COMET C/2024 G3(ATLAS) FROM BANGALORE

The most anticipated comet of the year successfully survived its close approach to the Sun on January 13th and even became a daylight comet. It was visible with small optical aids during the daytime, and many amateur astronomers managed to observe and photograph it under daylight conditions. Now, the comet is visible in the western evening skies during twilight hours.

The comet is still bright enough to be seen with the naked eye. To spot it, find a location with a clear horizon, free of obstructions like buildings or trees. This might be a bit challenging in cities like Bangalore. Just after sunset, start scanning the twilight sky for the comet. At first glance, it may appear as a dim, elongated, fuzzy object. As the sky gets darker, the comet will become more prominent. Binoculars can be helpful in spotting it, but remember to wait until the Sun has completely set below the horizon. The chart provided below will aid in locating and tracking the comet in the coming days.

The comet is currently approximately the same distance from us as the Sun—150,000,000 km—and this distance will continue to increase, causing the comet to appear dimmer. For those in Bangalore and nearby areas, the comet is well-placed in the sky; you only need a clear horizon. However, as the comet fades in the coming days and its brightness drops below magnitude 2, light pollution will become a significant factor. Try to observe it from a location with minimal light pollution.

Towards the end of the month, binoculars will be essential for spotting the comet. While it will appear slightly higher in the sky at sunset, it will also be dimmer. A dark sky and optical aids like binoculars or telescopes will greatly enhance your viewing experience at this time.

Bright comets are rare, but when they do appear, they offer a wealth of beauty and valuable insights into the formation of the solar system. Don't miss the opportunity to spot this rare visitor in the evening sky and enjoy the magnificent view.

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Watch Lunar Eclipse at Planetarium, Bangalore

Jawaharlal Nehru Planetarium is organizing Lunar Eclipse viewing at planetarium campus, Bangalore. Interested public can visit planetarium and enjoy the eclipse and get questions answered about eclipse and astronomy.

The event is from 6:15pm to 8:45pm on January 31st. 2018. Association of Bangalore Amateur Astronomers (A.B.A.A) members will also be there to help public understand and enjoy the eclipse.

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Venus and Jupiter Conjunction on July 1st

In the western evening sky we have 2 bright objects, one closer to horizon is Planet Venus and next is Planet Jupiter. As we are observing from past couple of weeks, we have noticed something curious, Venus and Jupiter are getting closer to each other.

These two planets appear getting close to each other, this is as seen from earth, the fact is Venus, the brightest planet in the sky and Jupiter the largest planet in the solar system are 0.5AU and 6AU respectively from earth (1 Astronomical Unit =14,95,97,871 km).  

We will continue to track these planets in coming days and we will notice that the separation will get even smaller. The separation of these planets as seen from earth is measured in angles.

In the middle of June the separation between Venus and Jupiter will be 14 degrees and on 20th the separation will be reduced to 6 degrees.

Minimum separation between Venus and Jupiter will happen on July 1st with a separation of 24 minutes, close enough to fit both planets in field of view of telescope. Venus and Jupiter will set at 9:30pm on 1st July.

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Daytime Occultation of Moon and Saturn August 4th

Daytime occultation, second of this year will be of Moon Occulting Saturn. Earlier this year in February we saw Moon occulting Venus in the daytime, both Venus and Moon were easily visible because of their brightness.  

 

On August 4^th, we will see Moon occulting Saturn in the daytime, but we will need telescope to see Saturn as the surrounding sky will be very bright.

Stellarium generated image.

 

The occultation will begin 2pm IST as seen from Bangalore, its always a good practice to start observing as early as possible. Saturn will disappear from dark side of the moon and emerge from the sunlit side at 2:40pm.

Do not try to locate Saturn with the telescope if you are new to finding planets during daytime. As bright Sun will be very close, accidental viewing of Sun through the telescope will be disastrous to the eye.

Here are the times and positions of the Planet for those who have setting circles

August 4th Occultation.

