Sunday, July 03, 2011

more ISS attempts (Blue Mountains)

Opportunities to view the International Space Station in the evening from the Carr Astronomical Observatory were winding down. Pity. That also meant we'd not have a chance to see The Last Shuttle on orbit. The chance to get a good video recording of the ISS alone was decreasing. But, of course, the ISS carries on. There would be many occasions where it would pass overhead, in the day time...

I was curious to learn how clearly one could see it. The math suggested it was doable. Even—if you know where to look—possible naked eye! If you were lucky! If the ISS went to magnitude -4, then it would be similar to Venus in the day time.


Midday, using Heavens Above, from the CAO, I looked up the next good flyover op. Today, at 3:05 PM. At 14 seconds into the minute, it would appear in the WSW at 10° elevation. At 3:08:25, it would reach maximum elevation of 85° in the NW. Then it would continue to the ENE fading from view at 3:11:40 while 10° up.

It occurred to me that we had a new worry during day time passes. The Sun!

I tried to check the path in Heavens Above. Unfortunately, for day time passes, the web site does not show the path against the background sky. I remembered suddenly that Stellarium 0.10 could simulate it, with the Satellite plug-in!

Yikes! Ah, maybe not. It would pass too close to the Sun. There was a risk for visual observing and risk to camera equipment. I had promised not to light anything on fire. I aimed the 'scope east of the Sun. Alas, the sky was covered in cirrus cloud.


Steve and I noted discrepancies between the various tools. Stellarium, TheSky6, and Heavens Above all were giving us very different numbers.

I double-checked settings (and found a few things off a bit) and reloaded the TLE data. Nope. Still different... I wondered if one of the data sources had received an update but it had not trickled down to the others.


It was 7:34 PM. I prepared for the 7:55 flyover. I set up both telescopes atop the Paramount for visual use.

It wouldn't be anywhere near the Sun for the bulk of the pass.

7:55:02 10 NW
7:58:15 66 NNE
8:01:27 10 ESE

8:02. It worked! We viewed the Space Station in daylight! Wow!

This successful attempt showed that we can see the station complex in a bright sky, an hour before sunset. Mind you it was difficult to see in the west; the further east it went the better. Everyone agreed the view was best on the east side of the meridian. The amount of detail was impressive! I saw the solar panels, truss, and central modules.

This was a another successful proof of concept. It will be worth trying to record onto video.

For the first time, I was able to successfully implement a quick flip with the equatorial mount. As the Paramount stalled at the meridian, I rapidly selected a target on the other side of the meridian. Then, fortunately, I was able to reacquire and track the ISS!

Lots of pleased customers. The raging horde was very happy. Earned my dinner on that one!


9:31. After the success with the 7:55 pass, I was anxious to repeat. And to record.

9:31:48 10 W
9:34:04 18 SW
9:36:20 10 S

Not very high...

9:38. No joy. I did not visually see the ISS through the 'scope or camera.

I tried to catch it naked eye. For the longest time I didn't see anything. But then, faintly, in the distance, I spotted it. It was near the end of the pass. While looking through the Telrad, I could see the mount was off a bit. I estimated about a degree.

I played with the Tracking adjustment. It helped. But it would normally be a two-person job. Not practical for an individual to run back and forth between the eyepiece and computer.

Curiously, the last 2 times both the Stellarium and TheSky6 compared well.


Meanwhile, in the darkening sky, Kiron spotted Mercury!

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