Book contents
- Frontmatter
- Contents
- How do you get to Albireo?
- How to use this book
- Using your telescope
- Know your telescope
- The Moon
- The Planets
- Seasonal skies: January–March
- Seasonal skies: April–June
- Seasonal skies: July–September
- Seasonal skies: October–December
- Northern skies
- Southern skies
- Where do you go from here?
- Behind the eyepiece
- Acknowledgments
- Tables
- Index
- What, where, and when to observe
- Finding geostationary satellites
The Moon
Published online by Cambridge University Press: 05 January 2013
- Frontmatter
- Contents
- How do you get to Albireo?
- How to use this book
- Using your telescope
- Know your telescope
- The Moon
- The Planets
- Seasonal skies: January–March
- Seasonal skies: April–June
- Seasonal skies: July–September
- Seasonal skies: October–December
- Northern skies
- Southern skies
- Where do you go from here?
- Behind the eyepiece
- Acknowledgments
- Tables
- Index
- What, where, and when to observe
- Finding geostationary satellites
Summary
You don't need a book to tell you to look at the Moon with your telescope. It is certainly the easiest thing in the nighttime sky to find, and it is probably the richest to explore. But it can be even more rewarding if you have a few ideas of what to look for.
Getting oriented
Setting the stage
The Moon in a small telescope is rich and complex; under high power in a Dob, you can get lost in a jumble of craters and all the mare regions seem to meld together. So the first thing to do is to get oriented.
The round edge of the Moon is called the limb. Since the Moon always keeps the same side facing towards the Earth, craters near the limb always stay near the limb.
The Moon goes through phases, as different sides take turns being illuminated by the Sun. The whole sequence takes about 29 days, the origin of our concept of “month” (think: “moonth”). This means that, except at full Moon, the round disk we see will always have one part in sunlight, one part in shadow. The boundary between the sunlit part and the shadow part is called the terminator.
The terminator marks the edge between day and night on the Moon. An astronaut standing on the terminator would see the Sun rising over the lunar horizon (if the Moon is waxing; or setting, if it's waning). Because the Sun is so low along the horizon at this time, even the lowest hills will cast long, dramatic shadows.
- Type
- Chapter
- Information
- Turn Left at OrionHundreds of Night Sky Objects to See in a Home Telescope – and How to Find Them, pp. 24 - 41Publisher: Cambridge University PressPrint publication year: 2011