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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