Guest MichaelDurban Posted September 12, 2014 Share Posted September 12, 2014 (edited) My second post... dob mods.. Another long story...sorry..just skip to the pictures... Skywatcher fans (and probably any other dob fan) will experience the dreaded words : stiction and friction...(no reference to marital partners..) Stiction meaning the force being applied -and overcoming- to move any object away from -or towards- the force of friction, thereby overcoming the apparant stationary 'stickyness' (for a lack of better terms) In other words...it's that 'jumpy thing' which happens when after keeping your dob static for about 10 seconds it decides to move under force (all of a sudden) and seeks out any stellar object totally unbeknownst to you. It jumps...annoyingly.. Little can be done about this...as friction (annoyingly) will always exist...on earth... So...a few mods for your dob are necessary... firstly...I bought a second hand 10" flextube... (I mean..I didn't buy it for this post...I had it already...just saying..) Now...I understand that most new SkyWatcher dob owners will frown upon my statements... "What's the big fuzz buddy...?" Well....those teflon pads are....how to put this mildly... no good... I'm sure a multitude of fellow ATM'ers have proposed solutions and mine is probably no different. Laaaaaaaaaaazzzzzzzzzzzzzzyyyyyyyy susan... First...a lazy Susan.. she will move your scope...lekker ! (south african slang meaning: realy well !) So...enter one lazy susan for a 10" flextube...(base diameter is about 52 cm??) I chose a LS from a catalogue....around 6" I think...I can't remember... ----- When I received it...I was happily surprised....meaning...I hadn't made a mistake. At the same time (as you can see in the picture) I had a setting circle printed out. It was the right diameter...but I had it laminated, cut it out and installed it... It didn't perform well...it warps in the south african humid nights... I went back and had the same setting circle printed out on something called Forex board(?) (mind you...this is South Africa...could have been formica board..) -although it wasnt- Anyway...the board was much stiffer...rigid... worked perfectly I only fastened the LS onto the bottom board, and let gravity and my center bolt do the rest.. In any case...my setting circle revolves around my LS. Thereby making North or South alignment obsolete. (it goes without saying -I hope- that the actual setting circle has a cut-out in the middle such that it revolves around the LS bearing..) just pick your star in Stellarium...and off you go... Next I had to cut into my bottom board....a potentially hazardous and painfull experience. So..I did...all you need is a jigsaw and some cohones.. finally the end result..(added a stick on light...redded out with nailpolish) The needle is exactly that...a needle stuck into the board, painted with Tippex.. So that's it... No..I'm no carpenter (as you can see...)... No jumping, no sliding, no tilting.....just....nice... The center bolt (withsome felt..) will add extra friction if needed.. Don't be scared...it will make Az. action so much better... Altitude bearing mod coming after this !! Cheers !!! Edited September 12, 2014 by MichaelDurban Link to comment Share on other sites More sharing options...
Doc Posted September 12, 2014 Share Posted September 12, 2014 So many of us have done this mod as well Michael. If you look through the DIY section you will see plenty, even I have done one to my dob. The degree circle is an amazing addition, so easy to install and use. In conjunction with the beloved wixey you have a push to system that cost peanuts compared to the commercial ones. Makes navigating pretty precise. Link to comment Share on other sites More sharing options...
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