Unit 9 : Constellations : Circumpolar : Spring : Summer : Autumn : Winter : Unit Questionnaire

Unit 1: How to Point to a Star
Unit 2: Where on Earth Are You?
Unit 3: Earth's Rotation and the Sun's Apparent Motion
Unit 4: Yearly Changes in the Sky
Unit 5: Seasons and Climate
Unit 6: Sundials
Unit 7: Navigation
Unit 8: Ancient Astronomy
Unit 9: Constellations

End of Unit 9 Assignment

This assignment consists of four parts. The first is a review with a couple of practice questions linked directly to their answers. The second is a short quiz that you take using Blackboard. It will be instantly scored for you by Blackboard; you only get once chance to take it, however, so be sure you are ready! The third part is an essay question. The question appears below; when you are ready to answer it, log on to Blackboard and submit your essay. Finally, for each unit, you should log on to Blackboard and contribute a question, an answer, or a comment to one of the posted topics. If you find the material in this unit challenging, you might want to start with the "discussion" part of the assignment in order to get some help with some of the ideas.

Brief summary of the unit

In this unit, the most easily recognized constellations are presented, and the best time to observe them is related to the apparent motions of the Sun over the course of the year.

Practice Question One

Which constellations are circumpolar as seen from Iowa, latitude 42N? Which of these will be circumpolar for an observer located in Uppsala, Sweden (latitude 60N) ? For an observer in Hawaii, latitude 21N? The coordinates refer only to the bright stars we usually count, not to the whole constellation; for example, the entire area assigned to Ursa Major runs from 28 to 73 degrees of declination!
Constellation dec range
Ursa Minor 71 to 90
Ursa Major 49 to 61 degrees
Cassiopeia 56 to 63 degrees
Cepheus 58 to 77 degrees


Practice Question Two

Separate the following constellations into ones that are easily observed in the winter and ones that are easily observed in the summer. Why aren't they all easy to observe all year? Hint: What right ascension does the constellation have? What right ascension does the Sun have in the winter; in the summer?

Orion, Taurus, Leo, Sagittarius, Scorpius, Andromeda, Hercules

Essay question

You have been awarded observing time on a big telescope in Hawaii to observe some stars in the following constellations:

Contellation Right Ascension Declination
Gemini 6 hours to 8 hours 12 to 32 degrees
Aurigae 5 hours to 6 hours 28 to 46 degrees

19 hours 30 min
to 21 hours

25 to 45 degrees


(a) During what month is Gemini most easiy observed (or, up in the sky the longest during dark hours) as seen from Hawaii? Ditto for Aurigae; ditto for Cygnus? Use the average position and the middle of the month. Explain.

(b) Going to Hawaii once for each constellation is expensive, in time and money. Is there any time of the year when you might be able to observe stars in all three constellations? In two of them? Explain.