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”

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!

Perseid Meteor Shower

Over the next few days the Perseid meteor shower will peak. As the most reliable shower each year this is also the most viewed meteor shower. Plentiful shooting stars combined with warm summer evenings makes this shower the easiest and most comfortable to view across much of the northern hemisphere.

The comfort of summer meteor observing marks quite a difference from the other reliable showers such as the Leonids and Quadrantids, that occur in November and January. Consider a warm summer night under a dark sky full of stars, a picnic blanket, relaxing while shooting stars streak across the sky. What could be better?

Leonids in Orion
A pair of Leonid meteors streak through Orion
The Perseid meteor shower occurs when the Earth passes through a stream of debris along the orbit of Comet Swift-Tuttle. This shower has been consistent throughout recorded history, mentioned in Chinese, Japanese and Korean records as early as the 1st century.

Active from July 17th to August 24th, the shower will build slowly for weeks before the peak. A week before or after peak the shower can still be seen with around 20 meteors each hour. With a radiant high in the constellation of Perseus this is a northern hemisphere shower, for southern observers the radiant never rises above the horizon.

Continue reading “Perseid Meteor Shower”

Quadrantid Meteor Shower Reminder

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.

Quadrantid Meteor Shower

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.

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 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.

Geminid Meteor Shower

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.

Leonids in Orion
A pair of Leonid meteors streak through Orion
First observed over 150 years ago this is a interesting meteor shower. The parent body for the Geminids is not a comet, but rather the asteroid 3200 Phaethon. It is somewhat of a mystery how this mostly rocky body gives rise to the debris stream needed to generate a meteor shower.

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.

More Video of Cosmos 1315

Even better video of the breakup of Cosmos 1315 over Hawai’i. Taken by Josh Lambus, of course.

Be sure to hit the HD button!

Fireball over Hawaiʻi

So last night a Russian satellite burns up over Waikoloa… And I miss it!!

Some of my friends and co-workers did not, asking me what it was this morning after personally witnessing it. There are videos all over Facebook. I am so envious!

The satellite was Cosmos 1315, a Russian signals intelligence mission launched in 1981. It re-entered just west of the Big Island about 11pm HST last night.

I have embedded a video below, the language is more than a bit rough, a few f-bombs. The language goes to illustrate just how dramatic the event was. Aside from the unfortunate choice of vertical format, the video is surprisingly good.

Several items stand out in the video…  The giveaway that it is man made is the very slow speed of the object, not the high speed typical of most meteors.  You can also see the satellite coming apart, fragments breaking away.  Larger meteors can also do this, breaking up upon re-entry.

The guy (I believe Chris Jardine) identifies the object as a meteor, a good guess. I first thought meteor when I saw the video.  I received word a bit later from Steve Cullen who passed along a link to information on the satellite.  The gal thinks comet? We need to do more public outreach and education around the island!

Perseid Meteor Shower

Over the next few days the Perseid meteor shower will peak. As the most reliable shower each year this is also the most viewed meteor shower. Plentiful shooting stars combined with warm summer evenings makes this shower the easiest and most comfortable to view across much of the northern hemisphere. Quite a difference from the other reliable showers such as the Leonids and Quadrantids, that occur in November and January. Consider a warm summer night under a dark sky full of stars, a picnic blanket, relaxing while shooting stars streak across the sky. What could be better?

Leonids in Orion
A pair of Leonid meteors streak through Orion
The Perseid meteor shower occurs when the Earth passes through a stream of debris along the orbit of Comet Swift-Tuttle. This shower has been consistent throughout recorded history, mentioned in Chinese, Japanese and Korean records as early as the 1st century. Active from July 17th to August 24th, the shower will build slowly for weeks before the peak. A week before or after peak the shower can still be seen with around 20 meteors each hour. The shower is a northern hemisphere event, for southern observers the radiant never rises above the horizon.

Continue reading “Perseid Meteor Shower”