28 March 2010

A new comet!

Don Machholz of Colfax, CA, has spotted an 11th-magnitude comet low in the morning sky in the constellation Pegasus. Read the full story at:


24 March 2010

Occlutation of delta Geminorum

Image generated from Cartes du Ciel

Tonight, 24.03.2010, the Moon will occult delta Geminorum a 3.5 magnitude star. The Occultation is visible from most parts of India. kanyakumari will miss the occulataiton. The times and altitude of the Moon is given for Bangalore co ordinates.

Occultation Details:

Delta Geminorum disappears at 8:02pm IST.

The star will be occulted from dark side of the Moon.

Star will re appears at 9:07pm IST.

Altitude of the Moon will be 78 degrees from the western horizon and will be 65 degrees from the western horizon at the end of the occultation.

It is better to start observing few minutes early before the mentioned start time. It is easy to idenify the constellation, Moon is in the constellation Gemini today, locate the Moon and match to the star map attached.

Happy observing and please do share your observations.

18 March 2010

Equinox 2010

We observe the Sun rising in the east and setting in the west every day, something that never changes.

At noon if we keep observing the shadows that are cast by the Sun every day, we see that on March 20th and September 22nd, if we are at the equator, there will be no shadow cast at noon. The reason is very simple, the Sun should be exactly overhead at noon.

We can conclude that, after observing the length and the direction of the shadows during one year, the Sun will be exactly overhead at noon in the months of March and September around the dates 20th and 22nd respectively at the equator. In the month of June, the Sun will reach a maximum angle in north and in December, the Sun will reach its maximum angle in south.

The day when there are no shadows at noon, which as we observed, happens on March 20th and September 22nd, at the equator is called the Equinox. We can also say that, the point where path of the Sun called the ecliptic, cuts the equator circle.

On this day of March 20th the Sun will be on the equator. In following days the Sun will move towards north in the sky. The angle keeps increasing and on June 21 the Sun reaches the maximum angle of 23.5 degrees. This is called Summer Solstice.

But, in Bangalore, where the latitude is 13 degrees north of the equator, we can still see the shadows on March 20th and also on September 22nd. Therefore we have to wait till April 24th for the Sun to be at the Zenith at noon, we know what will happen to the shadows when the Sun is exactly overhead, they disappear!

The Sun again reaches Zenith for Bangalore latitude on August 19th , making shadows disappear.

From June 21st the Sun starts moving towards south and the angle keeps decreasing till it reaches 0 degrees, reaching back to Equator on September 22nd . This is called autumnal equinox.

Now the Sun starts its journey towards south, the angle again steadily increasing, only this time the direction has changed, towards south. The Sun reaches the maximum southern angle of 23.5 degrees on December 21st, this is called winter solstice.

After reaching maximum south, the Sun starts moving back towards the equator. The angle keeps decreasing again till it comes back to 0 degrees when the Sun reaches the equator. This happens on March 20th, and is called Vernal equinox.

Astronomers have special interest for the Vernal equinox. We know that on the day of Vernal equinox, the Sun will be on the equator. The Sun on this day travels on this imaginary circle extended from the earth's equator. This circle is called the declination circle.

This point, where the Sun cuts the equator circle, when the Sun's angle is zero degrees, is also called the first point of Aries. From this point the circle is divided into 24 hours, with hours increasing towards west, 1 hour is equal to 15 degrees, if we draw circles on every hour or minute perpendicular to declination circle, and making sure all the Right ascension circles pass over the north pole and south pole, we have a co ordinate system just as latitude and longitude. The entire sky can be mapped using this system. This system is called Equatorial coordinate system.

Due to Precession of the Equinoxes the first point of Aries keeps shifting at a rate of 50.3 seconds of arc per year. Astronomers have to take this into account when assigning 0 hours on the Right ascension circle. If not corrected, it becomes almost impossible for astronomers to find the faint objects in the sky.

First point of Aries is not in the Aries constellation anymore. The First point of Aries now lies in the constellation of Pisces, close 4.5 magnitude star lambda Piscium.

17 March 2010

Sunday Talk - 14th Mar 2010

ABAA had organized a talk on "Modification of Altazimuth mount to Equatorial mount and Polar Alignment" on Sunday the 14th Mar 2010. The talk was given by Mr. Jayanth Basavarajaih, President, ABAA.
The duration of the talk was about one hour. Around 50 participants were present.
Mr. Jayanth started the talk by introducing the two types of Telescope mounts Alt-Azimuth and Equatorial. He talked about the advantages and disadvantages of both types of telescope mounts.
Then he talked about Simple Barn Door Tracker which is a simple equatorial platform which can be used to take wide-angle photos of the night sky using an SLR camera. He then discussed various types of errors that could occur in a Simple Barndoor Tracker and went on to explain the modifications to be done in order to reduce those errors. He suggested the use of a corrective cam and explained the math required for making such a cam.
He then talked about different methods of polar alignment and elaborated on drift method of polar alignment.

Here are some photos of the talk.

Mr. Jayanth explaining the principle behind the barn door tracker

Jayanth demonstrating the working of the Equatorial Mount to the audience.

Enthusiastic crowd listening to Jayanth.

ABAA conducts Astronomy talks every month. Be sure to visit this blog regularly to know more about them.

12 March 2010


In the month of March, amateur astronomers across the globe participate in a marathon famously known as Messier Marathon. The goal is to observe all the objects from the Messier Catalog in a single night. The marathon started in the 70's is becoming more and more popular as the years pass by.

In March, apart from Sun reaching the equinox, it is also a good time to observe the full catalog as the Sun will be in a region where there no Messier objects. In months apart from March many Messier objects will be hidden behind the glare of the Sun.

Messier objects are bright enough to be covered by a good pair of binoculars these days. Telescope show the objects in their full glory. Telescope with a six inch objective is sufficient to show the objects in some detail, bigger the diameter of the objective more the light gathering power it has, and this results in showing grater details.

Keep a log book and write down the objects M number / name, optical aid used like telescopes, binoculars or naked eye. In case of telescopes and binoculars mention the magnification used. Take down the time of observation in UT.

Messier catalog is available on the net, get a copy and take a print out and also star maps of the region. If you are using Laptop, planetarium software like Stellarium or Cartes du Ciel will be really helpful.

The catalog consists of 110 celestial objects compiled by French astronomer Charles Messier (1730 – 1817), the catalog is named Messier catalog in his honor.

Moonless nights are the best to observe celestial objects and this month 15th is a New moon, so weekend observation on 13th will be a good choice.

Just after the Sunset in the fading twilight, the marathon begins. First objects to be covered are the ones that will set soon. M74 a galaxy in the Pisces constellation is the first object, the object lies just one degree north east of eta Piscium.

M77 can be covered next, this again is a galaxy in the constellation of Cetus. The galaxy lies close to delta Ceti, just a degree towards east.

Then M33, galaxy in Triangulum constellation. The galaxy also know as Pinwheel Galaxy, best seen under dark skies and with low magnification. Binoculars are best for this one.

Andromeda galaxy is next in the list, M31, as its numbered is accompanied by M32 and M110. Andromeda galaxy can be seen as a hazy patch with naked eyes, an easy object to find and observe.

M76, also known as Little Dumbbell Nebula or Cork Nebula, is the first nebula in the list so far. This Planetary nebula is in the constellation of Perseus. It can be found three degrees north of 51 Andromeda .

First star cluster in the marathon list so far is M34 in the constellation of Perseus. The cluster lies around 5 degrees north east from pi Persei.

Next target would be open clusters M52 and M103 in the constellation of Cassiopeia. M103 can be found 1 degree north east of delta Cassiopeiae. M52 is 6 degrees from beta Cassiopeiae towards the horizon.

Now comes the most celebrated open cluster, the Pleiades star cluster, M45. This is a wonderful cluster for the naked eye, binoculars and wide angle telescopes. This lies in the constellation of Taurus.

One naked eye galaxy, one naked eye cluster was covered in the list, now its time for a naked eye nebula. In the constellation of Orion lies M42, the colorful Orion nebula, one the favorite object of amateur observers and astrophotographers. North west of the Orion nebula is M43 separated by a dark lane from M42.

Staying in the constellation of Orion, two degrees north east of zeta Orionis lies M78 nebula.

In the constellation of Lepus, lies the first Globular cluster in the list so far. M79, lies at three degrees south straight in line with beat Lepus.

