Fitting 1.25" Lp filter to 2" nosepiece

[Andre27 (Andre)]

Good Day All

I trust that this is the correct forum for my post.

I bought a 2" coma correcter for my 200P SW , and ordered a 2" focuser to accommodate the coma correcter .
What would the effects be if I made an adapter that would fit my 1.25"LP filter to the 2" nose-piece instead of having to buy a new 2" Lp filter.
I image with two cameras A) Canon 60d D) Nikon D7000.
The budget has been stretched to the limit, so I am looking for a more cost efficient solution.

Advice would be appreciated.

Clear skies to all.

Andre

[mental4astro (Alexander)]

Andre,

Just to clarify, you intend on putting the filter on the nose end of the coma corrector, right?

The consequence of this is you will be cutting off the edge of the light cone that is coming from the primary. This does two things: 1, stops down the aperture of the scope to a smaller one: 2, you end up with a fuzzy edge to the subsequently smaller field of view (this fuzziness is called vignetting).

The geometric shape of the light coming from the primary mirror is like a cone. You would be introducing an obstruction into the light path smaller than the diameter of the cone at the point where the nose of the coma corrector sits in the optical train. This goes for both imaging and visual.

How severe the consequences will depend on the focal ratio (so how sharp or stumpy the cone of light is), how long the focal length & AFOV of the eyepiece with visual, & how much of the FOV your camera can fit on its chip.

Alex.

[Andre27 (Andre)]

Thank you Alex

I had assumed in error that it would be fine as the 1.25 filter worked fine on my F5 200mm Sw with the Dslr cameras.

It seems that the purchase of a 2" filter is inevitable , I considered a clip filter for the Canon but it is just to expensive , and I actually prefer imaging with my Nikon D7000.

Thanks for the info.

Andre