16" vs 12"

[ausastronomer (John Bambury)]

Originally Posted by rmcpb

Steve hit the nail on the head. Having a lone 16" byitself as your only scope would not be a good idea regardless of how good your back is and the size of your truck.

I don't necessarily agree with this.

In the almost 7 months I have had the 18" Obsession, the 10" dob hasn't moved. Moreso, unless I have a need to have 2 scopes available, which I will do from time to time in the future, for my 10yr old to use; the 10" scope won't ever get a look in

The 18" Truss scope is not that much less portable than the 10" tube scope. When I do use a scope from home, which isn't all that often, it takes less than 2 minutes to wheel the 18" Obsession out of the garage, remove the wheelbarrow handles and start observing. From my Mag 5 skies at home, the 18" blows the 10" into the weeds. It doesn't get much more convenient actually.

CS-John B

[sejanus (Gavin)]

the obsessions are a bit better built with portability in mind aren't they? I have seen a vid where a fairly slim girl assembled a 20" model.

I guess you could chuck wheels on the lightbridge though. My backyard viewing location is 5-6 metres from it's storage location (garage).

[xelasnave]

So is the contest now between 18 and 20 inch?
When I started I wanted a 16inch five scopes later that want has only increased. The reality is if you go smaller you will justify the decision upon sensible consideration..bah being sensible is not what this gane is all about. Any money spent on a lesser version that what you desire is in fact money wasted..
good luck with the purchase
alex

[janoskiss (Steve H)]

fair point from John B. Whether you can make better use of a small scope depends on your observing habits/preferences. I like to have a smaller scope to take to non-astronomy parties and other events to show the sky to non-astronomers. Also when people pop around I might like to quickly plonk the scope outside to show them the Moon, Saturn, Jupiter etc. 5 mins is plenty for cooldown for a respectable 200x quick look with the smaller Dobs.

[Orion]

There is no substitute for aperture.

[Starkler (Geoff)]

Originally Posted by Orion

There is no substitute for aperture.

Quite right, as long as it's aperture that will actually get used, rather than something thats too big, heavy, and cumbersome to be bothered with.

I'm currently waiting on a 15" SDM truss dob. I have decided on this size as I wanted a 'large scope' that I could lift, transport and set up on my own without breaking my back in the process.
I feel that an 18" or larger just becomes that bit harder and therefore less likely to come with me to viewing nights.

My other scopes are 5" and 10" newts. The 5 gets more use as a quick look scope. After the SDM comes, the 10 probably wont get used much at all but the 5 still will.

[iceman (Mike)]

Gav lucky you didn't view through Rod's 20".. you'd be tempted to get a 20" very quickly

It depends how serious you are. The big scopes are awesome but if you don't use it much it's not going to repay you in WOW sights.

[sejanus (Gavin)]

i think from my flurry of buying and selling gear it may appear to some that I'm not serious but i am. i already miss not having old trusty 80mm to whip out.

[norm]

Hi,

Another factor apart from the size is also the quality of the scope and what your prepared to put up with. The 12" lightbridge appears to be without its own minor problems and by all accounts easy to fix (eg, new springs, collimation knobs etc). I would assume the 16" LB would be the same - one would hope Meade sorted these issues out. ???
If on the other hand you want say the best and money is not an issue, it would be hard not to consider an SDM truss dob. Sure your paying a lot more, but then again your getting an absolute premium product. One that will most likely require no mods or changes at all and something that your likely to keep forever.

NB: I'm not bagging the LB, none the least, the 12" LB is a beauty and its the one I'd get. The 16" on the otherhand is yet to be 'road tested' and it would be interesting to see how it goes.

Good luck with your decision!

[sejanus (Gavin)]

Ah yes. If our mate from SDM made something in the 16-18" range in the 4-5k range I'd be all ears. But as they are 10k or so, I can only look at them with envy

[ausastronomer (John Bambury)]

Originally Posted by sejanus

Ah yes. If our mate from SDM made something in the 16-18" range in the 4-5k range I'd be all ears. But as they are 10k or so, I can only look at them with envy

The problem here is that when a scope is "hand made" it takes "almost" as long to make a 12" or 15" scope, as it does a 20" or 25". The difference in the materials cost isn't major and the only real saving available by downsizing, is the savings realisable from buying a smaller primary and secondary mirror. People expect the cost of the scope to decrease exponentially as the aperture decreases. This may apply to mass produced scopes, but not to hand made ones. This is the reason Peter Read advertises his smallest scopes as 18". Below this aperture it is really a labour of love and he makes nothing. People expect him to be able to build 12" and 15" scopes, for a lot less money than an 18" and it just isn't so.

CS-John B

[Starkler (Geoff)]

Originally Posted by sejanus

Ah yes. If our mate from SDM made something in the 16-18" range in the 4-5k range I'd be all ears.

Well that just pays for the mirrors and doesnt leave much for the rest of the scope. eg a 15" OMI mirror was going to cost $3750.

Peter Reads prices dont look particularly cheap compared to importing an Obsession, but when you consider that his scopes come 'fully loaded' with loads of extras then the value becomes apparant.

[sejanus (Gavin)]

hi guys

I don't mean to imply that Peter is overcharging - just that he doesn't have anything in my price bracket. I'd love one of his scopes, the pics of Rods look like a work of art. Unfortunately even with 2 jobs I can't justify 10-12k on a scope, though maybe in 10 years I could after the house is paid off.