Astrophotography Page 3

Neutron Stars, page 6

Remembering Jean Texereau..Page 9

G is forpage 9

Planets for May- June-July 2014..Page 12

The Newsletter of ABAA Issue 19 | May-June 2014

Dance of Crescent...Occultation of Moon and Venus. Picture taken by Ravi using an 8 inch f/10 telescope.

The moon and Venus were both in crescent phase and the occultation occurred during day time on 26

th February 2014.

Akasha Association of Bangalore Amateur Astronomers

2

Editor Sanjay A Pai Editorial Board Jayanth Basavarajaiah Kiran Subash Prakash Subbanna Ravindra Aradhya Acknowledgements to

Dr Shylaja, as usual ;

And to Bhanu and Srikanth for

helping out with the layout

of this issue

Contact Akasha JN Planetarium T Chowdaiah Road, Bangalore, 560001 We meet at the JN Planetarium every Sunday at 5:30 PM Email: abaa_org@gmail.com Facebook: ABAA Bangalore Page Read our Blog: http://abaaonline.blogspot.in

Akasha is the newsletter of ABAA, Association of Bangalore Amateur Astronomers. We look forward to submissions, ideas, articles and photos from the universe of astronomy. All submissions including comments, criticism and feedback to: sanjayapai@gmail.com Reproduction of any material from Akasha is freely permitted. However, please mention the source [ Akasha/

ABAA ] when you do so.

Dear members

Here we are, after some delay - due to circumstances beyond our control. What were these circumstances ? Youd need to visit ABAA to find out ! Please expect the next issue to be slightly delayed intentionally - so that you have time to read and digest this issue.

However, we make attempts to make the newsletter a useful one by gving you information on the night sky for July 2014 as well, so you can hopefully put it to use. Of course, youd probably need to go out of Bangalore for this !

Besides a very useful article on astrophotography by Sathya, we also have Prakash telling us about a very early and great influence on his astronomical career as he pays homage to the late great Jean Texereau.

Sheldon educates us about neutron stars while Mars attacks !

What changes do you see in this issue ?

Clear skies !

Sanjay A Pai

3

My Experiments in Astrophotography

(A continuation of Equipment for Astrophotography)

M. Sathyakumar Sharma

Summarizing my earlier article, readers may recollect that its primary subject was the considerations one needs to make before investing in equipment for astrophotography. I explained the types of telescopes, mounts and as a secondary subject I explained a technique to obtain your first photos of the night sky. In the following article I shall explain further as to how you may delve deeper into the subject. This is not a recipe or how to article, but rather a collection of my techniques, experiences as well as a thought process.

At the beginning of the ongoing observing season (winter 2013 to spring 2014) two friends Sanath kumar, Aditya Ravi and I decided to use the temple premises at Ramakrishna Mission school, Shivanahalli for our visual observing and astrophotography sessions. Shivanahalli is located 15km from the entrance of the Bannerghatta National Park (BNP) and is relatively free from light pollution. It is also at a higher level compared to the city.

My list of equipment includes a Sky-Watcher 8 inch aperture Newtonian reflector telescope, an Orion 80mm ED Apochromatic refractor telescope, couple of 9x50 finderscopes, an Opticstar PL-131M monochrome camera I use for guiding the HEQ5-PRO equatorial

computerized mount.

All my adventures begin at home. I make it a practise to setup my equipment and test out a new technique repeatedly at home from where I image the galaxies or nebulae. This way even if I make a mistake I do not have to worry as I am at home and not in the middle of BNP where resources are limited. My first problem arose when I realised that my equatorial mount was faltering when I loaded it with my 8 inch scope, 80mm scope camera and counterweights. The mount simply could not bear the weight. What was the solution? The 80mm refractor weighed

a good 5 kilos and eliminating this scope was good enough for the mount. I used to use the 80ED for guiding, though it could be used as an imaging scope. So what was the solution? Actually two solutions arise.

a) I needed to purchase an

adapter ring to convert my

9x50 finder to a guide scope.

