It seems ALPY grisms out of adjustment is a common problem. I thought I remembered commenting on this here before
https://britastro.org/node/14085
Robin
British Astronomical Association
Supporting amateur astronomers since 1890
Supporting amateur astronomers since 1890
It seems ALPY grisms out of adjustment is a common problem. I thought I remembered commenting on this here before
https://britastro.org/node/14085
Robin