Planet Watcher’s Alert

Robert Bigelow

Each morning from the last part of January to mid-February, all five planets visible to the unaided eye (Mercury, Venus, Mars, Jupiter and Saturn) will appear together in the sky before sunrise, weather permitting. The last time this happened was in 2005. This can only occur when all of these planets are on the same side of the Sun as seen from Earth (see diagram).

Planet positions on January 25, 2016.

Planet positions on January 25, 2016.

If we have clear skies one of these mornings and you wish to see all five of these planets, begin observing about an hour or forty-five minutes before sunrise. Look to the southwest to find Jupiter. It will appear about a third of the way up the sky and will be brighter than any other star that that part of the sky. Mars will be nearly due south and at about the same altitude as Jupiter. Dimmer the Jupiter, its red/orange color will help distinguish it from nearby stars. Low in the southeastern sky is Venus, shining even brighter than Jupiter. Saturn will appear above and to the right of Venus. Don’t confuse Saturn with Antares, the brightest star in the constellation Scorpius. Antares has about the same red/orange color as Mars and will appear below and to the right of Saturn.

Mercury is usually the most difficult planet to spot as it never appears in a dark sky. It is so close to the Sun that it can only be seen during evening or morning twilight. Look for Mercury low in the south-eastern sky about 60 to 30 minutes before sunrise. It will appear below and to the left of Venus on approximately on the same imaginary line that passes through both Saturn and Venus. If my descriptions seem confusing, these diagrams might help.

Dress warm and good hunting!


Observing Report for January 27: This morning the sky was mostly clear of clouds. At 6:50 a.m. I was able to easily see Jupiter, Mars, Saturn and Venus. As Venus appeared just above the mountains from my location, I knew that Mercury would still be hidden behind them. By the time Mercury rose above the mountains about 7:10 a.m., morning twilight had become so bright that I could no longer detect Mars and Saturn with the unaided eye. I did need binoculars to see Mercury in the bright twilight. It should be higher in the sky and easier to see near greatest elongation on February 6.

NOTE: Care must be taken using binoculars in the morning to avoid any possibility of looking at the Sun as it pops up above the mountains.

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