Astronomy 110 Laboratory: Observing

WEATHER

The weather in Hawaii can change rapidly; 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

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.

SCHEDULE & LOG

We began with a brief review of the goals and rules for this lab. The class then went outside to view Venus, which was just half-full, using two 8 in scopes with 25 mm eyepieces (48 ×). Mars and Saturn were also briefly visible. We returned to the classroom to complete the discussion of lab policy. After a break, we worked with all six of the 8 in scopes, practicing setting them up and taking them down. For the last practice, we turned out the lights and used the red observing flashlights. The lab concluded with a discussion and demonstration of dark adaptation.

We met in PSB at 19:00, took a quiz, and went over plans for the evening. Outside, we had a quick look at Venus, using two 8 in scopes; Mars (to the right of Venus), and Spica (above Venus) were also visible. We then carpooled to Kapiolani Park, where we set up four 8 in scopes. We began by identifying compass points and describing the rotation of the Earth. To see the consequences of Earth's rotation directly, we viewed Polaris and Arcturus with the 8 in scopes; Polaris showed no motion, while Arcturus rapidly ascended in the telescope's inverted field of view. We then used 10×50 binoculars to scan Scorpius, Sagittarius, and the Milky Way through to Cygnus. We used four 8 in scopes to look at a few deep-sky objects, including globular cluster M22, emission nebula M8, open cluster M7, and planetary nebula M57. Finally, we turned the telescopes on Jupiter; all four satellites were visible, but only the northern equatorial belt could be seen on the planet's disk.

We met in PSB at 19:00, took a quiz, and went over plans for the evening. We then went to Sandy Beach, where we found some low clouds carried overhead by gentle trade-winds. Although these clouds initially blocked the sky from time to time, we had a good view of the Milky Way from Sagittarius through Cygnus, including the Great Rift. We then charted Scorpius. Passing clouds occasionally hid the constellation, but with perseverance we obtained a good view, emphasizing the magnitudes of various stars. After a break, we set up four 8 in scopes and one 10 in scope. Our targets included most of the objects we'd seen the previous week; in addition, we viewed emission nebula M17 (the Swan Nebula), open cluster M11 (the Wild Duck Cluster), and globular cluster M13. The darker conditions at Sandy Beach enabled us to see much more detail. We finished up by observing Jupiter.

We met at PSB and went outside right away to sketch the phase of the first quarter Moon in Ophiuchus. Using an 8 in scope, a 25 mm eyepiece with a scale, a digital camera, and a video projector, we previewed a way to measure the apparent diameter of the Moon. We also used an 8 in scope and 14 mm eyepiece to view Venus, which is now clearly crescent. After a quiz, we left for Kapiolani Park, where we set up six 8 in scopes. We began by observing the Moon, then at 20:30 we turned our scopes on Jupiter, where Io was just emerging from behind the planet. After a break, we sketched the Moon, concentrating on the shape of the lunar maria and craters along the terminator. We finished up by observing and sketching Jupiter again; by this time Io had moved well away from the planet.

We met at PSB and went outside promptly to view a crescent Venus. A nearly-full Moon was visible rising over the ridge. After the quiz, we carpooled to Kapiolani Park, arriving slightly too late to see Io disappear behind Jupiter. We then sketched the Summer Triangle and the constellation of Cygnus. After a break, we measured the apparent diameter of the Moon, using the 8 in scopes and 25 mm eyepieces with measuring scales. Finally, using the 8 in scopes and low-power 32 mm eyepieces (38 ×), Uranus could be seen as a blue-green point in the same field of view as Jupiter.

We began by viewing Venus, which was obviously crescent. After the quiz, we proceeded to Kapiolani Park and set up four 8-inch scopes. We sketched the Teapot in the constellation of Sagittarius. Shortly before 21:00 (9 pm), we turned the telescopes on Jupiter, where both Europa and its shadow were crossing the planet. The moon itself was not visible, but the shadow could be seen as a tiny black dot, especially using the 3× barlows and 25 mm or 20 mm eyepieces (144× or 180×, respectively). After a break, we began several new activities: estimating magnitudes of variable stars β Lyrae and δ Cephei, and plotting positions of Jupiter and Uranus.

