See the 6 or 7 Brightest Night Objects

The last week of February and first few days of March offer a rare

Tony Flanders
opportunity to people at mid-northern latitudes: the chance to see the night sky's six or seven brightest objects simultaneously 30 to 60 minutes after sunset. These are (in order of brightness):

the Moon (seriously bright!)
Venus (magnitude -4.3)
Jupiter (magnitude -2.2)
Sirius (magnitude -1.4)
Mars (magnitude -1.2)
Mercury (see below)
Canopus (south of latitude 37°N)

You will need a site with an unobstructed horizon to the west (for Mercury) and east (for Mars). People who hope to see Canopus will also need an unobstructed horizon to the south.

The timing for this observation is determined by Mercury, which is setting in the west at dusk. The later in the evening you observe, the darker the sky will be, but the lower Mercury will be. 45 minutes after sunset might be a good compromise.

All the objects in the list except for Mercury look better as the sky grows darker. Venus, Jupiter, Sirius, and the Moon remain above the horizon for several hours after sunset, and Mars rises higher as the evening progresses, peaking around midnight.

Tony Flanders
The best dates for the observation are toward the end of the window of opportunity, in early March. That's because Mars appears higher in the east each evening, while Mercury remains near its highest throughout the first week of March.

However, Mercury fades during the period, starting around magnitude -1.2 in late February, fading below Canopus (magnitude -0.7) around March 3d, and fading below Alpha Centauri (magnitude -0.3) around March 5th. That ends this viewing opportunity, because on evenings at this time of the year, Alpha Centauri is only visible from the Southern Hemisphere.

This opportunity is made possible by the coincidence of several factors. Venus and Jupiter are both high in the evening sky. Mercury is enjoying its best evening apparition of 2012 for northern viewers. Mars is almost at its closest to Earth for this orbit — the only time it counts among the night sky's 7 brightest objects. And this all takes place when Sirius and Canopus are near the highest in the early evening.

Tony Flanders
Canopus is visible anywhere south of latitude 37° north, assuming that you have an unobstructed southern horizon. The sky scene at right shows Canopus from latitude 34° north — roughly accurate for Los Angeles and Atlanta.

In case you're wondering, the northern limit for viewing the 6 brightest objects is around the Arctic Circle, beyond which Sirius becomes invisible. And the southern limit to achieve the feat without optical aid is around the equator. South of that, the angle of the ecliptic is so shallow that it's very difficult to spot Mercury.

However, people at mid-southern latitudes can probably see the night sky's eight brightest objects, including Alpha Centauri, 15 to 30 minutes after sunset in early March if they use binoculars, making it possible to catch both Mercury and Mars low in the twilight glow.

People all over the world should keep watching Venus and Jupiter as they approach each other during the first two weeks of March.

6 thoughts on “See the 6 or 7 Brightest Night Objects

  1. Anthony BarreiroAnthony Barreiro

    This is an amazing time to watch the sky, and a great opportunity for public outreach. Yesterday evening I walked to the park at the top of a nearby hill to catch a glimpse of Mercury and the crescent Moon. I accosted unsuspecting passersby with the names of the three naked-eye planets (Mars was on the other side of the hill) and offers to look at the sky through 11×56 binoculars. Children and adults really enjoy learning the names of things they can see easily. The Pleiades and the Orion nebula are easy and satisfying binocular targets for complete beginners. There was one guy with more experience and knowledge, but the mistaken belief that you can’t see anything in the city, so why bother. I talked him through star-hopping to the Andromeda galaxy and changed his mind.

  2. Gerald Marfoe

    Hi Tony,

    Alpha Centauri is quite visible around 3 a.m. – 5 a.m.
    in the southern sky at this time of the year, from a
    latitude of 10.5 degrees North (Port-of-Spain, Trinidad),
    and not just visible from the Southern hemisphere.

  3. Gaurav Karunakar

    I am in Bangalore, India, Lat. 13degree North. I can see not only all the planets, but also stars like Canopus and Alpha Centauri. Canopus especially is my favourite, as it shines in an area where there are no other bright stars.

  4. Tony Flanders

    Sorry for the confusion. Alpha Centauri is indeed visible at this time of year well north of the equator — even from southern Florida, in fact. But only in the morning, when all the other bright objects except for Mars are long gone.

  5. Warren Odom

    Well, I just bagged all 7 objects from northwest Texas, latitude 33+ (actually 8 objects! — see below), including seeing Canopus for the first time in my life (that I know of). The latter was difficult because I had to walk to the end of the block to a wide, busy north-south street with lots of streetlights and use binoculars to find it a little above an expressway overpass one block away. After locating it thusly, I was able to glimpse it by naked eye, but only by blocking all the lights (as if looking through an empty tube). The 8th object was the International Space Station at magnitude -2.5, gliding right past Jupiter.

  6. Bill Furnback

    You don’t mention Uranus. Right above Mercury now, though you do need at least binoculars. Mine are 10 X 23 so I do need to keep them steady.

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