Flextube collimation

[Stargazer_00]

Can FlexTube owners advise on how often they have to collmate their scopes?

I hear that you need to collimate them everytime you get them out (however its usually just primary mirror).

I am intending to get a flextube scope soon and am wondering how I am supposed to collimate the scope in the dark.

I am guessing you either need to set up while it's still light (which I never do currently in case a bird thinks my scope is some kind of perch and leaves me a present....) or laser collimate.

Can anyone please share their experience of this?

[Peter Drew]

Although the recollimation, if necessary, can be done with the primary on a flextube, it is the secodary that is moving up and down each time the tube is "flexed".

[littlebeagle]

I've done it twice since I had it in December, did the secondary the first time and haven't touched it since, though it does need a small adjustment. The primary is what moves the most and that was still pretty good even after several trips to remote locations.

It's very easy to become obsessed with collimating. It has to be pretty bad before you start to notice a problem.

[Stargazer_00]

ok so you think, if im quite careful storing and erecting the scope, then moving it 10 feet from a shed to my viewing spot and back will likely mean the collimation stays reasonably OK?

I just got the impression from some posts that I read that you just have to take it off the mount and the primary goes out of alignment - which did seem a little odd to me.

[littlebeagle]

Absolutely fine, I've had mine in and out of the house loads without collimating it and it's been fine. As I said even 4 trips of over 2 miles haven't really knocked it that much. Tweaking the primary is a couple of minutes at most. It's the secondary that takes the time and that only needs doing on rare occaisions.

[jimmyjamjoejoe]

Mines a solid tube version, but lives in my car, which is a rather stiff and bumpy celica. After the initial first collimation, i find it holds perfectly fine all the time. Sometimes it might need tweaking, but never so much that it NEEDS it. ie. the central dot will be ever so slightly to one side of the donut... to me, so long as it is somewhere within the donut it's fine.

Oh - and as for collimating in the dark... I usually point the scope at my cars interior light, and hold my phone screen up to the cutout part of the cheshire, gives me non-glare views of both mirrors and the crosshairs.

[Tribal-Wolf]

I pick mine up and walk three steps to put it away, the collimation is out almost every time. It takes a few minutes to set so I set it every time I use it. I am ultra careful because I can't lift things easily any more and I'm very careful extending the tube. The secondary is often ok but the primary usually is not. In saying that I have heard people with solid tube scopes find them out just as often. Don't let it put you off a great scope though, I am probably being too critical as I tend to be a bit of a perfectionist with things sometimes lol

[valleyman]

I check mine each time I use it and it only takes a minute to adjust the primary if it need soing. I have never had to adjust the secondry.

As for collimating in the dark just hold a light up to the hole on the side of the collimater it will reflect down onto the primer so you can check collimation.

[Paulb3098]

Hi, set of bobs knobs and a decent laser collimator and it only takes a minute. Half the fun of setting up

[brantuk]

"bobs knobs and a decent laser collimator and it only takes a minute"

I second this - it's no trouble to do in the light or dark - but do it in the light the first time you do it just so you can see what you're doing. I travel 20 miles to a dark site quite often and collimation holds pretty good for 2 or 3 sessions.

Do a star test before or during a session and you'll know if it needs collimating. I was pleasantly surprised at how little the flex tubes need doing. The trusses are very accurately configured and firmly installed.

[Stargazer_00]

really reassuring, thanks guys.

There is no way I could be put off I dont think. I'm craving a larger apeture from my 150p. When I started I didn't know what was going to be my thing but now I know its DSO I need the larger apeture. the 150p is lovely but I just want to see more.

i am guessing that a 12 inch should show roughly 2.5x - 3x more detail if the maths stacks up? I comapred the area of a 6 inch circle to a 12 inch circle and its approx 3 times more area, this tells me that is equal to the amount of extra detail I should expect to see?

[jimmyjamjoejoe]

Kind of. On paper the resolution and light grasp will increase a lot, but it is difficult for your eye to quantify it. Faint objects that require averted vision will become direct vision objects, more stars resolved in globs, easier details in nebs/galaxies etc...

But it doesn't mean that something will necessarily be 3x brighter, otherwise the orion nebula through a 16" would be practically blinding