Tele Vue’s 2021 Solar Gallery

It’s time to revisit the Sun! This nearby yellow-dwarf star is entering middle-age and is showing some spots! Here we have a  selection of solar images, taken from around the world, made with Tele Vue Barlows and Powermate image amplifiers.

We are currently almost 2-years into the 11-year Solar Cycle Nº 25. This Solar Cycle Progression diagram shows the observed Sunspot Number and forecast (red line). 

Sunspot numbers vary over longer periods than the 11-year cycle. One report in Nature magazine, based on tree ring data, says that solar maximums in modern times haven’t been so high in 8,000 years! We are living at an instant when the Sun is more active than in the past. 

Meet the Tele Vue Line of Barlows

Several of the images here were made with our Barlows. Properly designed Barlows do wonderful things: They amplify power, slow the telescope’s f/# (improving eyepiece sharpness), and give designers the opportunity to compensate for eyepiece aberrations.

Tele Vue Barlows use multi-coated high index glasses for optimum aberration correction, exceptional contrast with virtually no light loss. Observed performance is aberration-free, even when tested with f/4 scopes. They even improve our competitor’s eyepieces and telescopes!

For more info see the Tele Vue Barlow page (mobile site).

Solar Filter Safety
Solar imaging is done with filters. Often a filter on the front opening of the scope is used to reject most of the energy of the Sun. They may or may not require a second filter or filtering device on the focuser.  One must be careful to make sure the correct filter is used for the intent: front filters designed for imaging will not reject enough energy for safe visual observations.  Due to the wide variety of front aperture diameters among telescopes,  amateurs often make their own filter from solar film. If you go this route, be sure to label the filter for visual or imaging and if it needs another filter on the focuser.

Filter Types
White light filters cut down the light from the Sun across the spectrum. These allow observations of the solar photosphere. The photosphere is home to granulation (rising and sinking convective cells); faculae (bright patches of concentrated magnetic energy); and sunspot groups. 

Hydrogen-alpha filters allow views of the Sun in a narrow wavelength of light given off by hydrogen atoms. This allows views of the chromosphere. Much of the action in the chromosphere is above the photosphere. In addition to sunspots, here you see prominences, spicules, fibrils, flares, and more.

Features of the Sun
Sunspots are cooler regions on the Sun’s surface. The spots would appear to be as bright as the full Moon if seen by themselves. But against the Sun they appear dark. Sunspots reveal the presence of magnetic disturbances deeper in the Sun. Because activity like solar flares and coronal mass ejections (CME) are associated with these magnetic regions, they are labeled active regions. 

Plages appear as white regions around sunspots that are visible in hydrogen-alpha light. They are very apparent in the lead-off image of this blog.

The above image is teaming with Granules — irregular grains on the Sun’s disk caused by temperature variations. Granules deliver energy from deeper in the Sun to the surface through a convection process. Each granule survives about 5-minutes and delivers as much energy in that time as Hoover Dam does in a millennium.

Faculae are bright areas visible on the limb of the Sun between solar granules. Sunspots always have faculae but faculae may exist alone. In white light, they are usually most easily seen near the limb, or edge, of the solar disk due to limb darkening.

Spicules are furry-looking features visible along the edge of the solar disk. Made of super-heated plasma, they’re jets of hot gas that can reach 10,000 km high.

Fibrils are spicules against the solar disk on the solar disc.

Meet the Tele Vue Line of Powermate Amplifiers

Tele Vue’s Powermate line has some distinct advantages over simpler Barlows for visual and imaging. Powermate™ photo / visual amplifiers increase the focal length of your scope with reduced aberrations, greater magnification potential, and compact size compared to typical Barlow lenses. Also, Powermates™ can be stacked with no adverse impact. Powermates are available in different barrel sizes and powers to meet your mission needs: 1¼” (2.5x & 5x) and 2″ (2x, & 4x) formats.

Imaging with Powermates is easy: the visual tops all unscrew to accept a specific Tele Vue Powermate T-Ring Adapter for use with standard camera T-rings.

Read more on our Powermate page (mobile site).

Solar prominence is caused by plasma flow along a magnetic loop between sunspots on the limb of the Sun. Reaching thousands of kilometers above the apparent solar surface, they can last months.

Filaments are prominences away from the solar limb. They appear as dark ribbons against the face of the Sun. 

Solar flares are explosions that release a large amount of energy. It is caused by a loop of the Sun’s magnetic field that snaps. They can last for hours and if strong enough can form a coronal mass ejection (CME). CMEs are plasma bursts that move away from the Sun along magnetic field lines. CMEs arriving at Earth can cause auroral displays and impact radio communications and the power grid.

Tele Vue Eyepieces for Solar Viewing

The DayStar Quark (when used with an energy rejection filter) is a great Hydrogen-alpha filter for imaging the chromosphere. You’ll note that many of the images on this blog were created with the Quark. So how is it for viewing the chromosphere? That depends on the eyepiece.

 

If you read the DayStar manual, you’ll read the following: 

Daystar Recommends Tele Vue Plössl series eyepieces of 25mm, 32mm, and 40mm.

They explain why:

It should be noted that repeatedly in side-by side tests, we found Tele Vue brand Plössl eyepieces to offer the highest contrast, most even view and widest exit pupil. In Solar Observing, contrast is achieved by control of scattering. Tele Vue Plössls stand out in superior design. Furthermore, the adjustable eye cup offers additional contrast by allowing the user to dark adapt during sunny days.