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The article focuses on astronomical observations predicted in December 2017. It highlights the visibility of Geminids, one of the most prolific meteor showers of the year from December 4-16, 2017 but peak on the night of December 13-14, 2017. Observations regarding moon phases including new moon, full moon and last quarter are also explained.

Our target this month is the North America Nebula (NGC 7000, Caldwell 20) in the constellation Cygnus, the Swan. Their appearance as distinct objects is an illusion - the North America and Pelican nebulae are just the visible parts of a single, vast hydrogen cloud, only separated from our point of view by a dark lane of dust in the foreground (designated LDN 935). In 2020, the European Space Agency's Gaia spacecraft measured the distances to 395 stars embedded in the nebula, yielding an average of 2,590 light-years. [Extracted from the article]

To make matters worse, M71 sits in a dense stretch of the Milky Way. High magnification restricts the field of view so much that the cluster starts to blend into the rich galactic background, especially in poor skies. Our target this month is M71, an 8.4-magnitude globular cluster in Sagitta, the Arrow, hanging halfway between Delta ( ) and Gamma ( ) Sagittae. [Extracted from the article]

This whole stretch of sky, from Vulpecula, the Little Fox, down to Ophiuchus, the Serpent Bearer, is rife with star clouds, double stars, and asterisms. The two clusters do make a nice comparison - IC 4756 is larger, more ragged, and less dense than NGC 6633, with margins that are more likely to blend into the rich Milky Way background. This month we travel to Serpens Cauda, the tail of the cosmic snake, to take in the open cluster IC 4756. [Extracted from the article]

Imagine 3.7-magnitude Epsilon ( ) and 3.5-magnitude Mu ( ) Serpentis as two points of an equilateral triangle and M5, 8° to the west serving as the third point, completing the shape. Binocular Highlight by Mathew Wedel Our target this month is the globular cluster M5 in the constellation Serpens Caput, the head of the celestial serpent. MATT WEDEL likes to go big-game hunting, tracking down globular clusters in the halo of the Milky Way. [Extracted from the article]

If conditions are good, and ideally with 10×50 or larger binos, you may spot a third open cluster, 6.7-magnitude NGC 2423, a bit more than ½° north of M47. There are several ways to get to the clusters: scanning south from Alpha ( ) Monocerotis, or north from M93 (see chart at left), or my favorite way, east from the Great Dog, Canis Major. Our targets this month are the open clusters M46 and M47 in the constellation Puppis, the Stern of the celestial ship Argo Navis. [Extracted from the article]

Binocular Highlight by Mathew Wedel I never tire of exploring Monoceros - the celestial Unicorn is also a unicorn in the metaphorical sense of something rare and valuable. The constellation may not have any bright stars, but it is spangled from one end to the other with open clusters, nebulae, double stars, and asterisms. Scan 5° west-northwest of Delta Monocerotis to find the 6th-magnitude open cluster NGC 2301. [Extracted from the article]

Our targets this month are the open clusters NGC 1807 (magnitude 7.0) and NGC 1817 (magnitude 7.7), on the southern border of Taurus, the Bull. The two groups of stars are equally distant, at about 5,900 light-years, and astrometric studies suggest that NGC 1807 may be simply a clump of 8th- to 10th-magnitude stars on the western edge of a single extended cluster, NGC 1817. I grew up on the Great Plains of Oklahoma, and on cold, clear nights, the bright stars and clusters of winter remind me of moonlight on snow-covered fields and the warm lights of distant towns. [Extracted from the article]

Binocular Highlight At first glance, the open cluster NGC 1746 in Taurus, the Bull, seems to have everything going for it. The open clusters NGC 1750 and NGC 1758 are visually superimposed on each other in the southeastern quadrant of the region reserved for NGC 1746. Those two genuine clusters, plus a scattering of 7th-magnitude field stars, create the impression of a larger, rather ragged cluster - the illusory NGC 1746. [Extracted from the article]

The article describes some of the top attractions in the Milky Way for astronomical viewing using binoculars. Topics covered include the open cluster Collinder 121, open cluster M41 that is visible even to the naked eyes in dark skies, the M93 open star clusters, the NGC 2571 open star clusters and photographs of these star clusters.

