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View Full Version here: : Large Dob Owners: How Satisfied Are You?


Rodstar
19-06-2009, 07:53 AM
I came across the following thread on Cloudy Nights this morning, by a bloke who is reflecting (no pun intended) on his experiences with his 20" Dob, one year after purchase...

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3167863/page/0/view/collapsed/sb/5/o/all/fpart/1

I am interested to hear how other people are finding managing a larger scope, what they find are the pros and cons involved, and whether they are glad they went that way.

For my part, as reported in AS&T last year, I am really pleased with my 20" SDM scope. On nights of good seeing, I still have goosebump moments. It has taken a while, but I think I have now perfected the art of packing and travelling with my scope. It is a bit of an effort to take it to dark sky sites, but that effort is always rewarded. Sometimes I regret not getting a slighter faster mirror - perhaps an f/4.5 or even an f/4 - but I am very happy with the performance of the mirror I have, and I do not find the ladder unduly tiring.

One issue that preoccupies a lot of discussion and thought about larger dobs is whether 18 or 20 is the best size for a single person to operate. What are your experiences on the relative benefits of each? At f/4.5, the 18can be used with a simple step ladder, whereas a 20 needs three steps to reach the EP at zenith. Is that inconvenience of the extra steps worth it in terms of the extra light grasp of a 20 inch mirror?

So - how are you going with yours??:)

sheeny
19-06-2009, 08:32 AM
Its a good read, Rod. Thanks for posting.

As you know I don't have a big dob... I did consider one, but opted for the observatory and a smaller scope based on the wind and weather conditions I choose to live in.

But I will watch with interest. I love the views that big dobs give!

Al.

Paul Haese
19-06-2009, 10:33 AM
Large scopes are a trial I reckon. Yes they provide fantastic views, best Jupiter image I even saw was looking through the 18" SDM I had. Best view of the homunculous was through the same scope. Beautiful scope but a drag to get it out.

One day I plan on going with the ultra light version with a light weight 18". Great size for viewing. However, I reckon they need to be ultra light weight in construction.

erick
19-06-2009, 11:06 AM
Where do we draw the line these days on defining what is a "large dob". 15" dia and above?

What about an ultracompact 18" dia mirror with fast focal length? Not particularly "large" in the scheme of things?

Marclau
19-06-2009, 05:41 PM
Interesting post there.........ummmm by 'dragging it out' does this also apply to say a 10 or 12" DOB?? :scared: :sadeyes:

I think I have finally decided on my 'upgrade' scope and then I read this...... :eyepop::doh:

Ohhh the pain............!! :shrug::help:

Kevnool
19-06-2009, 07:09 PM
When you enjoy the observing nights who really cares about dragging the scope out, thats why we purchased or built them,we new what we were in for

Let the big scopes rule the fields.

Lets just say i love the big scopes,getting out before dark to tweak collimation and then have a yarn waiting to see the first star appear.

Cheers Kev.

lesbehrens
19-06-2009, 07:12 PM
hi. i have a 16" gso dob. i think its great. i love the views thought it i think its a great buy. the thing i don't like about it is the weight of it and i don't have a permanent set up for it a home so it takes time to set up. but i just love the views:eyepop::stargaze:.
i would recommend one to whoevere is considering to buy one.

astroron
19-06-2009, 07:37 PM
Do you mean Large as in Mirror size or Or Bulk?.
I have a 16" and love it:),when I look through smaller mirror sized telescopes I find I am a bit disappointed with the view.:(
Moving my scope about my property takes very little effort:)
ON nights when people are here for observing I have usually put my scope away whilst they are still packing up:whistle:

mental4astro
20-06-2009, 12:54 AM
Hi all,

I've only had my OdysseyII, 17.5", for about a month. Nowhere near a year, so it is still a developing relationship.

I need a step ladder to use it, and had to put some thought into the right one. Kids and giants and everyone inbetween will view through it, and the right ladder means no awkard balancing feats. Even as a truss form, the ladder will still be used. That being said, I never saw it as an impediment.

I'll add that it is also horses for coarses. I also have a C5, and a 10" DIY dob. Each has their place, and I'm glad to be able to have this Trinity. I love the Odyssey. The C5 is my ultimate travel scope. The 10" is the quickest and easiest to use.

Choose your weapon, ;).

Mental

Archy
20-06-2009, 05:51 PM
I have a 16"f 4.5 with Argo-Navis: they are great combination and will be better with fine tuning and better eyepieces

AstroJunk
20-06-2009, 06:14 PM
I have owned and worshiped SDM006 for 3.5 years now. All I can say is that bigger is better. Admittedly, my scope is equipped with cameras now and does not often see an eyepiece in between Astrofests, but it is a joy to use and still more than exceeds my every expectation.

For me, it couldn't be easier to transport and set up. I can have it set up in the dark, collimated, aligned and pointing at a 14th magnitude galaxy in under 30 mins on any dark sky site on the planet whilst taking my time. I will challenge anyone to beat me with an EQ mounted Newt!

My only regret - spending so much of my life looking at bugger all through silly little scopes.

I AM (still) AN APERTURE JUNKIE :thumbsup: