Monday, May 5, 2014

Here "Cometh halley's" Dust!!!

Here "Cometh halley's" Dust!!!

On 5th of May, as the earth while obediently circling its parent star for billions of years (making kepler so proud of the heritage which he had inherited from his guru “Tycho Brahe!!!!) comes across a patch of its orbit where Comet Halley spewed dust during its so many earlier visits to Sun, something is going to happen for the watchers of the heavens!! Yes you guessed it right, a meteor shower associated with Comet Halley - Eta Aquarids is going to peek on 5th May.

The Eta Aquarid meteor shower is the first of two showers that occur each year as a result of Earth passing through Halley's Comet debris, with the second being the Orionids. The point from where the meteors appear to radiate is located within the constellation Aquarius. Sadly, this location is a bit of a drawback to shower observers as this area in sky only rises an hour or so before morning twilight begins whereas usually when one observes Meteor shower, the radiant is quite high in sky during early morning.

Every year, the earliest Eta Aquarids can be seen around April 21 and they persist until about May 12; however, the number of meteors you are likely to see will be low until around the time of the peak on May 5/6. At this time, observers are likely to see about 10 meteors every hour.

Moon will not be interfering with the shower as it would set by midnight.

Eta Aquarid meteors are known for their speed. These meteors are fast -- traveling at about 66 km/s (148,000 mph) into Earth's atmosphere. Fast meteors can leave glowing "trains" (incandescent bits of debris in the wake of the meteor) which last for several seconds to minutes. The Eta Aquarids are viewable in both the Northern and Southern hemispheres during the pre-dawn hours. The Southern Hemisphere is preferable for viewing the Eta Aquarids as The constellation of Aquarius is higher up in the sky in the Southern Hemisphere than it is in the Northern Hemisphere. The Northern Hemisphere has an hourly rate of only about 10 meteors. This is due to the location of the radiant at different latitudes.. In the Northern Hemisphere, Eta Aquarid meteors can be seen as "earthgrazers." Earthgrazers are long meteors that appear to skim the surface of the Earth at the horizon.

Rest of the info about What are meteor showers and how to observe these can be found in my earlier articles.

C B Devgun, President, SPACE Foundation

Thursday, November 14, 2013

Leonids Meteor Shower
The Leonids is a prolific meteor shower associated with the comet Tempel-Tuttle. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky. 
This is one of the better meteor showers to observe, producing an average of 40 meteors per hour at their peak. The shower itself has a cyclic peak year every 33 years where hundreds of meteors can be seen each hour. The last of these occurred in 2001. The shower usually peaks on November 17 & 18, but you may see some meteors from November 13 - 20. The peak of the shower lies just ahead. It’s expected from about the evening of November 16 to the morning of November 18. Unfortunately, the full moon comes November 17, right in the midst of the shower’s peak. In 2013, the moon will wash out all but the very brightest meteors from view. As with most meteor showers, the best time to watch the Leonids is usually between the hours of midnight and dawn. 
Meteors in annual showers are named for the point in our sky from which they appear to radiate. This shower is named for the constellation Leo the Lion, because these meteors radiate outward from the vicinity of stars representing the Lion’s mane. If you trace the paths of Leonid meteors backward on the sky’s dome, they do seem to stream from the constellation Leo. The point in the sky from which they appear to radiate is called the radiant point.

Wednesday, October 16, 2013

The annual Orionid meteor shower is expected to rain down its greatest number of meteors before dawn on October 21.  The Full moon comes on October 18, 2013. That means there will be a bright moon in the sky during the morning hours, at the Orionids’ peak this year. The large waning gibbous moon will drown all but the brightest meteors in its glare.

