Skywatcher Dob 8inch solid tube vs collapsible

[Rami7]

Thanks to all of you who helped me I've decided to get the skywatcher sob 8 inch collapsible however it's not available now instead the solid tube 8inch is available though. Should I go for it? Is there any difference in terms of resolution whatsoever? Or is it a matter of portability? Please help

[dweller25]

Optically they are the same - the solid tube is LIGHTER and it can be mounted on an EQ mount if required.

[bingevader]

What he said!

No reason I can think of not to go for it. There's really not much of an issue with portability with the solid tube 8" dob. The collapsible was never a "suitcase" dob anyway, so other than being a bit shorter, you weren't gaining much (except more weight!). It would need more frequent and careful collimation too, where as my Skyliner has stayed pretty near bang on for the last 2 years.

[Myopicus]

Unless you are going to have to put it in a car every time you observe get the solid tube. You won't be disappointed, and it will leave loads more dosh for EP upgrades. Also less chance of stuff accidentally damaging primary mirror.

[wolfpaw]

Thanks to all of you who helped me I've decided to get the skywatcher sob 8 inch collapsible however it's not available now instead the solid tube 8inch is available though. Should I go for it? Is there any difference in terms of resolution whatsoever? Or is it a matter of portability? Please help

Hi Rami. That's a shame but both the collapsible one and the solid tube one should be very similar in performance. How does the price compare with the Orion XT8 that you were thinking of getting?

[wolfpaw]

Unless you are going to have to put it in a car every time you observe get the solid tube. You won't be disappointed, and it will leave loads more dosh for EP upgrades. Also less chance of stuff accidentally damaging primary mirror.

I think, from Rami's earlier thread, that he was going to use his car quite a lot to transport it around, one of the reasons why the collapsible one seemed like a better idea.

[Beulah]

Up to at least the 300p I would highly recommend solid tubes for many reasons - collimation stability, not needing a shroud and much more. The 300p solid tube can be transported in a car boot with the back seat down.

After the 300p (12"), a truss tube becomes more easier to cart around and can be stored in compact-ish spaces. You don't want to be looking for areas to store tubes in excess of 6ft in length.

It takes a little longer to collimate the 400p, but the aperture keeps me determined.  

[AlexB67]

Personally I find the flextube holds collimation really well for the 10 inch model when you don't move it around in a car.  I suspect most scopes solid tube or not will need collimation after bumping around a bit anyway. The OTA is made from steel for the flex model so they are really solid and a bit heavier compared to the solid tube, as are the trusses so for the collimation part I would not worry as that being something important.  Once collimated it holds it when out in the field.

In the end it will come down to whether it fits in the car since you mentioned you have a small car as well. I would not rush out and buy a scope and find you can't transport it and if you really want to, you may regret it, I almost made that mistake of under estimating the size of these things.  The flexi is a more manageable in that regard for a small car. An 8 or 10 solid tube would fit in my small ford KA but it would be really awkward. It will go in diagonally with the backseat down but than have pretty much nothing left for anything else. The ability to contract the tube has many benefits for transport even in bigger cars if you want to go on a holiday, since they can sit upright on the back seat or go in the car in various ways to suit. Much easier to get in the car as I have no backdoor and risk of denting with awkward manoeuvers as well.  

I would recommend to have a good look at your car with a tape measure as I did and see how and where you can fit it.

[LukeSkywatcher]

Optically they are the same - the solid tube is LIGHTER and it can be mounted on an EQ mount if required.

Amazingly, the solid tube is lighter then the truss tube. I'm still trying to get my head around that.

[knobby]

Its a bit like a convertible car... No roof but has to be strengthened / stiffened to accommodate the missing bit :-)

[cotterless45]

My Lightbridge primary is a dirt and dust magnet. Putting on and removing the shroud, putting the truss up and down , it all invites something being attracted downwards ! The upside is that it's so easy to transport and holds collimation well.

Plus I'm not hyper fussed over cleaning mirrors as I've seen worse.

Nick.

[AlexB67]

Amazingly, the solid tube is lighter then the truss tube. I'm still trying to get my head around that.

Interestingly on the SW site for the 10 inch model at least, the 8 inch flex is not listed but the OTA is specified at 15 kilos for both solid and flex but suspect that is a mistake, The base a bit heavier, at least the shipping weight is 2 kilos heavier on their site.  As far as I know the Flexi OTA is bit heavier though, since you have to add the rims which are solid steel and thick where the truss poles go through, the truss poles themselves are added as well.  The steel tube itself is large in area, but thin enough so there is not much weight taken away with that extra section in the middle missing I guess.

[Beulah]

Amazingly, the solid tube is lighter then the truss tube. I'm still trying to get my head around that.

The sheet metal is thin and the only heavy parts of the OTA is the mirror cell. Secondary & focusser second.

The truss tubes and the thick OTA rings to hold the truss tube assembly add to the weight.

The mounts are pretty much the same weight as you go up but  the 14 & 16" have additional support struts and thicker plyboard.

[LukeSkywatcher]

Interestingly on the SW site for the 10 inch model at least, the 8 inch flex is not listed but the OTA is specified at 15 kilos for both solid and flex but suspect that is a mistake, The base a bit heavier, at least the shipping weight is 2 kilos heavier on their site.  As far as I know the Flexi OTA is bit heavier though, since you have to add the rims which are solid steel and thick where the truss poles go through, the truss poles themselves are added as well.  The steel tube itself is large in area, but thin enough so there is not much weight taken away with that extra section in the middle missing I guess.

Ahhhhhhhh!!!!! that explains it. I had no idea that the truss tubes and rims are made of solid steel. I was assuming they were made of a much lighter material.

Thanks for educating me on this.

[bomberbaz]

I have a decent sized motor but putting a 300 solid tube in it was a major PIA. The flex tube 300p simply lies accross the bak seat behind the seat belts and the base fits into the boot. simples.

From a 200 down I am not sure of the dimensions of a flextube but am guessing if it would only take up one space in the car seat (ie on end) that would be even better.

[Rami7]

Hi Rami. That's a shame but both the collapsible one and the solid tube one should be very similar in performance. How does the price compare with the Orion XT8 that you were thinking of getting?

Yeah,, the prices are almost the same .. So ,, but you know what, now I'm confused again! I've just come across the celestron se and it looks nice too.. !!!!!

[wolfpaw]

Yeah,, the prices are almost the same .. So ,, but you know what, now I'm confused again! I've just come across the celestron se and it looks nice too.. !!!!!

If you're really not sure which to get then just wait for a bit if possible! I don't know what the Celestron SE is like but there will be lots about it on here.

[Karen]

A good idea to fit a shroud on the truss tube. I always worry about dropping something on the mirror.

[wolfpaw]

A good idea to fit a shroud on the truss tube. I always worry about dropping something on the mirror.

But Rami isn't getting a truss tube. He's thinking of either the solid tube Orion XT8 or the SW Skyliner 200P, or maybe the Celestron SE.

[russ]

Had both the Flextube and Solid Tube models. For the 8" adn 10" there was not a single good reason for going the Flextube route, i had no idea why i did it. I found the Flex a pain in the behind. It incurred extra expense with the shroud, didn't balance as well, couldn't be adapted to an EQ. One of the moments when you think i really didn't think this through. The 8" solid tube fits nicely across the back seat of a car, is lighter (as pointed out), holds collimation, balances beautifully and slap a couple of tube rings on and its ready for a HEQ5. Go for the solid tube is my advice.

The Orion and Skywatcher are identical, so it just comes down to price and accessories provided.