Time	Right Ascension	Declination	Altitude	Azimuth
13:45	15:00:00	-14:44:27	14:36	109:18
14:00 Start	15:00:00	-14:44:27	18:00	110:27
14:40 End	15:00:00	-14:44:27	27:15	114:20
	Deg:Mins:Secs	Deg:Mins:Secs	Deg:Mins:Secs	Deg:Mins:Secs

Its a matter of luck to have clear skies in this monsoon season, but its always better to be prepared and hope for the best. 

Clear Skies 

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City Constellations

It happens every time, we attend an astronomy talk or see an astronomy documentary and after finishing that when we come out, we always involuntarily look up at the night sky. We expect to see star-studded sky as seen in that talk or documentary, diamonds in the sky. 

Credit: ESO

However, as it turns out due to high light pollution, this is what we end up getting in the city skies. Light pollution is increasingly taking stars away from us. There is no immediate solution for the light pollution issue although efforts are on around the world.

 

Until then we have make use of what few stars we have under city conditions. I always advice new comers interested in night sky, to go and get familiarize with the constellation whenever they get time. Although sky may look disappointing at beginning with hand full of stars in the night sky, we can in fact make that work in our favour.

It will be easy to start and recognise the basic pattern of the constellation when there are few stars. Once we have the basic shape with the help of bright stars, when we have dark skies, it will be easy to pick up rest of the constellation.

We will take couple of examples here of constellations, bright ones that can be seen easily under city conditions.  These days at 8pm we can see the bright constellation Ursa Major in the north, even with light pollution its easily spot seven stars in the constellation. Now this forms the outline of the Ursa Major, if we are familiar with the bright stars, under dark skies we can pick up full constellation, which will help in finding deep sky objects.

We can see only few stars in Ursa Major, but I am sure you can spot all the seven bright stars.

Stellarium

 

Once we are familiar with bright stars, we are ready for dark skies; here is how it will look under light pollution free conditions.

 

Along with bright stars, we have many stars that complete the constellation.

 

Like Ursa Major, there are similar constellations that we can spot even with light pollution, and spending some time getting to know the bright stars and the constellation outline will really help when we have dark sky conditions, sometimes it is difficult for newcomers to recognize the patterns with thousands of stars around.

 Cygnus also has bright stars that make the constellation easy to pick up in light polluted areas. Deneb is the brightest star in the constellation and the stars that make the outline are close to or brighter than third magnitude. The constellation lies in the mily way band and its good idea to use light pollution to our advantage and get familiar with the basic shape of the constellation, under dark skies it is a highly star-studded region. Seeing the constellation under darks skies shows what light pollution is doing to our night sky.

 

Under Dark Conditions:

 

One more wonderful constellation is Scorpius in the south. Along with Scorpius, the constellation of Sagittarius lie in the most star rich region of the night sky, as these two constellations lie in the region of centre of our galaxy, the milky way. These two are easily visible from the city skies, shows in a very frustrating way on how light pollution is affecting astronomy enthusiast. This is a region with numerous star clusters and nebulae and a favourite region for astrophotographers.

 

Under Dark conditions we can see the milky way...

 

These are just couple of examples to show how we can use light pollution to our advantage and to show how it is affecting our night sky.

With a basic star map, keep practicing in identifying the constellations with the help of bright stars, which will really help under dark skies.

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Occultation Demonstration setup at ABAA

At ABAA, we try to make concepts of astronomy simple so that everyone can visualise and understand. This setup I made at ABAA using materials that we can find easily and we can build this at very low cost and fast. The setup is to show occultation concept, consists of a motor, a light source that acts as a star and a dick attached to motor to show an object coming in front of the star, Occulting the star.

Moon Occulting Venus 

Occultation is an astronomical event when one astronomical object comes between observer and a distant object. For example, moon in its journey in the night sky comes in between background stars and us, this we call moon is occulting stars.

I made the video with external lights on and off, to show the setup working. With lights on, we can see the disk coming in front of the light source and Occulting the Star and with lights turned off we can simulate night sky and we can measure star light disappearing and re appearing. Using different sizes of disc, we can show that occultation helps in determining the size and shape of an object using the time of appearance and disappearance to the star.  

