2" Extension and DSLR

[JKB]

This might seem a silly question but..

My SW 150 came with a 2" extension piece that drops into the focuser after removing the 1.25 ep holder.

I can then place the 1.25" with T ring screwed to it back into said extension. What effect would this have on a DSLR attached to it?

Essentially the camera will be about 3" further out than it is normally. Would it increase magnification? Would I be able to focus?

I would try but no chance due to cloud.

Thanks

[carastro]

As far as I am aware the extension piece if it has no lenses (i.e. not a barlow), does not increase the magnification. It is just there to help with focus should you need focus further out than the draw tube will go.

Try getting focus with and without during the day time. Take and image and compare the difference.

Carole

[Keiran]

From what you are saying, you wont get any extra magnification, as this has no lens in it. The only effect would be your focus.

How do you normally connect your camera to the scope, via a t adapter and nose peice?

On my 200p the 1 1/4 ep holder is removable from the focuser. This then provides the focuser to accept the 2" adapter. If i am imaging with this scope, you can take the 1 1/4 ep holder, hold the base and the top ( where the ep goes) in seperate hands and unscrew. This will then reveal a t thread to screw you t adapter on to.

[carastro]

I have a T adapter which screws to my DSLR and then the T adapter screws to my 2" flattener which goes into the 2" nose piece of the drawtube.

I can only say try it out in the day time on a land object and see what you get. I can't see any reason why the magnification should be increased simply by moving the camera further out but I stand to be corrected.

Carole

[Keiran]

Carole do you have a refractor, im not sure whether this is a 150 newt or frac if its a frac you will normally need an extension tube to get focus, or a diagonal, but if its a newt then you dont normally need an extension tube, normally comes with a 2" ep adapter. I may have got the wrong scope originally, i was talking about a newt.... Sorry

[JKB]

Thanks both for your replies. I didn't think it would make a difference but will have a go during daylight hours just to see.

Cheers

[Keiran]

Just wonderind was is it a refractor or a newt?

[carastro]

Carole do you have a refractor

I have a Refractor. In fact I have two:

WO Megrez 72 APO

&

SW ED120 and neither need an extension piece for focus when I use the flattener. I can also get focus without the flattener with my Megrez (but obviously in a different position) with the 2" extension piece. I have not tried this with my ED120 which is new).

I also need an extension piece for my ST80 Guidescope to get focus, I could not get focus at all with the ST80 and my guide camera until I put the extension piece in (this is a 1.25" ext piece).

Hope this helps.

Carole

[Keiran]

I use my flattener with my megrez too, but it does add about 2" which allows me to get focus with out this id need an extension tube or i wouldne get focus... i i have to use a diagonal to get focus on my st80 for guiding.... Why dont companies just add a few inches on to the draw tube, that would make things much easier...

[dmahon]

I suspect that you won't be able to acheieve focus.

I don't have a reflector, but have heard that many of them have problems getting enough "in-focus". Extension tubes give extra out-focus - which is good for refractors, that would normally have a diagonal when used visually - but completely the wrong thing for reflectors.

I believe that you can unscrew something on the focuser of the 150 and attach the T ring (and camera) directly to it. This will allow you to acheive focus. There are thread about it on here somewhere.