Quote:
Originally Posted by erick
Same here  . Very happy with the cheshire (Blackcat XL) and the autocollimator (Infinity XLK). The offset viewing pupil on the Infinity XLK is superb  .
But discovered something interesting in the last two weeks. At 30+ deg, the cheshire would stick about 1.5cm from fully seated as I inserted it into the Moonlight focusser drawtube? Differential expansion? The autocollimator was OK and the cheshire would insert when the temperature got back down to around 20 deg. But it seemed to stick neatly on axis without any wobble, so I could still collimate. |
Eric,
As you have experienced, the black Delrin (of which the
BLACKCAT XL is made) WILL expand with temperature rise. It is adviseable to keep it in the shade especially in the summertime. If you follow that suggestion and it continues to give you a problem, contact me via private email and we'll work out a solution.
Regards,
Jim Fly