On 7/8/2018 10:31 PM, Tim Crawford wrote:

We will get together this Tuesday, July 10 for a workshop. We meet in the Broder Building from 7:30-9 pm. Come join in if you get the chance. Jacques, may we please get the east gate open? Thanks.

I’m not sure where we are with projects, so let’s check in and assess where we are.

I have a new addition to the Dobsonian design- altitude bearings. Now, these are the genius design of Tom Whittemore. Here’s a look:

These altitude bearings slip over the Sonotube ( telescope tube of a Newtonian scope). What is brilliant is they tighten to the sides of the scope when you tighten the knobs you see in the image above. I truly believe in my heart this design could replace all the modern designs we see in magazines and articles.

We need a few tweaks to get there though. Come and speak to these issues.
1). Tube must be smooth
2). The tolerances have to be trued.
3). There is a “ rocking motion” when the bearing assembly is in place. Strategic placement of pads or Teflon pads may take up the “ raw fit” of this assembly.

Also, we may get a little figuring done to get ever closer to finishing an 8” mirror.

See you there.
Tim
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July 10th was my father’s birthday. He was a ship captain most of his life. He used to tell me he had been at sea since Christ was a deckhand.

Without going too far, I just  want to tell you of one incident. ( I had the extreme pleasure of going to to sea with him for a couple of years).

We were in the middle of the Atlantic Ocean. I was a young man just out of City College. I had just finished introduction courses in Physics. My dad came out to the boat deck and asked me if I could tell him how fast we were moving through the water. He gave me a couple of factors and I plugged these into newly studied motion laws.

I gave him my results and he shook his head and said, “ No Timmy. Wrong. You are missing another factor.” I asked him what and he simply said we are on a great circle.

He was using a sextant. That’s all he used to navigate the globe. It was just before GPS became the standard. And yes, he always got us there and almost to the minute. Try to imagine that. It wasn’t too long before that the long sought after “ Longitude” was used at sea.

It may not sound like much but, I got to witness it “live” right in front of my eyes.....