Observing the Brightest Star, the Sun
Preparation before the weekend observing session
Before coming to the weekend observing session, you should familiarize yourself with the following things that you will potentially observe on the Sun. Define and describe each of the items on the list before the lab, and turn them in when you arrive. A brief paragraph per item is fine. Pick your five favorites and bring pictures of them as well.
1. Sunspots (The dark inner part is called the umbra, while the outer, gray areas are the penumbra – do not confuse these words with the terms referring to solar or lunar eclipses.)
2. Prominences
3. Facula (plural: faculae)
4. Spicule
5. Granulation
6. Limb darkening
7. Chromosphere
8. Photosphere - describe only, and label it in one of your other pictures.
9. Sunspot Cycle - describe only.
10. Maunder Minimum - describe only.
What to do
Outdoor telescopes
- The outdoor telescopes are the same telescopes we have used throughout the class, except they are covered with a solar filter which blocks 99.9999% of the sunlight. Look through the eyepiece and draw a detailed sketch of the entire solar surface as seen through the telescopes. This sketch should include any visible large sunspots, any visible faculae (these can be tough to spot, ask for help if necessary), and limb darkening. Extra care should be taken to sketch the location of the sunspots on the face of the Sun if you plan on returning on the second day for extra credit. Move to a telescope that shows sunspots at high power and draw detailed sketches of the same solar features, and include details of the sunspots including the umbra and penumbra regions of them.Observatory telescope - This telescope is a 16-inch Cassegrain telescope similar to the C-8’s outdoors, except that it is equipped with a Hydrogen alpha filter, which allows only one specific wavelength (color) of light to pass. The only wavelength of light transmitted is at 656 nm (very deep red), which is the same wavelength of light emitted by ionized hydrogen. So you will be seeing features on the Sun more clearly that are due to ionized hydrogen. You should draw detailed sketches of part of the limb of the Sun that shows the chromosphere, granulation, a prominence, and hopefully some spicules. You should carefully note the size, shape, and location of the prominence. Look at the prominence an hour after you first sketch them and look for changes. Make a second sketch and carefully note any changes in their shapes that you observe.
What to submit
Please provide the following for each of the items on the list, above:
1. Define and describe each item.
2. Copy pictures from an outside source for at least 5 items from the first 7 on the list, and include those with your descriptions.
Turn in items 1 and 2 when you arrive on Saturday.
3. Two detailed sketches of the Sun with regular solar filters as described above. Label any features from the list that you see.
4. Two detailed sketches of the Sun through the hydrogen-alpha filter as decribed above. Label any features from the list that you see.
5. Compare and describe the changes in the prominence that you observed in the one hour between the two sketches of it that you made.
Turn in all four sketches and the comparison of the changes in the prominence before you leave.
You will receive
extra credit if you come to the observatory again on Sunday and you can see and draw evidence of the Sun’s rotation and new prominences that have formed since Saturday.