Using a filter with 13mm Ethos

[Graffy]

Hi guys,

Was very excited to get a big parcel in the mail the other day - my astronomy Christmas came early this year! Anyway amongst all the goodies were a 13mm Ethos eyepiece and a 2" Orion moon filter.

Now I may be missing something here (entirely possible!) but there doesn't appear to be any way to connect the filter to the eyepiece. The filter has threading but the eyepiece doesn't seem to.

Is anyone able to confirm whether these two bits of kit can be used together?

Cheers!

[Kunama]

The filter will thread onto the objective side of the 2" diagonal.

Edit : Just checked your equipment and I don't suppose you have a 2" diagonal on your dobbie, so the 2 " moon filter will not fit ! a 1.25" moon filter will be needed.

[barx1963]

The 13mm Ethos has dual 2" and 1.25" barrels but it only has capacity for a 1.25" filters. You can get a barrel extender to allow fitting of a 2" filter but I will have to do some research where it can be purchase.

Malcolm

[barx1963]

Do NOT attempt to remove the 1.25" barrel it will voide warranty and may not be easy to put back together.

Malcolm

[barx1963]

Here's is the part you need http://agenaastro.com/televue-barrel-extender-ebx-2120.html
There may be cheaper ones out there, not sure if local shops have an equivalent.

Malcolm

[Graffy]

Well there you go, that's what I get for ordering all my equipment in one hit as opposed to getting it bit by bit and seeing how it (should) all fit together :doh:

Don't worry, I'm not planning on pulling the eyepiece apart! Guess I'll grab some 1.25" filters and find a good home for the one I have. I spose every cloud has a silver lining... 1.25" filters are cheaper than 2" ones so I'll be better off if/when I grab some nebula filters!

Thanks for the replies guys :thumbsup:

Edit: scratch that, because 1.25" filters won't fit on a 21mm Ethos when I get it. I'll have to look into getting that barrel extender!

[barx1963]

There can be some traps for the unwary! At least its only an ND filter not an OIII, which can be expensive in the 2" version.
Personally, unless you are planning on a lot of lunar observing you may not find much use for that filter. When I had the 12" I found I never used my ND.
One thing to consider when buyoing filters is if getting an OIII, only get a 1.25" version, as you will mainly use it for PNs which are (usually) samll and need higher power eps anyway.
One option for filters is a filter slide (eg http://www.focuser.com/cgi-bin/dman.cgi?page=productdetail&plugin=dstore.cgi&product=FS-1 ) that allows you to mount filters and just slide them into position when required. I have this one on my 20" and works a treat. Only takes 2" filters though, but with a OIII and UHC both in 2" you are set.
Congrats on the Ethos, BTW. Lovely EP, personally I think the 17mm Ethos is the shizzle, with the 13 not far behind.
What other bits did you pick up?

Malcolm

[Graffy]

Thanks for that Malcolm, the filter slide looks like the ideal solution!

Picked up the Ethos and a 2x Powermate, a glatter laser collimator and tublug, and a few other odds and ends. I was blown away by the Ethos, I'm still very new to astronomy and until I got the Ethos I was using the 10 & 25 Plossls that came with the scope and while I was enjoying looking through them, I hadn't been "wowed" yet. I've spent the last week or so camping in the Snowy Mountains... proper dark skies down there, and the views through the Televue were incredible!

Next on the list are the 21 & 8mm Ethos, a 4x Powermate. That set should keep me happy for a long, long time I think :)

[barx1963]

Hmmm. I would be careful with the 8mm Ethos. I have a 10mm Ethos and found it was pusing the limits in my old 12" at 150x. Needed really still conditions to get a good view, an 8mm at 187x is going to be pushing even more.
Same goes for the 4x powermate. Using even the 21mm will give you 285x which is going to need perfect seeing.
The 21mm is a beaut in a 12", just be aware it is a heavy brick of an EP, over 1kg as against 590g for the 13mm so be aware of the balance of your scope.

Cheers

Malcolm