Few Solar Features

Approaching Solar Minimum

My solar telescope has been idle for eight months. During this time good observing conditions did not coincide with the presence of significant solar features. The Sun's roughly eleven year sunspot cycle is probably within a year of reaching minimum activity, so sunspots are rare these days.

Sunspots and large filaments have been mostly absent from the solar disc for many months. What a change from three years ago! In 2015 there wasn't a single day without sunspots. By 2017 there were 104 spotless days, about 28 percent of the time. So far this year the sun has been spotless 54 percent of the time. Any recent sunspots have usually been small and short-lived.

On May 24th a week of rain and clouds finally ended leaving lower humidity and a clear blue sky over my red dot location in eastern Virginia as you can see in the following satellite image taken that day.

Although few solar features were present, I decided to do some imaging anyway. Gentle puffs of breeze blew from time to time. The temperature ranged from a tolerable 75 to 78 degrees. Observing conditions would have been nearly perfect except for neighborhood noise. String trimmers and lawn mowers roared next door while a screeching rock saw cut patio stones for another neighbor. Occasional dust clouds from stone cutting blew towards my yard.

A bit out of practice with the solar observing routine, I took my time and consulted notes. Eventually, I captured some decent images. The first picture below is a 15-panel mosaic showing modest features on the eastern half of the Sun. Active area 2712 had just rotated into view near the limb. Active area 2710 is to the right of 2712. A number of prominences are visible around the limb. (Click on the image to see better detail.)

Aside from two small active areas seen above, the remaining eastern solar surface is relatively featureless. The next picture is a two-panel mosaic showing a closer view of the two active areas. During the time of image capture area 2712 on the left had emitted a small jet of gas toward the limb.

Area 2710 showed only the characteristic white color of increased energy emission but no sunspot umbra.

The Sun's west side contained only one obvious sunspot umbra contained within active area 2711 seen below.

I used longer exposure times to capture relatively dim prominences along the eastern limb. The brighter disc was, consequently, overexposed. I've blacked out the disc in the next 7-panel mosaic so only limb features are visible. Unfortunately, software used to combine separate images into a mosaic slightly distorted the limb from its true circular shape. The distortion isn't drastic, but it's definitely noticeable in the image below. (Click on the image for better detail and less apparent distortion.)

Longer exposure times did reveal more prominence features than those visible in the first mosaic image above.

As the solar activity cycle grinds through its minimum over the next year or so I'll have to patiently wait for good opportunities to observe.