Bobs Knobs

[rumples riot]

Hi there, just paid for the bob knobs mod for my Lx200 10" ad I also ordered a televue 3x barlow. Might be able to do some serious planetary work now. And bobs knobs make collimation easy, or so I am told. Anyone got these on their scopes and how hard or easy is it to collimate the LX200 with bobs knobs on it?

Paul

[Mick (Michael)]

I rarely have a sky good enough to use them. I've only had to tweak one screw in 4 years most of the time the seeing is my problem not the collimation.

[beren]

Paul its very simple , if you are a member of the LX200gps yahoo group in their files section is a page that can be printed that shows which knob to turn while following diagrams/directiions for collimating while using a star outside focus. For some reason the kit doesnt have this info , if you have trouble finding it i can send a copy .
Installation is a breeze , follow the instructions exactly especially the first stage of taking just a bit of tension all three screws before you start taking one screw off at a time and replacing with a knob. Some problems occur where people have trouble getting the 2nd /3rd screw in because tension hasnt been released slightly.
My collimation was good before installing but the knobs put it out , that night it took no more than five minutes to get it back in shape and no hassles since . Thing to remember for future adjustment always tighten the knobs before collimating .

Cheers

[Dave47tuc (David)]

Paul,
The Bob's knobs are easy to use, just follow the instructions carefully.

I don't think palying with collimation to much is a good thing. I have only adjusted mine twice in a year.

Tell me why did you get a 3x barlow?

That will get you a lot of mag, I doubt unless you are very lucky to get seeing that will warrant such high power.

I do not have a barlow and my shortest focal length eyepiece is 8.8mm. Gives me as you 284x.
I find i dont even use this eyepiece much.
I find my 16mm at 159x and my 12mm at 212x is plenty.

Mind you i live in a very poor seeing area.

So with a 3x barlow you get a FL 7620!!!!
If you seeing is good you could use eyepieces down to 15mm FL.
That would give you 508x.

Good luck with all this and happy viewing.


Best.

[rumples riot]

Dave the 3x barlow is for the LPI to image Saturn and later jupiter. I missed Saturn last year and don't want to miss the second best opposition for the next 29 years. Which is on 13 January 2005 (weather willing). So the barlow is not for viewing at all, just for imaging.

As for Bobs knobs, I just feel that my collimation could do with a bit of a tweek. I don't really want to attempt this without something that will make it easier. And; my deep sky shots seem to indicate that collimation may not be really all that flash.

Thanks all for the advice thus far, really appreciated. This scope is my first SCT. All my other scopes in the past have been Newtonians, which are easy to collimate. This SCT I am not so sure. I don't want to mess this up.

Incidently, I have noticed that with the focal reducer on, collimation seems more of a problem than without it. When I check for collimation without the focal reducer, it looks pretty good, but when I check with the FR on I get what looks like pretty bad. Is this a by product of the FR and if I collimate do I do it with the FR on or off?

Paul

[Dave47tuc (David)]

Paul,
I understand now re the barlow. Look foward to seeing the results.

I do not have a focal reducer so i can not comment, on its workings with collimation.

Best.

[rumples riot]

No promises as far the results go. Not one of my areas yet. I suspect that it will be like doing deep sky shots only more frustrations.

Paul