Cassiopeia Observatory

Some Observing and Observatory Maintenance

Posted: 17 May 2013

After some time away, I opened Cassiopeia Observatory again on Thursday, 16 May 2013, at 1825 MST, 97°F. The sky was mostly clear, with some clouds in the west and south. This was planned to be mostly a "maintenance" session. I began by removing some spider webs that had appeared in the POD bays during my absence.

At 1845 MST, took a quick look at the moon using the 2" 24mm UWA eyepiece (83X). At 1850 MST, viewed Jupiter, 83X. Although the sun would not set for another 26 minutes, Jupiter's cloud bands were nicely visible.

I then made a change to the PEC (Periodic Error Correction) setting on the LX200-ACF. I don't use PEC, but the telescope would always slew 15° in Right Ascension on startup as part of its PEC routine. I set the RA PEC to zero (using the Restore Factory Default) and set RA PEC to "On". I then Parked the telescope and powered it off. The telescope was then powered on and did its GPS Fix (which had been previously set to occur at Startup). This time there was no RA slew. Now my time to start observing is even shorter than it was previously.

I resumed lunar observing at 1900 MST. I switched to the 2" 9mm 100° eyepiece (222X). I monitored some mountain shadows at the northern end of the lunar terminator. Shadow changes as lunar sunrise proceeds are fascinating to watch. Seeing was initially good, but high thin clouds began interferring by 1930 MST.

My next observatory maintenance item was to sync the observatory digital clock to WWV. It had drifted about 30 seconds in the 2.5 weeks since the previous sync.

At 1942 MST, I began preparations to re-do the polar alignment of the telescope mount using the "drift method". I switched to the visual back and inserted a 12mm illuminated reticle eyepiece. I located a suitable "meridian" star and aligned the crosshairs to N-S/E-W. I monitored the star for several minutes; there was no N-S drift. No horizontal wedge adjustment needed. I then monitored an "east" star for several minutes; there was a slight drift north. I made a very small latitude adjustment on the wedge. I monitored the "east" star again; still had north drift, so made another small latitude adjustment. I repeated this process until there was no drift on the "east" star. I then returned to the "meridian" star and monitored it for drift. None was seen. Drift align was now completed. I then did a One Star Polar Align using the AutoStar II. I made sure the mount fork arms were horizontal using a level. Alignment was completed at 2018 MST. I did a GOTO the star Spica; the AutoStar placed it about halfway to the edge of the 12mm eyepiece (167X) FOV. Good.

I took a quick look at Saturn, 83X. Clouds were now in more of the sky, so I began closing up. Although this was a short session with limited observing, it had been great to be back in Cassiopeia Observatory. (Photos from our trip will be posted in a few days.)

I was recently interviewed (once again) by PicStop. Click the link to read the article "HOW TO PHOTOGRAPH THE MOON".

Comments are welcome; use the Comments section below, or you can Email Me. Thanks.