5.09.2022 The benefits of a fork mounting.

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 Monday 5th 60F, Bright overcast but no sun until this afternoon.

  I may have talked myself into building a fork mount. The difficulty of raising piers, tall enough to support a cross-axis mounting so far above the ground, would be prodigious!

 It has occurred to me that I don't need full sky coverage. I only image the sun and occasionally the moon. I have no interest in the northern arc of the sky. There are tall, dense, trees along the entire northern boundary anyway. Just as there are to the west and south west.

 A fork is a balanced mounting and can carry heavy loads without heavy and awkward counterweights.

 The great advantage of the fork, over an English or cross-axis mounting, is that it needs only one pier.

 The space between the fork tines can contain multiple instruments if desired. They do need to be balanced longitudinally and axially.

 Because the fork is leaning towards the North Pole the entire instrument load is offset to the north. Mass loading can be applied to the southern side of the pier to compensate. Safely bringing the centre of mass back over the pier.

 An extended polar axis can be mass loaded at the bottom without affecting friction in the oversized ball bearings.

 The length of the fork tines and bulk of the OTAs determines the clearance of the OTAs from the pier when pointing at the zenith. 

 A multiple instrument OTA can be housed in a simple framework without balancing issues. If the instruments are arranged side by side then the fork widens but pier clearance is increased at the zenith and horizon. A 6", 7" and 10" do not add up to much width.

 There is no need to change heavy counterbalance weights while standing on a stepladder. The risk is far too high. The dangers of a major imbalance midway through the procedure could cause serious injury.

 The danger has prevented me from changing telescopes as needed for particular tasks. Which is a complete waste of the instruments involved. My iStar 180mm/7" f/12 R35 iStar refractor and my 10" f/8 mirror sit idly by. Waiting to be brought back into use. 

 

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