ISON Update / Dusk Till Dawn Bright Planets / Mercury And Saturn Meet

Nice! Watching Comet ISON rise along with Mercury and Saturn, outside the Isaac Newton Telescope, Observatorio del Roque de Los Muchachos on a mountaintop in La Palma Saturday Nov. 23 at 6:45 Greenwich Time. Details: Canon 7D, 70mm f/4, 10 seconds at ISO 400. Credit: Alan Fitzsimmons
Another beauty. This one taken from a mountaintop observatory with a 300mm lens by Juan Carlos Casado of Spain on Sunday Nov. 24. He “stacked” or composited four photos to enhance the brightness of the comet against twilight. Click to enlarge.

Comet ISON is now next to impossible for many of us to see as it competes with morning twilight and horizon haze. Some of you tried for the comet Saturday morning without success, but those in more tropical latitudes had the edge. Two contributors combined the best of two worlds: low latitude and a view from a mountaintop! The pictures they took show ISON with a pinpoint head and thin tail glowing at about magnitude 3.

Comet ISON will now be under constant view by NASA’s sunwatching spacecraft. This picture was taken on Nov. 23 at 3 a.m. CST by a coronagraph on the STEREO A (Solar Terrestrial Relations Observatory) and shows the comet, Mercury and Earth. The sun is hidden off to the right; gases expelled from its corona spread to the left. Click to see more photos. Credit: NASA

NASA’s STEREO Ahead spacecraft has also been shooting high resolution images of the comet as it tracks across the same field of view as Earth and Mercury. We should be able to follow ISON in good resolution via space telescopes and coronagraphs (instruments designed to block the glaring solar disk) all the way through the end of the month, when it finally return to view at dawn.

Venus in a blue sky just 5 minutes after sunset on Nov. 23, 2013. Credit: Bob King

As we await ISON’s next move, five bright planets await your eyes the next clear night. We’ll begin with Venus. Yesterday it took little effort to spot this sapphire just five minutes after sunset a fist and a half high in the southwestern sky. A half hour later even those who pay little attention to the sky couldn’t have missed it. On Dec. 10 Venus reaches its greatest brilliancy for the year.

Jupiter comes up around 9 p.m. local time in Gemini the Twins. Because we see it against a dark sky, the planet appears almost as bright as Venus but it’s really about 6 times fainter.

You can use Jupiter to help you connect the “dots” to Gemini the Twins, a constellation with two bright stars representing the brothers Castor and Pollux. The pair lies just to the upper left of Jupiter. Once you’ve spotted them, follow the trickles of fainter stars to the right of each star fill in the rest of the constellation.

Jupiter clears the trees and buildings around 9 p.m. local time. Watch for it in the dual stick-figure constellation Gemini the Twins across from Orion. Stellarium

Next up is Mars which rises in the constellation Virgo around 1 a.m. My recommendation? Don’t bother with it until an hour before sunrise when the planet’s high in the southeastern sky above Mercury and Saturn. That way you get to see all three morning planets at the somewhat reasonable hour of 6 a.m.

To find Mercury, Saturn and Mars at dawn, look high in the southeast for Mars. Reach your balled fist to the sky and slide 3 fists down to Spica and another two fists to Mercury and Saturn. Stellarium

Find a place with a wide view to the southeast. Mars is easy to see by color and brightness, but Mercury may require binoculars at first until you know just where to look. Saturn will appear dimmest in part because it’s so low in twilight.

On Tuesday morning Nov. 26, the two planets will have switched positions and still be close.

Tomorrow morning the two will be very close together and nearly in conjunction. The time of closest separation is 7 p.m. CST Monday when neither is visible from the western hemisphere. Skywatchers in the eastern hemisphere will see them at dawn on the 26th separated by only 1/3 of one degree.

7 Responses

  1. Edward M. Boll

    I saw the planets I intended to this morning. Saturn was a little tough but easy in binoculars. Encke and ISON were not too far behind Mercury and Saturn. Of course, I saw none of these 2 but it would have been a cool view if the comets were a little brighter. A magnitude of 3 yesterday is not quite what we had hoped for, but could still yield for the record books a stunning magnitude at 12:24 PM Thursday CST. Unfortunately the comet may fade as fast as it is coming in, but we have a better declination to work with and a possible growing tail till mid December. That is if the tail is not too faint.

  2. Sean

    if you’re out early enough with a low enough (E-ESE in our part of the world) view mercury is easy to find naked-eye, although as twilight encroaches binoculars will be helpful in continuing to locate it. it was bright enough that i think i saw it within about a half hour of sunrise Saturday AM, naked-eye, tho i did know just about right where to look. i was a little annoyed because i hadn’t set an alarm to wake up and thus lost my chance to look 4 ISON, since it had been cloudy but must have cleared as dawn approached.

    1. astrobob

      I missed a morning like that last week when it was overcast at 5:20 but cleared just before 6. Frustrating.

  3. Edward M. Boll

    Nice morning to work. Cloudy. The Moon barely shown through. I was going to glance out before 6:30, but it was another 15 minutes that I did look into the twilight. Something was peeping through a hole in the clouds. I knew what it was right away, Mercury.

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