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Daytime Venus Occultation

Daytime skies are little boring to people with only one star to observe. Occasionally we get treats like solar eclipse and transits, amazing celestial daytime events that make the long wait worthwhile.  On 15^th February 2013, a meteor entered earth atmosphere and as it burnt up, it lit up the skies of Chelyabinsk, Russia. Apart from these rare events, the actions in the skies hide behind the glare of the sun during the day.

Lunar occultation of stars and planets are events normally associated with night sky. Moon occults stars and planets during daytime too but we cannot see these events because, the bright Sun outshines everything in the sky. However, every rule has an exception; we see Moon during daytime without any difficulty, and with practice, we can also spot Venus with naked eye and it is an easy target for telescope in the daytime.

This February 26^th there is an event involving Moon and Venus during daytime(Readers of AKASHA will already know this from JAN-FEB issue). Moon will occult Venus on this day. Occultation of planets by Moon is rare event, for example from Bangalore the next Occultation of Venus by Moon will be in 2023 March 24^th.

We have to take Extreme precaution when planning to observe the event, equipment  always has be pointed away from the Sun. Even very small duration exposure to Sun’s rays through telescope or binocular can damage the eyes permanently.

The brightness of both Moon and Venus makes it good challenge for daytime occultation observation with Moon at crescent phase and Venus close to half phase at -4.5 magnitude, will be a great sight through the eyepiece.

Venus will disappear from the lit part of the crescent Moon and reappear from the dark part of Moon. Venus will be close to 15 minutes of arc from the brighter edge of the moon at 10:30am IST, both should fit in to the same field of view in a 6-inch telescope.

 

Here are the times and altitude of Moon for February 26^th Occultation:

Venus will disappear at 11:05am IST and at this time the altitude of Moon will be 53 degrees.  Venus will reappear from the darker side of the Moon at 12:29pm IST. The altitude of Moon at the reappearance of Venus will be 38 degrees.

Hope for clear skies.

 

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Comet PANSTARRS(C/2011 L4) is Here

Comet PANSTARRS (C/2011 L4) has given a good show in southern hemisphere and it’s now time for northern hemisphere to enjoy the show. On 5^th March Comet will pass close to Earth at approx 1.1AU(1 AU = 149 597 871 km) and will reach perihelion(close to Sun in distance) on March 10^th at a distance of .3AU(1 AU = 149 597 871 km).  PANSTARRS(C/2011 L4) should be a good challenging object from 6^th of March from Bangalore and becomes easier to spot as days pass. The comet will stay low in the western horizon after sunset, the altitude of the comet PANSTARRS (C/2011 L4) will be 5degrees at 6:45pm on 5^th march and on 12^th of March the altitude will be 10degrees from the western horizon at 6:45pm. Due to the low altitude of the comet, it is better to plan the observation session in a place where there is no obstruction in the western horizon like trees or buildings. Here are few charts with the positions of the comet PANSTARRS (C/2011 L4) after sunset. The charts are from 5^th to 12^th of March with altitude of the comet at 6:45pm.

Chart of  5^th March Comet PANSTARRS(C/2011 L4)  altitude will be close to 5degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:10pm 

 

Chart of  6^th March Comet PANSTARRS (C/2011 L4) altitude will be close to 6.5degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:15pm.

 

Chart of  7^th March Comet PANSTARRS(C/2011 L4)  altitude will be close to 8degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:20pm

 

Chart of  8^th March Comet PANSTARRS(C/2011 L4)  altitude will be close to 8.5degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:23pm

 

Chart of  9^th March Comet PANSTARRS(C/2011 L4)  altitude will be close to 9.5degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:25pm

Chart of  10^th March Comet PANSTARRS(C/2011 L4)  altitude will close to be 10degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:28pm.

