Shortening a refractor

bloodhound31 · #1 26-05-2007, 10:13 PM

What effect would shortening the OTA of a refractor have?

I have a cheap and nasty 600mm refractor with a focal length of 900mm.

How much if any, can I shorten it by and would this improve anything?

Curious,

Baz.

ballaratdragons (Ken) · #2 26-05-2007, 11:35 PM

Depends on how much you want to cut off, Baz.

If you shorten it a bit you can use a focal reducer to give you wider FOV making it into a RichField Telescope. Too short and it will be useless I believe.

Garyh · #3 28-05-2007, 01:13 PM

If you cut it Barry this would mean that you would have to rack out the focuser further to get focus or a extention tube...both not good ideas on a cheap scope. Also you might vignette the light cone from the objective with the focuser draw tube, not good either..

bloodhound31 · #4 28-05-2007, 09:11 PM

Sounds like its a good idea not to bother. A well, ED80 APO, her I come!!!!

Now for astrofunds......anyone care to donate to the save A.S.I.G.N. Observatory cause?

Can't hurt to ask......

Baz