Category: Sky Events

Sky events

Comet 45P/Honda–Mrkos–Pajdušáková

This February will feature a very close approach of Comet 45P/Honda–Mrkos–Pajdušáková. The comet will pass about 0.08AU (11.9 million km or 7.4 million miles) from Earth on February 11th, making it an easy telescopic object, and a marginal naked eye comet at around 6th magnitude.

C/2014 E2 Jacques
Comet C/2014 E2 Jacques on the evening of 27Aug2014
This is a short period comet with an orbit only 5.25 years long. At aphelion it orbits out very close to Jupiter, while at perihelion it is well inside the orbit of Venus. As such it may occasionally pass very close to Earth.

The comet itself is rather interesting. Discovered in 1948 the comet has been a the frequent target of scientific observation as it may pass quite close to Earth. In 2011 it passed about 0.06AU from Earth and was the target of radar observations.

Currently in the evening sky the comet is sinking into the sunset rather rapidly. It will pass by the Sun around the end of January to appear in the morning sky. It will rise rapidly above the dawn, by February 5th it will be rising at 3:22am, about four hours before the Sun. On the day of close approach, February 11th, the comet will rise well before midnight in the northern sky.

C/2014 Q2 Lovejoy
Comet C/2014 Q2 Lovejoy as it appeared on the night of 20Dec2104, 28 x 4min with a Canon 6D and a TV-76mm ‘scope
The comet is predicted to remain quite bright, around 7th magnitude or better for all of January and most of February, possibly peaking at around 6th magnitude near close approach to the Earth. As this is a well observed comet these magnitudes are likely to be reasonably accurate.

Of course any comet getting this close to us will catch the attention of the doomsday preachers and assorted apocalyptic predictions. Comet 45P is already a bit of a YouTube celebrity with quite a few videos filled with dire predictions.

I predict that we will have a pretty comet in the new year’s sky to provide a nice target for telescopic observations and astrophotographers. I would suggest making a point to get out and observe this comet as it passes by.

Venus at Maximum Elongation

Today Venus is at maximum elongation, as high in the sunset sky as it will get for this evening apparition, about 47.1°. After today the planet will begin its slide back into the glare of sunset. It will disappear from view around mid-March and reach inferior conjunction on March 25th, 2017.

As Earth and Venus race about the Sun, Venus will complete about one cycle of appearances each year. We can expect one evening apparition and one morning apparition to occur in 2017.

Continue reading “Venus at Maximum Elongation”

Earth at Perihelion

Today the Earth is closest to the Sun, a point called perihelion. We will be about 147,099,000km (91,403,000miles) from the Sun. Compare this to the 152,096,000km (94,508,000miles) we will be at aphelion on July 3rd, a difference of about 4,996,000km (3,104,000miles) occurs throughout one orbit.

It may seem odd that we are actually at the closest for the middle of northern winter, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2017 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 14:18UT Jan 4 04:18HST
Vernal Equinox Mar 20 10:29UT Mar 20 00:29HST
Summer Solstice Jun 21 04:24UT Jun 20 18:24HST
Apehelion Jul 3 20:11UT Jul 3 10:11HST
Autumnal Equinox Sep 22 20:02UT Sep 22 10:02HST
Winter Solstice Dec 21 16:28UT Dec 21 06:28HST
Source: USNO data Services

 

Quadrantid Meteor Shower Reminder

A reminder that tonight is the peak of the annual Quadrantid meteor shower. Peak will occur around 04:00HST tomorrow morning, January 3rd. Given our 20° latitude here in Hawaii the radiant does not rise until 01:30HST, thus observations must wait until well into the morning hours. A first quarter moon will set early leaving a perfectly dark morning sky for meteor observing.

Watching meteors requires no more equipment than your eyes and a dark sky, and can be enjoyable for just about anyone.

The Sky for 2017

Looking ahead to 2017 it appears that the skies will be kind to us this coming year. We have good meteor showers, a total eclipse of the Sun, a bright comet or two, and the usual planetary conjunctions to look forward to. Below you will find some on my notes to what we can look forward to during the coming year.