 

Chart of  11^th March Comet PANSTARRS(C/2011 L4)  altitude will be close to 10.5degress at 6:45pm.  Sunset: 6:32pm. Comet PANSTARRS(C/2011 L4) sets at 7:30pm

 

Chart of  12^th March Comet PANSTARRS(C/2011 L4)  altitude will be close to 10.6degress at 6:45pm.  Sunset: 6:32pm.Comet PANSTARRS(C/2011 L4) sets at 7:30pm

 

 

 

 

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Arrangements for viewing Transit of Venus in Bangalore

JAWAHARLAL NEHRU PLANETARIUM, Bangalore and ABAA have made arrangements for viewing Transit of Venus on 6th June. The telescopes and other viewing aids will be kept for public from 7am to 9:30am at JNP campus. All are welcome to witness the event, remember next venus transit will be in 2117AD.

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Last Venus Transit of the Century

We have waited 8 years for this event on June 6^th this year and if we miss it, its just another 105 years wait for this event to re occur. This event is Transit of Venus, and the last time we observed was on June 8^th 2004 and its going to take place again on June 6^th this year. In 2004 we could see both Ingress, that is Planet entering Sun's disc, and also Egress meaning Planet coming out of Sun's disc. Many had luck observing the full event but a lot of us had to deal with clouds, as monsoon was just starting.

Since March 26^th 2012 after the Greatest Elongation of Venus, we are observing the planet slowly shrinking in altitude in the evening sky and also observing the changing phases of Venus through the telescope, Venus changing from Half lit to Crescent phase and also we have been noticing that the  planet is  getting bigger in angular size and with this we can conclude that Venus is coming closer and in a few days time it will be between the Earth and the Sun.

When Venus comes between Earth and the Sun, the planet is said to be in Inferior Conjunction. On June 6^th Venus will be in Inferior Conjunction, this day also happens to be when Venus and Earth lie in the same orbital plane making Sun, Venus and Earth lie in an exact line. When this happens, we can see Venus moving across the Sun's disc, This is called Transit of Venus.

Why  Venus transit does not happen on all Inferior Conjunctions? This is because, Venus's orbital plane is inclined at an angle of 3.39 degrees and only when Venus and Earth line up exactly in this  plane, we can see a transit. The alignment of Earth orbit meeting the Venus orbit happens in the month of June and December, during this time when the planet aligns exactly in line we see a transit. Venus Transits reoccur at intervals of 8, 121.5, 8 and 105.5 years, last was in 2004 and now in 2012, we are going to see it again in 2117 and 2125 both in December.

For our region Venus Transit on 6^th June starts at 3:40am so we have to wait till sunrise to see the transit. It would be a wonderful sight to watch sunrise with Venus as a black circular dot in the north on Sun's disc.

Sun Rise at 5:52am

Transit starts	03:40:00 AM
Minimum separation	07:00:00 AM	Sun Altitude 14degrees 30minutes
Transit Ends	10:20:00 AM	Sun Altitude 60degrees 18minutes

Make sure you are in an area where you have clear horizon and its not blocked by buildings and trees. Never look at the sun directly, the best way to observe the sun is through the sun filters.

Ways of observing the event :

NEVER LOOK AT THE SUN DIRECTLY, ALWAYS USE PROPER FILTERS.

Viewing with the help of Binocular:

If you have a pair of binoculars you can fix the binocular on to a stand and project the image of the Sun on to a cardboard or wall and safely watch the Transit. Do not point the binoculars at the sun for long duration at a time. Again NEVER LOOK AT THE SUN DIRECTLY THROUGH THE BINOCULAR use binoculars only to project the image.

Observing with help of telescope:

If you have a telescope, you can use the telescope to project the image of the sun on to a wall or a screen. Before doing that it is advisable to make a mask with small opening that is smaller than the mirror size, like the one shown in the photo and attach it in front of the tube to reduce intensity of the sun and also this will help in increasing the contrast of the image.

This is called an off axis mask.

NEVER LOOK THROUGH THE TELESCOPE AT THE SUN, THIS WILL DAMAGE YOUR EYES PERMANENTLY.

After attaching the mask you can use the telescope to project the image and observe it safely. 

Every few minutes move the telescope away from the sun so that the heat of the sun does not damage the optical system.

Buy a proper solar filter to observe the sun, do not use sun glasses to see the sun.

