a 100mm Mak-cass as a guide scope?

seeker372011 (Narayan) · #1 13-09-2005, 07:41 PM

Does this make any sense at all? I am wondering whether a 100 mm Mak Cass (1400mm focal length) would work as a guide scope for my ED80

The main attraction of this Mak Cass is that it is only 30 cm long so transport to a dark site will not be a drama..it is also priced reasonably as an OTA from AOS

I currently-well when I get a chance, the weather hasnt been very co-operative lately-use a 5 inch 900mm focal length Newtonian as a guide scope. This works well, never had trouble finding a guide star..but it is bulky and occupies a lot of space so it is a bit of a nuisance to take anywhere, and I find in the last twelve months I have taken it to a dark site only once

The Mak Cass OTA on the other hand weighs 3.5 kgs so my CG5 mount should handle it with ease, along with the ED80 and Canon 300d and webcam.

is any of this sensible or should I just learn to pack stuff m ore efficiently

?

TIA

atalas · #2 13-09-2005, 08:08 PM

It would work Narayan no reason why It shouldn't ! with a reducer It would be faster and wider field and more sensitive , Shorter and lighter tube leads to less flexture .
Sounds like a all round great idea, Only down side that I can see is loosing 1" of aperture.

Louie

avandonk · #3 13-09-2005, 08:18 PM

An even cheaper alternative is one of those 600mm F8 camera Mirror lenses or
use a cheap achromatic lens.Using a focal reducer gets more stars in the field.
A focal length of 300mm is adequate for autoguiding an ED80.

Robby · #4 14-09-2005, 06:49 AM

I'd use the Mak-Cass for imaging and the ED80 as a guidescope! But either way will work just fine. Good luck.

mch62 (Mark) · #5 14-09-2005, 08:29 AM

You just have to watch out for mirror flop from the mak may cause guiding errors.
Depends on the unit in question and how bad it is.