Log in

View Full Version here: : Bobs Knobs, are they worth it?


Poita
29-10-2011, 07:29 AM
My Meade 10" ACF SCT needs collimating, but before I tackle it I was considering getting a set of Bob's Knobs, but pretty much only because everyone else seems to!

Are they worth getting? Is there anything else better out there?

Anyone have any tips for collimating the LX200R that might save me some grief?

BlackWidow
29-10-2011, 08:49 AM
Yes Yes and Yes..:thumbsup: I have all the Peterson Mods done to my scope and they have all made an improvement on my system.. You will find the Bobs Knobs easy to use in the dark as they are easy to feel rather than messing around with an allen key. Also trying to use an allen key in the dark whilst not bumping your scope around is a pain in the bum.. Bobs knobs are cheap and will make you collimation very simple and painless..

Only tip with collimation is little adjustments (very small) and when putting in the Bobs knobs, only do one know at a time so the secondary mirror stays attached. If you remove all the screws at once the Secondary will fall off onto the primary mirror..



Regards
Mardy

Poita
29-10-2011, 09:24 AM
Well *that* is certainly worth knowing!

AndyK
29-10-2011, 09:47 AM
While I wouldn't argue for a second against them being worth having and making life very easy, I'm not sure I agree that they're cheap.
Cheap is relative. Keep in mind that these are nothing more than ordinary machine screws with larger, knurled heads and probably cost less than ten cents each to manufacture ... so paying around thirty bucks for a set isn't my idea of cheap.

GeoffW1
29-10-2011, 10:58 AM
Hi,

I have a set on the C8, after pinging the corrector plate with a screwdriver in the dark (just a slight touch, but wow) :eyepop:

I agree with Andy, they are way overpriced for what they are, but very very useful to have. I like to collimate a bit each time, and that is now a breeze, using the Knobs and this resource

http://www.asterism.org/tutorials/tut14-1.htm

Maybe you can find an alternative (I never bothered) somewhere like

http://www.smallparts.com.au/store/partslist/screwsthumb/fasteners/wide/1/

Cheers

Ausrock
29-10-2011, 01:01 PM
Does anyone know the thread specifations for the Meade and Celestron screws?

I'm thinking a length of brass rod, suitably turned down and threaded.

;)

Poita
29-10-2011, 01:07 PM
I have an engineering supplies firm just up the road, they have crazy amounts of that sort of thing, I guess I'll go take a look.
If I have to buy a pack of 50 or something, I'll give the rest away to anyone else who wants them.

SteveInNZ
29-10-2011, 04:38 PM
+1 for Bob's knobs. Yes, they're expensive if you compare them to a straight machine screw, but they only cost a few mouse clicks in time.

If you're a webcam kinda guy, Metaguide (http://www.astrogeeks.com/Bliss/MetaGuide/) has a collimation function. I haven't used it yet but I like the idea. You adjust the collimation knobs to put the red dot into the middle of the star. It even moves the mount to keep the star in view.

Steve.

BlackWidow
29-10-2011, 05:14 PM
Hey Andy... the guy has an LX200.. $30 is a drip in the ocean..LOL Sure $30 for a few screws seems alot, but they come with instructions that advise the dangers of removing all the screws... Cost hundreds if you stuffed up! They arrive at your door with no phone calls (click of a mouse). no petrol costs and little bother... I would not want to use an hour of my time to save $20 on the cost of some locally avaliable screws...

Oh and did I mention you get a sticker with them that you can put on your scope that says..Peterson Equipped.. That has to be worth at least $5.00 or the cost. and the screw are powder coated and match the scope :rofl:

But yes it's all relative, that I agree...

Poita
30-10-2011, 10:06 AM
I have no issues with spending $30, but I can walk to the engineering shop and it meant I had them in my hands in an hour instead of a week.
Thanks everyone for the advice, I'm keen to give metaguide a go.

Darth Wader
01-11-2011, 09:08 PM
While they are a little expensive, you can save a decent amount by ordering direct rather than buying through a local dealer. Mine were shipped to me for free and arrived promptly. They are an essential tool especially when dealing with fast dobs where precise collimation is paramount.

Cheers
Wade