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Skywatcher Dob Locking Knobs, Dirt Roads & Mirror

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#1 6th0

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Posted 11 December 2012 - 06:15 PM

Hello:

I took my 12" collapsible Skywatcher out to the desert this weekend. I switched vehicles from the base camp to the viewing site. When I pulled out my scope I noticed that all 3 locking knobs were missing and my primary had been bumped out of the screw holes--so it got a whole lot of bumping on those dirt roads.

I was still able to view but if I tipped the scope over 45 degrees then the primary would shift without it locked. I pulled a MacGuyver and used some dental floss to tie down then mirror assembly to the tube. Fearing that a loose mirror being jostled around while offroading would end up destroyed, I did some field surgery, removed the primary, wrapped it in some shirts, and carried it in a duffle bag.

When I got back to base camp I looked in the back of my truck and found all three locking knobs, meaning that the primary had been loose over a 4 mile rough road/offroading trip to the viewing site.

So, a couple of questions:

1) I see that some dobs don't even have locking knobs but in the Skywatcher if those locking knobs weren't there, then when I tipped the scope the whole assembly would move. Difficult to stay collimated that way! Is this a design issue with Skywatcher or are the locking knobs not needed and something else broke off that normally holds the mirror in place?

2) How do you keep your locking knobs on during rough trips? I know I tightened those damn things before I left.

3) Am I worried over nothing? That unlocked mirror traveled over some very rough dirt road/off road that lifted me physically out of my seat at times. Maybe it was dumb blind luck.

Anyway, the skies in the desert were the best I have ever seen as a newbie and I would hate to not be able to do it again if I didn't know how to take proper precautions against damage.

Any insight or tips?

--6th0

#2 panhard

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Posted 11 December 2012 - 10:27 PM

Scopes aren't meant to go through that kind of torture. They are like ladies treat them gently. :grin:
I don't put my scope in the box of my pick up truck, it rides in the back seat.

#3 mountain monk

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Posted 11 December 2012 - 10:37 PM

I put my scope---any of them--on a 3" piece of foam and strap it down. Creep around those ruts, don't drive through them. If it's only four miles, you have plenty of time.

Enjoy the night sky.

Jack

#4 panhard

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Posted 11 December 2012 - 11:30 PM

Jack I get the impression that they where more than ruts. :grin: In any case extreme care and caution should be taken.

#5 mountain monk

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Posted 12 December 2012 - 12:32 AM

We certainly agree about that!

Dark skies

Jack

#6 Jon Isaacs

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Posted 12 December 2012 - 04:52 AM

Any insight or tips?



- I am not sure exactly how the Skywatcher cell is done. I normally distinguish between "locking knobs" and "adjusting knobs." Many scopes have three screws to adjust the collimation and three screws to lock cell in place.

- I am not sure quite how your protected the scope, I have traveled over many teeth rattling roads with my various Dobs, I have never had such a problem. Typically the Dob will be well padded, if it is in the bed of a truck or in the trunk, I will use multiple blanks and sleeping backs to isolate it from vibration. Otherwise I would take an honored position on a seat in a car or a bed in the motor home.

Jon

#7 weinerat

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Posted 14 December 2012 - 10:23 AM

I tighten my mirror screws all the way, then the locking screws. Doing this, mine survived a two week road trip.

#8 csa/montana

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Posted 14 December 2012 - 11:18 AM

3) Am I worried over nothing? That unlocked mirror traveled over some very rough dirt road/off road that lifted me physically out of my seat at times. Maybe it was dumb blind luck.



That kind of torture might result in a severely scratched mirror, or even a cracked mirror; so no, you're not worried over nothing. :confused: Even "wrapping the mirror in shirts", could result in scratching the surface.






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