SJAA

Ephemeris

Planetary Conjunction by Day: Paul and David's Excellent Adventure

David Smith and Paul Graves


David: A bright planetary conjunction in the evening is always a treat, but Paul wanted to show it to his middle school students, who are only around during the day, of course, this time the closest approach of Venus and Jupiter was to be during the day. So, at C-minus-2 days, he asked me if I would bring my telescope to Dartmouth Middle School and help him out. Neither of us had ever gone looking for planets during the day, although I tracked Jupiter and Saturn through sunup. I was also skeptical about the weather, but when Tuesday dawned clear, I went for it. I arrived at Dartmouth at about 10:00, and Paul had already set up his telescopes on the Sun. Some students were observing and talking with him, including my daughter Melanie. I set up my scope, with rough polar alignment based on the bubble level, Paul's estimate of north, our latitude, and the current declination of the Sun. But objects kept drifting north in the eyepiece, so I kept adjusting the axis eastward until the drift ceased.

Paul: David had mentioned a suggestion he had seen on the internet to use a skyglow light pollution filter for viewing the sun (together with the energy rejection filter over the objective, of course), so I gave it a try with my C8. It worked well, increasing contrast of the solar surface features. The sun suddenly became more than its bright plain self. The faculae are more distinct and what was almost subliminal granulation, becomes obvious. The feathery nature of the sunspots also becomes much more apparent. The students were impressed.

David: Throughout the day, we had many students come by during class breaks and lunch-time, and randomly. They loved looking at sunspots, and considering their sizes relative to the Earth. As they kept coming by, I was beginning to wonder if we'd get an opportunity to go looking for the planets. But presently there came a lull while Paul was in his room teaching a class. I offset from the Sun's coordinates to where Venus should be and removed the solar filter. No Venus. It didn't appear with some movement to the north, south, and east. I didn't want to risk getting too close to the sun while blindly searching to the west, so I put the filter back on, lined back up on the sun, moved one hour east and to the expected declination, and started a systematic search pattern north and south, eastward from there. I found Venus just a little west of the original try. Jupiter was a little below it, but whereas Venus was bright and obvious, Jupiter was much harder to see. Although appearing bigger than Venus, it was dimmer and more washed out. It would have been easy to miss while scanning for it, if Venus hadn't been nearby. Venus was bright and sharp, but atmospheric limb darkening caused Jupiter to look out of focus unless carefully studied. The distance between Venus and Jupiter appeared to be about 1/3 of the diameter of a 50-degree eyepiece field, at a magnification of 126x. I went to the doorway of the classroom and gave Paul the thumbs-up. At the next opportunity, he came out with some students.

Paul: After a major adjustment to my wedge, I finally got the sun to agree with my declination and the ephemeris. The RA clock is set, wedge locked and then slowly move 20 to 30 degrees east of the sun, remove the solar filter, and set the circles for Venus. Within 1 to 2 minutes, Venus is in view at 100x. "Fantastic! I've got it!" Venus' gibbous phase is obvious and the air is marginally stable, causing intermittent "wiggling" of its pearl-like sphere. Jupiter was vastly dimmer. Most viewers missed it unless they lightly tapped the scope, causing Jupiter to wiggle. Its major cloud bands were obvious. The students were intrigued and very surprised that such objects as planets could be seen in daylight. It was a rare sight. We felt like we had really achieved something, and were pleased to be able to share it with the students. And Melanie was pleased to have her dad doing the showing. In my rush to get to school with all the equipment, I forgot my camera. I hope David's pictures turn out. I was pleasantly surprised at how well we got our platforms aligned using the sun and its drift. A small but very pleasant totem to add to a largely unrecorded life long observing list, though many have been caught on film. Quite a day! Thanks for the memories.


David Smith; last updated: October 04, 2007 Prev Next