Tag solarobserving

An April SolarQuest — Photobomb Included

Photonstopper
The Sun, as it appeared on April 17, 2025, in hydrogen-alpha light. The image was recorded using a Coronado solar telescope, a Sky-Watcher SolarQuest mount, and a ZWO ASI 678MM camera. Photo by James Guilford.

Taking advantage of midday clear skies, Thursday, we set up the hydrogen-alpha telescope and did a little observing and imaging. Seeing conditions were only good but we could make out several prominences along Sun’s limb. (The proms did not record well and we need to figure out how to enhance their visibility in our images.) Most notable, however, was the shear number of filaments in Sun’s northern hemisphere. None visible in the south! Fragments of exploding filaments launched from Sun and produced two CMEs that, when they reached Earth on April 16, caused strong geomagnetic storm activity and widespread auroras. The storm, however, died out before northern lights could be seen here.

The Sky-Watcher SolarQuest mount is shown here aiming our Coronado 60mm hydrogen-alpha solar telescope at Sun.

Aiding in our efforts was a device we used for the very first time in this session: The Sky-Watcher SolarQuest with its HelioFind system. The device is lightweight, easily supported our rather robust Coronado solar telescope, and was exceptionally easy to learn and operate. Essentially, all that was needed was to set the tripod up so that it was level, turn the device on, and let it do its thing! It is powered by four AA batteries, placed inside the unit. As an alt-az mount, no counterweights or muliti-axis balancing was needed; just mount the scope with its balance point at the center of the dovetail clamp. No remote control, no app, the compact and self-contained SolarQuest established GPS contact, leveled the scope, then looked for Sun. The SolarQuest turned and elevated the telescope, quickly acquiring our nearest star. When the motion stopped, we looked through the eyepiece to discover Sun well within the field of view. A few nudges of the system’s adjustment buttons and Sun was centered. Tracking was excellent throughout the observing/imaging session. Provision is made for further refinement of tracking but that adjustment was unnecessary for the day’s activity. The SolarQuest will make our daytime astronomy a whole lot more convenient and enjoyable!

A business-class jet airplane trailing twin contrails is seen in silhouette against the roiling surface of the sun. The image is recorded in hydrogen-alpha light. Photo by James Guilford.

We had just finished setting up for some solar astronomy and tapped the button to begin a video sequence when something flashed across the computer screen. A jet appeared for less than a second, contrails briefly persisting, silhouetted against the roiling solar disk! We’ve only seen this twice while observing Sun, this being the second time, and we only captured this image by shear luck. The first time we witnessed a solar “photo-bombing” was under similar circumstances. Previously, we had completed setup, was refining focus, and just about to begin recording exposures. We missed imaging that encounter by about the same interval as we succeeded this time!

Our best Sun images yet

Photonstopper
The complete solar disk as recorded in hydrogen-alpha light. The “worm-shaped” shadows seen in several areas are filaments. The dark spots are, yes, sunspots. And around the rim or limb of the solar disk are seen prominences — geysers of solar plasma riding magnetic field lines before crashing back into the sun. False color applied.

In addition to photographing Earth’s Sun in white light nearly every clear day, we occasionally set up the heavy telescope mount and bring out the new hydrogen-alpha (Ha) telescope for a bit of visual observing and unique imaging. It’s a bit of work since, without an observatory building we usually feel we need to take down and store away the mount after each session, so we don’t do that every day.

On November 8 we had clear skies, good atmospheric conditions, and the inclination to do the Ha setup and were rewarded with splendid views plus our best Sun images yet.

Using a Barlow lens to zoom for a closer view, we see large and small prominences and hints of spicules along Sun’s limb, and several large filaments. The dark spots in the upper left-hand corner of this picture is a group of sunspots at active region 3889.

Across the solar disk were visible large and distinct filaments — prominence loops seen from “above” — as well as sunspots and swirling patterns in the solar atmosphere around them. All around the Sun’s limb could be seen prominences glowing against a background of black space. Some of the prominences, which are fountain-like sprays and loops of magnetically-charged plasma, were quite large.

A major part of producing good images is what happens away from the telescope. Our usual practice is to record video of the telescope view and use software, in the office, to sort through thousands of video image frames, then stack the best few hundred to form a single still image. The still image is then edited to bring out as much detail and tonal range as possible. This process, which is common in astrophotography, produces a sharper image than what might be acquired via any single photographic “snapshot” owing largely to atmospheric turbulence.

Using a Barlow lens to zoom for a closer view, we see large and small prominences and spicules along Sun’s limb. The dark spot just above the center of this picture is a large sunspot at active region 3879.

There’s room for improvement, and we’re seeing excellent progress, but the images shown here are our best yet of Sun in hydrogen-alpha light.

Note: H-a light is that which Sun is producing in its chromosphere — the solar atmospheric layer between the outer corona and the lower photosphere — and is invisible even to protected human vision and white light cameras. Specialized optics are required to block other wavelengths found in white light and allow observation of Ha. When we observe or image in white light, we’re actually viewing features such as sunspots while looking through both the corona and the chromosphere!

Safety Note: It is not safe to look directly at the sun without specialized eye protection for solar viewing, and safe solar filters for telescope, binocular, or camera use. Permanent damage to vision can result from improper viewing of the sun.

The complete solar disk as recorded in hydrogen-alpha light. The “worm-shaped” shadows seen in several areas are filaments. The dark spots are, yes, sunspots. And around the rim or limb of the solar disk are seen prominences — geysers of solar plasma riding magnetic field lines before crashing back into the sun. Image was recorded and presented here in monochrome.