focal reducer..?

[resonator77]

can anyone advice what it is exactly for?

My understanding is it reduces magnification of an eyepiece, than why use focal reducer if you could use wider field view eyepiece.

Please help.....

[mike.brightmore]

A focal reducer reduces the focal length of the telescope so, as you say, it therefore reduces the magnification for any given eyepiece. This does give you a wider field of view and also makes faint objects like nebulae and galaxies a bit brighter and clearer - which you wouldn't get with a wider field eyepiece.

Just as an example my scope has a focal length of 2800 mm. Even with a 40 mm eyepiece the lowest magnification I can achieve is 70x (i.e. 2800/40) This is just too much for many faint deep sky objects. Remember that the more an object is magnified the fainter it gets. So I use a focal reducer to reduce the focal length. Its also useful for photography when you want to get more of a large DSO in the frame. Hope this helps.

[Merlin66]

It effectively reduces the focal length of the telescope ie a f10 SCT with a x0.63 reducer becomes a f6.3. ( effective focal length changes from 2000mm to 1260mm on an 8"sct)

It doesn't always affect the FOV with visual observing... as you say you can change to a lower power eyepiece and get the same result......

Probably more important for imaging and field of view.

[resonator77]

Thank you Merlin and Mike

you just confirmed my theory:)

You just saved me some dosh