Moon+Observing.pdf

Work on your own for this lab. You can discuss with classmates, but don’t need a group. Name: ______________________________ Please get a TA or Instructor to sign that you attended the night lab. TA/Instructor Signature (3 points) : ______________________________ ASTR1010 Night Lab Moon Observing This lab should happen when the Moon is visible, with any illumination from crescent to full. For this lab, you will need to make observations with the telescopes Artemis and Apollo, located on the observation deck at Sommers-Bausch Observatory. Goals ● observe the Moon through telescopes and binoculars ● develop familiarity with geographic features on the Moon through sketching ● appreciate the beauty of the Moon and the power of nice telescopes Introduction The Moon is bright! For astronomers trying to observe dim stars or distant galaxies, reﬂected light off the Moon can be a source of frustration, outshining these other objects. Yet, it’s also friendly, familiar, a great source of information about the history of the Solar System, and incredibly beautiful. In this lab, we’ll take a moment to look closely at the closest and brightest astronomical object in the sky. Instructions ● This lab’s observations can be completed only during a “Moon” observing session. ● Be prepared to be outside. Dress warmly. The observing deck is not heated, even in winter. ● Bring a pencil. Complete your Investigations directly on this observing sheet. Please try to avoid using bright screens on the observing deck, to not interfere with others’ night vision. ● Work mostly on your own for this lab. You may discuss with classmates, but observations, sketches, and write-ups should be done individually. ● Submit your Investigation as a single PDF document on Canvas within 1 week of attending the observing session.

This " Binocular View " map resembles the appearance of the Moon seen directly with your eyes or through binoculars, with some major features outlined.

This “ Telescope View " map resembles the appearance of the Moon seen through a telescope, which is a mirror image of how it appears to your own eyes. Be aware: North might not necessarily be “up” in the eyepiece.

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Investigations 1. Lunar illumination context. (6 points) Part of why the Moon is so interesting to observe is that its appearance changes every night, because we see it illuminated from different angles. a. (3) Which key lunar phase is the Moon closest to right now? Shade in the regions on the Binocular and Telescope View maps that are currently in shadow; if none are, say so. = new moon = waxing crescent = first quarter = waxing gibbous = full moon = waning gibbous = third quarter = waning crescent b. (3) Draw the approximate directions toward the Moon and Sun at the time you’re observing, relative to your position as a tiny human standing on Earth’s surface. Explain your reasoning. (You can’t draw positions to scale for this sketch. The goal is to get a rough sense of the direction from which the Moon is being illuminated.)

2. Lunar shadows. (5 points) The “terminator” is the dividing line between the sunlit and dark sides of the Moon. In partial phases, it will appear curved in an arc across the sphere of the moon. a. (2) If you were standing on the Moon, at which of the following two locations would you have the longest shadow? Explain your reasoning. b. (3) Look through a telescope ( T ). Inspect the appearance of craters or other topographic features near the terminator (or the edge of the Moon if near full phase) and those that are far from it. Do you have a better sense of the depth of craters near the terminator or far from it? Explain why. 3. Lunar details. (8 points) Sketching is a great way to focus your observational skills, to look closely at an objects’ actual appearance, and to notice details you might otherwise miss. a. (6) Draw what you see through the telescope eyepiece looking at one region on the Moon, inside the circle at right representing the eyepiece field-of-view. Your drawing does not need to be good, but please try to express approximate shapes, shading, and shadow. b. (1) Indicate which region of the Moon you drew on one of the Binocular View or Telescope View maps above. c. (1) Describe your reaction to looking at the lunar surface through the telescope in one word: ________________

4. Lunar topography. (8 points) Let’s look closely at some details on the lunar surface, exploring the processes that sculpted the surface of our celestial neighbor over the past billions of years. i. Read the following descriptions of various types of lunar features. ii. Use a telescope and/or binoculars to identify at least one example of each type. ( T ) indicates to use a telescope; ( B ) can be seen with binoculars. iii. Label each feature you saw on one of the lunar maps above. a. (1) Maria : These are relatively smooth and dark areas formed by ancient volcanic eruptions that filled even older giant impact craters. The maria make up the "(hu)man-in-the-Moon." These were once thought to be seas, during the early days of the telescope. ( B ) Shade in these dark patches with your pencil. b. (1) Craters with central peaks : Many large craters have mountain peaks in their centers, which can reach 5 km in height. These peaks are produced by a rebound shock wave produced by the impact that formed the crater. ( T ) c. (1) Craters with terraced walls : As some large craters formed, their inner walls collapsed downward, pulled by gravity. This can happen several times, giving the inner crater wall a stair-stepped appearance. ( T ) d. (1) Overlapping craters : An impact crater may be partially obliterated by a later impact, giving clear evidence of which impact occurred earlier, and which occurred later. ( T ) e. (1) Craters with rays : Some younger craters have bright streaks of light material radiating from them. These rays are created by debris tossed out by the impact that formed the crater. Craters with bright rays are relatively "young" (less than 1 billion years old); the rays of older craters have been obliterated by subsequent geologic activity or impacts. Rays are most prominent near the time of the full Moon. ( B ) f. (1) Walled plains : A few very large craters have bottoms that are partially filled by mare lava. The appearance is that of a large ﬂat area surrounded by a low circular wall. ( T ) g. (1) Rilles: Rilles are trenches in the lunar surface that can be straight or irregular. Although some of them look like dried riverbeds, they were not formed by water erosion, but rather by ancient ﬂows of liquid lava. Straight rilles are probably geological faults, formed by ancient "moonquakes." ( T ) h. (1) Mountains and mountain ranges : The Moon's mountains are the remnant rims of ancient giant impact craters. Because of the Moon's low gravity and slow erosion, these mountain peaks can reach heights of 10 km. ( B or T )

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