Be sure to write down the date and time of each observation. This is important information in all astronomical observations.

Open Starry Night and, if you haven’t already done so, set your home location.

If they’re not already displayed, turn on the Planet palette and the Display palette by clicking the corresponding icon on the Tool palette.

If it is daylight in your location, turn daylight off by clicking Daylight on the Display palette.

Turn on "mouse information" by selecting Mouse Info from the Window menu or clicking the arrow labeled Mouse in the Tool palette. "Mouse information" displays a box at lower left that gives the name of the object or constellation over which your pointer is resting. This makes it easier to be sure you’re selecting the correct object.

Turn on Onscreen Info by clicking Info in the Display palette. Click the button next to Info in the Display palette. Click in the RA and Dec. box. (Hint: You might want to change the label color to white for better contrast.) Click OK.

Turn on the Horizon view in the Display palette.

Set the date to March 22, 1997 in the Time palette.

Double click Hale-Bopp in the Planet palette.

1. In what direction can the comet be seen?

2. What are the comet’s celestial coordinates?

Turn off the Horizon view.

Use the Zoom-In tool on the Tool palette to increase the field of view to 8º.

3. Describe the comet in as much detail as possible. Can you see both the ion tail and the dust tail? Which is which?

Click the Now button on the Time palette.

4. What are the comet’s celestial coordinates now?

Use the Zoom-In tool on the Tool palette to increase the field of view to 4'.

5. Describe the comet in as much detail as possible. How has its appearance changed since March 22, 1997?

Turn the Horizon view back on.

Set the date to March 25, 1996 in the Time palette.

Double click Hyakutake in the Planet palette.

6. In what direction can the comet be seen?

7. What are the comet’s celestial coordinates?

Turn off the Horizon view.

Use the Zoom-In tool on the Tool palette to increase the field of view to 13º.

8. Describe the comet in as much detail as possible. Can you see both the ion tail and the dust tail? Which is which?

9. How does the appearance of comet Hyakutake differ from that of comet Hale-Bopp?

Click the Now button on the Time palette.

10. What are the comet’s celestial coordinates now?

Use the Zoom-In tool on the Tool palette to increase the field of view to 9".

11. Describe the comet in as much detail as possible. How has its appearance changed since March 25, 1996?