The adapter cost GBP 28.00

(Rs 2800) which was very

expensive for me, especially

given the fact that it was a

small metal ring and nothing

else. I then set about

designing my own, smaller and

lighter version of the same

ring and succeeded in even

manufacturing a few. It

worked brilliantly and I could

now guide my 8 inch scope

with a small, compact

guidescope.

b) Shivanahalli has open space

and lots of it. A lot of wind

blows across this space and

the bulk of the 8 inch scope

4

makes it an excellent wind sail,

and a not so excellent imaging

scope. With all the force

exerted on the scope by the

wind, imaging is near

impossible. The second

solution therefore was to use

the 80mm ED scope as the

imaging instrument. Instantly I

had a compact portable

imaging setup that I could

easily carry in the back seat of

my car without compromise in

the imaging ability. I have

since used this setup

extensively over this season.

Sky-Watcher 8 inch Reflector (big scope), Orion 80ED (piggy back)

9x50 finder in the front, all mounted on the Sky-Watcher HEQ5-PRO

computerized equatorial mount.

Obtaining beautiful images of deep sky objects like galaxies which are several tens of millions light years away is by no means an easy task. One may assume that all we have to do is attach the camera to the scope, the mount points and tracks, the laptop controls everything and we can take a nap while all this is on. Things are not as easy as they look. For starters, light from these galaxies is very faint and a very long exposure is required to capture the maximum about of photons from

them. For obtaining long exposures like 5 to 10 minutes and several of them at that totalling to an average of 3 hours, the astrophotographer needs to work on a super accurate polar alignment. We call it polar alignment, but we actually align the axis of the equatorial mount to the North Celestial Pole. The process of alignment is called drift alignment and even though it is done traditionally by the eye using an illuminated reticule eyepiece, we are now able to do it extremely accurately using software. Even then the process takes a good half an hour to complete and the photographer can expect to achieve guided exposures of 5 minutes each.

Therefore, for a 3 hour total exposure time, 36 such 5 minute exposures will be required. In the previous page is the image of the Leo Triplet galaxies M65, M66 and NGC 3628 taken using the 8 inch reflector on the HEQ5-PRO mount. Captured using the Canon 550D camera and the mount guided using PHD guiding software and drift aligned using the same software. About 2.5 hours of data taken for the image. The galaxies are on an average 35 Million light years away

from us.

5

An astrophotographer has several equipments that run on electricity and in the open field that is usually unavailable. The mount consumes 1.8 amps of current per hour and runs on 12VDC. The laptop runs for 3 hour only on a full battery

and so does the digital camera. Assuming that a certain galaxy requires 4 hours of exposure, what can one do to extend the lifetime of laptop and camera battery? For saving the laptop battery, change the power settings such that it switches off the monitor in 1 minute, but never puts the laptop to sleep. This way the CPU will run all the required functions and the battery does extend by about 1 hour. Similarly, the LCD screen of the DSLR camera can be turned off once again extending battery life by about an hour. Finally it is ideal to run the mount for about 8 or 10 hours which includes the setup and alignment times. Therefore a maintenance free lead acid battery of 40 to 70Ah will suffice. It will not weigh too much and still provide ample power to all the necessary equipment. One can also power the equipment from a wall socket, but electricity is not really reliable in rural India and if it fails in the middle of an exposure run, it will only cause undue frustration.

The beginner who wants to get into serious astrophotography needs to utilize every opportunity available. An hour is enough to practise drift alignment. However one must also take serious note that astrophotography is generally an expensive hobby and typically good equipment can easily run into 6 figures. Investing in anything less than Rs 75000 is but a waste of money. Since equipment generally last very long, in the long term it is a

worthwhile investment. Astrophotography requires not just hardware, but also software. Processing the data captured takes a while and depending on the budget of the photographer good softwares are available for free and some excellent ones for a premium price. The basic operation still remains the same. The individual exposures are first graded according to quality, reference stars are selected and the frames are stacked (superimposed) on each other to integrate the data. This integrated image is then post processed in an image processing software like photoshop to discard unwanted data like light pollution and to bring out hidden data like details in the galaxies arms or faint nebulae etc. I will write a full article on the nuances of image capture, pre processing and post processing at a later date. This article is a mere summary of all the topics that can be covered.

