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. In general, you should 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. The links below are helpful in planning observing sessions:

PLANS

If we have good weather, we will go to Kapiolani Park to observe. The Moon will be down, so fainter stars will be visible. If conditions are bad we will stay indoors and do the parallax lab.

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.

For a printer-friendly version with map, see the Directions to Kapiolani Park or Google Directions.

To reach our observing site at Sandy Beach, you

1. Take the H1 EAST.
2. When the freeway ends, continue EAST on Kalanianaole Highway.
3. Continue on Kalanianaole Highway past Hawaii Kai, Hanauma Bay, Molokai Lookout, and Blowhole.
4. Turn RIGHT into the Sandy Beach park entrance.
5. Drive through the park to the far end, where you'll find a small parking area with a bathroom/shower building.
6. Look for a truck with a `University of Hawaii' sign and State of Hawaii seal.

LOG BOOK

After a brief introduction, we went up to the 3^rd-floor breeze-way in PSB to view the conjunction of Venus and Mercury. Although clouds initially blocked our view, both planets were sighted shortly before 19:30, with an apparent separation of about two finger-widths (about 4°). Jupiter and Arcturus were also briefly visible; but later on the cloud cover became much heavier and no further observations were possible.

We first reviewed the orientation handout; despite passing clouds (and a few raindrops) we were able to view Sagittarius, Scorpius, Cygnus, Lyra, Cassiopeia, and Ursa Minor (the `Little Dipper'). We then set up four 8" telescopes and began by observing Jupiter and its satellites. Initially only three moons were visible, but shortly thereafter Europa was sighted as it ended a transit of the planet. Following the break we turned our attention to the Moon, and sketched it using 32mm eyepieces. A video of the Moon and a measuring reticle was made in anticipation of future measurements of the Moon's apparent diameter. Finally, we revisited to Jupiter, using 14mm eyepieces; the increased distance between Europa and Jupiter was apparent, and some people may have glimpsed Europa's shadow on the planet.

At the park, we began by observing and sketching Cygnus. Stars α and β Cyg were used to determine the scale. Due to moonlight, only the brighter stars of the constellation were easily visible, so we concentrated in α, β, γ, δ, and ε in sketching the constellation. After a break, we made a measurement of the Moon using 25mm eyepices and reticles. At ~21:20 we turned our attention to Jupiter, where Callisto was about to enter the planet's shadow. Since the satellites were all quite close to Jupiter, we used the 14mm eyepieces. Initially Callisto seemed only slightly fainter than the other satellites (Io and Ganymede), but dimmed rapidly over the next 10 minutes; by 21:35 it was invisible.

Due to unstable weather, we stayed in PSB and did the Simple Telescope experiment.

Despite an approaching front, we went to Sandy Beach in hopes of finding a break in the weather. Finding cloudy conditions, we began the Spectra in the Lab exercise, but gave up when rain began to fall.

We began by observing the occultation of &sigma Sgr by the Moon at 19:05 HST from the PSB parking lot. We then went to Kapiolani Park to sketch Scorpius. After the break and a quiz, we used four 8" telescopes with 25mm eyepieces to measure the Moon's diameter; by 20:45, &sigma Sgr had emerged behind the Moon and was now visible above the bright side. Another scope was used with a 10mm eyepiece to view the ``double double'' star ε Lyr; seeing was quite good, and most people were able to see all four stars. Around 21:00 we began observing Jupiter and sketched the planet and its satellites. Initially, only Europa, Ganymede, and Callisto were visible, but at 21:15 we watched Io exit Jupiter's shadow.

We left PSB at about 19:05 HST and carpooled over to WCC. The Imaginarium show featured constellations currently visible as well as those visible later in the night or season, the effects of traveling north to the pole or south below the equator, phases of the Moon, and planetary motion. The show concluded with a ``special effects'' extravaganza, cut short by technical difficulties (%#$%?*& software upgrades!).

