Observing Surface Features of the Sun for AmateurAstronomers

Nikhil Anand & Mustafa Shahid

Indian Institute of Space Science and Technology

March 20, 2015

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Why

There is a misconception that astronomy happens only at night.

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Introduction

Viewing the sun directly is harmful for the eyes

The sun surface offers a lot of interesting features for amateurs toview

Features we observed areI Sun SpotsI GranulationI Corona

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Sun Spots

Sunspots are temporary dark spots on the sun surface

They appear dark due to lesser surface temperature than thesurroundings

They are caused due to the differential rotation of the sun whichcause the magnetic field lines to twist and pop out of the surface

Hence they always appear in pairs

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Granulation

Convection currents of plasma within the Sun’s convective zone giverise to a bubble sort of structure

These are called granules

The center part is hotter (due to plasma), hence brighter. The outerpart is cooler and darker

The superficial granules have a life span of around 8-20 minutes andare about 1500 km in diameter

There is another layer of supergranules below the photosphere whichlive for a day and are 30,000 km in diameter

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Corona

Atmosphere of the sun

It is an aura of plasma that surrounds the Sun

Visible as a dark ring around the sun

It is much hotter than the visible surface of the sun

However

It is 10−12 times as dense as the photosphere thus produces aboutone-millionth as much visible light

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Equipment

Celestron Powerseeker 70AZRefracting TelescopeFocal Length : 700 mm;Eyepiece : 35 mm

Galileo Startracker 5.3 inch Newtonian ReflectorFocal Length : 900 mm Eyepiece : 25 mm

Solar Mylar Filters

X-Ray Sheets

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Methodology

Refracting Telescope

X-ray sheets

Projection

Reflecting Telescope

Solar filters

Projection

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Observations

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1r2 dependence of image formation vs distance

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Discussion

1 New techniques

2 Differential rotational period of Sun

3 Observing solar eclipses

4 Mercury and Venus transit

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References

Student Guide to Activity 1: Features of the Sun

http://science.howstuffworks.com/sun5.htm

http://csep10.phys.utk.edu/astr162/lect/sun/sunspots.html

http://en.wikipedia.org/wiki/Sunspot

www.spaceweathercenter.org/resources/05/solarscapes/Act1s.pdf

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Thank You

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