The image above is of the Needle Galaxy. Its shape dictates its name, though it has an assigned NGC number 4565. It was captured using the Orion 80ED telescope, Canon 550D DSLR controlled with Nebulosity V3 software, HEQ5-PRO mount controlled with EQMOD/ASCOM interface and guiding through the ASCOM

6

interface using PHD guiding software. Each frame captured was 180 seconds long and total integration time was two hours. Dark frames were captured at the same temperature; flats were taken indoors using a laptop screen as the diffused light source. Nebulosity V2 was used for the dark subtraction, flats were divided, intensities normalized and all frames stacked. Tracking was so good that none of the frames were discarded.

In the above paragraph I have tried to explain the process in as few lines as possible, though the entire capture and processing took in reality about 5 hours to complete.

In the next article I shall explain how to accurately drift align the equatorial mount for astrophotography using the Drift Alignment by Robert Vice Method and fine tune the alignment using PHD guiding software by Stark Labs.

Neutron stars

The substance of a talk delivered by Anirudha Mirmira on January 12, 2014. The world of neutron stars is a hair-raising and amazing one! These tiny star remnants are mindbogglingly dense due to the entire mass of the parent star being compressed into a few kilometer sized objects. There's also a popular fact that one spoonful of neutron star material weighs the same as 1000 elephants! They are called neutron stars because they're precisely that, small stars made up entirely of neutrons.These stars are what remains after a explosive death

of a star about 10 times as massive as the sun. These Supernovae are so powerful that neutrons are formed due to the atoms in the remnant collapsing and the outer electrons colliding with the inner protons.The neutron star is a stable system only because of the neutron degeneracy pressure holding up the crushing force of gravity. Though they're mainly neutrons they still have a layered structure with ions, electrons in the outer crust, neutrons in the inner crust, a neutron-proton Fermi liquid as the outer core and possible exotic matter (read Quark Gluon Plasma). The neutron star itself is not completely stable and has star-quakes, which are called 'glitches', occurring due to the presence of a solid exterior and a liquid interior. Now these bodies rotate at very high speeds and also very precise time periods, the rotation giving rise to a strong magnetic field which gives many properties to the neutron star including its ability to give out radio waves at precise wavelengths at precise time intervals. Many of these neutron stars are found to have a binary or a multiple star system. Because of their gravitational density, they can accrete matter from other stars or interstellar gas clouds. This accretion disc starts rotating and coils coils ever more tightly around the neutron star giving out radiation(generally X-ray) due to the friction between the layers of the disc. There are also some neutron stars which have a black hole for a companion and hence there is almost no accretion in such cases. Sometimes when two neutron stars get too close to comfort, they may hurl themselves into each other producing a massive explosion and also possibly forming a black hole in

7 the process. These are widely thought to be one of the factors responsible for the occurences of Gamma-Ray burst. Some neutron stars may have their radiation jets pointed in our direction and we call such neutron stars which we can 'see' as pulsars. These pulsars are the cosmic timekeepers which have a wide range of precise time periods ranging from milliseconds to thousands of seconds. Though they are almost always very precise with their time periods, a star undergoing the glitches can have its time period altered by a small extent. Also they slow by about one part in 10000 billion (10^-13) for every second they rotate. The observation of these pulsars is generally first in the radio followed by tracking them in the X-ray wavelengths. Chandra X-ray observatory has discovered very many of these exciting objects.The most famous of these pulsars are the one in Crab Nebula and also the one in Hand of God Nebula (PSR-B150958). The world of neutron stars is really too very magnificent to do justice to in these many linesand probably will only be surpassed by more exotic stars like Magnetars, Quark Stars or Preon Stars.

-Anirudha Mirmira

============================

UPCOMING EVENTS :

To Jodrell Bank and back talk by Sanjay A Pai on 29th June 2014

A non-linear history of the telescope, part 1

Gaurav SH , based on a talk by Sanjay A Pai

ABAAs topic for 27th April 2014 was on the history of telescopes; it was delivered by Sanjay Pai. It was the last Sunday of the month of April and topic being the History of Telescopes attracted many members. The talk was delivered with the aid of some beautiful slides in the presentation including sketches made by the great Astronomer Galileo, his hand writing and few good pictures of his telescope.