We left PSB promptly at 19:05 HST and carpooled to Sandy Beach Park. Although Manoa was almost perfectly clear, we found about 50% low cloud cover at the Park. Despite this, we were able to view the Milky Way intermittently, and scanned it using binoculars from Sagittarius to Cassiopeia. We also set up four 8" telescopes and viewed the Double Cluster (h+χ Per) in Perseus and the globular cluster M15 in Pegasus.

After meeting at PSB at 18:30 HST, we carpooled to Kapiolani Park. The atmosphere was exceptionally stable, although low clouds allowed only intermittent views of most targets. We set up four 8" telescopes. Our first target was Venus, which was less than 10° above the horizon; despite the low elevation, we could easily see the gibbous phase of the planet's disk with 14 mm eyepieces (86 ×). We then turned to Jupiter, where Callisto's shadow was transiting the planet. A first round of viewing with 14 mm eyepieces and 10 mm (120 ×) eyepieces showed the satellites and bands on Jupiter's disk; most people were able to see Callisto's shadow at about 8—o'clock about half-way between the center and edge of the disk. We then used 3 × barlows in two scopes, together with 25-mm eyepieces (144 ×) and 20-mm eyepieces (180 ×); these higher magnifications made Callisto's shadow very clear.

After a break we looked for double stars; despite the clouds, we were able to locate β Lyr, ε Peg, and β Cyg. The color differences ot the latter two pairs were quite evident.

At the park, we set up four 8" telescopes. We had a quick look at Jupiter, using 14 mm eyepieces (86 ×); the ``Great Red Spot'' was visible although not particularly well-placed. We then focused on the Moon, which was about 2 days shy of first quarter. The terminator was close to the trio of craters Theophilus, Cyrillus, & Catharina, providing a vivid display of the aging process of lunar features (see Sky & Telescope, Oct. 2004, p. 70). We sketched the Moon, concentrating on these craters and other features revealed along the terminator, using 10 mm (120 ×) and 14 mm eyepieces. We concluded our lunar observations by measuring the Moon's apparent diameter using 25 mm (48 ×) eyepieces. After a break, we sketched Cassiopeia, which was well placed to the North. We finished up by observing the double stars η Cas and ξ Cep, as well as the Pleiades.

Before commencing the lab, we set up two 8" telescopes with 25 mm (48 ×) eyepieces and reticles to measure the Moon's apparent diameter. A digital spectrograph was set up to display the continuum curve of a lightbulb. We then reviewed the nature of spectral lines and used hand-held spectroscopes to look at various light sources. These included (1) an ordinary fluorescent light, showing a continuum plus a strong emission line of mercury; emission sources containing (2) hydrogen, (3) helium, (4) mercury, (5) sodium, and (6) neon; and (7) a high-pressure sodium lamp, which exhibited both emission and absorption features.

At the park, we first reviewed the constellations of Fall and early Winter, including Cepheus, Cassiopeia, Perseus, Andromeda, and Pegasus, which we sketched. We then set up two 8" scopes, one 10" scope, and one 12" scope with a variety of eyepieces; a 40 mm eyepiece (30 ×) for wide-field views, and 16 mm and 10 mm eyepieces on the larger scopes. Our first target was the Andromeda Galaxy and its companions. We used to 10" scope with the 16 mm eyepiece (75 ×) to view M31, and the 12" scope with the 10 mm eyepiece (150 ×) to view the smaller companion galaxy M32; we then used the 12" scope with the 16 mm eyepiece (93 ×) to view both together. (Due to cirrus and ambient light, the other companion M110 was not easy to see.) Next, we looked at the Pleiades (M45) with the wide-field scope, which encompassed most of the cluster in one view. By this point, Orion was visible, and we used all three scopes to view the Orion Nebula (M42).

REPORTS

• An Occultation by the Moon

Joshua E. Barnes      (barnes at ifa.hawaii.edu) Updated: 06 December 2008 http://www.ifa.hawaii.edu/~barnes/ast110l_f08/observing.html