60mm refractor surprise?!

[robz (Robert)]

For a bit of fun last night, instead of dragging out my 8 inch newtonian and G.E.M., I thought I'd flash back to my early teens and before and quickly set up my recently purchased, second hand ($25)60mm TASCO LUMINOVA on altazimuth mount and wonky aluminium legs.

I observed Venus, The moon (medium power and high power-no barlows!) and then some deep sky on low power with a reasonable Plossl.

I expected heaps of chromatic aberration and a dull crappy image.
I got the opposite...........the moon was crystal clear and for a pathetic aperature of 2.4 inches, deep sky was surprisingly ''creepy''..........jet black with pin point stars and clusters.

I guess that there is a lot going for refractors that many of us ''mirror boys'' have bypassed in the aperature fever years.

I think my next purchase will be a 6 inch refractor?..........or bigger?

[noswonky (Peter)]

Maybe you can use the 8-inch as a guide-scope!

[michaellxv (Michael)]

refractors rule

[pgc hunter]

Sometimes I toy with the idea of buying 2.4" refractor, just for the nostalgia factor

[Steffen]

Originally Posted by robz

I guess that there is a lot going for refractors that many of us ''mirror boys'' have bypassed in the aperature fever years.

I think my next purchase will be a 6 inch refractor?..........or bigger?

The low chromatic aberration of small refractors comes naturally due to their small aperture and typically long focal ratios. Refractors are inherently achromatic if their focal ratio is longer than aperture (in mm) * 0.122. That's why the 60mm Tasco (which is probably f/9 to f/11) showed no issues there.

A 6" refractor would have to be slower than f/18 (more than 2.7m focal length) to benefit from this criterion. I can just picture it…

Cheers
Steffen.

[GrahamL]

I recently bought an 80 mm to take camping and get into some lunar observing from home and cant say I'm dissapointed.

Its easy to pick up the whole scope and walk outside and same to pack it away . Am currently working through the lunar 100 which is a lot of fun and quite interesting to boot.
http://www.skyandtelescope.com/obser...n/3304151.html
Best thing is those cloudless nights that seem to happen more regularly when the moons up gives me something to look at

[robz (Robert)]

Yes, it's fun to use a small scope that sets up without any effort at all and provides a respectable view of most objects.

I guess it'll end up as a guide scope eventually, but a large refractor will allways be on the cards after this '' retro'' trip through the skies

A large diameter, long focal length achromat can be folded I suupose?

[Steffen]

And there is nothing wrong with large refractors, even if not foldable.

http://upload.wikimedia.org/wikipedi...tRefractor.jpg

http://upload.wikimedia.org/wikipedi...Sternwarte.jpg



Cheers
Steffen.

[michaellxv (Michael)]

Originally Posted by robz

A large diameter, long focal length achromat can be folded I suupose?

Collapsible like a pirates' to fit in your pocket.

[robz (Robert)]

Originally Posted by Steffen

And there is nothing wrong with large refractors, even if not foldable.

http://upload.wikimedia.org/wikipedi...tRefractor.jpg

http://upload.wikimedia.org/wikipedi...Sternwarte.jpg



Cheers
Steffen.

Hmmm????..............now THAT'S a refractor!!!!!

[bmitchell82 (Brendan)]

leaning tower of telescope!

[Steffen]

Did you notice the sign above the observatory entrance? "Weddings under the Stars" - it's a sad thing that a place like this (Einstein gave his first public presentation of GR there) needs to sell out to pay its keep. Not an uncommon thing for observatories, I gather…

Cheers
Steffen.

[hotspur (Chris)]

+1 refractors rule!,love the 'crispness' of a refractor,the views I get through my refractor with the 'Black' background is amazing!.

[renormalised (Carl)]

If you want a good long focal length achro, go here...D & G Optical

[robz (Robert)]

Originally Posted by hotspur

+1 refractors rule!,love the 'crispness' of a refractor,the views I get through my refractor with the 'Black' background is amazing!.

Yeah, that's the ''creepy'' part of the viewing experience - sharp as a tack and jet black backgrounds.

I guess that the closest thing to a refractor would be a MAKSUTOV ?

There's allways been one brand of interest on this forum, but very little experience with it : the SAXON 200mm MAK.
It's the cheapest of the largest Mak's in that size and is made in the same factory as many others (including Celestron and Skywatcher)

Anyone care to comment?