Jupiter 14Apr2016
Jupiter on April 15, 2016, stack of the best 2000 frames of 7600, Celestron NS11GPS at f/20 and Canon 60D
As is my practice I have spent more than a few evenings loading up DarkerView with scheduled posts for the year. Well over a hundred posts are set as reminders for the interesting astronomical events for 2017. It is a useful effort, as I can see for myself what the year will bring and begin my planning.

Covered are elongations for Mercury and Venus, interesting conjunctions, oppositions, eclipses and meteor showers. Posts include notes for visibility in the Hawaiian islands for those events that are location dependent.

Continue reading “The Sky for 2017”

The Moon and Venus

Luna & Venus
A thin crescent Moon and Venus in the sunset, photo by Maureen Salmi, used with permission
This evening a pretty crescent Moon will be located close to a brilliant Venus. The Moon will be a slim 12% crescent a little over 5° from Venus shining at -4.3 magnitude.

Look for the two as the evening sky begins to darken, they will not be difficult to find. Tomorrow the Moon will have moved 7° to the east of Venus.

Quadrantid Meteor Shower

The first meteor shower of 2017 is the annual Quadrantid meteor shower. The Quadrantids are a reliable shower, producing 60-120 ZHR, one to two meteors per minute. The Quadrantids are named for the obsolete constellation Quadrans Muralis, now part of the constellation Boötes.

Leonids in Orion
A pair of Leonid meteors streak through Orion
Unlike other showers where activity can occur for days or even weeks, the Quadrantids have a sharp peak, activity falls off rapidly on the preceding and following nights, or even a few hours away from the peak. Thus it is important to observe the Quadrantids quite near the peak prediction.

This year’s peak is calculated for January 3rd at 14:00UT, this would be January 3rd at 04:00HST, well timed for observers in the islands. For northern observers the radiant is circumpolar, thus the shower is observable all night long. Given our 20° latitude here in Hawaii the radiant does not rise until 01:30HST, thus observations must wait until well into the morning hours. As this perfectly corresponds with the peak this looks to be an ideal meteor shower for island observers. Further, a first quarter moon will have long set leaving a perfectly dark morning sky for observing meteors.

A first quarter Moon on January 5 creates favourable viewing conditions for the predicted Quadrantid maximum on January 3. For many northern hemisphere sites, the shower’s radiant is circumpolar, in northern Boötes, from where it first attains a useful elevation after local mid-night, steadily improving through till dawn. The 14h UT timing for the peak is favourable for observers in the west of North America. Observers in the north of Asia will find the radiant close to the horizon in their evening skies. The λ⊙ = 283.15◦ maximum timing is based on the best-observed return of the shower ever analysed (IMO data from 1992), and has been confirmed by optical and radio results in most years since. Typically, the peak is short-lived, so can be easily missed in just a few hours of poor northern-winter weather, which may be why the ZHR level apparently fluctuates from year to year. A – IMO 2017 Meteor Shower Calendar

Watching meteors requires no more equipment than your eyes and a dark sky, and can be enjoyable for just about anyone. While most observers in the northern hemisphere must endure winter conditions to observe this shower, in the islands we have the option of observing from somewhat warmer locations. I think this year’s Quadrantids deserve an early wake-up and a trip into the dark!

Winter Solstice

Winter solstice occurs today at 00:44HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2016 Solstices and Equinoxes
  UT HST
Perihelion Jan 2 22:49UT Jan 2 12:49HST
Vernal Equinox Mar 20 04:30UT Mar 19 18:30HST
Summer Solstice Jun 20 22:34UT Jun 20 12:34HST
Apehelion Jul 4 16:24UT Jul 4 06:24HST
Autumnal Equinox Sep 22 14:21UT Sep 22 04:21HST
Winter Solstice Dec 21 10:44UT Dec 21 00:44HST
Source: USNO data Services