SPHEROMETERS

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These are the eight spherometers,

(1) A two pin type to measure concave and convex surfaces without having to allow for ball diameter.

(2) A two ball type to compare with (1). Drilled side by side with (1) on he same centre settings. Note the difference when measured.

(3) A two ball type to compare with (7).

(4) A two ball type for measuring the Cassegrain secondary.	(5) A three ball type to compare with (4).

(6) A ring type to compare with (5) & (6).	(7) The ring type I made years ago.

(8) A three ball type with extended legs to measure a Maksutov corrector and to compare with (1) & (2)

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