which to build

[tesla2002]

guys , I wanna build a 6 inch telescope and I don't know whether to build a reflector or a refractor and I was hoping that someone knows which to choose

[Scott]

how deep are your pockets?

To buy a descent set of six inch lens' is going to be pretty damn expensive, the theres mounting them in the tube just right. IMHO go for the reflector

[faulksy]

as scott says, has to be a reflector, how are you mounting it. might as well go dob

[alacant]

Hi. Do a side by side comparison, one of each. You'll not need a coin to decide!

[tesla2002]

i'm still figuring out the mount but I want to know about the picture , I can get the lens

[tesla2002]

I'd also like to know does the fraunhofer or the double achromatic lens remove chromatic abberations . Also mostly what I'll observe are planets so please think about that too , thanks

Edited April 30, 2016 by tesla2002

[ronin]

A sort of standard achro will not remove all the CA and the faster the lens the more CA will be apparent - this impacts therefore on the length. For a lens you are likely therefore looking at f/10 for moderate resultant CA so a scope of 60" in length. Something like f/12 would, or should, be a little better.

Should be able to get an aliuminium tube to house it, making baffles and getting them in place will be fun also you would need to blacken the whole of the tube inside length. All are best described as not difficult but will take time and a little ingenuity. Not sure if you would need to strengthen the tube to minimise flexing.

I would slightly disagree that you will observe mostly planets just for the reason there are not many planets to observe. The reality is you have Jupiter, Saturn and Mars everything else is just a small dot or small disk of no detail if they are even in view. Mars comes around every 2 years, Jupiter every 13 months, not sure of Saturn.

Difficult as a reflector is sort of the expected normal, and not often appealing unless you do something a little different - I am thinking of the ultraportables that "turn" into a wooden case format for ease of taking places. There is one option for an imaging reflector I would like to consider one day.

Edited April 30, 2016 by ronin

[Peter Drew]

Go for a 6" F8 Newtonian, as a self build it will be less demanding in every aspect and will outperform any 6" objective of similar cost consideration other than perhaps star image aesthetics.  

[tesla2002]

thanks guys

 

[catburglar]

could do a 6inch F15 folded refractor....minimal CA, no central obstruction and interesting design. I think I'm talking myself in to building one!