Astronomy 110 Laboratory: Observing

Fall 2011 Astronomy 110L Tue. 7:00 — 10:00 pm


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:

Kapiolani Park Forecast Current conditions and 7 day prediction
Synoptic Discussion General discussion of unfolding weather patterns
Satellite Interpretation Discussion of satellite images, emphasizing cloud cover
Oahu to N. Hawaii Close-up visible-light animation
Main Hawaiian Islands Wide-field IR-light animation
Weather Service Radar Radar images show ongoing showers
Satellite Image Browser Full-disk images and animations for the big picture
IfA Weather Links Other weather-related resources


Have a good break and a happy New Year!


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.


1. Introductory Meeting 23-Aug-2011, 19:00
Physical Sciences Building
Clear and calm
Waning crescent Moon

We met at PSB. After a brief introduction to the course, we went outside to look at Saturn. Three 8-inch scopes were set up with 25 mm, 20 mm, and 14 mm eyepieces, providing magnifications of 48×, 60×, and 85×, respectively. The planet and its rings were evident, as was Saturn's brightest moon Titan; another moon, Rhea, was also visible as the sky darkened. We also viewed Arcturus (α Boo) and Albireo (β Cyg). After a break, we went over the lab telescopes and practiced setting them up and taking them apart. Finally, we repeated the procedure with the lights out; this also demonstrated dark adaptation and averted vision.

2. Orientation & Introduction to the Mikly Way 30-Aug-2011, 19:00
PSB & Kapiolani Park
Mostly clear; light wind
Waxing crescent Moon

At PSB, we set up two 8-inch scopes with 32 mm and 25 mm eyepieces (38× and 48×, respectively) to view a crescent Moon barely two days old. After the quiz, we drove to Kapiolani Park, arriving around 20:00. The bulge and inner disk of the Milky Way were clearly visible. We reviewed some effects of the Earth's rotation and orbital motion about the Sun. After the break, we set up all six scopes with 32 mm eyepieces and used them to view the Milky Way in Sagittarius and Scorpius. We concluded the evening by viewing the open cluster M7, the emission nebula M8 (Lagoon Nebula), and the globular cluster M22; some people used 14 mm eyepieces (85×) to resolve bright stars in M22.

3. Scorpius & the Moon 06-Sep-2011, 19:00
PSB & Kapiolani Park
Slight haze; no wind
Waxing gibbous Moon

After the quiz, we drove to Kapiolani Park, arriving about 20:00, and set up five 8 in telescopes. One group of students used these 'scopes to view and sketch the Moon, which was two days past first quarter. Many lunar maria (lava plains) were visible; the mountains ringing Mare Imbrium were evident. A number of large craters, including Plato, Copernicus and Tycho, were also well-placed for observation. The second group of students charted the glittering constellation of Scorpius. To set the scale of this constellation, they measured the angle between α Sco (Antaries) and λ Sco (Shaula); we estimated 17°, which is very close to the actual angle of 17.3°. Charts were made at a scale of 2° = 1 cm. Scorpius nicely illustrates different stellar brightness, with three first-magnitude stars, seven second-magnitude stars, and five third-magnitude stars. After the break, the first group of students charted Scorpius, while the second group sketched the Moon.

4. A Simple Telescope 13-Sep-2011, 19:00
Physical Sciences Building
Clear and calm
Waning gibbous Moon

With a very bright Moon making all but the brightest stars invisible, we stayed on campus and completed the Simple Telescope Experiment. At the end of the class, we took our telescopes outside to view the Moon. We also began sketching the Moon's phase as part of an ongoing project.

5. Scanning the Milky Way 20-Sep-2011, 19:00
PSB & Halona Blowhole Lookout
Scatterd clouds; strong wind
Last quarter Moon

Arriving at the Lookout shortly before 20:00, we began by using our eyes and binoculars to view the sky between rapidly-moving clouds. Our first target of opportunity was the great spiral M31 (Andromeda Galaxy), which appeared in binoculars as a fuzzy, extended patch of light. As clouds to the south cleared, we could see our own galaxy, the Milky Way, extending from Sagittarius through Cygnus; the dark lane running through the middle was evident. With binoculars, we scanned the star cloud M24 and other rich regions of the Milky Way. We then set up a 10-inch telescope with a 15 mm eyepiece (80×). We revisited the emission nebula M8 (which was much more evident than it had been in Kapiolani Park) and the globular cluster M22 (which was easily resolved). We also observed the rich open cluster M11 (Wild Duck Cluster), the emission nebula M17 (Swan Nebula), and the planetary nebula M57 (Ring Nebula). With a nebula filter, the nebulae were easy to see against a dark sky.

6. Barnard's Star & Jupiter 27-Sep-2011, 19:00
PSB & Kapiolani Park
Scattered clouds; light wind
New Moon

At the park, we set up four eight-inch scopes. We began the evening by charting the constellation of Sagittarius; in addition to sketching the `Teapot', we used binoculars to view deep-sky objects and star-fields. Next, we used binoculars to find the V-shaped pattern of Poniatowski's bull in the constellation of Ophiuchus. A line drawn from 70 Oph to 66 Oph, continued a little further, arrives in the vicinity of Barnard's Star, one of our solar system's nearest neighbors. We finished up by getting a first look at Jupiter rising over the ridge to the east; the four Galillean moons were all visible.

