Aperture fever…

[mikeDnight]

I reckon that if you all crashed into one another at high speed, there's a chance you could make one good one! Of course there's nothing at all wrong with me!! 😉

[Piero]

A 12" is a nice and versatile aperture as well as a proper step up from an 8".

Personally, at 12" I prefer the truss design to a solid tube.

Anyway, if you only need to move it from a garage or shed, then aperture size is not really a problem when wheelbarrow handles are used. In my previous house, my 16" f4 was wheeled outside from the living room using ramps. The observing location was about 25m away. The process was very simple and not tiring at all. In my current house, the telescope is stored in the garage and wheeling it outside is even simpler.

My truss 12" f6 used to have attachments for wheelbarrow handles, but these are now no longer used following the structure redesign, which made the telescope more shallow and also lighter.

Yeah, aperture is a nice thing to have if things are reasonably organised so that handling it does not become a hassle.

[Louis D]

I would say 12" is right at the max for a solid tube Dob.  I've handled both solid and truss tube Dobs at around this size, and the former are definitely more ungainly than the latter to pick up and move.  Storage wise, the truss is more compact vertically.  Setup time wise, the solid tube is much quicker to get setup.

Once you go bigger, I definitely recommend truss over solid tube.  It took two to three of us at a star party to setup a 17.5" solid tube.  It also required a full size van with all the bench seats removed and a custom cradle to hold it steady.  By way of comparison, I could move and setup a 15" Dob all by myself before an auto accident tore up my back.  Now that there are ultralight versions, 12" to 14" Dobs are a fraction of their weight from 20+ years ago.

I don't know about the UK used Dob market, but 12" to 14" custom Dobs come up used quite a bit here in the US for a fraction of their original new price.  Most come with exceptionally well figured mirrors as a bonus.  Just keep your options open.

[Piero]

My 12" F6 truss dobson fits in my vauxhall corsa hatchback without any issue. It can also be fitted in my girlfriend's fiat 500.

A 12" f5 solid tube could fit in these cars, but one would need to take the passenger front sit down and drive next to this metal buddy hoping not to be stopped by the police!

Of course, if one owns a bigger / longer car, carrying this size of telescopes is not a problem. However, if I owned such a bigger car, I would carry around a larger truss dob with wheelbarrow handles and ramps..

Also, whilst it is true that a truss takes longer to assembly than a solid tube (12" size), this is not a big deal as some time is needed for cooling the primary mirror down anyway. The difference is that a truss dobson allows one to carry smaller and lighter components than two large and bulky parts.

 

Hope this offers a more balanced view of things. Of course, as far as I am concern one can do what s/he prefers, even carrying a 12" solid tube on the roof of a car as long as this does not slide off, causing danger to road users.

[Xilman]

On 15/01/2024 at 18:31, Ludd said:

I made the jump up to a 17.5” dobsonian a while ago and it is just about manageable by a mildly unfit 56 year old with coronary artery disease, short legs and minimal upper body strength (I am a cyclist). I have a few steps in the garden but the main challenge is the width of the base, which almost matches the width of my shed door.  The jump from an 8” aperture was astonishing but it’s not really ideal for quick observing sessions as it requires a bit of setting up, including a stepladder to reach the eyepiece.  I do wonder if 12” would have been more sensible (and cheaper)

Back in the day I had a 18" from Beacon Hill Telescopes. I could pick it up and move it around a little distance but I was only half my present age. I wouldn't want to do it now.

The solution was to build a custom wheelbarrow. A doddle thereafter.

[ollypenrice]

On 15/01/2024 at 16:22, bosun21 said:

A sack barrow makes moving a 12” a piece of cake even over a distance. As long as you don’t encounter any considerable obstacles.

They also exist with stair-climbing wheels which work astonishingly well. https://www.amazon.fr/Juskys-Diable-descalier-Pliable-Monte-escalier/dp/B07Z7R4CMY/ref=asc_df_B07Z7R4CMY/?tag=googshopfr-21&linkCode=df0&hvadid=649021427975&hvpos=&hvnetw=g&hvrand=13307743385287580903&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9109705&hvtargid=pla-834757222970&psc=1&mcid=bf1bb220886b3c24abf8ccf5663884be

Olly

[Second Time Around]

On 30/01/2024 at 16:55, Neutrinosoup said:

Sorry, for the delayed response to your informative post!

Are the mirrors better than the entry level Celestron/skywatcher dobs? And do Orion Optics have any rivals that  FLO might sell? I guess my ideal would be a 12 inch Dob that I can manage to lift in two parts by myself (46 and reasonably fit), with dual speed focuser and higher quality mirrors.

 

Be aware that are several ways of measuring the quality of a mirror.  For instance, I think I've right in saying that some scopes that are described as 1/8th wave may be no better than "diffraction limited".  Anyone?

If you decide on an OOUK scope bear in mind that they have very long lead times, that also frequently slip.

It seems as though OOUK don't have the best reputation for customer service, and many would recommend you buy from one of their retailers, Telescope Service in Germany, who usually have OOUK scopes in stock.

The OOUK mirrors are reputed to be better than mass market ones.  Certainly I'm very pleased with mine.  However, I can't comment further myself as I've not had any mass market ones to compare with.

 

Edited February 3 by Second Time Around
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