Astronomy 110 Laboratory: Observing

WEATHER

The weather in Hawaii is often hard to predict. Conditions earlier in the day are not always a good guide. The links below are of some help in planning observing trips. However, the basic rule is to be prepared for both outdoor and indoor labs; we will go observing whenever the weather is good, even if it was bad earlier in the day.

PLANS

05/13/03: Final exam in PSB110 at 7:00 pm.

DIRECTIONS

Most observing sessions will be held off-campus in Kapiolani Park. To reach our observing site in Kapiolani Park, you

1. Go SOUTH (downhill) on University Avenue,
   
   
2. Turn LEFT onto S. King Street,
   
   
3. Follow the signs for Waikiki through the Kapiolani Avenue intersection,
   
   
4. At the light beneath the overpass, turn RIGHT onto Kapahulu Avenue,
   
   
5. When you reach the Ala Wai intersection, turn LEFT onto Paki Avenue,
   
   
6. Continue on Paki Avenue through the Monsarrat Avenue intersection,
   
   
7. At Noela Street, turn RIGHT into the parking lot on Paki Avenue,
   
   
8. Look for a truck with a `University of Hawaii' sign and State of Hawaii seal.

LOG BOOK

Observed with two 8 inch scopes. Moon: used 32 mm eyepieces (37.5×) for global views. Saturn: used 14 mm eyepiece (85.7×) for close-ups. Titan sighted to West of Saturn. Planet and rings remained visible through scope even when hidden behind clouds. Sirius and Jupiter also sighted.

Constellations viewed include Cassiopeia, Perseus, Taurus, Orion, and Canis Major. Class sketched Canus Major rising to help visualize Earth's rotation. Winter hexagon (Sirius, Procyon, Pollux, Capella, Aldebaran, Rigel) quite conspicuous; Canopus sighted while rising. Binoculars showed rich field in Perseus, the Pleiades cluster, the Hyades cluster, and Orion Nebula.

Observed with three 8 inch scopes, using 32 mm eyepieces (37.5×). Targets include Jupiter and satellites, Saturn and Titan, Andromeda Galaxy (difficult to see against relatively bright sky), and Orion Nebula.

Despite some clearing around 18:00, returning clouds prevented observations of constellations. Instead, the class did an experiment illustrating the use of parallax to measure distances. After the experiment, two 8 inch scopes with 25 mm and 14 mm eyepieces were used to view Jupiter through drifting clouds.

At the park, the class made scale drawings of Gemini and Orion. Positions of Jupiter and Saturn were observed with binoculars and plotted. The crescent Moon was observed using two 8 inch scopes with 32 mm and 25 mm eyepieces.

At the park, we set up all six 8 inch scopes. Class practiced use of scopes by finding, tracking, and drawing Jupiter and the Orion Nebula, using 32 mm, 14 mm, and even 10 mm eyepieces. (Some students also observed Saturn despite its awkward position near zenith!) Class plotted positions of Jupiter and Saturn.

After waiting out some initial clouds, the class began by drawing Auriga, Perseus, and later Taurus. Two 8 inch scopes were used to view Jupiter and Saturn as well as the Double Cluster in Perseus. Class also plotted positions of Jupiter, which continues to move West, and Saturn, which is basically stationary.

On arriving at the park, the class observed the crescent Moon and an occultation of the 7th magnitude star HD 3024. We then observed a minimum of Algol, and began a series of observations of zeta Gem. During a period of intermittent clouds, the class plotted the positions of Jupiter and Saturn. Finally, all six 8 inch scopes were used to observe the Pleiades in Taurus, the Beehive in Cancer, M41 in Canis Majoris, M35 in Gemini, M37 in Auriga, and the NGC 884/869 double cluster in Perseus.

At the park, we used all six 8 inch scopes with 14 mm and 10 mm eyepieces to observe the Great Red (ie, Tan) Spot on Jupiter. Following that, the class began sketching the Moon at 1st quarter, as well as using 25 mm eyepieces with reticles to measure its apparent diameter. Around 21:00 (9:00 pm), we used the 7.3 magnitude star TU Gem as a reference point to plot the position of the Moon, and at 21:18:08 (9:18:08 pm), we observed the occultation TU Gem by the Moon. We continued plotting positions of Jupiter and Saturn (the latter difficult because of bright moonlight) and estimating the magnitude of zeta Gem. Students who stayed until 22:00 (10:00 pm) were rewarded by seeing Europa reappear after transiting Jupiter, as well as a view of the satellite's tiny but very dark shadow in the middle of the planet's disk.

