Bright Objects in the Morning Sky—December 2018

The other morning promised an interesting alignment of the planets Venus and Mercury, the waning crescent Moon (3.4% illuminated), and the bright star Spica (Alpha Vir, the brightest star in the constellation Virgo) in the morning sky. All that was required was clear skies.

Morning twilight with Mercury, Venus, Spica, and the Moon (0629 MST 05 December 2018).
Morning twilight with Mercury, Venus, Spica, and the Moon (0629 MST 05 December 2018).

Various weather models showed essentially the same forecast. There would be a band of high clouds to our northwest and another band to our southeast. Overhead it would be clear.

And the forecasts turned out correct. Below is a satellite image taken at ~1330 UTC (0630 MST) showing a nice clear gap in the clouds.

IR satellite image at 1332 UTC (0632 MST) showing the gap in the clouds across northern Arizona.
IR satellite image at 1332 UTC (0632 MST) showing the gap in the clouds across northern Arizona.
Model forecast for cloud cover. White/gray is cloud; black is clear.
Model forecast for cloud cover. White/gray is cloud; black is clear.

I drove to the overlook on Mars Hill, home of Lowell Observatory, in Flagstaff. It has very good views towards the east and is a location I have used many times over the years for astrophotography.

Four Planets and the Moon

This week the waning moon joined four planets in the eastern sky. Lowest to the horizon was Mercury with Saturn just above. The moon was located well above that pair. And high in the sky were Mars and Jupiter.

Earlier this month on 07 January 2018, Mars and Jupiter were in conjunction. The pair was only 0.25 degrees apart in the sky at its closest. By comparison, the full moon is approximately 0.50 degrees. And, then, on 13 January 2018, Mercury and Saturn were in conjunction—but not quite as close as the Mars-Jupiter conjunction.

On the 14th and 15th, the Moon was just above and just below the pair of Mercury and Saturn.

The waning crescent moon (~5% illuminated) sits above the planetary pair of Mercury and Saturn.
The waning crescent moon (~5% illuminated) sits above the planetary pair of Mercury and Saturn.
A wider view shows all four planets (Mercury and Saturn low; Mars and Jupiter high) plus the moon.
A wider view shows all four planets (Mercury and Saturn low; Mars and Jupiter high) plus the moon.

I had planned to photograph on both days but clouds intervened. All I got was this thin crescent Moon (~2% illuminated) that was visible for only a few minutes before it was obscured by clouds.

A thin crescent moon is visible for just a moment after moonrise.
A thin crescent moon is visible for just a moment after moonrise.

Coming up: at the end of the month there will be a total lunar eclipse that will be visible in the pre-dawn hours of the western states. I hope the skies are clear.

 

 

Jupiter and Venus Conjunction—and the Moon

Earlier this week (13 November 2017) there was an opportunity to view a conjunction of the planets Venus and Jupiter in the pre-dawn sky. Venus is the brightest planet in the sky while Jupiter is the second brightest (and, of course, the largest). Pairings of these two planets in either the morning or evening sky are always an amazing sight. At closest approach, the distance separating the two planets was less than the diameter of the full moon. Jupiter was rising a bit higher each morning while Venus was dropping closer to the horizon.

Conjunction of Venus and Jupiter in the morning sky.
Conjunction of Venus and Jupiter in the morning sky.

For three mornings I shot photos of the morning sky. I then took the images from each day and created a layered image. Next, I shifted each image up/down, left/right until the planet Jupiter lined up. The result was that the composite contains a single image of Jupiter along with three images of Venus. This makes it easy to see how the two planets were shifting relative to each other over the course of three days.

Moon, Jupiter, and Venus in the morning sky.
Moon, Jupiter, and Venus in the morning sky.

But the show wasn’t over, yet. The waning moon was dropping lower in the sky each morning and on 16 November was located just above the pair of planets. About 4% of the moon is directly illuminated by the sun; the remainder is illuminated by Earthshine.

The photos were taken from Mars Hill where Lowell Observatory is located and look over the city of Flagstaff, Arizona, the worlds first International Dark Sky City.

Other planetary conjunctions of Venus and Jupiter have appeared on these pages before (26 May 2013; 18 August 2014).