why are the tiny APO's so good?

perhaps its my lust for apature, but i cannot see why everyone raves about the small APO refractors. what makes them so brilliant? ( im not making a snide remark, i really wana know!)

For many years, cheap small refractors were useless, "good" ones were very expensive.
The fact they are now cheap and very portably is why people go on about them, they also usually excellent at widefield astrophotography.
If you want aperture, they are not the way to go.

is 500 sterling for an 80mm affordable though? thats as expensive as a SCT of twice the size.

Its fashion.

And they are stunningly good looking instruments to put in the corner of your living room!

Peter.

You'd be surprised. On the face of it they are a strange niche but once you think about the advantages they are truly excellent devices.

e.g. the following make them perfect for photography

1/ Massive field of view for those extended objects.
2/ Short focal length which makes it possible to use the new small pixel CCD imagers (which cost only about 1/4 that of an SBIG) and yet keep a reasonable image scale.
3/ Easy to piggyback.

Also, they are incredibly portable, quick to setup and you would be surprised at what you can see through them - I've seen the Leo Triplet, M81, M82 and similar objects through my 66 at a semi dark site. If you need more magnification it can easily go up to 150-180x.

That said they are not visual deep sky scopes. For that use your dob. But when you need a quick setup, portability or when your travelling they are excellent. For me it was that in conjunction with this scopes suitability with the Sac10 imager I have.

I also enjoy a bit of bird watching and these scopes are absolutely perfect for that activity.

Regards,

Trev

Nobody doubts their good qualities Trevor.

But take the Maksutov-Cassegrain design.
It is INHERENTLY an APO, with superior optical performance and more compact any refractor.
see:
www.amazon.com/gp/product/customer-revie...76897289&sr=1-14

I'd buy that (or such like) for $200 and go for a holiday in the sun with the money I saved by not buying the APO.

Peter.
(I love refractors myself mind you. I have a 6" Celestron RGT refractor.)