By Dave Fuller on 9/8/2015 8:08 PM

Check out the slim crescent Moon as it first appears above, then in between, the planets of Mars and Venus in the eastern morning sky. This video shows when and how to see the planets and Moon together. 


For more on what you can see, check out the blog's past posts, or the home page for the most recent video(s). There's also info on basic stargazing and how to understand telescopes

By Dave Fuller on 1/19/2015 4:11 PM
Mercury has just about had enough of us Earthlings gazing at it for the last couple of weeks during this greatest eastern elongation in the western sky (Mercury's furthest highest point towards the east above the horizon in the west after sunset is called the greatest eastern elongation.) But while the rocky innermost world was sharing the stage with brilliant Venus, with Mars hovering over the two, the Moon was finishing it's rounds on the morning side of our sky.

Mercury, Venus, Earth, Mars and Moon on Jan 21

Now it returns to the evening, and YOU can capture this event with either your naked eye (look carefully!), binoculars, or with a camera (use a tripod).

On January 21st, the Moon will be about "three finger width's at arm's length" or 5 degrees or so away from Venus, and a bit less than that from Mercury. These graphics display the Moon's...
By Dave Fuller on 1/12/2015 4:13 PM
Marveling at Mercury Have you ever seen Mercury? Not the metal found in thermometers; the actual planet. It is surprisingly bright, but many people don't know when or where to look. This month offers the perfect time to try and spot this elusive solar system speedster.

Mercury is the innermost planet of the solar system. As such, we refer to both it and Venus as "inferior" planets - that is to say, they orbit the Sun inside of Earth's orbit (the other planets are called "superior" planets). Because of this location in our solar system, these planets never cross the sky, and they never reach opposition with Earth. Rather, the best time to see them is when they obtain the position of "greatest elongation." Yet Mercury is somewhat elusive. It orbits the Sun in just 88 days - less than a full season on Earth. Despite shining at over magnitude 1 much of the time when it is brightest, it is forever stuck in the twilight glow of the Sun. One never sees it under a truly dark sky, so observers really HAVE to be...
By Dave Fuller on 7/25/2014 8:26 PM
Every so often the stars, planets and Moon make some lovely alignments in the sky. Despite appearing small and close together, they are often far enough away from one another than photographs do not do them justice. However, their proximity in the sky naked eye often makes for a lovely sight.

Moon position August 1-5, 2014 From August 1 through August 5 2014, the Moon travels near the ecliptic - that imaginary line in the sky along which the Sun appears to travel. Because the planets of the solar system are mostly along the same plane, so do the Moon and planets. This week, the waxing crescent Moon will first stop near the first magnitude star Spica in Virgo on August 1, then split the space between Spica and Mars the folowing night of August 2nd. The following night it will have passed Mars and have Mars to the west and Saturn to the east. On August 4 the Moon...
By Dave Fuller on 1/26/2014 11:20 PM
Slim crescent Moon near Mercury

On Friday Jan 31 of this week (see above graphic), a very slim crescent from a just-past-New-Moon will pair up with Mercury in the evening sky. Ideal times to look are about 45 minutes to an hour after sunset.  The planet is surprisingly bright, though you will need to look in what I call the "middle twilight" area of the sky. That's the area of twilight between the darker sky above it, and the brighter sky below from the already-set Sun. In that transition zone, the bright point of Mercury pops out - if you have access to a relatively flat and clear western horizon.

These types of situations are when binoculars can be your friend to see the Moon. The planet - despite having the smaller angular diameter / size in the sky, may appear brighter. Point-like objects at lower magnitude can seem brighter...
By Dave Fuller on 1/26/2014 10:34 PM
The waning crescent Moon near Venus

This is truly a week for the Moon to be nearby objects. About an hour before sunrise on the morning of January 28, look out towards the east-southeastern sky where you have a clear, unobstructed view. Venus will be hard to miss, it's vivid, bright sparkling light dancing about 10 degrees above the horizon. 