In 1054 AD, Chinese astronomers observed a bright new star in the constellation of Taurus and documented it. It is now known that it was a supernova explosion, cataclysmic death of a star. It is M1 in Messier's catalog and is commonly known as Crab nebula. It lies little more than a degree, north west of zeta Tauri.

In the constellation of Auriga, there Messier objects can be covered, M36, M37 and M38. All three are open clusters.

M35, a wonderful open cluster is in the constellation of Gemini. M35 can be found two degrees NW of eta Geminorum.

Four degrees south of the brightest star in the night sky, Sirius, in the constellation of Canis Major open cluster M41 can be found.

In the constellation of Puppis Messier objects M46, M47 and M93 can be found. Again all are open clusters.

M50 in Monosores is the next target. This open cluster can be found 4 degrees NE of theta Canis Majoris. An Easy target for binoculars.

M44 or Beehive cluster as its well known is visible to naked eye as a hazy patch in the constellation of Cancer. Open cluster M67 is also in the same constellation.

In Hydra again an open cluster M48 and also Globular cluster M68 and spiral galaxy M83 can be found.

Now the constellation of the Leo, there are 5 Messier objects, all of them Galaxies. M65, M66, M95, M96 and M105. When observing M65 and M66 in the same field, there one more galaxy seen in the same field, NGC 3628. These three galaxies together is called Leo Triplets.

Ursa Major contains M81, M82, M 101, M108 and M109. These are all galaxies. It also has M40 a double star. This constellation contains M97, a Planetary Nebula more commonly known as the Owl Nebula.

Continuing to cover galaxies in the list, Constellation Virgo offers large number of galaxies. It contains M49, M58, M59, M60, M61, M84, M86, M 87, M89, M90, M104. Good sky chart will help in identifying the galaxies.

North of constellation Virgo is the constellation of Coma Berenices. It contains the globular cluster M53, galaxies M64, M85, M88, M91, M98, M99 and M100

Canes Venatici a small constellation in the north, has some interesting objects to offer. Globular cluster M3, galaxies M106, M94, M63, M51 can be found in this constellation.

Constellation of Serpens and Ophiuchus consists of mostly Globular clusters. M5, M107, M12,M10, M14, M9, M19 and M62. The famous Eagle Nebula, M16, can be found in Serpens Cauda.

North of Ophiuchus is the constellation of Hercules. Globular clusters M13 and M92 can be found here.

Constellation Draco, the northern constellation, contains galaxy 102.

Towards east of Hercules, the constellation of Lyra can be found. In Lyra the famous Ring nebula, M57 and globular cluster M56 can be found.

Constellation Cygnus follows Lyra and the constellations Vulpecula and Sagitta are south of Cygnus. Cygnus had M29 and M39 open clusters. Vulpecula has nebula M27, also known as Dumbbell Nebula and in Sagitta globular cluster M 71 can be found.

Finally before the twilight starts, its time to end the list by observing star rich Scorpius and Sagittarius region. This region contains large number of clusters. M4, M80, M6, M7, M11, M26, M16, M17, M18, M24, M25, M23, M21, M20, M8, M28, M22, M69, M70, M54, M55, M75

Pegasus constellation contains the globular cluster M15.

Constellation Aquarius contains globular clusters M2 and M72 and also M73 an asterism with four stars.

M30, a globular cluster in Capricornus will end the Marathon. Make sure you have a clear Western and Eastern horizon. In the evening when the marathon starts the objects will be low in the horizon. And in the morning M30 will also be very low in the horizon, it has to be observed before the glare of the Sun hides the object.

07 March 2010

Telescope Making Workshop: Summer 2010

ABAA has been conducting Telescope Making Workshops for more than 20 years. 100's of individuals and schools from all over Karnataka have made their telescopes at ABAA. ABAA specializes in making Newtonian Reflector type telescopes.

One such workshop was started on Sunday the Feb 21st 2010.
In the workshop, the participants will grind and polish and assemble the telescope. They will be guided throughout the process by experienced telescope makers of ABAA. The workshop will be conducted only on Sunday evenings. The duration of the workshop will be around 10 weeks. The workshop is conducted freely by ABAA and the participants have to pay only for the cost of the materials needed for making the telescopes. Eleven such participants have started making their dream telescopes in this workshop.
The telescope making workshop informally started on 21st of Feb with a brief lecture on Newtonian Telescopes, different types of mounts and the art of mirror making.
The actual telescope making started on 28th Feb with Mr. Ravindra Aradhya showing the off-center stroke for rough grinding. Participants started grinding the primary mirrors which are the most important part of the telescope.