The talk started from the times of the Thomas Digges (1520-1559), English astronomer and populariser of science, who was the first to expound the Copernican system in English and who discarded the notion of a fixed shell of immoveable stars to postulate infinitely many stars at varying distances. In 1551, he invented theodolite, in 1553, wrote A prognostication and in 1554 - a bad political move ended his career ! Then, his son Thomas Digges (1546-1595) continued in his fathers path.

But in 1608 there was a sudden impact on the field of astronomy in Middelburg, Holland. Hans Lippershey, a Flemish spectacle maker had an apprentice who while playing around with lenses made a startling discovery lenses kept at a certain distance from each other magnified objects ! Lippershey created what he called a looker with a metal tube. In the month of October in 1608, he applied for a patent - but it was refused!! But the

8

news of the gadget spread across Europe.

We learnt about Thomas Harriot (1560-1621) - was he the first to turn the telescope towards the sky? At any rate, he mapped the Moon... and possibly introduced tobacco in England! Then of course, we came across the much familiar name - the great astronomer Galileo from Pisa, almost a Priest, then almost a Doctor and finally a Mathematician. Galileo was professor of Mathematics in university of Padua. Galileo worked out the mechanics and made a 8-power telescope, a 20 power telescope and finally a 33-power telescope with which he discovered moons of planet Jupiter, spots on Sun and phases of Venus. (Warning at this point to all readers never look at the sun directly through a telescope !). Galileo, unlike is popularly believed, did not lose his eyesight by looking at the sun : there is clear evidence that he projected images of the sun onto a screen, like we still do today.

Later Galileo used a concave lens for eyepiece and a convex lens for objective in a lead tube of 4.2 cm diameter to get a 3X magnification! It was used for military purposes, then a 1.2 meter long tube with 4.4 cm diameter to get a 33X magnification.

In 1610 from January 7th to 13th, Galileo observed Jupiters moons with his 33X telescope. Galileo drew sketches of Moons hills and valleys by observing the shadows from his telescope.

He even observed the phases of planet Venus and observed spots on Sun. The spots on the Sun were even discovered by Christoph Scheiner while the phases of Venus were seen

The movements of Jovian moons during Jan 7th to 13th 1610

9

by Galileo, as predicted by Benedetto Catelli. Galileo also saw what he thought were Handles of Saturn in July 1610.

Simon Marius (1570-1624) , a German astronomer claimed to have observed Jupiters moons prior to Galileo but the Jovian moons were eventually named by him as Io, Europa, Ganymede and Callisto..

In 1612 Ioannes Dimisiani suggested the world telescope, which in Greek means to see at a distance.

The Galilean telescope.

In the same year Saturns ring disappeared and confused Galileo ! Later, of course, they reappeared in the coming years.

After the talk was concluded, ABAAs 6 telescope was kept

outside along with Bharaths 12 telescope to show the planets Jupiter, Mars and Saturn!

G is for..G is for

G is for Ganymede, G is for Galileo, G is for gravity, but for Rohan, G is for Golden record.

The Golden Records are among the most unusual and spectacular ideas of mankind. They are best seen as a time capsule or a symbolic statement rather than a serious attempt to communicate with an extraterrestrial. It was the brainchild of the legendary astrophysicist Dr. Carl Sagan. Golden records are the phonographic records which are included aboard Voyager spacecrafts which were launched in 1977.

I'd like to stress on the contents of Golden records. Carl Sagan noted,"The launching of this 'bottle' into the cosmic 'ocean' says something very hopeful about life on this planet". The contents of the record were selected for NASA by a committee chaired by Dr. Sagan. He and his associates assembled 116 images and a variety of natural sounds, such as those made by surf, wind, thunder, rain, animals, etc. The collection of images include photographs and representation of Solar system, DNA, human anatomy and reproduction. In addition to these, pictures of various animals, insects, birds, plants and

10

landscapes were included. Images of humanity depict a broad range of cultures showing food, architecture and portraits of around the world. The musical selection features artists such as Mozart, Beethoven, Bach, Chuck Berry, Kesarbai Kerkar and Igor Stravinsky. Interestingly, the record also contains "Diagram of vertebrate evolution" by Jon Lomberg -drawings of anatomically correct naked male and female, showing external organs. In additional to all these, the plaques also contained 'welcome note' addressed in 55 different languages from around the globe including Hindi, Bengali and Telugu.

