Mk2 Micrometer

[lunator]

I have finished making the next micrometer.

I bought a 360 degree protractor from WHSmith, photocopied and laminated it. (pic 1)

I also bought some Card from the art shop to provide some extra rigidity.

Part 1

Step 1- The laminated card is cut out and the central hole . (pic2/3)

step 2 - to check aligment the dial is placed over the eyepiece. (pic 4)

[FLO]

Looking good Ian 8)

[lunator]

Part 2

step 3 - is too mark out the hole in the backing card. Simply draw around the focusser tube. (pic 5)

Step 4 - check the backing and the dial fit closely on the tube (pic 6)

Step 5 - Cut out the pointer, I used another copy of the dial. as I could follow the same curvve for the inside cutout (Pic 7)

Step 6 - Place pointer on top of dail to check ease of movement. You want it mvoeable but not loose. (pic 8)

Prt 3 below.

[lunator]

Part 3

Step 7 - Check the assmbly on the scope to ensure iti is managable. (pic9)

Step 8 - wait for the clouds to go away to do a test run..........

Cheers

Ian

[The Warthog]

So, I gather the protractor on the backing card does not move, but the pointer does? Is this a cross-hair ep, and just how do you measure something with it? I'm all curiositiness.

[lunator]

WH

The dial does rotate but it once you have orientated it you leave it alone.

The pointer rotates with the eyepiece so when you line up the 2 stars to so the wire is in the same orientation as the stars the pointer shows the PA.

To measure the separation you rotate the eyepiece to 90/180 or 45 degrees and measure the time it takes for the stars to cross the wire.

Using a simple equation you can get the separation.

Cheers

Ian