dobsonian standard vs flex tube

[Bowdie]

Hi all.

Im trying to research for my first telescope and am getting confused. After trawling these forums the wealth of experience (and my budget) pushes me towards a 6, 8 or 10 inch dobsonian. With this in mind i went looking at supplier websites and now have another question... do I go with the cheaper standard tube or flexi tube???

Any thoughts?

[freeflyjay]

i brought my first scope just over a week ago, and like you took age`s to make up my mind, got a 10" skywatcher, not the flex tube, as with the flex i`d need to spend out extra for a light shield, the ground space between the 2 is the same, just with the flex can collapse down so not as tall and easier to transport but i think the flex is a bit heavier, for transport, i have a Citroen saxo and can fit the standard non flex tube on the back seat strapped down with the seat belts then the dob base on the passenger seat or boot, from what i`ve read the only advanage of the flex is loosing some height for storage.

[Tribal-Wolf]

I have a flex and and don't use a 'light shield' and have had no problems yet. I only bought a flex because I wanted the auto tracking and I got it from someone while it's still new and at a price not much more than a standard dob. Unless you need the collapsing bit then I would go for a classic. Obviously there is the goto flex which has it's own reason for buying. Keep a watch for a good second hand scope and it will leave you money for 'extras' plus you may even get some with it.

[brantuk]

For portability truss tubes become more necessary above 10" apertures (eg 16" 20" 24" etc) cos they can be disassembled to fit in a car. You can just about get a 10" solid tube in most familly sized cars.

Depending on design the larger mirrors would need a massive and heavy tube so truss tubes become far more convenient and desirable

[RikM]

I would agree. Solid tubes up to 10" are quite manageable and actually lighter than flex tube equivalents.

From 12" and, truss tube designs have some advantages but disadvantages too.

[Pappy Nick]

I own a 130p Flextube and the biggest advantage I've found, apart from the obvious one of storage, is that I can effectively change the focal length of the scope by pushing the secondary back towards the primary. I've found this useful when I couldn't get my webcam to focus with the standard setup.

[RikM]

I own a 130p Flextube and the biggest advantage I've found, apart from the obvious one of storage, is that I can effectively change the focal length of the scope by pushing the secondary back towards the primary. I've found this useful when I couldn't get my webcam to focus with the standard setup.

Just to clarify, this doesn't alter the focal length, it just shifts the focuser towards the primary a bit. Still useful though

[SeedyF]

I have a 10" flextube and it's great for compact storage, easy manoeuvring and theoretically transport - I haven't taken it anywhere yet in 5 months though! But I will.

It makes a big difference to lifting my scope if I try with the tube extended. It moves the centre of gravity and makes it feel like its going to topple forward. My scope weighs in at 32kg with OTA and base and I am fine moving it collapsed, less happy extended. It's worth considering the weight if you go up to a 10" and might be worth seeing and feeling before you choose, maybe at a star party of retailers if either is nearby.

I have to admit that a light shroud is pretty much essential for solar observing - but that's pretty obvious. The light doesn't seep in during the day, it floods in. But I rarely put the shroud on at night, I do if its really moist as it keeps dew at bay, but often I don't bother.

PS - my light shroud is homemade, a camping mat, some sticky back velcro and a couple of strategic holes to go over the ever-so-handy-for-attaching-a-light-shroud handles that a flextube has. Total cost less than £6

[Pappy Nick]

Just to clarify, this doesn't alter the focal length, it just shifts the focuser towards the primary a bit. Still useful though

Thanks for pointing that out Rik. I wasn't sure if that was the right terminology. Every day's a day at school !!

[Eastridge]

I haven't regretted going for the classic personally. It will fit into the car for travel as described above and I (5'4" weak middle aged female) can move it around the house & onto patio easily. Would only have gone flex if had wanted AUTO or GOTO when would have had to. Figure I can spend what I saved on upgraded lenses which give real value.

