focal reducers

[red dwalf]

can anyone help me to understand how focal reducers work, i understand that they reduce the focal length of the scope and inprove field of view but does the magnification stay the same or is that reduced as well ?also what other equipment would i need to use with a dslr camera for imaging i.e. any adapters, scope is a nexstar 6se sctwith thanks Rob

[Macavity]

I found the following link illustrated the "theory", neatly

and could be useful for subsequent calculations...

Focal Reducer Calculator

P.S. For general fiddling, e.g. my ATIK (visual) field reducer is a negative lens packaged into a THICK 1.25" filter-type housing, and threaded correspondingly front and back...

[Milamber]

A barlow (or tele negative) effectively has a smaller hole and so allows less light to get through. That light though still has to fill an area the same (eyepiece field of view) size as normal so it gets stretched a bit to cover that area, making the light thinner (so darker) but stretched (so bigger). A reducer does the opposite - more light gets in so that light is brighter but it has to squeeze into the same area so the image is smaller (reduced).

Arthur

[Merlin66]

To use the DSLR with a x0.63 reducer, you'll need a SCT thread to T thread adaptor, probably a 50mm T thread extension tube, T thread to EOS adaptor which fits the camera ( assuming a Canon)

This will position the CCD chip in the camera at the correct spacing of 110mm behind the reducer.

Hope this helps.