Astrosat Picture of the Month

Sharing the excitement of India's first dedicated space observatory, every month!

Image of the Month

The AstroSat Picture of the Month for September 2018 is a photograph of AstroSat itself. The top panel has two photographs of the fully assembled AstroSat. The bottom panel is an artists's conception of the observatory in space. Can you identify each of the five telescopes in the top panel photographs?

Pic Credit: Top panel - ISRO; Bottom panel - ASI POEC, ISRO and Adrita Das

Click here for a full resolution image.

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“AstroSat Picture of the Month” is an initiative of the Public Outreach and Education Committee of the Astronomical Society of India and the AstroSat Training and Outreach Team.

AstroSat: A 5-in-1 Observatory

AstroSat is India's first dedicated multi-wavelength space observatory. It was launched into space by ISRO exactly 3 years ago, on 28 September 2015, on board the PSLV-C30. This unique observatory has five instruments on board, four of which can look at the same piece of sky simultaneously. These telescopes give AstroSat the capability of observing in the ultraviolet, X-rays as well as gamma rays. Thus, the range of wavelengths that AstroSat can observe spans a factor of about 16000, from the lowest (200 nm in the Near UV) to the highest (0.012 nm or 100 keV in the gamma rays). These five instruments are the Ultra Violet Imaging Telescope (UVIT), the Soft X-ray Telescope (SXT), the Large Area X-ray Proportional Counter (LAXPC), the Cadmium-Zinc-Telluride Imager (CZTI) and the Scanning Sky Monitor (SSM).

Over the last one year, we have brought you 12 images from AstroSat. These APOMs, or AstroSat Pictures of the Month, have mostly been from the UVIT, since it is best suited for producing images. The strength of the X-ray and gamma ray telescopes lies in their incredibly precise timing and spectral capabilities. We will be bringing you spectra and light curves of interesting objects from time to time too.

Today is the 3rd anniversary of the launch of AstroSat and the 1st anniversary of the APOM project. Hence, this month's APOM is of AstroSat itself! The top two panels are photographs of the fully assembled AstroSat from two different angles. All five telescopes, along with many sensors can be seen. The golden colour is due to the layer wrapping the satellite that thermally insulates it in space. Compare these two photographs with the artists conception of Astrosat in the panel below. Here, each of the five telescopes are labelled, along with the solar panels which were unfurled in space after launch. Can you identify each of these five telescopes in the two photographs in the top panel? Note that the LAXPC is made of three similar units, and the UVIT consists of two telescopes next to each other.

Click here for the booklet published during the launch of AstroSat.

Click here for the entire APOM archive.


AstroSat, India's first dedicated multi-wavelength space observatory, was launched by ISRO on 28 September, 2015. It has five instruments on board – the Ultra Violet Imaging Telescope, the Soft X-ray Telescope, the Large Area X-ray Proportional Counter, the Cadmium-Zinc-Telluride Imager and the Scanning Sky Monitor.

Get answers to your common queries about ASTROSAT in English, in हिंदी, and in मराठी.


  1. Pale Blue Dot (EARTH): Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.

    The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

    Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

    The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

    It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.


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