X'mas mass in Goa Velha

I attended the midnight mass on 24th December night with Angela and her family, along with Devart (Bablu) Rana. The main attraction was to see the localization of the global X'mas tradition: the celebration of the birth of Jesus.

Some curious points:
1) Everyone, irrespective of where they were born, celebrate some birth of a man thousands of Km away. They do not know most of the names (Bethelhem, Jerusalem, sea of Mediterrainean) and the times involved.
2) Continuing the above, all think Jesus was white. No mention was made to Judaism and the roots of christianity in Judaism.
3) For common folk, there were skits presented, where common public problems (drinking, gambling, etc.) were shown to have a common cure (christianity). No efforts were made to understand the psychological problems possible, how healing is possible without invoking the Lord, or without any reference to His greatness.
4) Most the examples above were very crude. Indeed, how can theft (possible social and economic factors being dominant) be bracketed with smoking or drugs (where personal factors may dominate)? To localize such problems and separate the different factors behind the cause of such 'illness' is vital to find a cure.
5) Political statements were inserted slyly, for example, SEZs were bad. No reasons were given, except vague statements about nature. How economics matters and how it can sideline sustainable growth is never openly discussed. Perhaps I am expecting too much from an organized religion.


On the other hand:

6) Hindu way of 'pooja' (prayers) was adopted, priests were using 'agarbatti' (incense sticks) to make circular movements in front of the Lord and were chanting. This is very similar to our Ganapati pooja, except the 'arati' is different.
7) Songs were in all local languages, Marathi, Konkani, and (most amusingly) English and Portuguese. English is the medium of choice for the upwardly mobile (like yours truly). Portuguese was displaced from that position after 'independence'...
8) Occasion was treated as a way to show-case local fashions by many. In fact, some local people explained that " 'too many reveling' clothes by front-bencher women kept the priests from falling asleep". The one in the rear rows promptly closed the eyes and caught on their sleep.

After this foreword, here are a couple of songs in Konkani

1) San Kiteak ailai balla?
Sang konnem tuka dhadd-la?
Sorg soddun koso denvloi?
Khoim Mhonn tthikann kortoloi?

Patkantlim soddounk ailam
Devjivit vattunk tumkam
Devmogan tumkam bhoronk.
Bapache vengent vhorunk.


2) Mogan thevlem monxeachea hatant
Devalem dan (3) ball Jezu rupan (2)
Dan tem omolik, kitlem tem vichitr
Guttlailolem soddvonne ghuttant

Natalm disa ailo denvum mog
Amchea kallzamni ravunk dovrunk tog,
khuxalkaie-dan sonvsarbhor vanttunk
pavla konnkonim chol-ia moganuch.

Natalam disa ailo denv'n sontos
Dukh-khoddamnin bhorunk visvas vhodd,
Bhorvanxachem dan jivitant vosunk
Niraxiponnam dium-ia soddun.

Processing HI cube - II

A) We now have a cube V_los(x,y,z)

1. Compute V_min and V_max (extrema) of V_los matrix,
2. Create new array V_obs, where velocity values (V_los) range from V_min to V_max, in steps of 1 km/s,

B) We want an output image matrix, OUT(x,y,z), where x_i corresponds to V_obs(i)

1. Scan the V_los(x,y,z) matrix; say, V = V_los(x,y,z)
2. If V1 < V < V2, then OUT(v,y,z) += rho(x,y,z)
   
3. Repeat a & b for energy and pressure.

Processing HI cube - I

Computing the orientation of each cell w.r.t. the central pixel

We would like to keep the simulation cube at a distance d (element: X=0, YMAX/2, ZMAX/2 is at a distance d).

Now, we compute angle subtended by all cells, and compute differential rotation velocity as per Brand and Blitz (1991).



1) Read velocity cubes Vxx,Vyy,Vzz

a) Compute projects of components of V_rot (due to galactic rotation) along the los.
b) Compute projection of velocities Vxx, Vyy & Vzz along the line of sight (los)
c) V_los = V_rot + components from step a


Formulae

a)
tan(theta) = y / (d+x)
(D * D) = (d+x)^2 + (y*y)

R' = sqrt ( D^2 + R^2 + 2*R*D* cos(theta+L)

Compute V(R') using Brand & Blitz (1991)

R" = D sin(theta + L)
phi = 90 - (theta+L)
phi" = arccos(R"/R)

V_rot = V(R') * cos(90 - (phi+phi") ) = V(R') * cos(theta + L - phi)

b)
theta = arctan(y / (d+x) )
V"yy = Vyy cos(theta)
V"xx = Vxx sin(theta)

chi = arctan(z/ (d+x) )
V"zz = Vzz cos(chi)

c) v_los (x,y,z) = V"xx + V"yy + V"zz + V_rot

Fractals and image characterisation

Some links are in order

1. Fractal Dimension: Wikipedia
   
2. A course on Fractals in Yale U
3. A course on Fractal dimension from images: Munich U
4. Fractal Dimension explained
   

So, once you know about fractal dimensions, come to read the stuff on the right (Conti, 2001)


One can treat the image 3-D object. Compute the total number of occupied boxes in X-Y-I dimension box, as a function of size of the box. D = ln(number)/ ln(radius).

It is a little bit more complicated. Check the paper by Conci, a PPT talk can also be found.

How to distinguish between landscape and portrait pictures?

1. Perhaps we can search for a large number of pixels with same natural colors: green, blue and black (shadows). look if a large fraction of pixels contain the same 'Hue' and 'Saturation'.
2. Another try: Look at the Fourier spectra of images, and mark radii of 60%, 90%, 99%, 99.9% power. they should be distinct for landscape images and facial portraits or nearby objects.
   
3. Human objects have a lot more symmetry than the natural objects. In fact, there could be some fractal pattern seen over the different length scales of an image of a natural scenery. Try to capture 'fractal' properties of pixels.

speaking of the last one: one could look at fractal dimension of a picture pixel values. How? Perhaps in the next blog post...

PHY GC 471 : Astrophysics, a first course

Course Description

This is a first course in astronomy aimed at a wide section of audience. We will introduce concepts with minimal use of mathematical tools. We would like to give a broad perspective of science to students, from regular night-sky astronomy to fascinating space astronomy. We will discuss historical context of some ideas and how they have evolved today. Keeping the engineering background of student population in mind, we will also emphasize on techniques, some challenging instrumentation, and details of space exploration.

Scope and Objectives

This being a first course to a variety of students from engineering background, we prefer to teach fundamental ideas about astronomy, and defer a detailed astrophysical treatment to another higher-level course. Astronomers study properties of light emitted by various sources in the sky. We will start by studying concepts of brightness, flux measurement and spectral-line observations, followed by instruments used these measurements. We will then discuss various astronomical objects, starting from our solar system, stars, to galaxies. In each case, we discuss basic astrophysical mechanisms to understand nature of light emitted by objects under consideration. We then discuss how to estimate physical parameters of stars, galaxies and the cosmos from the properties of light detected in various wavebands.

Textbook

IGNOU study material PHE-15 (Astronomy and Astrophysics), Indira Gandhi National Open University, 2006.

Astronomy Discussion Meetings: Proposal to the Astronomical Society of India

Over the past few years astronomy meetings have not been held regularly in India. Astronomical Society of India (ASI) only organizes bi-annual meetings, which are woefully short on discussions. To increase their frequency, topical discussion meetings involving a small number of active participants were proposed. Such meetings will allow a close interactions between astronomers, mainly from India. They will have an added benefit of smaller number of participants and of being focussed on topics of LOC's interests. The costs and local organization efforts will also be reduced significantly.

The ASI has accepted the proposal in principle. Here are the basic tentacles of such meetings. The ASI has granted a sum of 1 Lakh towards expenses of the meeting. One could further approach DST/ISRO/UGC for more funding. Given Ranjan being in DST committee, it would be easier from them.

There will typically be sessions over 2 and half days, with about 15 presentations. The emphasis is on discussions. Hence, followed by one 45 minute talk, there is 15 minute's break for Q/A session. At the end of each session, there will be an hour of open debate on possible new work, or comments on on-going work. This is place for on-board calculations, and some laptop demos, etc.

The meeting crucially depends on 4/5 resource persons. These will chair sessions, seed discussions and direct the course of the meeting. Their participation is vital, as is the willingness of the public to discuss issues and settle them on the spot, rather than defering to person-to-person discussion.

There will be about 10-15 faculty and 10-15 PhD scholars. Most members will stay during the entire two and half days of the meeting. There are no frills, except perhaps one institute buffet and some drinks from the LOC. The number is restricted to a number of 25, and is by invitation only. Most participants will not be provided travel support, and the local travel support will be provided on pay-per-use basis.


All these are thought to make the arrangement work of the LOC minimal, allowing for more groups from India to host meetings. This will allow a larger number of meetings, wider set of meetings, and dispersing meeting venues.


Amen to that!

Stop Sexual Harrassment

The title says it all...

Data Acquisition Block Diagram

The data acquisition of a band-limited signal has the following broad steps:

1. DC removal



2. 2-bit ADC (0.5 MHz speed)




Collect 4 such samples at one time (for simplicity, copy the same signals 4 times)




3. Build a sampler, of 0.5 MHz.




One could take 10 MHz signal, and use every 20th pulse (simple counter) for sampling.




4. Put together four 2-bit samples on a bus with an isolator for i/o.



5. Feed the signal to the data acquisition card sitting in the PCI slot of a PC.

BITS Goa Radio Telescope : Software Correlator

Thanks to Aniket and Mandar, we will get a data acquisition card interfaced to a PC by next semester.

All the card does, is to accept AC voltages of 250 KHz bandwidth, digitize it (2-bit ADC) and sample it at Nyquist rate (500 KHz). Four samples (2x4 bits = 1 byte) are then packed together on the fly to form one byte. The resultant one-byte is stored on a PC for processing. So, the pipeline looks as below


--- signal ---- >>-- ADC -->>--Linux PC-->>- FILE
(0.5 V AC________3-level____bit packing
0.25 MHz band)___2-bit_________program


ADC has two comparators (NE 521 ?). Depending upon the input, one of the the following 00 (-2), 01 (-1), 10 (+1), 11 (+2) is the output of the ADC.

The sampler signal of 0.5 MHz samples the ADC output voltages. Four of the samples are fed to the acquisition card through data cables.

The data rates are slow, 500 k Bytes per second. Given the modern computer disk rates, it is possible to sustain a on-the-fly bit packing program in PC. The program accepts 4 bytes, and based on a precalculated table, stores corresponding 1-byte output onto a file.

LO and Sampler Frequency Solution

We have our RF band as 73 - 74.6 MHz. Using one of the frequencies given by the Oven Controlled Crystal Oscillator, we would like to generate LO (of) such (frequency) that, our band is folded at some suitable IF. The end of the IF band should be the sampler frequency, again one of those given by the oscillator.

The first image is one such combination for the RF band and LO (plotted very quickly using PLOT program in Mac).


Given the 0.26 MHz band ending at 4.096 MHz beyond LO (70 MHz), the IF band looks as given in the second figure. The IF band now falls between 0 MHz and 4.096 MHz, although mostly empty (0-3.75 MHz), due to our RF filter.

The band is now sampled with 8.192 MHz, the sub-harmonic of 16.384 MHz from the oscillator.

Since both LO and sampler frequency are derived from the same ref, there should be more stability in the system.

One can have another combination of such a LO and sampler frequencies. As an exercise, try these two frequencies and draw the plots: LO (76.8 MHz) and Sampler (5 MHz).

Using the Crystal Oscillator

Our Band is 73-74.6. How do we use a Oven Controlled Crystal Oscillator, referred in the earlier post? We need to generate an LO signal (between 70-80 MHz) to bring RF signal to an IF of 2-5 MHz. We also need to use one frequency for our sampler.

We have a few frequencies at our disposal, 10, 12.8, and 16.384 MHz, etc. We should use 10 MHz for sampling, after some downconversion (0.5 MHz for 0.25 MHz band). This would be easy, using a digital counter. How do we go about LO? we need one frequency such that a bandwidth of 0.25 MHz in the above band gets down converted at IF.

It depends upon a combination of IF, and bandwidth we choose. The problem is, if the band has a lot of interference, we should be able to switch to some other location nearby (within 73-74.6). A smaller bandwidth makes this possible, while bringing down data rates.

I have a couple of solutions, I will detail two in the next post.

Oven Controlled Crystal Oscillator MCOCXOW

I looked for crystal controlled COs. Here is one data sheet from Golledge. Excellent stability, we do not know the price. It is their featured product, from price and availability point of view.

AIPS : initial calib idea

Initial Calibration steps in AIPS

1. INDXR
   
2. First clip source for arbitrarily high points (100 KJy), due to correlator errors. (CLIPM)


3. SETJY to set fluxes of prim calib sources in SU table
   
4. CALIB on prim calib to find antenna solutions, SN tab 1
   
5. CALIB on second calib : SN tab 2
   
6. GETJY to calculate second calib fluxes to second calib (using SN and SU tables)
   
7. CLCAL apply second calib source calibration to target sources: CL tab 2
   

Now, one is free to excise interference. once one has cleaned all the data, return to step 4 above to redo the calibration process (after deleting all SN and CL tables generated above).

Is our PM senile?

One of Gandhi's letter goes on sale somewhere in the world, and some concerned 'Gandhians' wake up and write to the PM. Our ever-ready prime-minister orders Ministry of External Affairs to intervene to 'acquire' the letter from the Christie's.

Now, either those Gandhians have no better work to do than asking my poor country to pay up 10,000 pounds for a stupid piece of paper. Or PM has gone senile to provide so much of attention to some old, half-dead people. Or, perhaps I have too much time to ponder over such matter.

BUT, NO! It's my fu***ng tax money, and some oldies are looting it. They, by virtue of their age, do not pay any tax, if I remember correctly.


Update: India may serve a notice to Christie's, looks like the Law department has nothing much to do either. There are so many legal reforms pending, all we think of is one piece of paper...

fruitful day!

things done:

1. AIPS processing tutorial by Chiranjeevi, it has given a new perspective about GMRT interference removal and calibration.


2. ms for SAX 1808 paper is ready for desh's view.



3. there has been tons of discussion about radio telescope.
   
   
   • the 2-bit samples from 4 elements could combined in one byte per sample rate.
   
   
   • Cross-correlations of each two-element pairs (total 6 pairs, called 'baselines') can be done for N delays. Resultant array of N correlations can be passed over to FFT, resulting in amplitudes and phases for N/2 spectral channels. (This job can be simplified by using tabulated results for all 8-byte combinations).
   
   
   • The value N above is decided by delta-u and delta-v that we can have, using 1/imsize for our map (possibly 1/60 deg).
   
   
   • We need to keep computing such cross-correlations over a large time, integrating amplitude and phases over a large time (about 8 seconds or so).
   
   
   • These integrated amp and phases are the output (dynamic spectrum) of an effective software correlator.
   
   
   
   
   

BITS Goa Radio Telescope

when i spoke about our plans for hardware for our radio telescope, there was some feedback from my supervisor (Deshpande, RRI). he was of the opinion, that

1. our telescope was a fantastic idea, and could eventually do international science using 4 element dipoles. we have to plan and execute it well, of course.


2. in the beginning, we could make images using 2 antennas only, with Mandar and Aniket's data acquisition cards. this means, as soon as we demonstrate 2-slit interferometer, we can think of maps in the second semester.


3. we should think of using 2 bits and less bandwidth. eventually, we will have 4 element dipoles. so, we will have to store 4x2 = 8 bits = 1 byte at nyquist rate. if we opt for smaller bandwidth (0.25 MHz), we could be saving 0.5 MBytes per second on the disk, with each byte being a sample each from 4 elements.




In the immediate plans:



4. we should converge using "Mini Circuits" ICs for our RF components. See their website



5. also, for LO stability, either
   
   

   a) opt for GPS receiver, and use its 10 MHz signal for LO

   
   

   b) use a "oven controlled crystal oscillator"

   
   
   the second option is better for us for now. we will continue to explore the second option for better eventual stability of frequency signal. for better mapping, we need our sampler and LO to be really stable.
   
   

Freakonomics

I read the book Freakonomics. The book entertains and just gleams economic incentives in many daily issues (of largely American life). However, the best thing was the data about education gleamed from US schools, the incentives for cheating in high-stake exams. Thinking on that line, here are a few questions that arose in my mind:

1. What is the incentive for a student to join a school? Or, in other words, can we convince every parent and child to take education seriously, think long term, invest time and money in it?



2. What is the incentive for a bank or financial company to fund a student for his schooling? Can a micro-finance company find some benefits in spreading basic education in rural areas?



3. What is the reason that students sleep in my class? Or what incentive do they have in listening to me and to work harder on the course material?



4. What is the incentive that I keep myself in education? What would make me stop and move away from Goa?

The last one is a serious question too!

Adopt Your University ! Part 2

How to go about it?

I am elaborating a solution to remedy the mess in higher education, whereby a university is adopted by a local community, making the process very interactive, transparent, and responsible. I introduced in my earlier post the "Adopt Your University" campaign.

The basic idea: To adopt a university, and create a fund from the local community, council, city by `trading its shares', whereby common man buys those shares individually or through societies. The university is run from one-time fund and other running local funds. Then, local population will remain involved in deciding the content and direction of university programs.

Here we lay out ways to raise enough funds for the university from the public around, and involving the local community in growing and maintaining the university operations.

1. Create funds for the university by selling certain number of shares to the public. The shares are sold in such a way that no one person or group gets entire control of the shares. This will create a large amount, about 50 crores for the university. This will remain a one-time generation. In case of Shivaji University, Kolhapur district generates about 1000 crores each year, if my information is correct. A fraction of it is required here. People can trade these shares, under certain conditions. A part of the sales profit will go to the university.
   
   What do these shares mean to the public? It is similar the stock market companies in spirit. However, there are bound to be differences, for example, clearly there are no yearly dividends in cash or cheque.
   
   The shares will imply different things to different kind of people.
   
   For most, such as middle-class citizens, they would mean immediate benefits in the form of priority access to university facilities. These could include, but not limited to, astronomical observatory programs, auditorium lecture/demo programs, sports gymnasium and weight training, or discount in training fees for vocational courses (music, computers), etc.
   
   For farmers or small industrialists, it could mean priority access to different orientation programs, manpower training camps, or awareness campaigns. They could also mean, higher priority listing in receiving solutions of their queries/problems from the university.
   
   Any major change in University policy is explained in a general investors' meet (like Reliance Companies did). An approval is sought and then major decisions are taken to a vote.



2. Local community pledges support to the university by providing certain amount yearly. This will pay the salaries of the staff. This guarantees that the staff remains loyal to the cause and if the administration is lethargic, the city council could (in principle) stop their salary payments.


3. The research funding should come mainly from services to the local population, industry, including farmers. Some of it will also come from the central government grants, mainly for basic sciences.



4. The above conditions mean that
   
   • University remains committed to the local cause. Those programs which are not relevant for the community will not naturally receive any money. This is similar to ways of mother nature, where an organism has to evolve to remain relevant. University will keep transforming itself to grow.
   
   
   • Staff and administration will be responsive. If not, they will be unpopular in the local community, and the community can demand correction.
     
   • University is not subjected to large-scale politics. Since money is generated locally, it will not remain hostage to state/central government policies. The initial funds (50 Crores) will serve as a buffer if the local funds drop over a short period of time (5 years or so).
     
   
   
   
5. Programs of the university are decided by a committee of citizens. However, there is a danger in going local, one will certainly loose sight of global standards. Such issues of quality of university programs and maintaining standards is a major task.
   
   
   
   • The global focus is maintained through an expert senate committee with many outside experts in various fields. The committee, through independent enquiries, ascertains quality of university programs. It will also guide academic/research programs on campus...
   
   
   • There would be, in general, no fixed idea about having degree and doing a certain kind of work. Someone with BA (English) can dabble in other areas, if certain level can maintained. The pay scale will be less biased towards those with higher degrees.
   
   
   • Programs are implemented by administration adhering to global standards set by the committee, without any local interference. Rejection of political influence will be ensured by direct citizen support to the committee.
   
   
   
   
   
6. The operations could be decentralised. No one needs to come to university campus, one could log on the website and do many things. It will involve a generous use of radio network and computers to ensure quick communication and dissemination of knowledge to the community. One could use cheap and easy tools, such as campus radio station (by students perhaps?) or hand-held mobiles, with specialised programs developed for this need. With minimum training, volunteers & workers should be able to operate computer data bases, involving tools such as voice recognition and internet transfer of information from the central server to mobiles via SMS, etc.