Best time to watch the Orionid shower is between the hours of midnight and dawn. The Orionids don’t really begin to streak the nighttime sky until late evening, when the magnificent constellation Orion ascends over the eastern horizon. After their radiant point rises, you see many more meteors, and as the radiant rises higher in the sky throughout the night, the meteors will increase in number. That’s why the wee hours between midnight and dawn are best.
The Orionids radiate from a point near the upraised Club of the constellation Orion the Hunter. The bright star near the radiant point is Betelgeuse.The Orionids radiate from a point near the upraised Club of the constellation Orion the Hunter. The bright star near the radiant point is Betelgeuse.

you don’t need to know this constellation to see the meteors. The meteors often don’t become visible until they are 30 degrees or so from their radiant point – and remember, they are streaking out from the radiant in all directions. So the meteors will appear in all parts of the sky.

Meteor showers are more subtle than rain showers, and the Orionid shower isn’t as rich a meteor shower as, for example, the Perseids in August or the Geminids in December. On years when the moon is out of the sky during the shower’s peak, you can expect to see about 15 to 20 meteors per hour at the peak. In 2013, the moon will decrease the number of meteors you see … but you still might see a few!

The Orionid meteors are debris left behind by Comet Halley. The object at left isn’t a meteor. It’s that most famous of all comets – Comet Halley – which last visited Earth in 1986. This comet leaves debris in its wake that strikes Earth’s atmosphere most fully around October 20-22, while Earth intersects the comet’s orbit, as it does every year at this time.
Particles shed by the comet slam into our upper atmosphere, where they vaporize at some 100 kilometers – 60 miles – above the Earth’s surface.

The Orionids are extremely fast meteors, plummeting into the Earth’s atmosphere at about 66 kilometers per second. Maybe half of the Orionid meteors leave persistent trains – ionized gas trails that last for a few seconds after the meteor itself has gone.

Bottom line: In 2013, the Orionid meteor shower is expected to rain down its greatest number of meteors on the morning of October 21. The day before might feature meteors, too. Unfortunately, in 2013, there will be a bright moon in the sky during the peak hours for watching meteors. But you still might see a few meteors streaking along in bright moonlight!

Tuesday, October 8, 2013

Draconids Meteor Shower 2013 
Peak tonight
Every year in early October earth passes through the debris trail left behind by Comet Giacobini-Zinner (a periodic comet in the Solar System). The comet orbits the sun with a period of 6.6 years. During each pass through the inner solar system, it sheds a trail of dust along its path, as earth passes through this debris, and lots of shooting.  For the last few nights, Draco the Dragon constellation has been spitting out shooting stars, also known as meteors. Draconid shower is predicted to produce the greatest number of meteors today at 17:30 UT, which translates to 23:00 IST. It occurs annually thanks to the ribbon of space dust left behind by Giacobini-Zinner, a comet that travels around the sun every 6½ years.

Watch for them first thing at nightfall. Once again, watch at nightfall and early evening because that’s when the radiant point for the Draconid shower is highest in the nighttime sky. Most meteor showers are best after midnight … but not this one.
Fortunately, the thin waxing crescent moon won’t interfere with this year’s Draconid meteor display.So for a full-sky view, lie down under a dark, open sky on a blanket or reclining chair and enjoy the Draconid meteor display.

Monday, August 5, 2013

Fire from the skies 
(in monsoon!!)

Perseids Meteor Shower
Seeing a shooting star in the sky makes one feel that a star has died, but is it really so. Death of a star results in one of the biggest celestial shows in the universe and definitely a shooting star is not that. The words “shooting star” itself is a misnomer. We all know that when a small particle of space dust enters earth atmosphere, it burns up while travelling towards Earth and result is a streak of light in the skies. It has nothing to with star death. Sometimes the particle is so big that part of it burns in the atmosphere and the rest falls on earth.

Meteor observers will finally be breaking out of their slowest time of the year when the Perseids meteor shower peaks on the night of August 11/12th 2013.

The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides (Περσείδες), a term found in Greek mythology referring to the sons of Perseus.

The stream of debris is called the Perseid cloud and stretches along the orbit of the comet Swift-Tuttle. The cloud consists of particles ejected by the comet as it travels on its 130-year orbit. Most of the dust in the cloud today is around a thousand years old. However, there is also a relatively young filament of dust in the stream that was pulled off the comet in 1865.The rate of meteors originating from this filament is much higher than for the older part of the stream.

