Wandering through the realms of the cosmos, pondering its huge vastness

Posts tagged “january 2011 sky

Moon in the Predawn Sky this Week (Jan. 28 – Feb. 1)

Last Jan. 25, Saturn, Spica and the Moon formed a beautiful triangular celestial grouping. During the following days, early risers can watch the waning crescent Moon pass bright Venus, with Antares and Scorpius looking on. Check southeastern sky a few hours before sunrise.

Location of the Moon in the predawn sky for the next few days:

Jan. 29 — Moon is near the red star Antares in the constellation Scorpius
Jan. 30 — Venus and Crescent Moon are almost 5 degrees apart
Jan. 31 — Moon will be located just above the “Teapot” asterism in Sagittarius
Feb. 1 — Moon and Mercury will be less than 10 degrees from each other

This is a good opportunity to spot these celestial objects because of their proximity with one another and because of their perfect location within the prominent constellations. Clear skies! 🙂

 

Reference: Stellarium Planetarium Software

Advertisements

The 2011 Quadrantid Meteor Shower [UPDATED]

The year 2011 will begin with an eye-catching sky show for well-placed observers when the annual Quadrantid meteor shower hits its peak during the first week of January. The new year promises to be a great one to see the Quadrantids since the moon, which can sometimes outshine the display, will be completely out of the picture.

This shower has one of the highest predicted hourly rates of all meteor showers, comparable to the two great annual showers, the Perseids and the Geminids, occurring in August and December respectively. However unlike the Perseids and Geminids, the Quadrantids peak is very narrow, occurring over just a few short hours.  (You can read the IMO’s rather technical summary of the 2011 Quadrantids here.) Quadrantid meteors are of medium speed : slower than the Leonids and Perseids, yet faster than the Geminids. They usually appear bluish, accompanied by fine, long spreading silver trains.

This annual celestial event is active from January 1st through January 10th and peaks on January 4th. The peak is defined as the moment of maximum activity and the most meteors can be seen by observers.

The predicted Zenith Hourly Rate for this shower is around 120. According to British meteor astronomer Alastair McBeath, the narrow peak is predicted to occur some time between 2100 (UT) on 3 January and 0600 (UT) on 4 January 2011, however the radiant* of the shower – the now-defunct constellation Quadrans Muralis – is very low in the evening hours, rising higher towards dawn. Current sky maps place the radiant near the constellation Bootes.

This sky map shows where to look in the northeastern sky to spot the annual Quadrantid meteor shower, which peaks overnight on Jan. 3 and Jan. 4, 2011. It will appear between and below the Big Dipper and Little Dipper constellations. Credit: NASA/JPL

Most almanacs are highlighting 8 p.m. EST Jan. 3 (0100 GMT Jan. 4) as the “most likely” time, because that is about when Earth is expected to pass through the densest part of this meteor stream, based on observations dating back to 1992. But McBeath points out that other investigations have found that the Quadrantid rates can vary from year to year, so that its peak timing may not be consistent.

If the 0100 prediction is correct, then the best chances of seeing the peak of the 2011 Quadrantids would be for Europe east to central Asia, where the radiant will be rising in the northeast during the morning hours of Jan. 4.

Quadrantids Viewing  in the Philippines

Time Zone: UTC/GMT +8 hours

Best time to observe:

2:00am – 05:30am (PHT) on January 4 and  5, 2011

Shower rate: 60-120 per hour

The radiant will rise due N and get to its highest before dawn due E, so look roughly in a NE direction to maximize your chance of seeing some Quadrantids. As always with meteor showers, don’t use binoculars or a telescope – your naked eyes are best.

Where are you observing from? Limiting magnitude Number of Quadrantids per hour if peak occurs at 21:00 UT  Jan. 3 (5 AM PHT Jan. 4)
50 %  cloud cover (actual weather forecast by Wunderground.com) 0 % cloud cover (perfect clear sky condition)
Very light polluted city center 3 4 8
Suburban Site 4 8 17
Rural Site 5 17 49
Dark Sky Site 6.5 49 99
Note: These values were computed using the ZHR and formula by IMO.

Actual Hourly Rate = (ZHR x sin(h))/((1/(1-k)) x 2^(6.5-m)) where

h = the height of the radiant above the horizon

k = fraction of the sky covered in cloud

m = limiting magnitude

Using Stellarium (a free planetarium software available from here), I estimated the height of the radiant at 5:00 AM PHT for the Philippines to be at around 56 degrees above the northeastern horizon. I also assumed two values for k to illustrate the difference between seeing meteors during a 50% cloudy sky and a perfect clear sky condition. Special thanks to Steve Owens — a professional science communicator, writer and astronomer — for giving me a guide on how to compute for the number of meteors that could be seen during the peak of this shower. Some parts of this article were also taken from his very informative Quadrantids blogpost that could be found at the website http://darkskydiary.wordpress.com. UK observers may consult his post to find out what they might see during the Quadrantids Meteor Shower there.

Weather forecast for Manila, Philippines

(includes %  probability of precipitation and % cloud cover)

As a bonus, a partial solar eclipse on January 4 will also be visible at, or soon after sunrise. (Visibility: Europe, North Africa and central Asia )

No matter how many meteors are observed during the 2011 Quadrantids Meteor Shower, just remember to have fun and use this as a learning experience. 😀

Enjoy and clear skies to all!

=================

*Radiant – point from where the meteors appear to come from throughout its peak

Other References: