Tonight's Sky
Sun
Sun
Moon
Moon
Mercury
Mercury
Venus
Venus
Mars
Mars
Jupiter
Jupiter
Saturn
Saturn

Tonight's Sky — Change location

OR

Searching...

Tonight's Sky — Select location

Tonight's Sky — Enter coordinates

° '
° '

What is the best and cheapest way to get into solar observing?

Jonathan Scott, Atlanta
RELATED TOPICS: OBSERVING | SUN | ECLIPSE QUESTIONS
Solar-observing
One of the simplest and least expensive ways to dive into solar observing is to project the Sun's image onto a white backdrop. Use the scope's shadow to align the Sun — do not look through the instrument. // Michel Huet
Solar observing is a great way to extend the pleasure of backyard astronomy into daylight hours. It can be one of the least expensive facets of amateur astronomy, but also one of the riskiest. A brief telescopic peek at the Sun without proper precaution can result in permanent eye damage. That said, let’s look at the best and cheapest ways to safely view our star.

First, there’s solar projection — using a telescope to project the Sun’s image onto white cardboard or a sheet (see the photo above). With a low-power eyepiece in place, point your scope sunward; use the scope’s shadow — not the finder — to aim. You’ll know you’re on target when sunlight illuminates the eyepiece. Position the cardboard a foot or two from the eyepiece, and focus until the bright circle of light (the projected image of the solar disk) is sharp at the edges. If the Sun is active, as it currently is, sunspots will appear as dark blotches. Daily observations will reveal the spots’ ever-changing appearance and stately drift across the solar disk as the Sun rotates.
 
Solar projection doesn’t re-quire a large, expensive telescope — a big plus for the budget-minded astro-hobbyist. In fact, an ideal instrument for solar observing is a 60-millimeter refractor, available from many retailers for under $100.

If you want to see more detail (and who doesn’t?), consider an “aperture filter” that affixes to the front of the telescope and prevents most of the sunlight from entering. The method is slightly riskier than solar projection because an improperly secured filter can fall off with disastrous results. It’s also a bit more expensive, but not excessively so. Solar filters for small-aperture scopes typically run from $50 to $65. Using such a setup, you’ll see more intricate detail in sunspots, as well as the bright cloudlike features called plages that often accompany them. The Sun’s visible surface (the photosphere) will appear grainy — dramatic evidence of its turbulent nature.

For more information about safely viewing our nearest star, check out my Observing Basics articles “Good Sun behavior” (June 2005) and “Solar safety” (July 2009) in the archives at www.Astronomy.com/Chaple.
Glenn Chaple
Contributing Editor and
longtime observer
0

JOIN THE DISCUSSION

Read and share your comments on this article
Comment on this article
Want to leave a comment?
Only registered members of Astronomy.com are allowed to comment on this article. Registration is FREE and only takes a couple minutes.

Login or Register now.
0 comments
ADVERTISEMENT

FREE EMAIL NEWSLETTER

Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter.

ADVERTISEMENT
ADVERTISEMENT
asy_observingMars

Click here to receive a FREE e-Guide exclusively from Astronomy magazine.

Find us on Facebook