• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Need long extension tube (1 Viewer)

opticoholic

Well-known member
Hello,
I have a new telescope with a 630mm focal length that I'd like to use with my Olympus E-M1 II, but it looks like I will need a much longer extension tube, ideally ~5.5" or 5.75"... That's a full 2 inches longer than the one I use on my 480mm scope. Darn. Do any of you astro-scopers know where I can get a very long extension tube like this?

Dave

Addendum: For now I ordered an additional 2" extension, which I will stack on top of the one I already have. It will be interesting to see how much harder it is for me to use this much longer scope. I'm a little worried about how straight and rigid this "pieced together" extension will be... Also I expect gentle breezes may become an issue. I will probably only be able to use this longer scope when there is very little or no wind.
 
Last edited:
Hello,
I have a new telescope with a 630mm focal length that I'd like to use with my Olympus E-M1 II, but it looks like I will need a much longer extension tube, ideally ~5.5" or 5.75"... That's a full 2 inches longer than the one I use on my 480mm scope. Darn. Do any of you astro-scopers know where I can get a very long extension tube like this?

Dave

Addendum: For now I ordered an additional 2" extension, which I will stack on top of the one I already have. It will be interesting to see how much harder it is for me to use this much longer scope. I'm a little worried about how straight and rigid this "pieced together" extension will be... Also I expect gentle breezes may become an issue. I will probably only be able to use this longer scope when there is very little or no wind.
Hi Dave,

I have been using stacked extension tubes at times, when using the scope for semi-macro e.g. butterflies and other larger bugs. The longest I have used is 80mm + 80mm.

The setup is straight/rigid however the torque on the focuser increases substantially. In my case the scope is fitted with a heavy duty 3" focuser which is designed to hold quite heavy loads so I don't perceive it as an issue but for 2" focusers it might be an issue. A dovetail camera support would remedy this, but it's extra work.

BR
Tord
 
Warning! This thread is more than 5 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Users who are viewing this thread

Back
Top