05 December 2012

Spotting Planet Uranus with Binoculars

Uranus is a very easy target for binoculars and telescopes. Now in the constellation of Pisces, planet Uranus will be close to Zenith at the time of sunset giving lot of time to spot and observe the planet. Uranus is at 5.8 magnitude, close to naked eye limit of 6th magnitude and the planet can be seen with just a pair of 7X50 binoculars even in light polluted city.

Here is a wide angle view of the position of Uranus.

We can use stars in Pegasus or Cetus as guiding stars for getting Uranus in the field of view of 7X50 binoculars.

Here is binocular field guide from Iota Ceti in Cetus constellation to Planet Uranus.
Each circle represents field of view of 7X50 binoculars and here we can see how much we have to move and in what direction to get Uranus in the center of the field. In this map we are moving towards Pegasus from Iota Ceti.  

From Pegasus

Here the map is from Gamma Pegasi to Uranus, we take Gamma Pegasi in the center of the field of the binocular and move south in a straight line, after passing omega Piscium we should get Uranus in lower field of view of the binocular. 

Field of Uranus

This is the reference field of view to confirm the we have Uranus in the binoculars. Hope you will enjoy spotting and observing Uranus.  

09 October 2012

AstroNews: Large water reservoirs at the dawn of stellar birth

ESA’s Herschel space observatory has discovered enough water vapour to fill Earth’s oceans more than 2000 times over, in a gas and dust cloud that is on the verge of collapsing into a new Sun-like star.

Herschel’s infrared view of part of the Taurus Molecular Cloud, within which the bright, cold pre-stellar cloud L1544 can be seen at the lower left. It is surrounded by many other clouds of gas and dust of varying density. The Taurus Molecular Cloud is about 450 light-years from Earth and is the nearest large region of star formation. The image covers a field of view of approximately 1 x 2 arcminutes. 

Credits: ESA/Herschel/SPIRE

Stars form within cold, dark clouds of gas and dust – ‘pre-stellar cores’ – that contain all the ingredients to make solar systems like our own.
Water, essential to life on Earth, has previously been detected outside of our Solar System as gas and ice coated onto tiny dust grains near sites of active star formation, and in proto-planetary discs capable of forming alien planetary systems.
The new Herschel observations of a cold pre-stellar core in the constellation of Taurus known as Lynds 1544 are the first detection of water vapour in a molecular cloud on the verge of star formation.
More than 2000 Earth oceans-worth of water vapour were detected, liberated from icy dust grains by high-energy cosmic rays passing through the cloud.
“To produce that amount of vapour, there must be a lot of water ice in the cloud, more than three million frozen Earth oceans’ worth,” says Paola Caselli from the University of Leeds, UK, lead author of the paper reporting the results in Astrophysical Journal Letters.
“Before our observations, the understanding was that all the water was frozen onto dust grains because it was too cold to be in the gas phase and so we could not measure it.  

“Now we will need to review our understanding of the chemical processes in this dense region and, in particular, the importance of cosmic rays to maintain some amount of water vapour.”
The observations also revealed that the water molecules are flowing towards the heart of the cloud where a new star will probably form, indicating that gravitational collapse has just started.
“There is absolutely no sign of stars in this dark cloud today, but by looking at the water molecules, we can see evidence of motion inside the region that can be understood as collapse of the whole cloud towards the centre,” says Dr Caselli.

“There is enough material to form a star at least as massive as our Sun, which means it could also be forming a planetary system, possibly one like ours.”

Close-up of L1544 with the water spectrum seen by Herschel, taken from the centre of the pre-stellar core. The peak of the graph shows an excess in brightness, or emission, while the trough shows a deficit, or absorption. These characteristics are used to indicate the density and motions of the water molecules within the cloud. Emission arises from molecules that are approaching the centre where the new star will form, from the back of the cloud from Herschel’s viewpoint. The amount of emission indicates that these molecules are moving within the densest part of the core, which spans about 1000 Astronomical Units. The absorption signature is due to water molecules in front of the cloud flowing away from the observer towards the centre. These water molecules are in less dense regions much further away from the centre. Together, the emission and absorption signatures indicate that the cloud is undergoing gravitational contraction, that is, it is collapsing to form a new star. Herschel detected enough water vapour in L1544 to fill Earth’s oceans more than 2000 times over. 

