Alun,
Thanks for the link, some good modifications.
I can put one cover back on once I have got the belt gripping properly, will try putting o rings over the lens thread.
The Lhires is contained in a film changing bag which should keep dust and light out.
A question, as I do not operate the spectrograph remotely is there any point in motorising the micrometer arm ?
Regards,
Jack
Essex UK