C9.25 and Bobs Knobs

[Mr Spock]

I fitted Bob's Knobs to the C9.25 a week or so ago but haven't had chance to get out until tonight.

The fitting was quite easy. The recommended method of changing one screw at a time didn't work for me though - too fiddly. As I was going to have to collimate anyway I found it easer to take the secondary out. There's a collar you can unscrew and, once that's off, the secondary housing comes out easily. It only fits one way so you can't put it back wrong. With the secondary out, the knobs fitted in seconds. It was also a good opportunity to get a little dust off the secondary.

I did a rough collimation in the house by looking down the tube from about 2-3 metres away. It's not easy holding steady enough to get concentric rings but near enough is ok.

Tonight I was able to do a star test. Using Bob's Knobs is so much easier than trying to use a screwdriver. As I never know which way to turn the screws it took me about ten minutes to get a perfect star test. I must learn which way to turn things!

And the result? I have stars with a clean airy disc and Jupiter's belts are full of detail. In fact, I'm going back out there right now! Success

[DeanB]

Bob’s Knobs were the first thing I bought for my CPC925, but I’ve been putting off fitting them until I feel the collimation need. :-) Just the thought of going anywhere near the Secondary is giving me the heeby-jeebeez.

D

[Grotemobile]

Join the club.I am in the same boat with

the C11.I don't wont to make it worse

than wot it is.

Steve

[deepspacehunter]

Bob's Knobs are om my C11... When doing a collimation... put your hand IN FRONT of the Correcter Plate and you will see the shadow of your hand... and at that point you can tell what screw to turn first... and then go from there !

[Tinker1947]

My C11 had phillips screw for secondary adjusters, just plain stupid anyway there a 3mm thread and 3 knurled knobs from A2A4.com and a pack of 3mm washers i found in my workshop has sorted the problem.....

http://www.a2a4.com/acatalog/M3_KNURLED_THUMB_SCREWS_H_T_464-1.html

[clarkent]

Thanks Tinker1947.  Great tip/source. 

Mr Spock, appreciate the thread and your procedure. Cheers

[rob0971]

My C11 had phillips screw for secondary adjusters, just plain stupid anyway there a 3mm thread and 3 knurled knobs from A2A4.com and a pack of 3mm washers i found in my workshop has sorted the problem.....

http://www.a2a4.com/acatalog/M3_KNURLED_THUMB_SCREWS_H_T_464-1.html

Great tip! Can you remember what length you ordered?

[Tinker1947]

Great tip! Can you remember what length you ordered?

My A2A4 invoice shows ( M3 X 20 K/T Screws 464) so i think 20mm but i did need to pack them out a bit with some 3mm washers, which also makes them easier to turn as there's a better gap, i think there's a £5 minimum order so you could go for 20mm and 16mm 3 of each....

http://www.a2a4.com/acatalog/M3_KNURLED_THUMB_SCREWS_H_T_464-1.html

[Tinker1947]

A picture always helps, fresh of the sensor today.....

[rob0971]

My A2A4 invoice shows ( M3 X 20 K/T Screws 464) so i think 20mm but i did need to pack them out a bit with some 3mm washers, which also makes them easier to turn as there's a better gap, i think there's a £5 minimum order so you could go for 20mm and 16mm 3 of each....

http://www.a2a4.com/acatalog/M3_KNURLED_THUMB_SCREWS_H_T_464-1.html

Many thanks mate.

[recceranger]

Just out of curiosity, how often would you say a C9'25 would need collimation?

[Mr Spock]

They hold collimation well and it's vary rare for them to need adjusting. Even then it's only tiny adjustments.

[recceranger]

Thanks Michael

[Brian Nordstrom]

Bobs Knobs were the 1st thing I got for my C9.25 and I am glad I did , they are fabulous . So easy to use  , much better than s screwdriver and as said earlier they hold columation very well .

Here they are .

Brian.