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View Full Version here: : Big Dob vs small Refractor


HCR32
15-08-2010, 01:40 PM
Hi guys

What is best to use for great planetary views a big aperture dob or a high quality 4-5 inch refractor. What's going to give me high quality visuals?

Thanks

wavelandscott
15-08-2010, 02:05 PM
Talk about an unanswerable question!!!

The answer can be either!

For me the best view of a planets has been in my big dob...but there is a catch. To get the best views it must be properly collimated and the mirror must be cooled. Achieving those two states gives great views...

Having said that, the views I get in my 130 mm APM on planets are amazing too! The upside was that this scope is "ready to go" much faster than the dob.

Either scope can get you great planetary views...

casstony
15-08-2010, 02:46 PM
Have you noticed Ausastronomer's 10" dob in the classifieds? A high quality 10" optic would be very good for planetary - easily out resolve a 5" refractor for a lot less money and be able to do DSO's too. All the mods are done too.

Alchemy
15-08-2010, 06:04 PM
Scotts answer is correct, however give ALL of the high quality planetary images are taken with 12 inch or bigger newts.... Ie bird, iceman, quark etc
That's where I would head. Cheaper by far too.

Hmm there are a couple of largish cadioptrics that do ok too, I'd still go the newt though

dannat
15-08-2010, 06:57 PM
for planet viewing i don't think APO is a necesity, long f/l will do it - i am lazy & don't like collimating - waiting for warm down so refractor is better for me - a 6" gathers alot of light , a 5" would still be very good- get osme good orthos for it
also i can fit it across the back seat of my wife's small 1.4L car - bid dob is much more difficult - i had a 12" & hated moving it

HCR32
15-08-2010, 10:03 PM
What have I done some say mid size glass others large mirror. Seems to me that Im still sitting on the fence. Lets refine this arguement a bit would you pick a refractor say between the sizes of 106mm-130mm, top brands only (tak,tmb,tec) or a big 16inch dob purely for the wow factor when viewing planets.

By the way thanks for the posts guys.