Constellation of the Month: Lynx, The Lynx

Hiding among the stars in our northern sky this month is a big cat, Lynx. This constellation is made up of faint fourth-magnitude stars, making it as hard to find as a lynx is to find in the mountain forests around here. The American lynx, Lynx rufus, or bobcat, ranges freely through much of North America including all of New Mexico and Arizona. The constellation Lynx, however, ranges only around our northern sky, never slipping south of the zenith.

Click image to enlarge. This month we are still facing north, looking high in our northern sky. This month's constellation is the faint zigzag line that makes up Lynx. This constellation has two deep-sky objects in it, the Bear Paw Galaxy and the Intergalactic Wanderer globular cluster. Lynx fills in the space between Ursa Major and Auriga.

This faint constellation hides between Ursa Major and Auriga, filling in the gap between them. It has no ancient mythology and came into existence in the 17th century when Polish astronomer Johannes Hevelius' star atlas, Firmamentum Sobiescianum (1690), was posthumously published. This star atlas of 56 sheets mapped out the 1,564 stars in his Prodromus Astronomiae (1690) star catalogue. It contained seven new constellations delineated by him, including Lynx, which are still in use today (in addition to some now obsolete).

Hevelius purportedly named the constellation Lynx because only the lynx-eyed (or those of good sight) would have been able to recognize it. His mapping of the constellation is little more than a few dim stars wandering in a zigzag line. The brightest one is third magnitude, and the rest are fourth and fainter.

The most interesting object in Lynx is the globular cluster NGC 2419, also known as the Intergalactic Wanderer. This cluster is believed to be the farthest one from our galaxy yet still gravitationally bound to it. Remember, globular clusters formed from the gas cloud that formed our galaxy before it collapsed into the current spiral disc. William Herschel discovered this four-minutes-of-arc-across globular on Dec. 31, 1788.

NGC 2419 is 300,000 light-years away from the center of our galaxy, and from us. This is so far away that it is twice as distant as the Magellanic Clouds, those two dwarf galaxies that orbit the Milky Way. Even though it is so far away, it is still magnitude 10.4. This makes it intrinsically very bright, indeed being the fourth-most in intrinsic brightness among the Milky Way's globulars—after Omega Centauri, NGC 6388 in Scorpius and M54.

Photographically, NGC 2419 looks orangeish, indicating that it has few young, blue stars. Most are older red stars whose spectrum signifies that NGC 2419 is an old cluster that must have been one of the first to be formed. It is heading back toward the Milky Way now, having just passed the farthest point away from us in its long elliptical orbit. It is now traveling toward us at 12 miles per second.

The Planets for March 2007

(Note: We change from Standard to Daylight Savings Time this month on March 11. This is a change that was ordered by Congress two years ago. Times listed below are Mountain Daylight Time.)

The two planets brightening our evenings are at the opposite ends of the sky. Venus shines brilliantly in our western sky, while Saturn is in the east. Venus appears about 30 degrees up in the west just after sunset. Shining at magnitude -4.0, it is in Pisces at the beginning of the month and moves into Aries at mid-month, where it remains for the rest of March. Venus' phase will shrink from 87-percent illuminated to 78-percent illuminated during the month. Venus is swinging around the Sun, coming closer to the Earth, so it is getting larger, 13.7 seconds-of-arc across by month's end.

Saturn is in western Leo this month, already well above the eastern horizon at sunset, setting around 5:30 a.m. The Ringed Planet is just past opposition, so it is still relatively large with its disc 19.8 seconds-of-arc across. The rings are 44.8 seconds-of-arc across and tilted up 15 degrees with the southern face showing. Saturn is magnitude -0.1 and is best observed around 11 p.m.

Jupiter remains in Ophiuchus this month, rising just before 2 a.m. in the east-southeast about 11 degrees east-northeast of the first-magnitude star Antares. So far this year, the King of Planets has been moving eastward among the stars ("prograde motion"). This month it will stop and turn back westward in what is called retrograde motion. This is caused by the Earth trying to catch up with Jupiter in their respective orbits. Since the Earth moves faster, Jupiter appears to travel backward among the stars. Jupiter is magnitude -2.2 and 38.2 seconds-of-arc across.

The constellation Capricornus harbors the planet Mars all month. It rises around a quarter to five in the morning and is visible until the Sun comes up. The Red Planet is magnitude 1.2, and its disc is 4.7 seconds-of-arc across, still hard to see with a telescope.

Mercury is in the morning sky this month. This will not be a particularly good apparition, since Mercury will be hugging the southeastern horizon. It begins March sharing Capricornus with Mars, but as the month progresses, it will turn and head back toward the Sun after reaching greatest elongation on March 22. On that date it will be 53 percent illuminated at magnitude 0.2, and 7.3 seconds-of-arc across.

March 21 is the northern hemisphere Vernal Equinox, when day and night are of equal length. It also marks the official beginning of spring, so enjoy the warming weather and "keep watching the sky"!

An amateur astronomer for more than 35 years, Bert Stevens is
co-director of Desert Moon Observatory in Las Cruces.

Return to Top of Page