Skywatcher ED80 Vs ED100

[**Space*Hopper**]

Hi all,

Just as I think I have got my scope choice sorted with the ED80, along comes a kind person with an attractive offer on a 2nd hand ED100

Now for the majority of what I want to image I think that the ED80 f/600 f/7.5 is the best choice in terms of physical size and magnification. However I believe that by adding a F6.3 focal reducer to the ED100 I would end up with an F5.8 F/580mm imaging tool or have I got this all wrong ? If correct, this f/6.3 combination would be faster than the f/7.5 ED80 yes ? (pressumably because of its larger objective lens) ?

However, obviously the advantages of the special glass used in these apos is to reduce / eliminate CA, will the addition of a focal reduced not made of the same special glass in any way degrade the advantage of the APO scope ? I must admit that if the ED100 / focal reducer combination would work well for my imaging, also being able to use it without the focal reducer on the odd target where more magnification is required is very appealing.

Anyway as always thanks in advance for any advice offered.

Ian

[GazOC]

I'm no imager so I'll leave that side for somebody else to comment on but I can't see a focal reducer adding much or any noticable CA to an image. For general visual use the ED100 is a far better scope than the ED80, the extra inch makes a big difference on a whole host of objects, its not actually that much larger than the ED80 as the ED80 uses and the same 100mm tube. Its slightly heavier due to the larger objective and around 12" longer, but the same width.

Unless mounting, transporting or carrying the larger scope is an issue I'd go with the ED100.

[**Space*Hopper**]

A little late I know but I just wanted to say a quick thanks Gaz. I ended up taking your advice and buying the 2nd hand ED100 and I must say you were spot on and I am absolutely thrilled with the scope :hello1:

Thanks again

Ian

[CELESCOPE]

One scope never seems to be enough , the ED80 used with the 6.3 reducer gives a super wide field , for instance allowing the flame and HH to fit in ,this of course edepends on the chip size of your imaging camera , the ED100 is also an excellent scope , it just a matter of finding the right scope for what you want to image , we all go through these stages chopping and changing ,till we hopefully get what suits us best,

have fun

Rog