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whats a dob knob

faulksy

By faulksy
in The Astro Lounge

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ronin

ronin

Posted
Posted

Thought they were better designed bits to enable the mirror to be adjusted for collimation and also to adjust the position of the secondary.

Many of the standard items need alan keys etc to make adjustments, these or  sort of designed for the purpose. Rather like the bolts on EQ5/HEQ5/EQ6 mounts, better to get a replecement set that do the job and are easier to adjust.

Well know sets are Bob's Knobs, which you can get a set for adjusting the corrector of an SCT for collimation.

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scarp15

scarp15

Posted
Posted

Well one feature my former flextube had which the Orion UK newts do not, is a slewing knob, situated close to the top and underneath side of the tube. Would require drilling yet would  be easy enough to fit one I expect.

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NGC 1502

NGC 1502

Posted
Posted

Question  -  Wots a Dob knob ?

Answer    -  It's a knob wot goes on your Dob  :smiley:

Seriously, could be 'bobs knobs' for easier no tools collimation, or could be a knob or handle at the upper end for guiding the Dob, better than grabbing the end of the tube.

Regards, Ed.

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brantuk

brantuk

Posted
Posted

As above - you can get a screw on knob or handle for manual slewing - usually on the underside of the top box of a truss dob (or under top end of a solid tube). You can also get collimation knobs for the secondary so you don't have to risk dropping an allen key down the tube onto the primary. You can also get replacement collimation knobs for the primary (where they previously had hex bolts or allen key bolts fitted). And you can get stronger replacement primary springs to go with - for supporting heavy mirrors better. :)

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JamesF

JamesF

Posted
Posted

I've always understood a "dob knob" to be a handle (usually a knob) attached to the OTA for moving it whilst viewing.  Saves grabbing the end of the OTA which is what I've seen some people do.  Mine has one on each side for some bizarre reason.

James

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simmo39

simmo39

Posted
Posted

the name on it gives you a bit of a clue :icon_confused: , rolson load strap £1.99 from a cheap shop in Cardiff , most of the S Wales Dob Mob got them on their tubes one member uses two straps to carry his 12" tube when setting up 

Lenny

Doh, Thanks anyway, will look into getting one.

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