7. The proposal keeps a lot of faith in committee running the university. This requires that the rule book is good, and the wo/men in charge must be honest and tough. They will be responsible for all the activity and retain all the rights and freedom to carry out every activity to perfection. This is possible, although expect political influences of all kinds. It is imperative that the local community is made aware about this issue and it has to support the persons-in-charge against any pressure.

In a future post I will outline one example, using Shivaji University from my hometown.

Adopt Your University !

A solution for higher-education crisis in India


Given terrible neglect of education sector in India, there is a serious concern about no viable education, and therefore competent jobs, for millions of deserving Indians, especially those who are dying to pay any fees for it.

The problem is, that we have heaped the entire responsibility of educating the populace on to a mythical entity called 'government'. In India it amounts to a large number of babus, arranged in a rigit vertical/horizontal structure. None of this structure was created for India's sake, but for usefulness of a certain Elizabeth. One of the best ways out to reform the university system is to again involve the local community in running the university.

Here is a solution, whereby a university is adopted by a local community, making the process very interactive, transparent, and responsible. I call this "Adopt Your University" campaign. In the current post I will outline the idea, details will be provided in the near future.

The basic idea: To adopt a university, and create a fund from the local community, council, city by `trading its shares', whereby common man buys those shares individually or through societies. The university is run from one-time fund and other running local funds. Then, local population will remain involved in deciding the content and direction of university programs.

Short background:

Apparently, Cambridge and Oxford universities were run by local townships through local funds. London came in the picture only in 19th century. Nalanda was sustained by Magadha kings, for the benefit of their population. Why can't present Indian universities be run like those, where local population sustains a university for their purpose and thereby gets more involved in its affairs. No one will look to government for funding, university will sustain itself by 'selling' its expertise and providing services to the community directly. It will justify its existence and underscore its relevance.

Goals:

1. University remains open to the public directly, through a Public Relation Office. Comments, complaints, request for advice and proposals are immediately attended to.
   
   

   University provides many services to the local community, such as:
   

   
   
   • Studies water harvesting strategies, rain-forecast based planning of crops, and tree plantation between farms and around.
   
   
   • Studies strategies in other farming practices about seeds, organic farming, bio-fertilisers, crop deceases, etc.
   
   
   • Studies local human/animal deceases, or pandemics (bird-flu or) and provides expertise to the community immediately.
   
   
   • Preserves knowledge about local history, ethnology, archeology, geology, zoology, botany is preserved and research conducted.
   
   
   • Promotes technology development for local community, such as agricultural tools (e.g., making of jaggery with improvisations in traditional methods) or industry solutions (e.g., cast iron technology and small, inexpensive improvements).
   
   
   • Promotes research in the local communities, to enable them to solve their own problems in innovative fashion. Any resultant local solutions could be marketed/patented (like GNU patent scheme) for the benefit of the community.
   
   
   • Promotes and preserves local arts and culture, through focussed efforts in those disciplines.
   
   
   
   
   
2. The university will be locally grounded, with local population and its needs. It is based on mutual need, for people can pay for information they need, and university personnel can earn a good living in turn.
   
   
   
   
   • Local human/animal deceases, or pandemics (bird-flu or) are studied and expertise provided to the community immediately.
   
   
   • Knowledge about local history, archeology, geology, zoology, botany is preserved and researched.
   
   
   • Promotes technology development for local community, such as agricultural tools (e.g., making of jaggery with improvisations in traditional methods) or industry solutions (e.g., cast iron technology and small, inexpensive improvements).
   
   
   
   • Promotes research in the local community, to enable them to solve their own problems in innovative fashion. Any resultant solutions could be marketed/patented (like GNU patent scheme) for the benefit of the community. This is modelled on the so-called "Barefoot College".
   
   
   
   • Promotes and preserves local arts and culture, through focussed efforts in those disciplines.
   
   
   
   
   
3. University will promote science and technology in the region.
   
   

   It will provide training and research foci for college and school teachers and students. It will also serve as knowledge center, where national and international experts can converge to interact with local scientists and engineers.




4. Although local issues get more prominence, they do not overshadow other research/training. Other disciplines, such as mathematics, psychology or business management will be pursued as well, however, with similar local bend.
   
   

   For example, the university could be involved in teacher's workshops, training other persons (laboratory technicians) from schools, who will avail this facility on payment of fees. Latest research in child/adolescent psychology and its links with education could be pursued, which will improve the grass-root education. Although this deserves an entire new thread on its own. Those who are interested should read Atanu Dey's posts on the topic of education.
   

   
   

Astronomy in Goa - V : Demands on Design.

Physical Needs

One student asked me for some comments about an Astronomy center in Goa. Here are my comments to her.

In my guide post I had outlined aims of the project and which communities would benefit from the exercise. Based on the answers to the first two, in my subsequent posts on this blog, I outlined activities that could be conducted for school, college and general audiences. Depending upon all these, we would know the physical, electro-mechanical, human and space needs of this project.

We will do this step by step: first work out physical and space needs of this projects. These are most crucial, for astronomy can not be done well from cities, even amateurs gain a world by being in remote, dark locations. No wonder our forefathers were fascinated by stars and we (those who live in light-polluting and claustrophobic cities) miss out on that wonder of stars and the Milky Way Galaxy!

