Saturday, August 24, 2013

Comet ISON’s Dates with Bright Notable Celestial Objects

The orbit of Comet ISON (C/2013 S1) is quite precisely known from observations. It is inclined to the plane of the ecliptic at an angle of 62°. Almost the entire orbit is on northern side of the ecliptic. The only time it travels towards the southern side of the ecliptic is inside the orbit of Earth, on November 9th, 2013, till its perihelion on November 28th, 2013.
The perihelion of sungrazer ISON is the quick turning point. The speed of the comet will increase near the sun, and at the perihelion it will travel at 680,000 kmph, around the Sun.
As seen from the Earth, before perihelion, the comet travels in the zodiacal constellations of Cancer, Leo, Virgo and Libra. The turning point of perihelion occurs in Scorpio. Thereafter the comet moves northwards through the constellations Serpens, Hercules, Corona Borealis, Draco, Ursa Minor and Ursa Major. Here are some of the dates ISON will be close to bright celestial objects. 

September 2nd, 2013, ISON will be 5° from Mars and 11° from crescent Moon. The trio will be seen near the naked eye star cluster – Beehive in Cancer.

September 23rd, 2013, Mars will be just 2° away from Comet ISON in Cancer Constellation.

In its orbit Comet ISON physically passes close by Mars, just 11 million kilometres from its North Pole. Observed from Earth, Comet ISON will remain close to Mars entire September and almost the entire month of October.
October 1st, 2013, ISON and Mars are joined by the crescent Moon forming a beautiful trio of different types of objects in the Solar System, a Comet, a Planet and the Moon.

During the months of September and October, it may possibly be difficult to locate the comet because it may not have brightened much. The presence of nearby bright star or bright Mars would be an important indicator or a sign post to locate the comet.

The best instrument to locate and view the comet is a pair of binoculars. A binocular mounted on a stand would be even better than a handheld one as the vibrations would be eliminated and the view would become steady. A binocular has a wide field of view as compared to a telescope, uses two eyes to peer at the sky, so it is a comfortable astronomical instrument for a layman as well as experienced sky observer. Binocular of any size would be an asset to watch the comet. Bigger sizes like 15x70 would be better, but would require a mount, on the other hand a smaller size like 7x50 could be used hand held.

October 15th, 2013, Comet ISON is close to Regulus, the brightest star of constellation Leo, just 2° away. Interestingly Mars lies in between the comet and Regulus. This would really be a close and interesting conjunction to watch.

Before perihelion, in the months of September and October comet ISON can be seen in the morning sky towards the east. The best time to observe it would be 1 hour before sunrise. At this time your observing instrument should be ready to scan the skies. The observing location should be preferably on terra firma i.e. solid ground rather than a vibrating terrace. The view towards the eastern horizon should be clear of buildings, trees or any other obstructions. Ideally you should be on a hill station where the horizon is clearer than plains.

October 30th, 2013, Comet ISON is joined by crescent Moon, 6° away. Mars, also 6° away, but in the direction of ISON’s tail. The daily motion of the comet is increasing day by day. It leaves the vicinity of Mars and starts moving towards the Sun at an increasing speed each day.

Comet ISON has become famous because:
a)    It is intrinsically bright and probably this is the reason it was discovered so early when it was still outside the orbit of Jupiter.
b)    Immediately after discovery, it was located on a few pre-discovery images too and its orbit was calculated. The orbit was found to be a sungrazing one.
c)     This is the first visit of the comet to the inner Solar System.
November 18th, 2013, Comet ISON, lies less than a degree away from Spica, the brightest star of Virgo constellation. The comet is just 10 days away from perihelion. Locating it in the dawn sky could be difficult, unless it has brightened considerably.
November 28th, 2013, is the comet ISON’s date with Sun, the perihelion. Astronomers as well as amateurs all over the world would be anxiously waiting on 29th November morning to see the sungrazer’s ultimate fate. Will it evaporate in a blaze of glory, or will it become a string of pearls travelling in the same orbit or something else?

The first half of December 2013 would really be an interesting one with news coming in from all around the world about the comet.

