Warm and somewhat hazy. High today was 85 – predicted low 65. Medium to high humidity.
Rig #1: Deneb & P-Cyg
I focused the collimator lens and set the grating micrometer so that the Neon 6532 line was a close to column 558 as possible. That is where it was located a few nights ago when I did lamp flats. To measure – show the crosshairs and measure at the central Y position. Micrometer reading is 1578.0. I also re-focused the guide camera, looks like the best focus spot on the slit is around x=115. For the Si lines in Deneb set the micrometer to 1511.2 – place the Ne 6334 line at around 559.
I need to come up with a good cadence. Basically need to start with Zeta Aql (ref star) in Ha – then to P Cyg, then to Deneb. Change grating micrometer for Si lines – get Deneb, then back to Zeta Aql. Then change micrometer back for H-alpha and back to P-Cyg. Noel says he needs 3 to 4 sets of P-Cyg images around H-alpha – but I’m not sure what sort of time separation is needed for each set. Tonight I got two sets – though I almost forgot to get Zeta Aql at the setting for the Si lines! Done at around 2:30am.
Rig #2: UX UMa
I got the first sequence started for UX UMa around 9:35pm – gotta love those late summer sunsets! Seeing is around 2.0 arcseconds, perhaps a bit better.
Guidestar Fade Issues
One thing that is still and always has been a PIA with Maxim – the dreaded “guide star fade” issue. Despite the star being clearly visible in the guider image with reasonable s/n (in this case s/n was about 10) the guider function cannot find the star in the image. I lost about 15 minutes of imaging (right during eclipse, of course) due to what is a way too common problem. Lots of discussion about this on the Maxim Yahoo group site as there is every time there is a new release for Maxim DL (I just installed 6.03 on the main computer – though the observatory computer is running 5.24). But it’s been a problem for as long as I’ve used Maxim – which is about 8 years now!
Out at about 2:30am. Excellent night overall.