Every 11 years, the Sun reaches a peak in its activity. This period is known as a solar cycle, and we are now witnessing the peak of solar cycle 25. During such times, sunspots, flares, prominences, and other solar phenomena become far more frequent and pronounced.
This cycle doesn’t follow a strict 11-year pattern. It varies between 8 and 14 years, with the average length being approximately 10.7 years.
A Look Into Solar History
Although sunspots were noticed as early as the 18th century, it wasn’t until 1843 that Samuel Heinrich Schwabe, a German amateur astronomer, formally recognized the Sun’s cyclic behavior. Based on Schwabe’s decades of observations, Swiss astronomer Rudolf Wolf identified the cycle that began in 1755 as the first official one — naming it solar cycle 1.
Wolf also introduced the Wolf number, still used today to count sunspots daily.
Quiet Times in the Past
Solar activity has dipped dramatically in certain periods over the past 3,000 years. These events are known as grand solar minima. Long before telescopic records, scientists examined tree rings and elemental deposits to assess solar fluctuations.
The earliest recognized minimum is the Homeric Minimum, which spanned roughly from 800 BC to 600 BC. These quiet phases lasted from 40 to 150 years, and during them, sunspots appeared rarely — sometimes not at all.
This Cycle Is Not One of Those
Unlike past lulls, solar cycle 25 has been highly active. Sunspot activity has been strong in recent years, giving both amateur and seasoned astronomers ample opportunities for observation and photography.
But remember: observing the Sun can be dangerous without proper equipment. During eclipses, millions of eclipse viewing glasses are sold or distributed. These cardboard glasses use Mylar lenses that safely reduce the Sun’s brightness for the human eye.
These glasses are great for casual viewing. However, you won’t see most sunspots unless they’re twice Earth’s size — which is rare.
Observe the Sun Safely
To observe sunspots in detail, use a telescope with a certified solar filter. This filter must be attached to the front of your telescope — never at the eyepiece. Adjusting magnification is simple: just swap eyepieces as you would for night sky observation.
The same rule applies for binoculars — you’ll need a solar filter on each lens. Without a front-mounted filter, the Sun’s light can cause permanent eye damage within seconds.
By using proper filters and precautions, your telescope’s utility doubles — allowing for both daytime and nighttime exploration of the cosmos.
Whether you’re a beginner or an experienced stargazer, now is the perfect moment to turn your telescope toward our nearest star. Take advantage of solar cycle 25‘s heightened activity while it lasts.