Credits: ESA/Herschel/SPIRE/HIFI/Caselli et al.
Some of the water vapour detected in L1544 will go into forming the star, but the rest will be incorporated into the surrounding disc, providing a rich water reservoir to feed potential new planets.
“Thanks to Herschel, we can now follow the ‘water trail’ from a molecular cloud in the interstellar medium, through the star formation process, to a planet like Earth where water is a crucial ingredient for life,” says ESA’s Herschel project scientist, Göran Pilbrat

News Credit: ESA 

08 October 2012

ABAA NEWS: Discussion on Altazimuth CO-Ordinate System

Every Sunday evening we meet at ABAA and discuss topics related to astronomy. This Sunday, 7th October, members had a discussion on Altazimuth coordinate system and using telescopes on altazimuth mount. Here are few photos of the session.

Anybody who is interested in Astronomy and/or telescope making can join ABAA's sessions every Sunday after 5:30pm, All are welcome.

ABAA members discussing altazimuth coordinate system

ABAA member Sanath Kumar taking questions from other members 
ABAA members during altazimuth coordinate system discussion

ABAA member Anirudh Mirmira explaining concept of Altaz co ordinate system

ABAA member Leela Kalyanaraman summarizing the concepts 

ABAA member Ravindra Aradhya explaining concept of dobsonian telescope

Members during discussion

Jayanth Basavarajaiah, President of ABAA involved in explanations 

ABAA members demonstrating pointing of dobsonian telescope

ABAA members Anirudh Mirmira and Ravindra Aradhya in discussion session

ABAA members explaining Altitude in dobsonian telescope

28 September 2012

Sun's Angualr size as seen from different planetary distances

When we look at the sun, we always wonder how big it would appear looking at it from different planets. I have made this Image to show the relative size of Sun as seen from different planetary distances (scroll down after the table). The angular size of Sun with respect to distance is easy to calculate. Divide diameter of Sun by its distance form earth and then multiply the result by 57.3 to get the angular size of sun. Using this we can get angular size of Sun from different planets...

Angular size = diameter/distance * 57.3

Diameter of Sun = 1391000km
Distance from Earth = 150000000km

Angular size = 1391000/150000000

= 0.0092 * 57.3

Angular size of Sun as seen from earth = 0.531degrees.

We can calculate and compare the relative angular size of Sun seen from different planetary distances.

Sun Diameter = 1391000 kilometers
Distance from Sun 
(when planet is closest to sun)
Angular diameter(in degrees)
150000000 (mean distance)

Here is the a graphic of sun's appearance at different distances...

26 September 2012

ABAA News: Discussion on Kepler and Titius-Bode Law

On Sunday 23rd September, members were discussing about Kepler laws at ABAA, when calculating periods of planets, to remember the distance in AU, members spoke about Bode's law...Here is a small Jpg I made explaining Titius-Bode Law...until Uranus, numbers match beyond that the error increases...Now you will never forget the distances of Planets from the Sun :-)

Here is the Image and couple of photos of the session

Titius-Bode Law for remembering Planets distances in AU

Ravindra Aradhya explaining  Titius-Bode Law

ABAA Members at the session

10 September 2012

Venus visits M44

These days planet Venus is in the constellation of Cancer and rising early at 3am. From September 12th to 15th September Venus will pass very close to open cluster M44, popularly called Beehive cluster. Under good sky conditions, M44 is visible to naked eyes but best view is with a pair of binoculars. Take the binoculars out from 12th to 15th of September and point it to the brightest morning star, Venus, in wide angle binoculars like 10X50 M44 should be visible right-away left of Venus., in little smaller field of view binoculars like 15X70 you may have to take Venus to the right corner of the field to make both Venus and M44 visible in the same field. 

Twilight starts creeping in from 4:45am, the time before twilight should make it an amazing sight. 

Beehive cluster or M44 as its know is an open cluster has a magnitude of 3.7. The age of the cluster is approximately 700 million years old and its distance is 577 light years. Venus on the other hand is bright -4.2 magnitude and distance is approximately 140 million kilometers.

06 September 2012

ABAA NEWS: Demonstration of Planets motion in curved space.

First Sunday of September members had fun with demonstrating and discussing the motion of planets in a curved space created by massive objects like Sun. The discussions and experiments went on to different size and different density planets and also binary objects revolving around center of gravity.

These were just few updates on Sunday activities at ABAA, you can get involved by visiting ABAA on Sundays evening and take part in all the activities.

Here are few photos of the session, members called it...Come Roll the Planets...

Ravindra Aradhya

Ravindra Aradhya

ABAA NEWS: Discussions on Gravity

Last Sunday of August members had a discussion session on Gravity, The Force of Gravity was discussed in detail, motion of planets, escape velocity, gravity of Sun, tides and related topics. Every Sunday we have some discussions on Astronomy related topics, you can join us and get involved in ABAA activities.

