Hi Woody

Tony Rodda

Sorry for being off-grid recently – a very unpleasant cold after returning to the UK!

Yes, the vernier adjusts the grating as standard.  I’d just placed everything so as to zero in on Ha. I can effectively ‘lock-off’ the adjustments to stay Ha orientated.  That’s what I crudely mean by Ha ‘tuned’.

I’ve just refitted both the ‘printed’ scpectroscopes ready for observing – just need a break in this terrible weather!  Oh, for Arizona skies!

PS, I got Wayne’s latest treatise and will respond asap.

Regards T