Another monsoon season thunderstorm hit Monday afternoon, 31 August 2015. Received 0.2" rain in about 15 minutes from this storm when it passed through:

I checked the observatory afterwards and the dome pivot joint that leaked from the previous very heavy rainstorm did not leak this time. But a few drops got in from the other pivot joint. Guess the Arizona Sun-dried sealant needs updating on both sides. Will have to get some new sealant as my old tube of sealant dried up from dis-use as these are the first leaks in years. Once I got new sealant I then had to wait to before applying it to ensure there would be no rain.

After sunset more storms came through with an amazing lightning show. My webcams captured some nice strikes:

The storms dropped even more rain overnight; unfortunately the rain gauge stopped reporting. Not certain what went wrong but I was able to force a fake measurement the next morning. Then had to wait for real rainfall to confirm I fixed it. Finally Thursday afternoon, 3 September, had some light rain and the rain gauge reported the amount (0.08"). Whew.

Cloudy skies continued. Had another 0.12" rain on Saturday, 5 September. Sunday, 6 September, dawned mostly clear but with a forecast of rain in the late afternoon (so didn't apply the sealant this day). However, we did install a NWS rain gauge to be a backup to the Netatmo rain gauge:

Of course, it did cloud up by mid-afternoon but no rain occurred (could have applied the sealant; grrr). As sunset approached, the sky began clearing up with just a few clouds remaining. Decided to open the observatory since it had been a month since my last night time session.

Open: Sunday, 6 September 2015, 1835 MST Temperature: 96°F

Session: 856 Conditions: Partly cloudy

After opening the observatory I synced the observatory clock to WWV. 1844 MST: sunset. 1846 MST: viewed Mercury, very low in the western sky, 83X and 222X. Seeing was bad but the planet appeared slightly less than 50% illuminated.

There were some monsoon storm clouds to the south:

The clouds were moving slowly northward.

1857 MST: slewed to Dwarf Planet Ceres using the AutoStar. It was currently low in the southeastern sky. It would be my first imaging target, assuming the clouds to the south stayed away.

There were also a few clouds in the west:

1909 MST: powered on the GC Wi-Fi Adapter and used SkySafari Pro on the iPhone 5s to GOTO to Ceres. (SkySafari Pro has a more current database for solar system objects than the AutoStar.) Ceres was nicely visible, 83X.

1922 MST: viewed Saturn, 83X and 222X. Then slewed back to Ceres. 1938 MST: the clouds to the south were holding off, giving me some hope of imaging Ceres. Switched to the 77X and the MX-1 Afocal Adapter. 1948 MST: lightning from the now severe thunderstorm in the south was appearing in the southern sky. 1952 MST: mounted the iPhone 5s on the 8" LX200-ACF for afocal 77X imaging of Ceres using NightCap Pro (Long Exposure, Light Boost, ISO 8000, 1/2sec, 1 minute exposure). 2000 MST: I took this image of Ceres with the iPhone 5s:

I repeated the imaging every 15 minutes until 2100 MST, with the intention of showing the movement of Ceres against the background stars. Unfortunately, tracking issues and then increasing clouds at the location of Ceres made those additional images unusable. I was able to view Ceres on the Apple Watch with NightCap Pro, as seen in this Watch screen capture of the live view (Ceres near center):

After completing the Ceres imaging, dense clouds were now in the southern 1/3 of the sky, with thin clouds over most of the sky. Decided to defer other imaging plans to a future session. But it was nice to be back in the observatory at night after a month's absence. Began closing up for the night.

Close: Sunday, 6 September 2015, 2113 MST Temperature: 76°F

Session Length: 2h 38m Conditions: clouds increasing

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I finally got the photos from the August 2015 road trip edited and posted: California, Washington, Idaho, and Utah Trip.

The Friends of Oracle State Park is holding a "Dessert in the Desert" social event on Friday, 11 September, 1500-1700 MST, at Oracle State Park. One of the raffle drawing prizes will be a night time visit to Cassiopeia Observatory for two people. Good luck to all who enter the raffle.

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