The Perseid meteor shower has been observed for about 2000 years, with the earliest information on this meteor shower coming from the Far East.Some Catholics refer to the Perseids as the "tears of St. Lawrence", since 10 August is the date of that saint's martyrdom.
What is a meteor and a meteor shower?
Does it mean that when meteor shower occurs we expect fireballs from the skies falling on earth, or does it actually look like shower of meteors? Let’s find out the facts one by one. As mentioned earlier a meteor is “A meteor is the visible path of a meteoroid (a small sand size particle) that enters the Earth's atmosphere, commonly called a shooting star or falling star. These shooting stars can be seen on any night and they fall at random. But when the number of meteors is large, it is called a meteor shower or meteor storm. The shower always happen on a particular day or a time period as it is associated usually with comets. During meteor showers (which usually last a few days), the majority of the meteors appear to come from a particular point in the sky, called the radiant of the shower. The meteor shower is commonly named after the constellation in which this

radiant is found, and occurs annually during a well-defined time period. For example, the Perseid meteor shower occurs every year from about July 25th through August 18th, with a peak on August 12, and has its radiant in the constellation Perseus. In this shower, the typical maximum number of meteors that can be seen per hour at its peak is about 70, which is 10 times the rate of random meteors. Now how or why this shower occurs? As comets move about their orbits they leave a stream of debris because dust and rocky material is liberated from the head as the ices vaporize. If the earth crosses the cometary orbit, this debris leads to an increased number of meteors
The Perseids are the most famous of all meteor showers and never fail to provide an impressive display. Records of Perseid activity go back to 36 AD. In 1839, Eduard Heis was the first observer to take a meteor count and discovered the Perseids had a maximum rate of around 160 per hour. Other observers have since continued these studies to find the fall rate varies considerably. Astronomer Giovanni Schiaparelli was the first to relate the orbit of the Perseids to periodic comet Swift-Tuttle.
How does one see the meteors?
Meteors generally appear as streaks of light in the sky, appearing javelin-shaped. They will typically last only a fraction of a second and will be about as bright as most stars. Brighter meteors will occasionally appear, very roughly about one every ten meteors, which will usually be brighter than any star. They will usually last less than a second.
The brightest meteors are often termed fireballs, which will appear like brighter meteors, except will be brighter still. These often fragment as the pass through the atmosphere and glow a brilliant green. These brightest of meteors are often claimed to be UFO sightings
The show
The Perseid meteors will streak across the short summer nights – August 10-13 – from late night until dawn, with little to no interference from the waxing crescent moon. Plus the moon will be near the planet Saturn in the evening hours, giving a colorful prelude to late-night Perseid show. 

Best mornings to look: August 11, 12 and 13. 

It will peak on the night of 12th August 2013, Best time to observe is to watch late night/early morning when the Moon has already gone down the horizon. Showtime usually begins as soon as the radiant (near the Double Cluster in Perseus) clears the horizon, an hour or so before midnight, and it climbs higher in the sky throughout the night. This should be a great year for the Perseids, because a fat crescent Moon should be setting just when the shower is starting to increase.
Only problem would be the clouds as we have the Monsoon season here.

