made focus Y-mask for ETX

Made a focus mask for the Meade ETX 90 Maksutov.

Measured the circumference of the OTA. About 327 millimetres. Maybe 328? That put the OTA diamter at just over 104 mm. 104.1 to 104.4.

Fired up Visio and loaded my Y-mask VSDX file previously made for the Canon camera lens. Lines at the magic angle...

Made the mask out of light-weight card stock and solid copper wire.

Ready for testing.

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Tested the mask in the backyard on the evening of 21 May.

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Oops. Totally forgot to try my new approach.