Archives For Sun

Image: Path of the August 21, 2017 Total Solar Eclipse - Courtesy NationalEclipse.com

Path of the August 21, 2017 Total Solar Eclipse – Courtesy NationalEclipse.com


 
Planning is underway for a public event celebrating the upcoming August 21, 2017 solar eclipse. The eclipse will begin at 1:07 PM and end at 3:52 PM Eastern Daylight Time. Maximum eclipse will occur locally at about 2:30 PM EDT. Details are developing but the Hiram Eclipse Watch will take place on the Hiram College campus and will be free and open to the general public — everyone’s invited!

The so-called “American Eclipse” or “National Eclipse” will be a total solar eclipse (Moon covering the entire solar disk) only for those situated on a relatively narrow path stretching from the Pacific Northwest to South Carolina and the Atlantic. For the balance of the Continental United States, the eclipse will be partial — the Moon will cover only part of the Sun. Northern Ohioans will see a bit more than 80 percent of the Sun covered by the Moon reducing the Sun to a brilliant crescent!

We have created and are regularly updating a page on this website dedicated to Hiram’s eclipse event; check there for event details as they develop. We hope to see you August 21 for a fun and memorable experience.

To reach our Eclipse Watch page see the menu at the top of this page, or click here!

Photo: 2016 Transit of Mercury. Photo by James Guilford.

Mercury’s Transit in Progress: Mercury is the tiny dot at the lower-left. Smudge near the center is a group of sunspots. Photo by James Guilford.

Our Solar System doesn’t care about the local weather. When something rare and interesting like today’s transit of Mercury across the solar disk takes place, it happens and there are no “rain checks.” And so it was this morning when the day dawned clear to partly-cloudy allowing us to glimpse the beginning of Mercury’s trek only to have the show stopped by rapidly encroaching clouds progressing to solid overcast!

Photo: Transit of Mercury blocked by clouds. Photo by James Guilford.

Transit of Mercury: Mother Earth’s atmospherics begin to block the view! Photo by James Guilford.

At the predicted hour Mercury appeared as a tiny dot, silhouetted in the lower left-hand quadrant of the Sun’s bright disk. Using special protective filters, observers on the ground watched as the small dot slowly moved inward from Sol’s limb. Here in Northern Ohio, transit watchers were treated to the beginning of the show. Much of the nation missed out entirely, cloud cover already in place at dawn!

Photo: GOES weather image, May 9, 2016.

Weather Satellite Image: Much of the US cloud-covered during the transit event.

NASA’s Solar Dynamics Observatory, a spacecraft, is unaffected by Earth’s pesky atmospherics and its technology produces some very dramatic images. One of my favorites shows Mercury about to cross between the satellite (us) and the Sun’s glowing photosphere; the planet has the active solar atmosphere as backdrop. Planet Mercury is 3,030 miles in diameter, not much bigger than Earth’s Moon, and looked every bit as tiny as it is compared with our nearest star!

Photo: Mercury's transit about to begin. Data courtesy of NASA/SDO, HMI, and AIA science teams.

The View from Space. Credit: Data courtesy of NASA/SDO, HMI, and AIA science teams.

Today’s transit of Mercury took place over several hours. For us in Northern Ohio, the transit began at about 7:12 AM Eastern Daylight Time with the Sun barely up. Midpoint of Mercury’s passage was at 10:57 AM, and the transit ended at 2:42 PM. Because of the orbital inclinations of the inner planets, the alignment needed to produce a transit of Mercury happens only about 13 times per century making even a glimpse of the event something special. After today’s, the next transits of Mercury will take place in November 2019, November 2032, and November 2049.

At least we won’t have to wait for so long as we must for the next transit of Venus — that happens in December 2117.

 

On Monday, May 9 solar observers in North America will be able to see the silhouette of planet Mercury as it passes between Earth and our Sun. The event, called a transit, is relatively rare — though not so rare as a transit of Venus — and may cause interest in viewing the Sun. WARNING: Looking at the Sun, especially through optical instruments, requires extreme caution! Permanent vision damage can result if proper precautions are not taken! Click here for a good article on safely observing the Sun.

At present we DO NOT plan to open Stephens Observatory for the transit but if plans change, the announcement will be made here — check back later. If conditions are clear, we hope to post images made via telescope at a remote location.

Tiny planet Mercury will appear as a correspondingly tiny black dot against the Sun’s brilliant disk. If any sunspots are present on Sol’s face, compare them with Mercury: the planet will be distinctly round and noticeably darker than sunspots, and from minute to minute it will move — sunspot motion takes days!

Image: Planetary positions on May 9, 2016.

May 9 Transit of Mercury – Note how the orbits of Mercury, Venus, and Earth are “tilted” making line-of-sight alignment a rare occurrence.

Viewed from Earth, transits occur when one of the inner planets crosses the line of sight between our world and the Sun; only Venus and Mercury are ever able to do that. A transit, then, is a bit like a solar eclipse only viewed at a greater distance and blocking only a small amount of the Sun’s light.

Transits would occur more often but for the fact that the orbits of Mercury and Venus are “tipped” so that they do not align along the same plane as Earth’s path. Only when the planets are in the right position where the line of sight passes straight through to the Sun do we see transits and with Mercury, that happens only about 13 times per century. After May 9, the next transits of Mercury will take place in November 2019, November 2032, and November 2049. The most recent transit of Venus took place in June 2012 and will not be seen again until December 2117.