Physical Needs:

Given that general public, students and teachers are going to observe the sky, the prime importance has to be given to an unhindered access to "dark sky" from all sides. Also, given that one would use academic tools, astronomy instruments and expects amateur crowds of variable numbers, it would desirable to split space into a number of smaller areas of variable sizes, which would be accessible to different populations at times desirable.

1. A well-connected set building which should host the following:
   
   
   • a library: with books in Konkani, Marathi, English. Books such as "Hubble Images" are needed for general audiences, whereas some elementary textbooks from Indira Gandhi Open University would be great for college students. Astronomy and science magazines and newsletters from around the world could be obtained and provided to the interested students.
   
   
   • Two display halls: poster exhibitions, astronomy and science-game rooms, general information displays (history, geography and ideas in Astronomy), introduction to historical figures, local communities and their small projects can be highlighted.
   
   
   • Three lecture rooms of variable sizes, say roughly 30, 80, 250, to allow for a large audiences in some interesting demonstrations or lectures. The display halls could doubled up as a lecture room of 200+ capacity, if built with appropriate scale in mind, they could be interconnected using video link, to allow even larger audiences. The lecture halls could be connected to the internet, allowing for video lectures, internet demonstrations, and virtual observations.
   
   
   • Demonstration labs for electronics and computers. Electronics laboratory would enable students to study, calibrate and use astronomy instruments. The computing laboratory is especially keeping in mind virtual observatory concept (remote observing and online content access).
   
   
   • Office space for visiting astronomers and lecturers: they could keep their belongings in these spaces, share material with support staff of the center, and keep a regular contact.
   
   
   • Observatory platform: space for a couple of telescopes. Ideally, one would like a single large telescope (16 inch) for serious amateur work, and perhaps four smaller telescopes for popular amateur demonstrations. The large telescope could be housed in the main building. To maintain light levels and low disturbance from crowds, perhaps this part could be a little away from remaining building.
   
   
   

   Given that a large population would use this building frequently, we need to special care about light levels around this building. Careful arrangement of parking, walking space, building interior lighting is required in order to minimise impact on local observers.

   
   
   
   
   
2. Open flat spaces: preferrably not green lawns, but higher from the ground to avoid stray animals entering. Perhaps we could use the terrace space over the above-mentioned lecture halls? We need to allow space for large crowd to sit outside and lean skywards to watch celestial events. We could build a terrace sloping gently (15 degrees?) towards south. This would align us towards to the Earth's axis, as we keep our feet towards the South. Stars would follow from left to the right. Given the slight tilt, it would be easier to watch the skys using a simple cushions.
   
   

   One would expect spaces with downward-facing lights, which will emit very little amount of light towards the sky and would be just enough for one to watch where they walk.
   

   Such flat spaces could be divided in multiple different locations, so that students, amateur astronomers, and general public can be segregated depending upon their needs of observations. All could use smaller (8 inch) telescopes and binoculars for their sky gazing.
   

   
   



3. Planetarium: A mobile planetarium could have a semi-permanent base in this center. It could visit various localities within Goa with a pre-planned (on demand) schedule.



4. Most importantly, we need to plant tall trees all around, so as to cover about 15 degrees altitude. This should cut down glows from large cities, it would also isolate us from oncoming traffic lights and any habitation disturbances. Trees such as jackfruits, Peepal and Neelgiri are good along with dense shrubs found in Goa. They grow fast, so no one needs to tend them much. We would avoid cash-crop trees, such mangoes, not only for obvious reasons, but also to save ourselves from animals, such as monkeys!

Average and the statistics of Poisson

Devan produced a lot of images using Poisson Statistics. But he could only see 20% frames with any photon at all. Why, can we not explain this using average number of photons from the sky?

Yes, we can. We get only average of 0.17 photon over all pixels of the detector put together. This gives a probability of ~84% to have zero photons incident on the detector. That is perfectly acceptable! Statistics can be trusted :p

Astronomy in Goa - IV : General Public

This post is a part of a series on Astronomy Center activities in Goa. I have outlined the aims and target communities for it, read my guide post for details. The current post will outline main activities for general public. The next post will examine the physical and other needs of all such astronomy activities.

It is highly recommended that activities for general public to be carried out while conducting school- and college-level activities. Not only is it easy to do so, but without such activities general public will not be aware about such a center and will not support it at the local level.

Goa is poor on astronomy awareness, as is most of India, even though Goans are quite enterprising and curious people. There are hardly any facilities for astronomy activities, except for Public Astronomy Observatory, a group in Panjim that does lots of good work. So, there is much to do with such a center in Goa.


The aims is to spread awareness about astronomy, physics, and general science related to both, to general public, students, policy makers, alike.


Activities:

1. Astronomy awareness camps (mobile and stationary in Surla): To educate common public about important astronomy events, regular calendar events, etc.
2. Regular in-house open-air (naked-eye) astronomy activities: meteor showers, eclipses, and like. This is to maintain public involvement in astronomy center.
   
3. Planetarium-based activities: Much of the Summer and Monsoon season, when skies are not clear, a mobile planetarium would be an ideal instrument of astronomy display. A mobile planetarium has been active in IUCAA, Pune, and has been a successful venture.
4. Panel discussions and lectures by experts on topics of interest for general audience
   
5. To question astrology and dubious connections used to sell it using astronomical terminology. This is to clearly identify difference in science of astronomy/astrophysics and what different astrological practices follow. In particular, calendars, astronomical events of planets and terminologies.
   