When Perseus rises in the northeast. This is the time to look for Perseid Earthgrazers--meteors that approach from the horizon and skim the atmosphere overhead like a stone skipping the surface of a pond. Earthgrazers are long, slow and colourful; they are among the most beautiful of meteors. An hour of watching may show only a few of these--"at most"--but seeing even one makes the long night worthwhile. The thin, crescent moon will be out of the way early, setting the stage for a potentially spectacular show. For best viewing, look to the northeast after midnight. Other things which will spoil the show will be monsoon clouds.
How to observe the meteor shower?
Don’t expect hundreds of meteors in the skies at one time. Perseids meteor shower usually have ZHR of around 100-120 meteors. Now what is this term ZHR? Official figures for meteor numbers are given as the ZHR or Zenithal Hourly Rate. This is the number of meteors you could expect to see given perfect conditions if the radiant (the point from where all the meteors seem to be coming) was directly overhead - i.e. at the zenith. Obviously, if the radiant is on the horizon, you can't see half the sky around the radiant, so you will only see half the number of meteors. Again, if half the sky is cloudy, you will only see half the number of meteors. Hence, for a ZHR of 110 (about what you can expect for the Perseids shower), you might only see two-thirds or half because the radiant isn't directly above your head. So expect to see around a meteor per 2 minutes !!
The first and last rule of meteor observing is look up. If you do not look up, you will not see any meteors, because by the time someone else has seen it, it will be gone before you look in that direction. Rules for meteor observing are generally the same as for all astronomy observations. The exception to that rule is that you should be looking up at all times. You can employ an easy chair for this purpose, but the best way is to get a sleeping bag and find a dry, comfortable spot to lie down on.
For observation make sure that you have the widest area of sky visible possible. Try to get away from light pollution. If you can see the Milky Way, it will be dark enough to see meteors. Typically, meteors will be about the same brightness as Venus or Jupiter down to the brightness of medium-brightness stars).

Depending on your location and disposition, insect repellent like odomos gel might be advisable as well. On the whole, just use common sense and try to enjoy yourself. Meteors can provide some of the more spectacular sights in the sky, so stop reading about it and get out there!

Tuesday, November 22, 2011

Fireballs in the Sky - 
Geminids Meteor Shower on Dec 14th, 2011

Star gazers can soon witness another sky theatre spectacle in the mesmerizing night skies - the Geminids Meteor Shower, peaking on 13th/14th Dec. This is one of the best meteor showers of the year and never disappoints observers. Unfortunately the peak of the shower this year falls 3 days after the Full Moon and that will hamper the observations. Geminids peak on 14th December 2011 at 16:35 UT or 10:05 IST

The source of the Geminids shower is asteroid 3200 Phaethon. There's a cloud of dust trailing the asteroid and the Earth plows through it every year in mid-December. Bits of dust traveling  at 80,000 mph hit our atmosphere and turn into glowing meteors.The Geminids got its name because its radiant position, from which it appears to originate, lies in the constellation Gemini.

Observe and Photograph the Geminids:
SPACE has the following handouts and suggestions to ensure that each one of you can go out and observe this wonderful spectacle (Though Moon will be a deterrent) .

SPACE suggests that students, amateur astronomers and the public go out on Dec 14th morning to a dark site away from lights and observe this nightsky spectacle. Details about timing and observing suggestions can be found listed below.

Meteor Showers provide a wonderful photographic opportunity. Another post in this blog  provides details on techniques and suggestions by SPACE to employ for meteor photography.

Record and Report:
We would like all observers to become Citizen Scientists and record their results and report it to IMO (International Meteor Organization). Details can be found in the attachment, as well as on the IMO website, listed below. Each citizen scientist who reports their observations will have the privilege to have their names and results listed on the IMO website.

SPACE has been observing Geminids for past few years and reported successfully to IMO. This can be found on the blog listed below.

Geminids Details:
Maxima - 14th December 2011 at 16:35 UT or 10:05 IST
ZHR (Zenith Hourly Rate) - around 120.
The best time to watch the activity near the peak in India is on 13th December night/early morning on 14th.

Relevant Websites:
SPACE astrophotography of Geminids:

IMO website reporting location:

Enjoy the last meteor shower of the Year.

Monday, November 21, 2011

Shoot the Geminids

Photographing meteors such as the Geminids is possible using a Single Lens Reflex (SLR) camera. The camera must have a "T" (time) or "B" (bulb) setting for taking time exposures. You will also need a cable release, a tripod or a very stable surface to place the camera on, for best results. The camera will need a lens that is between "fisheye" and 50mm. Lenses larger than 50mm may capture too small a field of view. This article is written for the film camera but can be used as it is for digital SLRs.