Monday’s transit of Mercury will take place over several hours. For us in Northern Ohio, the transit begins at about 7:12 AM Eastern Daylight Time with the Sun low in the east. Midpoint of Mercury’s passage will be at 10:57 AM, and the transit ends at 2:42 PM.

Cloudy skies? Don’t have proper gear to view the Sun? Fret not! There will be “live” webcasts of the event from various sources during Mercury’s passage. Use your favorite web search engine to find good sources and check for a planned broadcast via NASA TV. NASA will stream a live program on NASA TV and the agency’s Facebook page from 10:30 to 11:30 AM — an informal roundtable during which experts representing planetary, heliophysics and astrophysics will discuss the science behind the Mercury transit. Viewers can ask questions via Facebook and Twitter using #AskNASA.

We hope to post a few links here later.

Sunspot Photo: Photo Info: Canon EOS M3: ISO 250, 1/1600 sec., f/8, 400mm lens. Photo by James Guilford.

Sunspot AR2529

Changing a word from an old song lyric by The Police, there’s a big black spot on the Sun today. Sunspot AR2529 is the dominant feature on our otherwise quiet star. Visible to the unaided eye through solar-safe filters, the sunspot is several Earth-diameters across and roughly “heart” shaped! This image was recorded Wednesday, April 13, at 2:19 PM. The bright orange color resulted from use of a solar filter covering the camera lens.

Here is what SpaceWeather.com says about the sunspot: “Since it appeared less than a week ago, AR2529 has been mostly, but not completely, quiet. On April 10th it hurled a minor CME into space. That CME, along with another that occurred a few hours later, could deliver a glancing blow to Earth’s magnetic field on April 13th.” A CME is a Coronal Mass Ejection wherein the Sun flings plasma from its atmosphere out and into space. CMEs reaching Earth can cause auroras.

Photo (above) Info: Cropped from full frame, Canon EOS M3: ISO 250, 1/1600 sec., f/8, 400mm lens. Photo by James Guilford. Photo (below) Info: Canon EOS 6D: ISO 400, f/4, 1/1250 sec., observatory telescope afocal technique.

Photo: Sunspot AR2529 - April 14 - Through the Vintage Cooley Telescope. Photo by James Guilford

Sunspot AR2529 – April 14 – Through the Vintage Cooley Telescope

Train of Sunspots, November 4, 2015. Photo by James Guilford.

Train of Sunspots, November 4, 2015

An impressive train of sunspots has been making its way across the face of our nearest star this week. In the photo above: Designated AR2447 (small group to the left), AR2443 (bigger and darker, near center), and AR2445 (far right), the “Active Regions” have the potential of unleashing flares. In fact, AR2445 was the source of a flare that caused this week’s “northern lights” sighted across northern latitude locations around the world. Now rotating over the Sun’s limb, AR2445 won’t be aimed at Earth for a while — if ever again — but AR2443 has potential for high-energy flares.

Photo credit: James Guilford. Canon EOS 7D II: ISO 400, f/11, 1/1250 sec., 400mm lens with Astrozap film solar filter, heavily cropped, November 4, 2015, 2:22 PM.

Latest solar image

StephensAstro —  October 26, 2015 — Leave a comment
The Sun - October 26, 2015. Photo by James Guilford.

The Sun – October 26, 2015

 

Preparing for this week’s expected heavy rains and wind, I went to the roof of the observatory to clean out the rain gutters and check the downspouts. Chores done and with the dome open, I made another experiment at solar imaging through the big vintage Cooley Telescope. I found I could focus on the Sun (through a safe solar filter) and, with a Canon DSLR camera at the telescope’s prime focus, recorded a few one-shot images at ISO 400 and 1/500 second. The telescope is a 9-inch refractor with a focal length of 3,327mm. The results appear better than last time but show the apparent effect of atmospheric turbulence: that’s my story and I’m sticking with it! A few sunspots were visible and details of Sol’s roiling atmosphere show up. The photographic technique is the simplest we can use; more sophisticated processes are employed these days to achieve best results. Still, proof of concept is a good thing and getting the image focused is a critical step. I think next time we may try a dimmer subject.

Photo: Image showing granular structure of the Sun's photosphere. Photo by James Guilford, Stephens Memorial Observatory.

Granular Sun – July 20, 2015

Testing out a modified eyepiece adapter today, I had the vintage Cooley Telescope pointed at the Sun. Since everything was set up, I decided to see whether we could capture decent images of our nearest star, near noon on this clear summer day. While the sky was clear, the seeing — quality of the view — was not as good as I’d hoped. Apparently, midday heat was causing the image to “shimmer” in the eyepiece and the photographs reflected that. Examining the pictures on the computer screen, I was disappointed because I saw no details in the several sunspots visible. As I made some photographic adjustments, however, other features came into view: granulation and faculae! The granules, upwelling super-hot cells of solar atmosphere, are easy to see; they give the image above a “grainy” appearance. Faculae are a bit trickier but if you look along the darker right-hand edge of the solar image, you will see some light-colored patches — those patches are faculae! So a bit of disappointment changed to a sunny day surprise.

NOTES: Sunspots in this image are #2387 (L) and #2386 (R). For more information on the Sun’s photosphere and what can be seen there, visit this page at NASA/ Marshall Space Flight Center.