[Adz]

Does anyone know if it is possible to fit a solid tube 12" dob into a small hatchback?

Their focal length goes up to 1500mm as opposed to 1200mm for 8" and 10" scopes.

Would it still go along the back seats I wonder, or do people fold down their passenger seat?

[SeedyF]

Does anyone know if it is possible to fit a solid tube 12" dob into a small hatchback?

Their focal length goes up to 1500mm as opposed to 1200mm for 8" and 10" scopes.

Would it still go along the back seats I wonder, or do people fold down their passenger seat?

Bizarre as this may sound my Dyson vacuum cleaner might help here

I have a ford focus hatchback and on Saturday I happened to put the dyson on the back seats to take to my son's flat. The dimensions listed for the dyson sy it stands at 109cm. It went in easily but there wasn't much room either end. I would say that 1200mm would be a snug fit in that car and 1500mm would be out of the question. Folding one side of the back seat would probably not allow a 1500mm tube either but I have no household appliance to help me judge that.

[Adz]

Ha ha brilliant thanks Chris

[RikM]

My 1200mm 10" goes either across the back seat, or in the back with the seats folded. I have a 2005 Honda Civic. It is possible to fit a solid 12" in a small car if you fold the back seats flat and pull/fold the passenger seat forward as far as it will go.

[Adz]

Thats what I was thinking Rik, not too much work for me!

[acey]

The issue is not just whether a 12" solid tube would fit in the car, but whether getting it in and out of the car would be possible without a lot of back ache.

I have a 12" flextube, the OTA is heavy but perfectly manageable to lift in and out of my car boot. The base goes on the back seat.

My 8" solid tube was very light and easy to transport, I would never have needed an 8" flextube.

With a flextube you need to take more care with collimation: a solid tube scope holds it better. You don't need a light shield with a flextube. You do need to be careful that you don't drop anything down the open space onto the primary.

[Tribal-Wolf]

My scope cost twice as much as my car so I'd saw a hole in the roof if I needed to

[RikM]

The issue is not just whether a 12" solid tube would fit in the car, but whether getting it in and out of the car would be possible without a lot of back ache.

I have a 12" flextube, the OTA is heavy but perfectly manageable to lift in and out of my car boot. The base goes on the back seat.

QUOTE]

That's the reason I have a 10". Couldn't manage a solid 12" on my own and the difference in views (to my eyes), didn't justify the higher cost of a 12" flex tube over a solid 10"

[SeedyF]

My scope cost twice as much as my car so I'd saw a hole in the roof if I needed to

Now that you mention it my scope is worth a lot more than the 2003 Focus that the wife thinks doubles as a skip at weekends. I'll have it re-classified as a deluxe telescope case

[Tribal-Wolf]

Now that you mention it my scope is worth a lot more than the 2003 Focus that the wife thinks doubles as a skip at weekends. I'll have it re-classified as a deluxe telescope case

You posh git, after handing back my motability car I decided I wanted an automatic as the wife's car's a manual. Walking through Waitrose carpark I see a car for sale which is an auto and promptly buy it after speaking to the owner. I'm now the proud owner of a 1995 Corsa GLS(posh) Auto lol for the grand sum of £200, no rust and 60k on the clock..............I love the fact that it just goes and I never worry about scratching it etc.

[littlebeagle]

Just to clarify, this doesn't alter the focal length, it just shifts the focuser towards the primary a bit. Still useful though

I've found this a useful "feature" on my 200p flextube.

[Bowdie]

Thanks for the advice! I ended up going for the classic 250 px tube...

[brantuk]

Good choice

[assasincz]

I have a 12" solid tube dobsonian by SkyWatcher and was genuinly surprised that I can easily trasport it in my Renault Clio 3-door hatchback. The OTA fits nicely on folded passenger seat and the dob base first in the boot with half of rear backrests down although, Im solo from then on

[knobby]

My scope cost twice as much as my car so I'd saw a hole in the roof if I needed to

Loving that image ... mobile observatory ...