Comet ISON is being followed by many different spacecrafts at different location in the Solar System, viz. Hubble Space Telescope, Deep Impact, Spitzer Space Telescope, Curiosity – Mars Science Laboratory, International Space Station, Messenger – Mercury Orbiter, Solar Dynamics Observatory (SDO), Solar Terrestrial Relations Observatory (STEREO), Solar and Heliospheric Observatory (SOHO), Swift, Balloon Rapid Response for ISON (BRRISON), Chandra X-Ray Observatory.
December 22nd, 2013, Comet ISON travels close to the Great Hercules Cluster (globular cluster of stars).

December 29th, 2013, Comet ISON will become circumpolar for northern India, visible all night and never setting below the horizon. Over the next few days the comet will progressively become circumpolar for southern latitudes.
January 8th, 2014, Comet ISON is seen close to the Dhruv Tara or the Pole Star.

Friday, June 14, 2013

First Light at Dongla Observatory

Hello Fellow Astronuts,

     I am indeed fortunate to be instrumental in installing the 20inch Planewave CDK telescope and photographing its First Light. 

     The observatory built by Madhya Pradesh Council of Science & Technology is situated at Dongla , Ujjain District and is the first observatory in the state of Madhya Pradesh. From the concept stage to the installation of the telescope, the observatory has shaped up at quite a fast pace.

     In the all-sky image below you can see the observatory dome as well as the facilities building just across. The area is surrounded by fields all around. (On my January visit I tried the fresh, large and wonderfully tasty 'Dollar Chana', which is grown in this area).

     This modern robotic observatory is located at the confluence of two important great circles - the ancient Indian Time Meridian and tropic of Cancer.  Time in India was reckoned from the longitude of Ujjain, and Tropic of Cancer is where the Sun lies at its northernmost in summers.
     The coordinates of Dongla Observatory are:
     Latitude:  23° 26' 42.91" N
     Longitude:  75° 45' 43.31" E
     Height: 515m
     You can see the site in Google Maps at this link.

     The observatory dome is of 5 metres diameter and installed at a height of 10 metres above the ground level. Construction of the structure and the dome has been done by Pedvak of Hyderabad.

Ajay Talwar & Tarun Bangia at the observatory floor

     Here are a few good men responsible for bringing shape to the observatory, from left - Dr. Tarun Bangia (ARIES Nainital), Mr. Bhupesh Saxena (MP-CoST Bhopal) and Dr. Padmakar Parihar (IIA Bengaluru).

     Climbing inside the dome we see the Telescope and the German Equatorial Mounting. The telescope is a 0.5 metre or a 20-inch Planewave CDK Telescope. It is a corrected Dall-Kirkham Astrograph. The word astrograph means that it is specially designed for photography and produces a flat field of 52mm diameter, without any curvature, off axis coma or astigmatism. The f/6.8 telescope has a apparent focal length of 3454mm. This focal length is quite interesting, it will produce a field of view on any sensor which will be equal to the dimension of the sensor in milimetres. So if you attach a full frame camera of dimension 36mm X 24mm, the field of view captured would be 36' x 24'.

     The Mounting is a German Equatorial from Paramount. This mounting is capable of robotic control. You can program the entire night of photography, and even control it over the ethernet.

     The CCD camera procured along with the telescope is the Apogee Alta U9000, a large format, 38 x 38mm square sensor with 3056 x 3056 pixels (9 megapixels) which will result in a field of view of 38' x 38'. The field of view is ideal for imaging medium and small galaxies. All the instruments have been supplied by Audo Viso Pvt. Ltd. of New Delhi.

     Well, as I said in the beginning, I am indeed fortunate to have been involved in setting up the telescope, balancing, polar aligning and conducting its First Light on the night of 10th June 2013. (The inauguration of the telescope was done by the Chief Minister of Madhya Pradesh Mr. Shivraj Singh Chauhan on 11th June 2013). Here are four photos of the First Light captured by my Canon 5D-II camera attached at the prime focus of the 20-inch Planewave CDK telescope.

     There are many large telescopes present in India, as large as 1 metre, 2 metres, 2.2 metres and upcoming 3.6 metre and 4 metre in the Himalayas. The size of this telescope  may seem to be small in front of other telescopes but it is no less important. This size of telescope fills an important need in astronomy research. The time available at large telescopes is limited and at a premium. In fact many such 'small' telescope are required across the country to fulfill the need of astronomy researchers and even amateur astronomers. This kind of observatory is also very important for outreach to all public, children.