But despite being technically brighter by almost 50 times, the larger surface area of the Moon may be harder to see, due to the very slim crescent of a Moon phase just a day or so before new. in the northern hemisphere, look to the right of Venus about 10 degrees or so (will vary somewhat based on location and time zone). Binoculars can help you pick out the narrow lit section of the Moon, though unfortunately the...
By Dave Fuller on 1/12/2014 10:51 PM
Check out these three fantastic looking features on the Moon's surface. Aristarchus is a very bright, very young crater. It is so bright it can be seen even when the section of Moon in which it is located is dark, but lit from earthshine. It is 45 kilometers across, and about 3,600 meters deep. Aristarchus was a Greek astronomer - he was the first to teach that the Earth orbits the Sun and rotates on its axis. (Continues below)Northwestern section of the Moon featuring crater Aristarchus

Immediately adjacent to Aristarchus is Herodotus, named for the Greek historian known as the "father of history." This is a lava-flooded crater, and therefore appears more flat and darker than Aristarchus. But the sinuous valley-cleft known as Vallis Schoteri (or Schroter's Valley) appears to start about 25 kilometers north of here, winding 200 kilometers in total length. It's deepest section is 1,000 meters. It appears like a dry river bed, but requires excellent atmospheric seeing and very high magnification to see detail here well.

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By Dave Fuller on 1/12/2014 10:17 PM
Lunar libration gif animationThe Moon is tidally locked with Earth, meaning it only shows one "face" to us, no matter where it is in its orbit around Earth. However, from Earth, we can see more than 50% of the Moon's surface due to libration. See graphic at right for what libration looks like over the period of a month. 

Here's the Wikipedia entry detailing why we see more than just 50% (in fact, up to 59%):



There are three types of lunar libration:



Libration in longitude results from the eccentricity of the Moon's orbit around Earth; the Moon's rotation sometimes leads and sometimes lags its orbital position. Libration in latitude results from a slight inclination between the Moon's axis of rotation and the normal to the plane of its orbit around Earth. Its origin is analogous to how the seasons arise from Earth's revolution about the Sun....
By Dave Fuller on 1/5/2014 10:00 PM

On January 9, 2014, the Moon will be about 68% illuminated for the Americas. The terminator - that is, where the shadow of the Moon begins and sunlight ceases - is the best place to view the lunar surface with a small telescope. The shadowing makes for dramatic-looking surfaces, and the detail seen is incredible. Because the Moon continues to orbit the Earth every 29.5 days, that terminator shadow moves across the Moon. As more lunar surface is bathed in sunlight, the details become washed out, and the new terminator details are the places to look.

But on Thursday.....

Straight Wall / Rupes Recta detail area

By Dave Fuller on 12/30/2013 3:18 PM
Here's what's happening in the night sky for the week of December 30, 2013 thru January 5, 2014 Want to see what's up in the sky this week? This daily reminder chart will let you know lots of individual, time-sensitive events occurring in the night sky for amateur astronomers to observe naked eye, with binoculars and sometimes a telescope.

Not sure how to convert the Universal Times to your local time zone? For U.S. observers, click here. For other visitors, check this site.

Monday, Dec 30:  Find and observe colorful double stars in Cassiopeia See more colorful doubles and the open cluster NGC752 in Andromeda...
By Dave Fuller on 12/22/2013 6:01 PM
Here's what's happening in the night sky for the week of December 23 thru December 29 Want to see what's up in the sky this week? This daily reminder chart will let you know lots of individual, time-sensitive events occurring in the night sky for amateur astronomers to observe naked eye, with binoculars and sometimes a telescope.

Not sure how to convert the Universal Times to your local time zone? For U.S. observers, click here. For other visitors, check this site.

Monday, Dec 23:  Find and observe colorful double stars in Cassiopeia See more colorful doubles and the open cluster NGC752 in Andromeda Tuesday,...

The Nightlight

This blog includes what to see in the night and daytime skies, thoughts on telescopes, binoculars, and other astronomy observing accessories and equipment, plus my own occasional notes on objects I've seen and observed. Oh, and the random theater or other "my take on life" post. In other words, there is always something interesting. Check it out.