6. To highlight astronomy education and research issues in front of common public and policy makers. This is to advocate more participation in national and international activities, such as Olympiads, telescopes, collaborations, etc.

In the subsequent parts I will outline physical and other needs to conduct the activities for three types of audiences.

Astronomy in Goa - III : School Activities

This post is a part of a series on Astronomy Center activities in Goa. I have outlined the aims and target communities for it, read my guide post for details. The current post will outline main activities for school children. The next post will examine the physical and other needs of such astronomy activities.

It is highly recommended that activities for general public to be carried out while conducting school- and college-level activities. Not only is it easy to do so, but without such activities, general public will not be aware about such a center and will not support it at the local level. One will have to sell the above activities for general public in some form or another. To think of it, school/college audience is only a part of "general public".


Coming to specific activities for school students:

non-academic:

a) To do simple naked-eye astronomy: get acquainted with stars, planets, comets, and meteors.

b) Seasons and astronomical bodies,

both the above activities are expected to stimulate astronomy discussions and general background.

c) To recount history of sky monitoring and astronomy, in India and abroad.

d) Stories of famous Indian astronomers and mathematicians.

f) To study the connection with science/physics through simple examples.

g) To understand role of astronomical observations in calendars




academic


a) To develop graded astronomy curriculum material:

1. For 8th to 10th level classes. We need to start from simple concepts of Earth as a rotating, spherical body.
2. Learn about the Sun as a star, moon as a satellite, and planets as satellites of the Sun.
3. Gradually, we need to introduce higher concepts along with simple physical interpretation (for example, mass of the Sun).

b) Simple naked-eye activities can be used to do geometrical interpretation of events, such as planet motions, Earth's rotation axis, Moon's motion around itself and the Earth, etc.


c) Techniques of detailed observations of planets, stars, and other heavenly bodies using a telescope and CCDs. Understand the difference between eyes and an external 'detector'.


d) Relating measured quantities to class-room physics and mathematics learnt previously by students. In particular: concept of angles, motions of planets using Kepler's laws, radii of and distances to planets assuming some parameters, etc.


e) Conduct astronomy quizzes and competitions.


f) Encourage astro-photography and virtual observatory : internet-based observations using web-cam connected telescopes and astrophotography.


g) Print and digital media interaction to reach wider audience.





Community-based activities



a) Students could help spread astronomy awareness at their homes.


b) Elder students could work with junior students to explain science and techniques of astronomy.

Astronomy in Goa-II : College Activities

This post is a part of a series on Astronomy Center activities in Goa. I have outlined the aims and target communities for it, read my guide post for details. The current post will outline only activities for college students. The subsequent posts will discuss school and general public, and examine the physical and other needs of such astronomy activities.

It is highly recommended that activities for general public to be carried out while conducting college-level activities. Not only it is easy, without such activities, general public will not be aware about such a center and will not support it at the local level. One will have to sell the above activities for general public in some form or another. To think of it, college audience is only a part of "general public".


Coming to specific activities for college students:

non-academic:

a) To do simple naked-eye astronomy: get acquainted with stars, and planets.
b) Naked eye observations, particularly of comets, meteors, planets, and other variable objects,

both the above activities are expected to stimulate astronomy discussions and general background.

c) To recount history of sky monitoring and astronomy, in Indian and abroad.

d) To understand connection between astronomy and religion in India.

e) Stories of famous Indian astronomers and mathematicians.

f) To study the growth of science/physics through stories of astronomy and astronomers.

g) To understand role of astronomical observations in calendars

h) To question and contrast astrology from astronomy/astrophysics.



academic


a) To develop graded astronomy curriculum material:
For 11th, 12th and degree level classes. We need to start from simple concepts of stars, planets, moon/sun, etc. gradually, we need to introduce higher concepts along with simple physical interpretation. An ideal starting point for such material will be Indira Gandhi Open University (see their course PHE 15 for astronomy and astrophysics).

b) Simple naked-eye activities can be used to do quantitative analysis of events, such as meteor showers, variable star brightness, etc.

c) Techniques of Quantitative estimation of brightness of stars, planets, etc. using a telescope and CCDs.

d) To make simple measurements of star/planet spectra using narrow filters.

e) Relating measured quantities to class-room physics and mathematics learnt previously by students. In particular: concept of temperature of stars and planets using above spectral measurements, radii of stars assuming temperatures, distances to planets using Newton's laws, binary parameters based on eclipsing binary stars, etc.

f) Conduct astronomy quizzes and competitions.

g) Encourage astro-photography and virtual observatory : internet-based observations using web-cam connected telescopes and astrophotography.

h) Short and long astronomy projects through collaborations with other astronomy institutions, such as IUCAA.

i) Print and digital media interaction to reach wider audience.



Community-based activities


a) Students could help spread astronomy awareness through school-level camps at various schools

b) Elder students could work with junior students to explain science and techniques of astronomy.

Astronomy in Goa - I

One student asked me for some comments about an Astronomy center in Goa. Here are my comments to her in brief. More detailed comments for individual parts (College, schools, etc) are on separate blogs.