We observed the Sun using an 8 inch scope with a full-aperture solar filter as well as a special-purpose H-alpha scope. Initially, clouds prevented any extended viewing, but a large sunspot with a well-defined penumbra could be seen intermittently. Around 12:40 we got an extended break in the clouds, and good views were obtained with both instruments. The H-alpha scope showed several pyramid-spahed prominences, as well as a dark filament extending across roughly one-third of the solar disk.

At the park, we set up four 8 inch scopes. Observing was difficult; bad seeing conditions prevented most observers from seeing much detail on Jupiter, although we were able to see the start of a transit by Europa. After the Moon came up, we measured its apparent diameter. Other ongoing observations included plotting positions of Jupiter and Saturn (which is finally moving away from its stationary point!) and estimating the magnitude of zeta Gem.

Before departing for the park, we set up two 8 inch scopes to observe the start of Io's transit of Jupiter, which began at 19:24 (7:24 pm). We then went to the park and set up all six 8 inch scopes. The class charted the constellations Canis Major, Leo, and Ursa Major, and continued ongoing observations of zeta Gem, Saturn, and Jupiter (which was nearing its stationary point). After 21:00 (9:00 pm) we resumed viewing Jupiter using the 10 mm eyepieces for maximum magnification and contrast in unusually good seeing conditions. The Red Spot and associated cloud structures were well-placed, and the shadow of Io was apparent as a dark point between Jupiter's two equatorial bands. At 21:40 (9:40 pm), Io itself reappeared as a tiny `bump' on the edge of Jupiter's disk, and then rapidly pulled away from the planet.

At the park, we set up six 8 inch scopes and began by measuring the Moon's diameter; this proved a bit difficult as slightly less than half the lunar disk was illuminated. The class continued ongoing observations of Saturn and Jupiter; zeta Gem was not observed due to excess moonlight. We observed the double stars zeta UMa (Mizar), alpha Gem (Castor), and gamma Leo (Algieba), as well as the multiple star systems beta Mon and sigma Ori. From 21:00 to 21:15 (9:00 to 9:15 pm) we watched the beginning of Io's transit of Jupiter; at this time, Io, Europa, and Ganymede were all in the same positions as last week!

The class went directly to the park. We set up four 8 inch scopes and began by looking for Mercury; low level clouds to the West made observations difficult, but the planet was briefly seen through the clouds and some people managed to view it through the telescopes. The nearly-full Moon was viewed rising in the East and its apparent diameter was measured. The class also charted positions of Saturn and Jupiter and estimated the magnitude of zeta Gem.

The class met at Sandy Beach. Although conditions were promising earlier that evening, there was a lot of cloud cover which interfered with observations. A few people were able to view galaxies M81+M82 in Ursa Major and M104 in Virgo. We ended the session early.

After meeting at PSB, the class went to Sandy Beach where we set up all six 8 inch telescopes. Despite some initial clouds, we were able to observe a number of galaxies, including M81+M82 in Ursa Major, M51+NGC 5195 and M63 in Canes Venatici, M104 in Virgo, and Cen A (NGC 5128) in Centaurus. Several people confirmed seeing the dust lanes in M104 and Cen A. We also viewed the globular cluster omega Cen (NGC 5139), which was quite spectacular and easily resolved even though close to the horizon. At 21:00 (9:00 pm) we tried to see Ganymede emerging from Jupiter's shadow, but clouds blocked the view at the critical moment. Constellations sighted included Ursa Minor, Crux, Centaurus, and part of Scorpio. Finally, alpha Cen was viewed with an telescope; its binary nature was evident.

After a final meeting in PSB, we went to Kapiolani Park and set all 8 inch telescopes as well as a 10 inch model. Class practiced finding objects - mostly Jupiter, Saturn, and the Moon. We used the 10 inch scope with a wide-field 40 mm eyepiece to view the Beehive cluster in Cancer. Shortly before 21:00 (9:00 pm) we set up a video camera and monitor so the entire class could view Ganymede entering Jupiter's shadow. The camera was mounted on one of the 8 inch scopes; the other scopes were used to observe the eclipse visually. Shortly after 21:20 (9:20 pm) we saw Ganymede fade rapidly. The fading seemed much faster than expected; a simple estimate implied it would take 8 minutes for the satellite to fully enter the shadow. However, the satellite was faintly visible for several minutes after its rapid drop in brightness; thus it appears that our simple estimate is correct, but that much of the light we normally see from Ganymede is reflected from a fairly small area of the satellite's surface.

REPORTS