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Sky events
A reminder that tonight is the peak of the annual Quadrantid meteor shower. 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 28% illuminated moon will rise about 02:13 to create some interference in observing the shower.
Watching meteors requires no more equipment than your eyes and a dark sky, and can be enjoyable for just about anyone.
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 4th, 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.
| 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 | ||||
Looking ahead to sharing a fun and pretty 2016 with everyone. As usual you can come to Darker View for heads up on everything happening in the sky for 2016. I have spent the last month setting up pre-scheduled posts with all of the significant sky events for the year. We have a couple interesting eclipses, including a total eclipse across the Pacific, and some nice conjunctions. Comet C/2013 US10 Catalina continues to be naked eye into January and C/2013 X1 PanSTARRS should be marginally naked eye in June.
Below are tables of all of the new and full moons of 2016 for those who prefer to plan early for those observing outings. Eclipses are noted with an asterisk in the tables and are explored more fully in the following section.
For those who like supermoons you will have to wait for later in the year when the orbit and lunar phase align. November will be the best supermoon of the year when full moon occurs only two hours away from perigee on the 14th of the month. For a few months either side of the November full moon you will find perigee occurring within a day or two of full, allowing for larger and brighter than average full moons.
Continue reading “The Sky for 2016”
The first meteor shower of 2015 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.
This year’s peak is calculated for January 4th at 08:00UT, this would be January 3rd at 22:00HST 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. A 28% illuminated moon will rise about 02:13 to create some interference in observing the shower. Thus for island observers the predawn hours of January 4th is when you want to observe this meteor shower, this will be several hours after the predicted peak.
The 08h UT timing for the peak will be too late even in the extreme west of mainland Europe while North American observers are in a better position. The λ⊙ = 283.16° maximum timing is based on the best-observed return of the shower ever analysed, from IMO data collected in 1992, as confirmed by radio results in most years since 1996. Typically, the peak is normally 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. Model calculations of Vaubaillon provide indications that the peak may occur earlier and may show a maximum between January 3, 22h, and January 4, 2hUT. This timing would be optimal for European longitudes. An added level of complexity comes from the fact mass-sorting of particles across the meteoroid stream related to the comet 96P/Machholz and the minor planet 2003 EH1 may make fainter objects (radio and telescopic meteors) reach maximum up to 14 hours before the brighter (visual and photographic) ones, so observers should be alert throughout the shower. – IMO 2016 Meteor Shower Calendar
Watching meteors requires no more equipment than your eyes and a dark sky, and can be enjoyable for just about anyone.
Today Mercury will be at maximum eastern elongation, as high in the evening sky as it will appear for this current apparition. After today the planet will slide back into the sunset, passing through inferior conjunction on January 14th to reappear in the dawn around the beginning of February.
Winter solstice occurs today at 18:48HST. 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.
| 2015 Solstices and Equinoxes | ||||
|---|---|---|---|---|
| UT | HST | |||
| Perihelion | Jan 4 | 08:59UT | Jan 3 | 22:59HST |
| Vernal Equinox | Mar 20 | 22:45UT | Mar 20 | 12:45HST |
| Summer Solstice | Jun 21 | 16:38UT | Jun 21 | 06:38HST |
| Apehelion | Jul 6 | 12:59UT | Jul 6 | 02:59HST |
| Autumnal Equinox | Sep 23 | 08:20UT | Sep 22 | 22:20HST |
| Winter Solstice | Dec 22 | 04:48UT | Dec 21 | 18:48HST |
| Source: NASA Sky Calendar | ||||
A reminder that tonight is the peak of the Geminid meteor shower. Meteors will begin to appear around 8pm when the constellation Gemini and the radiant rises. The peak occurs at 8am on the 14th, favoring the early morning hours. As the Geminid meteors have a broad peak activity can be expected to be good all night long.
The annual Geminid meteor shower is one of the most reliable annual meteor showers. The shower is noted for a steady stream of bright meteors with rates of well over 100 per hour.
The shower peak is predicted for December 14th, at around 18:00UT (14Dec 08:00HST). For viewers in the central Pacific this favors the evening of Dec 13th into the morning of Dec 14th, starting around 8pm as Gemini rises in the east. The peak is broad, with near peak rates occurring a day either side of the maximum, thus allowing everyone with a dark sky to enjoy this event. Thus the evening of the 14th may also provide a good viewing opportunity.
Even from more southerly sites, this is an excellent stream of often bright, medium-speed meteors, a rewarding event for all observers, whatever method they employ. The peak has shown slight signs of variability in its rates and timing in recent years, with the more reliably-reported maxima during the past two decades (HMO, p. 171) all having occurred within λ⊙ = 261.5° to 262.4°, 2015 December 14, 01h30m–23h UT. Near-peak Geminid rates usually persist for almost a day though, so much of the world has the chance to enjoy something of the shower’s best, regardless of when the maximum actually happens. Mass-sorting within the stream means fainter telescopic meteors should be most abundant almost a day ahead of the visual maximum, with telescopic results indicating such meteors radiate from an elongated region, perhaps with three sub-centres. Further results on this topic would be useful. The 2015 peak arrives just three days after new Moon, so observing conditions are ideal. – IMO 2015 Meteor Calendar
As noted by the IMO calendar entry above, new Moon will be on the 11th, placing the peak just a few days after new, a thin crescent in the evening sky that will set early. This leaves a perfect dark sky to enjoy the meteor shower. In the islands Gemini will rise around 8pm, bringing the constellation Gemini and the shower radiant over the horizon and marking the start of the show.
Watching meteors requires no more equipment than your eyes and a dark sky, and can be enjoyable for just about anyone.