The grinding of the mirrors continued on Day 2 (7th March 2010).

Update on 14th Mar:
The participants started fine grinding with grit #220 which is a smaller grit than #120. They will continue to grind the mirror with smaller grits to make the surface of the mirror smooth.

Here are some photos of the workshop.

Mr. Jayanth, President of ABAA introducing the workshop participants to the world of telescope making.

The glass blank and tool ready for grinding.

Participants grinding the primary mirror.

Jayanth testing the curvature of the mirror. Testing is an important step in making a good mirror.

Participants wait anxiously for their turn.

Ravindra Aradhya thoroughly testing a troublesome mirror.

03 March 2010

Sky this month

This post is an attempt to cover some highlights of the night sky of March 2010.


Mercury and Venus: The two inner planets Mercury and Venus will remain very hard to observe the whole month of March 2010. By the end of this month they can be observed with difficulty in the evening sky. Planet Venus will continue to climb higher in the months to come.

Mars: Mars is shining bright at a magnitude of -0.6 in the constellation of Cancer. The red planet appears as one of the brightest stars high in the eastern sky after sunset. As the earth is moving away from Mars, Mars will fade in the days to come. It will be Mag +0.2 by the end of the month and will continue to fade in the months to come.

Jupiter: Jupiter was at conjunction on 28th of Feb which means, it will not be visible this whole month. Jupiter will be visible next month in the morning sky. Jupiter is currently located in the constellation Aquarius.

Saturn: Saturn is the most beautiful object as seen from a small telescope. Saturn with its rings is a treat to the eyes. Saturn is currently located in the constellation Virgo. Beginning this month it rises by about 8PM. Saturn will be at opposition on 21st of this month when it will shine at a magnitude of +0.5. By the end of this month, Saturn will be visible all night.

Uranus: Uranus is going to be pretty low in the western sky and will not be visible this month.

Neptune: Neptune continues to be in the constellation Capricorn and will be visible through a telescope before sunrise in the eastern sky.

Moon: The calender for the moon is as follows.
Last Quarter New Moon First Quarter Full Moon
2010/03/07 15:43 2010/03/15 21:02 2010/03/23 11:01 2010/03/30 02:26
If you are new to the fascinating hobby of watching the sky, moon could be used as a pointer to identify some prominent stars and planets.
Mar 3rd: Moon 3 degree away from Spica at 11:30 PM (Spica is the brightest star in Virgo)
Mar 7th: Moon near Antares in the morning sky (Antares is the brightest star in Scorpius)
Mar 25th: Moon 5 degree away from Mars
Mar 29th: Moon near Saturn

Astronomy Activities in Mar 2010:
Mar 13: Mar 13th is a good day for Messier Marathon. Charles Messier was a French astronomer and comet hunter who catalogued 110 deep sky objects. Messier Marathon is an attempt to catch all the Messier objects (catelogued as M1 to M110) in one night. Normally Messier Marathons are conducted in the month of March (when sun will be located in a favorable position away from most of the Messier objects) near new moon day.

Mar 20: Vernal Equinox - is the day when sun rays fall directly on the equator.

Comets and Asteroids:
Comet 81P/Wild2 -> Visible through small telescopes in the constellation Virgo.
Asteroid 4Vesta -> Visible through binoculars and small telescopes in the constellation of Leo near the sickle of Leo. Vesta is quite bright at a magnitude of +6.8 due to its big size and highly reflective surface.

01 March 2010

SOHO image of Jupiter Conjunction

Contd... from previous post on Jupiter Conjunction.

SOHO (Solar and Heliospheric Observatory) is a spacecraft that was sent to space by NASA and ESA to study the sun. It consists of a lot of instruments like Spectrometers, Coronagraphs and Imaging systems to study the sun.
SOHO continuously sends near- real time data of the sun. Most of this data can be found on their website.
One can visit this website to monitor solar activity such as sun spots, flares and prominences.
The image below is an image from a coronagraph LASCO C3. (Coronagraph is an instrument which blocks the bright light from the sun and observes its surroundings. Visit this link to know more about coronagraph. )
The image shows sun's corona and its surroundings. The streak seen at the bottom center of the image is the planet Jupiter.