Dobsonian

For some time now my father and i have been contemplating buying a dobsonian! new or second hand! but we need advice like what brand what aperture, guided or not, mounts etc! also what prices are good, where to buy, maybe truss tube dob? anyone got a second hand for sale? at least a 10 inch!
Plaese help!
thanks
matthew

Matthew - what do you want to do with it? Visual observing, astrophotography or both? Does it need to be very portable? Answers to these and similar questions will guide you in the right direction...

Dave

it really does matter what kind of work you want to do in the field of astronomy, if you primaraly want to view planets you would be better with a refractor, the prob with the truss is you have to collimate every time you set up which is time, and this is ireland, clouds roll in faster then schmac into the pits for a refuel and a set of tyres. if you was to do astrophotography you need a eg mount with motors, and if you spend a few more euro you can have a goto mount, celelestron's cg5 mount is a good mount at a ok price around 1000 euro. dont buy one of these second hand becuase the older (more then 6 mounts ) are crap and nothing but probs with there goto, the motors and tracking id fine, but your buying a goto so you should have goto. one other imperfaction is as dave would say that tar for a lub has to go, use a white litium grease.

Just observing not just planets really deep sky objects! was thinking of the revelation 12"! yes it would have to be portable enough!

yes a 12 inch dob would give lovely images, shops around on the net, I seen dobs vary by serveral hundred euro in price, prices in Germany are good, you dont really need a super mirror at low mags I rearly go over 100x for deep sky. but you do need a good mirror for the planets.

regards,
rob

I think your idea of a revelation 12" dob is the way to go. Got one last year for ST£450 + ST£50 delivery to my front door. Spent another €50 on a lifting trolly (like the ones used for moving washing machines).

Set up quicker than my 8" on equtorial mount. I was suprised how easy it is to find and track objects. Big difference betweeen 12" and 8" is that objects you are just about seeing with 8" jump out of the sky with 12". I never use the finder scope as I find it fustrating with all that upsidedown, back to front stuff. Most of my viewing is done with a simple Telrad (€40) finder and a 2" SWA 36mm eyepiece (I use my Meath SWA, however there is 2" provided with scope) .......... it really is point and view objects...... its hard to miss most of the M and Cadwell objects.......

Threre are two negatives: 1) for good results you need to let scope cool down for about 1 hour. 2) Unless you have a big car / jeep transportation is a problem. But if you want a 12" scope at a reasonable price this is just a price you have to pay and to be honest its no big deal. I use the lifting trolly to move tube assembly and just carry the base by the handle provided. If using in back garden set up is about 5 min. I then put the kids to bed, have a cup of coffee and start viewing.

Good luck with the new purchase. Damon