I believe much of this material would be useful for similar centers in India, although there will be local variations.

First let us focus on

1. What are the aims of the project?
2. What communities will benefit from the exercise?
3. To achieve these, what activities will be conducted? Based on the answers to the first two, one would develop the 3rd answer. Depending upon all the answers, you would know
4. What are the physical, electro-mechanical, human and space needs of this project?

Goa is poor on astronomy awareness, as is most of India, even though Goans are quite enterprising and curious people. There are hardly any facilities for astronomy activities, except for Public Astronomy Observatory, group in Panjim that does lots of good work. So, there is much to do with such a center in Goa.

Briefly:

1) According to me, aims should be to

• spread awareness about astronomy, physics and general science (related to both) to general public, students, collegians, and teachers.
• help students acquire astronomy/physics skills using direct experimentation, and appreciate how much astronomy can be a part of their daily activity.
• impart training in astronomy techniques and ignite students' faculty of inquiry.
• train general teachers in schools and colleges to provide general astronomy course in curriculum.

2) Communities targeted are:

• general public
• school and college students
• school and college teachers

Awareness levels, requirements and activities of all groups vary, hence our approach to them is going to be different.


3) Activities:
a) general public:
i) astronomy awareness camps (mobile and stationary in Surla)
ii) open-air (naked-eye) astronomy activities: meteor showers, eclipses
iii) planetarium-based activities: a mobile planetarium has been active in IUCAA, Pune, and has been a successful venture.
iv) panel discussions and lectures by experts for general audiances
v) to question astrology and dubious practices used.


b) schools (students and teachers)

i) simple exercises to illustrate relation between mathematics and planetary movements, meteors, eclipses, etc.
ii) physical measurements of planets, moon and the Sun and stars using naked-eye measurements, telescopes, and binoculors.
iii) curriculum course development for students of secondary school, to increase awareness about astronomy and astro-physics.
iv) to specifically question assumptions in astrology, and contrast it with astrophysics.

c) college (students and teachers)

the above practices, however at a higher expertise level. one needs more detail, more sophistication, etc. for example, a college student (esp. an engineer) would appreciate instruments used in astronomy and their detail. they may like to demonstrate radio telescope and understand instrumentation in space-based telescopes.

QUARK'07

Our campus celebrates the tech-fest over the next 3 days, 17-19 March. Visit QUARK'07 website for more.


We are organising an Astronomy Workshop for participants, where I will present one talk. I am also involved with Image Processing contest, where students will be grilled for their skills with images.

Modified algorithm for UVIT frames

Make a table (dimentions 4x1000) for Poisson statistic. x-axis is average photons at a pixel P_ij and Y-axis is the number of photons. X-axis values range from P_ij = 0.001, 0.002,... 1.000, in steps of 0.001 (1000 values). Y-axis has 4 values, which are equal to probabilities of number of photons incident = 0, 1, 2, 3.

For example: at x = P_ij = 0.1, the four values (corresponding to probability of 0, 1, 2, and 3 photons incident on that pixel) are P₀ = e^-0.1 (= 0.9048), P₁ = 0.1 P₀ (= 0.09048), P₂ = 0.01 P₀/2 (=0.0045242), and P₃ = 0.001 P₀/6 (= 0.0001508).

For a given frame_k, find a random number R equally distributed between 0 and 1. For each pixel

1. If R <>0, then number of photons for that pixel = 0.


2. If (P₀ + P₁) > R > P₀, then number of photons = 1; and if (P₀+P₁+P₂) > R > (P₀ +P₁) then number of photons is 2; and so on.
   

For the next frame, compute a new random number R and repeat the above steps again...

UV image simulation from Galex

This is an algorithm to generate frames from Galex image.


You make a table (dimentions 4x1000) for Poisson statistic. x-axis is average photons at a pixel P_ij and Y-axis is the number of photons. X-axis values range from P_ij = 0.001, 0.002,... 1.000, in steps of 0.001 (1000 values). Y-axis has 4 values, which are equal to probabilities of number of photons incident = 1, 2, 3, 4.

For example: at x = P_ij = 0.1, the four values (corresponding to probability of 1,2,3 and 4 photons incident on that pixel) are 0.1, 0.035, 0.002, and 0.0005.

For a given frame_k, for each pixel

1. Find a random number R equally distributed between 0 and 1.


2. If R > 0.1, then number of photons for that pixel = 0. If R > 0.035, 0.002 and 0.0005, then number of photons incident on that pixel are 1, 2, 3.
   

Program out of beta phase

Oh well, finally my program on MHD simulations works ok. It was tested in different ways and now produces proper FITS files and plots. No bugs so far in this version. It reads inputs from a preset input file and then processes the data file listed in the input file, based on other inputs from the same file.

Our time table is up, classes started today for me, but I am away from Goa. I will return to a full weeks' schedule, with one more new course this semester. So, this blog will see much more on Electromagnetic Fields and Waves.

MHD simulations

I have been working with MHD simulations of my collaborator, Miguel de Avillez. My C++ program still sticks like a sore thumb, even after 6 months of work. There is still a bug in reading/plotting the data. However, I think I am on top of it for now. The next step is to create position to velocity maps for comparison with Miguel's own column density plots.