Here is what you will need to do.

Set up your photography equipment in an area that is shaded from any stray lights that may interfere. This is absolutely necessary!

Set the camera on a tripod or some other surface that is very stable. Make sure the focal ratio is set to the lowest possible setting. This means that the aperture of the camera is "wide open". Make sure the camera is set to "B" or "T" for time exposure. Set the focus to infinity.

Aim the camera at the area of the sky that you intend to photograph. Once positioned properly, make sure the tripod is locked down to prevent its "head" from moving under the weight of the camera. If you do not have a tripod, use things to prop the camera up in a way so that it is stable and so that you can still look thru the view finder.

Depress the cable release button and lock it in place. Allow the camera to take a picture for anywhere from 15 to 30 seconds, maybe more. Once the desired time has elapsed, release the cable release lock which will end the exposure. While taking the picture, do not move the camera at all.

The length of time that you should expose the film can be a tricky thing. Light pollution will shorten the amount of time that an exposure can be made before the file reaches it's "Sky Fog Limit" or is effectively overexposed. Experimenting with the length of time an exposure is well worth the effort!

The speed and grain size of the film is an important consideration. Generally speaking, ASA 400 film is "fast" enough for these purposes. Fine grained film such as ASA 100 will give you sharper images than ASA 400 but the pictures would be much darker. With low light levels, "fast" film is highly desired. ASA 800 will expose quicker than ASA 400 but will be grainier. Kodak Gold and Fuji Film's of ASA 400 or ASA 800 should suffice.

The "F" stop or "focal ratio" setting is very important. As mentioned above, you want the camera to be "wide open" or set to lowest focal ratio setting. The reason is that the film will be able to gather more light if the aperture is wider. Your pictures will capture more fainter meteors at a lower focal ratio than at a higher focal ratio. If your camera produces fuzzy results and it is indeed correctly focused, close the aperture down one stop.

Go out on a clear night and test your setup! On a clear night prior to the Geminid meteor shower, set your camera up and take a few pictures. This will help you determine what works best for your camera and how the film reacts to the night sky in your area. Try a few exposures of 15 seconds, 30 seconds, 1 minute, 2 minutes, 3 minutes and 4 minutes using the lowest focal ratio, and record the frame number and exposure time on a scratch pad. Repeat the process with the focal ratio backed off one stop. When you get the film developed, you'll be able to compare the results with your notes and determine what works best for your camera and sky conditions. What you will see are called "star trails". Every star in the photo will appear to be "trailed" for all photos over 20-30 seconds in duration. This is OK though as many meteor photographers do use this method. You would need an "equatorial" mount with a tracking motor to eliminate this effect. Knowing how your camera records light before the main event is essential!

Warn the film developer that your pictures may be very dim! When getting your photographs developed, it is a good idea to make sure they know your photographs are dim and to the untrained eye, may appear to be of nothing at all. If the developer uses normal processing, you should at least get some kind of results. The important thing is that they print them! It is a better idea to have them developed locally, where you can discuss what's on the film prior to processing it.

Some Geminids are exceedingly bright and may possibly overexpose or ruin a time exposure. If a very bright fireball crosses the camera's field of view, end the exposure shortly thereafter. Know where your camera is pointing! Sometimes, a bright meteor will leave a "train" or trail. These make very interesting photographs as the trails become twisted and contorted by winds high in the upper atmosphere.

Framing your picture with natural landscapes will help to make it more interesting and will provide the viewer with a better perspective of the event. Trees, cactus, rock formations and distant mountains are all good objects to try this on. A wide field photograph of meteors while looking across a very still lake or pond may make for astounding poster quality shots, especially if the water surface is very still and reflects the meteor well. If you have a lake or pond nearby, give this a try. It may actually be possible if the meteor counts are high and if they are bright. Although the moon will significantly interfere with meteor observing and photography this year, it may provide a bit of foreground illumination to the setting.

Enjoy the show and Good Luck!