University of Michigan - Department of Astronomy




Version: Computer

Solar Observing using the Computer

You are going to use a website to view the Sun today in multiple wavelengths.  In addition to current images, the website also has lots of information on the Sun, and the effects of solar activity here on Earth.  You may want to check out the Illustrations, visualizations and interviews for more information on the Sun or solar activity.  For example, the first two illustrations show our model of the Sun.

One caution: if a satellite or instrument is down, the latest image will NOT be available.  Always read the information, and check the date on the images.  The date is generally along the top or bottom edge.

First load the web page:

Make sure the image tab is expanded.
Spend a couple minutes clicking on the images, zooming in and out, moving around the image and familiarizing yourself with the controls.

If the Sun is quiescent or the viewer won't load, a set of static images is available.

Part 1: Visible Light images

These are the same types of observations we would be able to make from the roof of Angell hall, but in more detail, and without the cloudy or cold weather.

Find the white light image (normally comes from Michelson Doppler Imager – more information on this instrument and how it creates the image is available in the sunspot visualization)

  1. Find the date of the image and record it here: ________
  2. How many sunspots are visible today?

  3. Sketch the Sun. Include some notes about visible features as well.
    Space for white light sketch
  4. Find the largest sunspot.  What number is it? _______
  5. Zoom in until you can see the edges of this sunspot.  Compare it to the Earth size (lower right corner).  Is it bigger or smaller (circle one)?  By what ratio? (e.g. ½ as big)

  6. Is the granulation visible?

Find the h-alpha image

  1. Is it the same date? If not, how many days different is it?

  2. Sketch this view, including anything visible on the limb. You do not have to be highly detailed.  Label any features that are visible, especially (dark) sunspots, plages, filaments and prominences(see the image description if you don't know what these are). Also make some notes about how this compares to the white light view.
    Area for H-alpha sketch
  3. Look in the same area as the biggest sunspot from above. How does the region in the H-alpha image compare to the sunspot?

  4. Is the granulation easier or harder to see than in the white light image?

Part 2: Images not normally visible to humans

Find the magnetogram.  Bright indicates magnetic field lines coming out of the Sun, dark is where the magnetic field lines are running in, and grey is where the magnetic field lines are close to parallel to the surface (but watch out for sections of missing data, which are usually white lines). Find the same region as the sunspot from the white light part

  1. What can you say about the magnetic field in the sunspot regions?

Check out the UV images.  They should be similar (except in color). Compare the sunspot region again. 

  1. What can you say about the sunspot regions in UV?

  2. Find a region that looks active (either bright or dark in all the current images) that didn’t look like much in the white light image. Place an x on this region on your white light image sketch.

  3. Go back to the white light image and look at this region. Is there anything there?

  4. Check out the same region in the H-alpha image: does it show any activity?

  5. Look at this region in the magnetogram.  Is the magnetic field in this area fairly quiet, or rather messy?

Part 3: The Solar Corona

Find the coronagraph images.

  1. Are there any flares, CMEs,  or major activity?  (You may want to check the multi-mission view of a solar flare or Coronal Mass Ejection under visualizations)

  2. Find the graph of X-ray flux.  Is the X-ray flux large or small?

  3. Is there a lot of activity on the Sun today?  Defend your answer using all your observations so far, including parts 1 and 2.

  4. Check out the image of auroral activity on Earth. Are you likely to be able to see aurora tonight from Ann Arbor? How do you know?

  5. Does this make sense given your answer to the question 19? Explain

created: 1/30/08 by SAM

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