Here are few photos of the session


ABAA NEWS: Discussions on Magnitude system.

Every Sunday evenings there are discussions on astronomy topics at ABAA, Here is a summary of discussion that took place in the middle of August. The discussion was on Magnitude system.

Apparent magnitude

Members had discussion on Magnitude system in astronomy. Starting with Apparent magnitude, the brightness of stars as seen from earth. Hipparchus, Greek astronomer grouped the brightest stars as first magnitude, little fainter stars became second magnitude, and the faintest star eye could see as sixth magnitude. The difference in brightness from one magnitude is 2.512 times, that makes 1st magnitude star is 100time brighter than 6th magnitude star.

Sirius (brightest star)
Venus (at brightest)
Full Moon
The Sun
Faintest naked eye stars

In magnitude system, negative is brighter and positive is fainter. As negative number increases the brightness increases, for example our sun has apparent magnitude of -26.8 making it brightest and Uranus has apparent magnitude of +5.7 which is fainter. 

Absolute Magnitude:

Apperant magnitude are brightness of stars as seen from earth irrespective of distances. The brightness of stars, the magnitude they appear when placed at a constant distance is called Absolute magnitude. The magnitude that stars will appear when placed at a distance of 32.6 light years which is 10 parsec( 1 parsec = 3.26ly).

Our Sun placed at this distance will have magnitude of 4.8 and Sirius, brightest star in the night sky with apparent magnitude of -1.46 will have absolute magnitude of 1.4. Members discussed in detail on these topics like calculating apparent magnitude of Sun.

The colour of sun, the topic was good in the sense that most of us think it should be yellow or red as seen from earth. But in the course of discussion it was concluded that Sun will appear white.

The topics like Luminosity, distance modulus etc were discussed in detail.

ABAA NEWS: Celestial co-ordinate system discussion

As monsoon is covering the skies, ABAA members are spending time in discussing astronomy topics and helping newcomers in understanding basic concepts in astronomy. I am updating couple of such activities at ABAA from past few weeks.

Celestial co-ordinate system discussion:

Members discussed on the celestial sphere and co ordinate systems in astronomy, getting better understanding on different types of co ordinate systems. In Equatorial Coordinate System how the declination circle is defined, the zero declination circle is projection of earth's equator. Members discussed on Right Ascension(RA) on how first point of Aries is defined and where the actual first point lies now due to earth's precession. Here are few photos of the session

Planets for the Month of September

Morning Planets:


Mercury will reach superior conjunction on September 10th and it will towards the end of the month that Mercury will be placed well for observing.


Jupiter is well placed for observations in the constellation of Taurus. The giant planet rises early at 11:45pm and has a magnitude of -2.4.  


Morning star Venus is well placed of observations through out the month. Venus rises at 3am in the constellation of Cancer shining at a magnitude of -4.2. The planet will just 2 degrees from M44 or beehive cluster as popularly known, on September 14th making it a fantastic view in binoculars. Seen through the telescope Venus will appear just more than half phase, moving towards gibbous phase as days go by.

Evening Planets:


Mars is in the evening twilight in the constellation of Libra. The red planet is at a magnitude of 1.2 and will set at 9:20pm.


Saturn is also placed low in the Western horizon, in the constellation of Virgo. The planet sets early at 8pm.


Uranus is well placed for observetion through out the month. Uranus rises early at 7pm giving full night for observations. This planet is visible through a pair of binoculars is at a magnitude of 5.7. Uranus will reach opposition on September 29th.


Neptune is also well placed for observations through out the month in the constellation of Aquarius. Neptune has a magnitude of 7.8.

Moon Phases:

Last quarter: 08-Sep-2012
New moon: 16-Sep-2012
First quarter: 22-Sep-2012
Full moon: 30-Sep-2012


On September 22nd Sun will reach autumnal equinox, when Sun's declination becomes zero and Right Aessionsion(RA) becomes 12 h. The Sun will reach this co ordinates at 9pm IST on September 22. Although this point is called First point of Libra, the Sun will be in Virgo constellation.

08 June 2012

Venus Transit Photos by Prakash Subbanna

Here are photos of Venus Transit taken by Prakash Subbanna Vice President ABAA. He took these photos with his Canon EOS 1D mark IV, Lens CANON 600MM L IS USM, Tripd MANFROTTO PRO,  ARCA SWISS Z1 BALL HEAD, Filter:  BADER.