed ! - I don't use one even with my 12" scope.

With most 1.25" to 2" adapters there is a 2" filter thread on inside the 2" barrel which is the solution that Ed suggests above. However, not the Skywatcher 2" adapter unfortunately and thats unique to the Skywatcher focuser arrangement so I don't think other 1.25" - 2" adapters will fit the SW focuser.

Looking at your kit, I have a feeling you are stuck with having to move the filter from eyepiece to eyepiece.

[Astro Imp]

My suggestion would be to keep it in your accessories case but thats because I don't feel they are needed ! - I don't use one even with my 12" scope.

With most 1.25" to 2" adapters there is a 2" filter thread on inside the 2" barrel which is the solution that Ed suggests above. However, not the Skywatcher 2" adapter unfortunately and thats unique to the Skywatcher focuser arrangement so I don't think other 1.25" - 2" adapters will fit the SW focuser.

Looking at your kit, I have a feeling you are stuck with having to move the filter from eyepiece to eyepiece.

When I saw the thread title that was exactly my thought.

Do you feel you need a filter? I saw on another thread a low cost option - use your sunglasses.

[Sirius Starwatcher]

Thank you for the advice guys.

Astro Imp asked do I need filters ? Yes I do use them I find the ND IR and the OMIII, has improved my views no end when observing the Orion Neb. Looks like he answer is to keep changing filters as required for different EPs.

Regards Garry

[LukeSkywatcher]

Would a filter wheel work on a Dob?. I'm not too sure myself as ive never used or held one. Looking at images of them i'm thinking they are designed for other types of scopes?. A bit pricey too considering all you have to do with the Dob is to swap out the filters for each eyepieces manually.  When i use a filter on my refractor scope, i attach it to the end of the star diagonal and insert the diagonal into the OTA. I can only use one filter at a time so have to remove diagonal. If i plan to use different filters..............like everyone else..........its a case of unscrewing it from the EP. 

Sorry i am not much help, but i'm curious about the filter wheel all the same for use on a Dob (not for myself).

P.S.~~regarding a Moon filter.................

Keep it in your case. You dont need one and the only time you might use one is when the Moon is full and you are looking at the Moon and even then the Moon shows no contrast, so its not really worth observing it when its full.