Those arriving early were able to view a slender crescent Venus, but by 19:00 it was too low to see. After the quiz, we carpooled to Kapiolani Park. We reviewed the constellations and estimated the magnitude of β Lyrae. We then used finding charts to locate Barnard's Star. This involved two steps: first, we used binoculars to find "Poniatowski's bull", a V-shaped group of stars in Ophiuchus. From 66 Oph, we then used the 8 in scopes with 32 mm eyepieces to zero in on Barnard's Star. After a break, we plotted positions of Jupiter and Uranus, and finished up by estimating the magnitude of δ Cephei.

We went directly to Kapiolani Park, where near-perfect conditions prevailed, and set up six 8 in scopes and one 10 in scope. The first event of the evening, the occultation of 5 Sgr (mag 6.6) at 19:23 HST, was observed visually with all seven telescopes using 32 mm eyepieces (38 times). For later events, the 10 in scope was used with an 18 mm eyepiece coupled to a video camera; the real-time video output was displayed and captured using a laptop. Stars observed include 7 Sgr (mag 5.4) at 20:39 HST, 9 Sgr (mag 5.9) at 21:11 HST, and several others as faint as mag 8.2. In between occultation events we measured the apparent diameter of the Moon, estimated magnitudes of variable stars β Lyrae and δ Cephei, and plotted positions of Jupiter and Uranus.

We reviewed some basic optics and the formula for the magnification of a simple keplerian telescope. We examined image formation, measured the focal lengths of objective and eyepiece lenses, and assembled our telescopes. After measuring their magnification direcly, we took them outside to view the Moon and Jupiter. We also used our 8 in telescopes to measure the Moon's diameter and sketch Jupiter and its satellites. Finally, we estimated magnitudes for β Lyrae and δ Cephei.

We began the evening with a demonstration of a mid-IR camera by Mike Nassir, along with a discussion of "Black Body" radiation. We then reviewed some ongoing projects: (1) The of the Moon's Orbit, (2) Lunar Occultation Observation, (3) Variable Stars, and (4) Phases and Motion of Planets.

After proceeding directly to the park, we set up six 8 in scopes and one 10 in scope. Our first target was Jupiter's Great Red Spot, which crossed the meridian at 19:55 HST. The spot was visible with 14 mm eyepieces (86 ×) although the contrast was quite low; by 20:30 it was clearly off the meridian. We next observed several double stars: ε Lyr (difficult quadruple star), β Lyr, β Cyg, γ Del, and η Cas. After moonset, we used binoculars to scan Perseus and surrounding regions; viewing h and χ Per (Double Cluster), M 31 (Andromeda Galaxy), and M 45 (Pleiades). We also observed β Per (Algol) at minimum brightness. We finished up by plotting positions for Jupiter and Uranus, and had a final look at M 45 with the 10 in scope and a wide-field 27 mm eyepiece (44 ×).

After the quiz, we went to Kapiolani Park and set up four 8 in scopes. We began by observing the Moon and Jupiter. We then continued our survey of double stars, targeting 61 Cyg, β Cep, &delta Cep, γ And, and α¹α² Cap. After a break, we made a parallax measurement. Using binoculars, we estimated the magnitude of δ Cephei. Finally, we plotted positions for Uranus and Jupiter; for the latter, we used the scopes with 32 mm eyepieces (38 ×) to view the planet and two nearby stars.

After the quiz, we stepped outside to estimate the magnitude of β Lyrae, which was close to minimum. We then returned indoors, reviewed the method of measuring variations in the Moon's distance, and obtained lunar diameter measurements for non-lab nights from photographs. After a break, we went outside again to estimate the magnitude of &delta Cephei and observe the Moon. After waiting out some clouds, we were able to measure the Moon's apparent diameter one last time; it was significantly larger than previous measurements.

Shadow transit on Jupiter.

We met at PSB to review results from the Lunar Orbit and Variable Star projects and complete class evaluations. We then carpooled to Blowhole Lookout, where we set up 10 in and 15 in scopes. Targets observed include Jupiter, where a shadow transit by Io was easily visible, the Crab Nebula, the multiple star σ Orionis, the Andromeda Nebula, and the Orion Nebula, where the 15&bsp;in scope showed six stars in the Trapezium. We also plotted final positions for Jupiter and Uranus; Jupiter had clearly resumed direct motion, while Uranus was essentially stationary.

REPORTS

Joshua E. Barnes      (barnes at ifa.hawaii.edu) Updated: 20 December 2010 http://www.ifa.hawaii.edu/~barnes/ast110l_f10/observing.html