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Asteroid 7 Iris, Perseid Meteor Shower

Posted: 12 August 2013

Sunday, 11 August 2013, dawned mostly clear, but monsoon cloudiness increased as the day progressed. There were even some monsoon thunderstorms in the area as sunset approached. At sunset had a brief sprinkle of rain here. Satellite image showed clearing skies approaching so I decided to open the observatory and set up for the Perseid Meteor Shower. The observatory was opened Sunday, 11 August, at 2059 MST, 81°F. The sky was mostly clear. I first set up my recliner, table, and the LXD55 mount outside of the observatory in preparation for the Perseids.

At 2125 MST, I powered on the 8" LX200-ACF and began preparations to image Asteroid 7 Iris. It would be in opposition on 16 August 2013, but with the unpredictability of our monsoon skies, I decided to image it while I had clear skies. I mounted the D7000 DSLR at prime focus + visual back on the 8" telescope. After doing a focus test on the star Altair using the Bahtinov Mask, I powered on the GC Wi-Fi Adapter and used SkySafari Pro on the iPhone 4 to GOTO to the asteroid, currently Mag. +8.0. At 2141 MST, I captured this image of the asteroid, 30 seconds, ISO 6400:


I took a second image 30 minutes later. A third exposure was taken after an additional 30 minutes. In between exposures, I sat in the recliner and viewed the night sky. Saw the first Perseid meteor at 2148 MST, followed by a second one at 2200 MST. At 2200 MST, clouds were coming in from the southwest and lightning flashes were frequently seen in the northeast and east. Saw two more Perseids at 2216 and 2218 MST. At 2220 MST, a strong breeze came up and clouds in the south and southwest were getting higher in the sky. Saw the fifth Perseid of the night at 2231 MST. As the time for the 3rd and final image of the asteroid approached, clouds were rapidly approaching the position of the asteroid. I took the exposure anyway, but the clouds ruined it. This is an animated GIF showing the movement of Asteroid 7 Iris over a 30 minute period:


I powered off the telescope at 2248 MST. Extensive cloud cover was now in most of the sky. I decided to wait a short while to see what the clouds were doing. At 2255 MST, saw the 6th Perseid. By 2300 MST, the breeze was gone and the sky was clearing up. I mounted the D7000 DSLR with 8mm fisheye lens on the LXD55 tripod. Then did a couple of framing test exposures. Saw five more Perseids during this time.

I began sky photography at 2330 MST, using f/5, 2 minute, ISO 5000, exposures. I also started counting hourly rates of the Perseid meteors:

2330-0030 MST: 10 Perseids
0030-0130 MST: 34 Perseids
0130-0230 MST: 34 Perseids
0230-0330 MST: 47 Perseids

I ended counting and imaging at 0331 MST, and began closing up for the night.

The observatory was closed at 0350 MST, 70°F.

My Perseid count for the night was 136. Many of the Perseids were faint, but others were very bright. Several non-Perseids were also seen. No "fireballs" were seen. The following are four of the 101 images taken during the four hour period. The first image shows a very slow moving satellite, magnified in the inset:


The satellite was visible on several consecutive 2 minute exposures, fading in to view and then out of view.

Perseid meteors were captured on only a few of the images:




It was a fun night with the Perseid Meteor Shower.

On Sunday, 11 August 2013, I posted an important announcement about the status of "Weasner's Mighty ETX Site". Please read the announcement, as the upcoming Internet access change will likely have some impact on my "Cassiopeia Observatory" web site and other online activities.

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

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