Home › Forums › Spectroscopy › Focal reducers for Alpy! › Celestron versus Meade
Slightly confused… Given the discussion at the workshop i was left with the distinct impression that I need a focal reducer for my f10 SCT to get the best Aply match. I have both Meade and Celestron reducers. I’ve copied the following from an old community discussion and there appears to be a big difference in the respective focal lengths.
Which one is the best match for mating the f10 SCT to the Alpy? Am I right in assuming the longer FL will produce less chromatic aberration? but if so what does that do to the SCT/Alpy focal length match?
“I recently measured the focal length of a Meade 0.63x and a Celestron 0.63x focal reducer – the Meade had a focal length around 145mm and the Celestron around 235mm. So the “optimal” distance between lens and focal plane is greater for the Celestron; about 50-55mm for the Meade and around 85mm for the Celestron. The focal length measurements were pretty crude (+/- 5mm?) but clearly a difference.”