7. Parallax in the Lab 04-Oct-2011, 19:00
Physical Sciences Building
Scattered clouds
Waxing gibbous Moon

After completing parallax measurements in the PSB parking lot, we set up three 8-inch scopes to measure the Moon's apparent diameter.

8. Moonlight in the Park 11-Oct-2011, 19:00
Kapiolani Park
Mostly clear; light breeze
Full Moon

At the park, we set up five 8-inch scopes and one 10-inch scope. We viewed the full Moon and measured its apparent diameter. We then turned our scopes to Vesta, which was near ψ Cap. The star and the asteroid were both visible using the 32 mm eyepieces (38×); within this field of view, Vesta appeared adjacent to a 6.8 mag star (HP 102869). We next looked at Jupiter, where Io and its shadow were transiting the planet's disk. Moderately poor seeing made it difficult to see the shadow, but some people were able to glimpse it. After the break, we sketched Jupiter and the three major satellites then visible, and waited briefly for Io to appear at the end of its transit; the satellite was first spotted as a bright `pimple' on Jupiter's disk around 21:35 HST, and separated from the planet about 10 minutes later.

9. Spectra in the Lab 18-Oct-2011, 19:00
Waning gibbous Moon

10. Motion and Phases of Planets 25-Oct-2011, 19:00
New Moon

11. The Inverse Square Law 01-Nov-2011, 19:00
Waxing crescent Moon

12. Moonlight at the Beach 08-Nov-2011, 19:00
Sandy Beach
Mostly clear; moderate breeze
Waxing gibbous Moon

We first observed the Moon from the PSB parking lot and measured its apparent diameter. We then carpooled to Sandy Beach, arriving about 20:00 HST. We reviewed Fall constellations and took a first look at Perseus and Taurus. Despite the bright moonlight, the Hyades were faintly visible to the naked eye and easily seen with binoculars. We compared them to the Pleiades, which were easily visible even without binoculars. After waiting out some clouds, we made a first estimate of the magnitude of β Lyr, an eclipsing variable star; it appeared about as bright as its fainter comparison star ζ Lyr. We then observed δ Cep, the prototypical Cepheid variable star; it appeared intermediate in brightness between comparison stars ζ Cep and ε Cep. After the break, we used four 8 inch scopes to observe β Lyr and δ Cep, noting that both are actually visual double stars. We also observed the Pleiades, Jupiter, and the Moon.

The Fool
         The reason why the seven stars are no more than seven is a pretty reason.
King Lear
         Because they are not eight?
The Fool
         Yes, indeed: thou wouldst make a good fool.
King Lear, Act 1, Scene V

13. Clouded Out at the Park 15-Nov-2011, 19:00
PSB & Kapiolani Park
High clouds; light breeze
Waning gibbous Moon

After the quiz, we proceeded to Kapiolani Park to see what we could see. High cirrus clouds covered much of the sky, but a handful of stars were visible, as was Jupiter. We were able to observe ε Lyr and resolve all four stars using a 10-inch telescope and 15 mm eyepiece (80 ×). We also observed 61 Cyg, `a little old couple of stars'. Finally, we looked at Jupiter; the belts were quite clear thanks to the relatively stable atmosphere. Unable to find further targets, we finished early.

14. Indoor Lab Activities 22-Nov-2011, 19:00
Physical Sciences Building
Mostly cloudy; variable trades
Waning crescent Moon

15. Occultation Obscured 29-Nov-2011, 19:00
PSB & Kapiolani Park
Partly cloudy; light breeze
Waxing crescent Moon

After briefly meeting at PSB, we arrived at the park hoping to see the crescent Moon occult the 7th magnitude star HP 103037. Alas, thin clouds hid the star, although the moon itself was easily visible. When the clouds shifted, we were able to see several faint stars close to the Moon using the 15-inch scope. We used the 8-inch telescopes to measure the Moon's diameter. Through gaps in the clouds, we were also able to observe the double stars β Cygni (Albireo) and η Cassiopeiae; both pairs present contrasts in color and brightness, but η Cas has a much smaller separation than β Cyg. We then began observing Jupiter, with the intention of comparing views in 8-inch, 10-inch, and 15-inch telescopes; however, clouds followed by light rain cut the evening short.

16. Finale with Cupcakes! 06-Dec-2011, 19:00
Physical Sciences Building
Partly cloudy
Waxing gibbous Moon

We met at PSB to complete several projects, including the Orbit of the Moon and Phase of the Moon exercises.


The apparent diameter of the Moon, measured on 42 occasions over nearly three months, yields this Graph of the Moon's Distance. In this plot, the grey curve is the center-to-center distance between the Earth and Moon. The red dots show results from measurements of photographs, while the blue dots show actual distance from Oahu to the Moon on lab nights.

The 10-Dec-2011 Lunar Eclipse was beautiful even through clouds! I watched it and took some pictures.

Joshua E. Barnes      (barnes at
Updated: 13 December 2011
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