     The unique capability of this telescope is that it can be programmed to collect data for entire night without human intervention. This makes this robotic observatory suitable for automated sky surveys to detect near Earth objects,  asteroids, supernovae in galaxies. This observatory can also be utilised for the new and important field of exo-planet discovery and confirmation. These are some exotic astronomy research fields prevalent in the world today. The Dongla observatory is capable of conducting all these research fields. 

Ajay Talwar
15th June 2013

Sunday, September 23, 2012

Three Asterisms, King of Planets and a Dwarf Planet

There is not much difference between a Constellation and an Asterism. It is just that the constellation has made it to the official list of eighty eight, areas of sky as defined by the IAU.

There are plenty of asterisms that exist in the sky and lore, large such as the Big Dipper & small such as the Kemble's Cascade and the Coathangar. Asterisms may be seasonal like the Summer triangle, The Winter Hexagon, The Square of Pegasus in Autumn and the Diamond of Virgo in Spring. An asterism may span several constallations e.g. Summer Triangle or it may be one single  constellation e.g. the "W" or the Cassiopeia.

Here are three asterisms which I photographed this morning. The Pleiades, Hyades and the Kids of Auriga. The area of this part of the sky is rich in bright stars and star clusters. The area is presently also being populated by the King of Planets - Jupiter as well as the only Dwarf Planet  in the inner part of the Solar System - Ceres. (See the photo below for annotations).

The details of the astrophoto are as follows:
Camera: Canon 5D Mark II
Lens: Rockinon 35mm prime lens
Exposure: 90 seconds
No. of Exposures: 8 exposures (stacked)
Mount: Polarie mount (tracking the stars)
Date: 24 September 2012
Time: during the astronomical twilight
Location: Gurgaon

Ajay Talwar

Thursday, November 25, 2010

False Dawn

Many have been fooled into thinking that it marks the start of morning twilight. Indeed the Persian astronomer Omar Khayyam referred to this ghostly glow as the "false dawn" in his poem, The Rubaiyat.

When false dawn streaks the east with cold, gray line,

Pour in your cups the pure blood of the vine;

The truth, they say, tastes bitter in the mouth,

This is a token that the “Truth” is wine.

Unlike the stars of the Milky Way, which stretch away from Earth for light-years, the source of false dawn lies between the inner planets of our Solar System. Billions of dust grains orbit the sun in a flattened disk spread out along the ecliptic. Many of these particles were ejected by comets. The dust reflects and scatters sunlight creating a visible triangular glow above the horizon.

It can be seen for up to an hour before true dawn begins to break. Unlike true dawn, though, there’s no rosy colour to the false dawn. The reddish skies at dawn and dusk are caused by Earth’s atmosphere, false dawn originates far outside our atmosphere. You are looking edgewise view into our own solar system.

The sub zero cold, early hours would bring this humongous Zodiacal Light right on schedule each night at Indian Astronomical Observatory, Hanle, Ladakh brighter than the Milky Way and rising to great heights. It was a sight to fix your gaze upon, one could never get used to it.

Hope this image conveys just a little of how I felt the 6 nights I was at that
wondrous place on top of the world.

Ajay Talwar
November 26th, 2010

Thursday, November 18, 2010

Kemble's Cascade

The constellation of Camelopardalis, no not a camel, but a Giraffe, is a northerly one surrounded by Cassiopeia, Perseus, Auriga, Lynx, Ursa Major, Draco & Ursa Minor. Milky Way wanders into the territorial area of the Camelopardalis towards the side touching Cassiopeia & Perseus. Camelopardalis contains a colourful asterism called Kemble's Cascade containing more than 20 stars, spanning more than 2½° in the shape of a cascade. The cascade contains colourful 8th mag stars leading to open cluster NGC1502.

Kemble's Cascade can be seen easily in binoculars. Start from Algol, proceed to Mirfak, the brightest star of Perseus and continue the same distance to locate Kemble's Cascade. Another way to locate it is using Cassiopeia. Start from Caph, head towards Segin and follow the same distance and direction to Kamble's Cascade. Caph and Segin are the two end stars of the W of Cassiopeia.