Another open cluster, NGC 957, sits less than 2° north-northwest of the HD star, making a sort of squashed parallelogram with Trumpler 2, the Double Cluster, and Eta Persei. How many times have I traced the line from Delta ( ) Cassiopeiae to Eta ( ) Persei, connecting the Queen and Hero, looking to find the Double Cluster (NGC 869 and NGC 884) floating between them? Trumpler 2 is also more than just a fuzzy blob - in my 10×50 binoculars the brighter stars of the cluster form an arc or sickle shape whose horns point to the Double Cluster and Eta Persei, as if it were a hammock slung between them. [Extracted from the article]

Start with 6th-magnitude NGC 129, which sits about halfway between the 2nd-magnitude stars Caph, or Beta ( ) Cassiopeiae, and Navi, or Gamma ( ) Cassiopeiae, and just north of an imaginary line connecting them. Our second target, NGC 225, glows at 7th magnitude a little more than 2° northeast of NGC 129. Cassiopeia, mythological queen of Aethiopia, was the first constellation I learned, but it's so rich that I'm still making new connections as I explore it further. [Extracted from the article]

Delta ( ) Cephei is one of the more interesting stars in the constellation Cepheus, the King. At magnitude 3.3, Zeta ( ) Cephei approximates Delta at its brightest, and 4.2-magnitude Epsilon ( ) Cephei is close to Delta at its dimmest. Zeta, a true red giant, looks more distinctly yellow or orange to my eyes than either Delta or Epsilon. [Extracted from the article]

North of those stars lies the compact open cluster NGC 6231, and farther north the superimposed clusters Collinder 316 and Trumpler 24. My favorite trick with the False Comet is to treat myself to the naked-eye view, and then to get out an array of binoculars and telescopes and observe the cluster at different magnifications. Our target this month is a personal favorite, the False Comet in Scorpius. [Extracted from the article]

M6 is also called the Butterfly Cluster owing to its appearance, while M7 is known as Ptolemy's Cluster after Claudius Ptolemy, who first recorded it around AD 130. Our targets this month are the open clusters M6 and M7 in the tail region of the constellation Scorpius, the Scorpion. I like to imagine the bright stars of the Teapot and the tail of Scorpius as hands supporting a cat's cradle, with M7 firmly ensnared and M6 having made a narrow escape to the northwest. [Extracted from the article]

The article discusses an observations of the Sun, Moon and planets for April 2017. It mentions that tiny planet climbs to its highest altitude of the year in April while Jupiter reaches opposition. It notes that Mercury stands above the west-northwest horizon after sunset that day with Mars to its upper left.

APRIL 2021 OBSERVING Lunar Almanac Northern Hemisphere Sky Chart LAST QUARTER April 4 10:02 UT FIRST QUARTER April 20 06:59 UT NEW MOON April 12 02:31 UT FULL MOON April 27 03:32 UT DISTANCES Apogee 406,118 km Perigee 357,381 km April 14, 18h UT Diameter 29' 25" April 27, 15h UT Diameter 33' 26" FAVORABLE LIBRATIONS • Pingré Crater April 26 • Bailly Crater April 27 • Boguslawsky Crater April 28 Planet location shown for mid-month USING THE NORTHERN HEMISPHERE MAP Go out within an hour of a time listed to the right. Exact for latitude 40°N. WHEN TO USE THE MAP Late Feb Midnight Early Mar 11 p.m. Late Mar 11 p.m.* Early Apr 10 p.m.* Late Apr Nightfall *Daylight-saving time MAP PHOTO (COLOR): Yellow dots indicate which part of the Moon's limb is tipped the most toward Earth by libration. [Extracted from the article]

M3 is over the border in Canes Venatici, the Hunting Dogs, but it's an easy star-hop from Coma Berenices. For a small constellation with no stars brighter than 4th magnitude, Coma Berenices, or Berenice's Hair, has a lot to offer: one of the finest nearby open clusters (see S&T: Apr. 2019, p. 43); galaxies galore in the Coma-Virgo Cluster; and an easy-to-find globular cluster, Messier 53. [Extracted from the article]