Cassegrain telescopes should not be used to project sun, as the internal heat can damage the optical system. 

You can visit transitofvenus.org website for further information on observing advice.

Hope you all have a wonderful observing session this June 6th. Make sure you spread the word and educate people about the Transit.

All the best and Clear skies.

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ABAA Outreach

ABAA had been to Neev - Indiranagar to introduce kids to astronomy and show them Venus and Moon through the telescope. The talk soon converted into a interactive session with kids asking and sharing their understanding of astronomy. Its amazing how much kids know. After the talk kids enjoyed the view of Venus and Moon through the telescope. 

ABAA conducts outreach programs from time to time in schools and colleges to create awareness and help students understanding Astronomy and Telescopes better.

Here are few photos we want to share with you of the session.

ABAA member Bharath giving the talk.

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ABAA News:Talk on Stellar Parallax & Distance measurement to Stars

Last Sunday at ABAA there was an interesting talk and discussion on Stellar Parallax. I had asked Jayanth if he could send a small write up of the talk that he gave on the "Stellar Parallax & Distance measurement to Stars" so that it can be made available to all our blog readers. In his busy schedule Jayanth did manage to find some time to write a summery of the talk on Sunday. Here is the Article and Photos of the session.

What is Parallax?

To visualize this, See any object close to you say a few centimeters away, and look at it alternatively with your left eye closed and then with the right eye. You will notice that the position of the object seems to be different with reference to a far off background objects. You will notice that the object shifts from one position to other alternatively when you see the same once with your left and righ eye. The reason for this is not the object shifting but shifting the place you watch the object from. Your right eye and left eye.

The angles at which your eyes have to look obviously depend on the distance of the object and the distance between your two eyes. nose. The angle gets smaller with larger object to eye distance and smaller eye to eye distance. Therefore the difference in angles can be used to measure the distance to the object if you know the distance between your two eyes!. This difference in angles is called theparallax. The distance between your eyes is called the baseline; the bigger the baseline is, the bigger the parallax is, for the same distance of the observed object to the baseline.

The stars are very far away from us and their parallax is so small that the short baseline from one eye to another is too small to detect or even measure. In order to measure this small parallex of stars, we need a larger base line. A large base line is available which is the diameter of earths orbit = 2 Astronomical Units (AU) = 300 million KM.arth. Simply look where (at which angle) a star is in summer in the sky, and then look again where (at which angle) the same star is in winter in the sky, determine the difference in angles, and you have the parallax for this star. Now you can compute the distance to the star. The following picture should illustrate this:

Here in this calculations Parsec (parallax second) is the distance of a star that would have a parallax of two arc seconds, or, equivalently, the distance from our sun at which the angle between earth and sun (1 AU) would be one arc second. Using this unit t is useful because for large distances involved, distance is inversely proportional to the parallax. Hence a star with a parallax of x arcseconds is 2/x parsec away. This way we can calculate, one parsec is approximately 206,000 AU, or 3.09 × 10¹³kilometers, or 3.26 light years.

The closest star is 4.2 light years away which means parallax of the closest star  will be less than one parsec. In order to measure such small angles, instruments with great precision are needed. Parallax to a star 61 Cygni was measured by astronomer and mathematician Wilhelm Nessel in the year 1838 from Konigsberg observatory and the value was 0.314 arc seconds. The modern value is 0.292 arc Seconds (total angles) which computes the distance to this star close to 10 light years.

Due to the precision of measurements required by this method and the atmospheric distortions limiting the accuracies, 1989 the satellite Hipparcos was launched which has the capability of measuring parallax down to 1 milli arc second. This means Satellite Hipparcos was capable of using Parallax method to estimate distance to near by stars up to 1600 light years. Another satellite named GAIA  launched in 2010 is  able to measure even more distant stars, up to 32000 light years.

By using radio waves instead of visible light, one can measure even smaller parallaxes, even down on earth, without the need for satellites. Using Very Long Baseline Interferometry (Two radio telescopes with a large distance between them which is usually on different sides of the earth) improves the measurement of angles greatly. The precision is in the order of 100 micro arc second.

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