I shot this asterism through a 200mm lens from IAO, Hanle, Ladakh. Hope you like the photograph.

Wednesday, June 2, 2010

DOT, and my visit to that dot on the map

DOT – Devsthal Optical Telescope

Kathgodam, Bhimtal, Khutani, Padampuri, Dhari, Dhanachuli Bend, Jhirapani, Devsthal. No internet mapping sites makes or measures the route for you. The pine filled road is not even visible in Google Earth. The route to Devsthal is approximately 40 kms through the hills on a road with very few vehicles and not many tourists. In about one hour from Kathgodam, which is at a height of less than 500 metres, on to Devsthal, you climb to a height of 2424 metres. Dhanachuli bend is the last four road crossing you encounter on the route upwards where you have a few shops, tea stalls and restaurants. The last village that you encounter, Jhirapani, seems like an abandoned one. The road to the observatory campus leads from in-between two houses; you would certainly miss the turn unless you’ve been told. I just wonder when the transport carrying parts of the biggest telescope arrives here, how it will turn towards the last road. A sky blue coloured board proclaims the site to belong to ARIES and that entry is restricted.

The road leading inside the campus has been metalled recently and the 3 km drive inside is smooth. The campus is full of Pine, Oak, Cedar and other exotic trees, all tall, old and majestic, rising till great heights, on the hilly slopes. The campus is 3 kms long but has very little flat or clear area. The observatory would have to be built only in places where nature allows. Continuing on the observatory campus road, you see that some essential buildings like the store room, power distribution room, have already been completed and a guest house is under construction.

Halfway on the road, there exists a beautiful meadow. A vacant grassy plot surrounded on three sides by the natural sky scrapers, trees! I settled my 8” telescope at this beautiful spot for the Venus Occulatation the next day, right beside the ancient 22” telescope shed. A little distance away, is a prefabricated, and assembled two room guest house, complete with all facilities including an internet & UPS enabled windows desktop, wow, all within 50m of my observing site. Ideal is the correct word, and all thanks to the hospitality provided by ARIES to me. Thanks Prof. Ram Sagar and thanks Dr. Wahab Uddin.

It’s almost a secret new site. It’s almost like no one knows about it. I am sure that is about to change in a few months from now, but for now the meadow was beautifully welcoming for the three nights I spent at Devsthal. Soon enough the meadow will be the busy place to store the arrival of all the parts of the 3.6 metre telescope, the largest in Asia. The large, thin mirror telescope will be setup at the end of the 3 km road on the peak. The telescope will be on a modern Alt-Azimuth mounting and a new style dome, a la observatory at Girawali, as opposed to a classical dome with a vertical window. The natural prevailing winds from the north west would be effectively used to cool down the telescope temperatures before it is time to open the observatory in the evenings. The actual telescope would also be at a good height from the ground level, on the peak. One, because the trees would not have to felled and second, the height of telescope would eliminate the local thermal effects of the grounds surrounding the observatory, both of the reasons more important than the other! The telescope is scheduled for installation completion at the end of year 2012.

Closer in time though, is another telescope, a 1.3 metre telescope, which should be ready by the beginning of the next year. I went and saw the enclosure, unconventional for such a large telescope, is a roll off roof, completely baring the telescope to the weather outside, which would make it perform better. The 1.3 metre telescope would be installed on an equatorial fork mount. At the time I was at Devsthal, the news was received that the telescope had arrived at Delhi and customs inspection was being carried out.

And little in the future, as Prof. Ram Sagar told me, Devsthal will have a 4 metre Liquid Mirror Telescope installed. As the telescope will be fixed, it will only be able to ‘Look Up’, at a narrow band of the sky, and will not be able to track any sky objects. The only small amount of tracking that would be possible, when the object would fall within the field of view of the large CCD installed at its focus, as the object would traverse the CCD pixels, software would negate the moment.

As you can imagine I was excited being at such a beautiful astronomical spot with clear blue skies, and equally excited at the prospects of this site, DOT, to becoming a great centre of optical astronomy in India. A future that I can almost imagine effortlessly. Here is one photo that I shot here during my 3 night stay at the DOT, which almost describes the meadow where I was.

Will the meadow stay though?

Ajay Talwar