The metaphors of manger and beehive both evoke the messiness of living systems, but when I look at M44 in binoculars, I tend to see stars laid out in an almost geometric grid, like a well-planned city seen from above. Binocular Highlight by Mathew Wedel Our target this month is one of the finest open clusters in the northern sky: Messier 44, in Cancer, the Crab. These are the "northern and southern donkeys" that the ancients envisioned eating from the trough of M44, which they accordingly knew as Praesepe, or "manger" in Latin. [Extracted from the article]

Follow the Dog's tail to its tip, Aludra, or Eta ( ) Canis Majoris, and you'll find the two clusters south and southwest of the 2.4-magnitude star. I stumbled into a wonderland of bright stars, clusters, and asterisms that ran from the tail of the Dog, then across Puppis and into Vela, the Stern and the Sails, respectively, of the ancient constellation Argo Navis. Our targets this month are the open clusters Collinder 132 and Collinder 140 in the southeastern corner of Canis Major, the Great Dog. [Extracted from the article]

The article discusses observations on the universe depicting its planet visibility during dawn, morning to afternoon and evening and presents chart that lists the right ascension and declination of sun and planets in August 2016 including Mercury, Venus and Uranus.

I have to specify the cluster because technically the NGC 2264 designation also includes the Cone Nebula, which, even if an interesting feature, is more of a challenge object for folks with dark skies and big scopes. Our target this month is NGC 2264 in the constellation Monoceros, the Unicorn. Scan slightly more than 3º south-southwest to find 15 Monocerotis, a 5th-magnitude blue-white star that sits at the base or trunk of the Christmas Tree asterism. [Extracted from the article]

To the naked eye, the light of Lambda Orionis, Phi1 and Phi2 Orionis, and the brighter cluster members combine to make Orion's head almost as misty as his sword. Together with Phi1 ( 1) and Phi2 ( 2) Orionis and the open cluster Collinder 69, Lambda forms the head of the imaginary hunter. Binoculars resolve quite a few stars and dispel much of the unfocused glow in this area, but take a close look: You might spot some remnant brightening - the star-forming nebula Sharpless 264 occupies the same region of space. [Extracted from the article]

It's a heady thought to observe NGC 1647 and imagine such bizarre animals existing when the cluster formed, while our shrew-sized ancestors hid in burrows and trees and waited for their turn to rule the world. Binocular Highlight A favorite obsession of mine, both in this column and in my feature articles, is thinking about what was happening here on Earth when various celestial objects formed, or when their light began its journey earthward. On the south edge of the cluster you'll see a fine optical double star formed by HD 30197 and HD 30179. [Extracted from the article]

MOON PHASES FULL MOON July 5 04:44 UT NEW MOON July 20 17:33 UT LAST QUARTER July 12 23:29 UT FIRST QUARTER July 27 12:33 UT DISTANCES Apogee July 12, 19h UT 404,199 km Diameter 29' 34" Perigee July 25, 05h UT 368,361 km Diameter 32' 26" FAVORABLE LIBRATIONS • Mare Australe July 2 • Mare Smythii July 4 • Mouchez Crater July 13 • Pascal Crater July 14 Yellow dots indicate which part of the Moon's limb is tipped the most toward Earth by libration. NASA / LRO Planet location shown for mid-month USING THE NORTHERN HEMISPHERE MAP Go out within an hour of a time listed to the right. Ignore the parts of the map above horizons you're not facing. [Extracted from the article]

Our destination this month lies the northeastin ern reaches Orion, the Hunter. Right away you' notice arc bright stars an of running east-west like lopsided smile, bounded a HD 44033 the east and Nu ( ) Orionis the by in in west. Last are the percentage of a planet's disk illuminated by the Sun and the distance from Earth in astronomical units. [Extracted from the article]

One of the most appealing clusters for November evenings is NGC 7789 in Cassiopeia. Most new observers assume that the famed Messier catalog contains the best and brightest deep-sky objects in the night sky. Caroline Herschel discovered the cluster in 1783, hence its nickname Caroline's Rose. [Extracted from the article]