=============================

God of War

The session on 13th April was on Mars and was led by Ravi. Son of Jupiter and Juno, Mars is considered the Roman God of war, while in Hindu mythology, he is considered Mangala (a sugar coated way to indicate the inauspicious) ; he is also identified with Kartikeya. All in all, he shines red in our night sky. Angular size, colour, retrograde motion and the plane of Mars can be enjoyed via unaided eye observation. Angular diameter of Mars is around 3 to 25 arc seconds. Mars angular size in the year 2005 was around 20, and is expected to reach the same in the year 2015 or 2018; for now (2014) angular size of Mars is around 15 arc seconds. The color of the Mars is red, owing to its composition (mostly rusty iron, iron oxides). Retrograde motion, the path appearing in the backward direction with respect to the fixed constellations, is 72 days for every

two years. Retrograde motion can be observed from March 2014 to around May 2014. The brightness of Mars can go up to -2.78 magnitude and in 2014 its magnitude is around -1.4. The first telescopic observation was made by Galileo Galilei while Huygens was first to discover strange features on its surface and ever since there has been some fear of Martians! However, it was much later it was clear that the crisscross lines were channels. Telescopic observation of Mars helps to see clouds, Olympus Mon Mt. (thrice bigger than the biggest Mt. on Earth), ice caps, craters (like the famous Hellas Planita/Hellas impact basin), moons (only after a long exposure with a special lens and with expertise eyes) and of course the red color. Mars, sister planet to earth has an atmosphere made mostly of C02 and is considered to have locked water in its ice caps. Its temperature on the planet varies from about -140C during the winter to approximately 20C during the summers. Its tilt is around 24 degrees, close to earths axial tilt. It has valleys, canyons, craters and other fascinating features to be observed and studied. Mars is second to earth in having the highest number of artificial satellites. To know better about our sister planet many rovers have been sent, few among them are Viking, Phoenix, Spirit, Opportunity and presently Curiosity. The session was interactive and informative. The red taint now looks more interesting and fascinating after the discussion. Harshitha SC

11

Jean Texereau - The art of telescope making

- - Prakash Subannas tribute to

Texereau

The bug of making my own telescope bit me since I joined ABAA IN 1979. Commercial scopes were neither available nor affordable for me. Come what may I wanted to build my own scope and look at the cosmos. So, with this bug entrenched deeply, I set out to do some homework about how exactly a was made. A refractor, which involved multiple lenses as objective and eye-piece were ruled out due to its complexity. Next was a reflector which uses a circular glass of a relative thickness ground and polished to a concave mirror.

With interaction with some senior members then ( 1980s ) at ABAA, I was able to get a fair idea of how a telescope can be made and how laborious the process was. Nonetheless I wanted to make one.

The book How to make a telescope authored by Jean Texereau was discussed and one of the members had a copy of it. A reading of it (though complicated and complex at that time) encouraged me to take up the project.

Having some idea of making a telescope I set out to source the raw material. This is where the biggest challenge and hurdle that I faced. None of the specified material or required material was readily available off the shelf. For example, the max circular glass diameter was about 4 inches and thickness was 12

mm. It was not Pyrex ( low expansion glass ) as specified but a plate glass used in windows and Boiler view glass which was hardened ( not suitable for us).

After some months of foot work I managed to catch hold of a 4 inch glass and small quantity of grinding abrasive and the work beganinterlacing the DIY project of ATM (amateur telescope making ) with

Engineering studies, months passed before things could take shape -not to forget the extreme financial constraints in those days.

Here I would like to mention the usefulness of Jean Texereaus book. Repeated reference and reading of the book helped us understand the complex process of building an optical telescope ( a reflector).a whole lot of things go into making a telescope.

12

The best part of it was, I along with other interested members over a period of time, did adapt the ATM book to locally available materials and simplified the procedure of telescope making. Mind you there were a lot of simplifications done. but the end result was the same, resulting in very fine optics.

Jean Texereau who is no more with us was an inspiration to many, including me in learning the art of telescope making. This led to series of telescope making workshops at ABAA for all those interested. This still is a tradition at ABAA.[ Eds note Ravi, are you reading this ? ]

For anyone who wishes to build their own telescope, a read through Jean Texereaus book will be an eye opener. Of course there are many other books and many more ways of doing it. But this was the one which opened my thought process.

I still have a copy of this book and a copy is available at ABAA library for reference.

RIP....Jean Texereau.

The sky at Night May/June/July 2014

Ravindra Aradhyas usual column

Mercury:

Mercury is visible in the evening sky from the month of May until middle of June. From the beginning of the month of if, we start observing the planet in the evening at a set time; we can observe that as the days go by, Mercury seems to be higher in the sky. The angle between Horizon and the planets seems to be increasing. This will continue until May 25th and after that as we continue our observation, the angle starts decreasing. The point where the angle was the greatest is the Greatest Elongation of Mercury. From middle of June planet Mercury will start getting closer to Sun in angle making it difficult to find in the Suns glare reaching Inferior conjunction on June 22nd.

Mercury will be closest to Earth on June 18th.

Venus:

Venus is well placed in the morning skies, shining bright at -4 magnitude throughout May and June. Brightest star in the morning sky, when seen through a telescope we can see the gibbous phase of the planet.

Mars:

Mars in the constellation of Virgo will be high in the sky at sunset giving us plenty of time to observe the red planet. Mars will set at 3am in the

13

middle of May and towards the end of June, it will set at 00:30am.

Jupiter:

The giant planet is setting earlier and

getting closer to Sun in angular separation giving little time of observation. At sunset Jupiter will be 45 degrees from western horizon and it will set at 9:30pm in middle of May. The giant planet will set even early in June; by the end of June Jupiter will set at 8pm.

Saturn:

Saturn will reach Opposition on May 10. This means the ringed planet, earth and the Sun will be in line on that day. As Saturn rises at sunset, we will have lot of time for observations of the planet and its rings. In the middle of May the planet will rise at sunset, and by middle of June the planet will be already at altitude of 30 degrees in the eastern horizon at sunset.

Uranus:

Uranus will rise at 4am in the morning in the constellation of Pieces. For good observation we will have to wait until middle of June when Uranus will start rising at 2am and will reach good altitude before twilight sets in.

Neptune:

Neptune rises in the early morning at 2am in the middle of May giving some time to observe the planet before the twilight sets in. Middle of June will be good opportunity to observe the planet as ti will rise at 12:30am.

Sun:

Sun will reach its north most

declination on June 21st at 23.5degrees. This is called solstice of Sun, from June 21st Sun will start moving towards equator.

Moon:

First Quarter: May 7th

Full Moon: May 14th

Last Quarter: May 21th

New Moon: May 28th

First Quarter: June 5th

Full Moon: June 13th

Last Quarter: June 19nd

New Moon: June 27th

July 2014 :

Mercury:

Mercury will be in morning sky during the month of July and will be easy to spot in the middle of July when the planet will be at Greatest Elongation, this will occur on July 12th. After elongation, the angular separation between Sun and Mercury keeps decreasing. Mercury will become difficult to spot at end of July, as it will be very close to Sun.

Venus:

Venus will start coming close to sun in angular separation in the months of July and August. Visible easily in the morning skies before sunrise, Venus is the brightest star in the sky. Venus starts the month in the constellation of Taurus and move to Gemini in the middle of July.

Mars:

Mars will be high in the sky when the

14

sun sets giving good time for observations. Mars will set at 11:45pm in the middle of July.

Jupiter:

Jupiter in the evening sky will be very close to sun for good observations reaching conjunction with Sun on July 24th.

Saturn:

Saturn is in good altitude for observations during July and August. The planet will be close to 50 degrees at Sunset during first week of July. The planet will set at 2 am giving lots of time for observations.

Uranus:

Uranus will rise at midnight at the start of July at magnitude of 5.8, which is easy target for binoculars.

Neptune:

Neptune will rise early in July and is an easy target for small telescope.

=============================

*********************************************