May 13 2024

11 May 2024 Auroral Storm

This has been quite the spring for astronomical activity! We’ve enjoyed a total solar eclipse, and now one of the largest auroral storms in some 20 years (the last big one was the Halloween storm of October 2003). Leading up to this event was the appearance of the huge sunspot groups 3668 and 3664.

As this group started to send out massive coronal mass ejections, it became apparent that these were headed right towards Earth: a good sign for geomagnetic phenomena, storming and auroral activity. The Space Weather Prediction Center started posting advanced watches then warning as the 11th of May approached. Sure enough, several of these CMEs combined into one large mass of solar material and slammed into our planet’s magnetosphere: aurora!

Starting out as faint greyish clouds, we knew these were not regular clouds as they danced and shifted shapes every few seconds. One moment, they would be small patches of light, the next, they would shoot up to the zenith and glow brightly before vanishing completely. As the storm progressed, color became apparent to the eye: pinks, greens, and violets started to show among a wall of color and light that filled most of the northern half of the sky.

We had set up two cameras to watch the storm progress: 20mm f/1.4 1000iso 1.3 second exposures all night long. Occasionally we’d shift their pointing direction to discover that fainter aurora was visible all the way to the southern horizon! Activity was rapid, changing constantly and colorful.

At the peak of the storm, there was considerable merging of aurora at the zenith. Below id a time lapse of this. The camera took a 1.3 second exposure with a separation of 1 second between each image. Here in the time lapse, each photo frame is 1/10 second in duration. The bright light passing through the video is a med-evac helicopter that passed overhead from Exeter Hospital.

Jun 10 2021

10 June 2021 Annular Solar Eclipse

From NH this was a partial eclipse, but we had good weather and the opportunity to watch the sunrise with the eclipse already in progress. The choice location was one of many spots along the NH seacoast. We chose North Beach in Hampton which had easy to reach parking and plenty of locations to settle a tripod, telescope and camera.

Brought to the event was a Questar 3.5″ telescope with full aperture solar filter for visual use and a Nikon D810, 500mm telephoto and full aperture solar filter for video and images.

We arrived just after 4:15am EDT: nobody was there! Just us, the stars and the eerie red glow to the northeast. Jupiter and Saturn gave us wonderful pre-sunrise views through the telescope as we waited for the sun to get above the horizon. People started to arrive at about 5:00am. By 5:15am the lot was full. Clouds? Oh yes, there were clouds throughout the entire event, but we still had great chances to see and photograph the event. Here are some to enjoy:

Oct 31 2019

The Pier is Poured

Yesterday the concrete for the telescope’s pier was poured. What an exciting moment in this telescope’s history. The contractors used a very large Sonotube held rigidly in place with a temporary framework of wood and cables. Internally there is quite the framework of rebar to help reinforce the pier’s strength. A few conduits were also placed inside for electrical and data lines which will drive the telescope. Images (click on them to enlarge):

A view of the building’s site with the framework around the Sonotube for the pier.

A closeup of the pier near the completion of the pour.

A wide field view of the site.

Oct 24 2019

0.7m Telescope Observatory Construction Begins

This will likely be a series of posts involving some very exciting news here at the observatory: We are adding a new observatory building complete with dome and telescope! Very much exciting times! The new structure will be 16’25’ in dimension with a 16′ diameter dome on the south side. The interior will be divided into two sections: the telescope/equipment room and the control room. A wall with large glass window will separate the two so that people can work with low-level red lighting while keeping the telescope and its sensitive instrumentation in the dark and away from the heat of humans which can cause disturbing air currents.

Artists Impression of the 0.7m Telescope Dome.

The telescope is a PlaneWave 0.70m diameter modified Dall-Kirkham optical system with two ports. One port will hold a CCD imager with filter wheel. The other will attach to a fiber-fed echelle spectrograph. It is difficult to imagine the scale of such an instrument. The telescope alone weighs over 1500 pounds! For a comparison here I am standing besides the same model of instrument at a recent American Astronomical Society meeting.

Ground breaking started a couple of weeks ago. Concrete pouring started today for the pier footing and the footing for the building’s foundation. This will help give a sense of scale the final structure.

The boundaries of the structure have been posted here with wooden stakes. The ground is being prepped to dig for the base level foundation.

The gravel base for the concrete has been laid here. Looking closely you can see the inset region in the gravel where the pier for the telescope will rest.

The initial concrete pour which took place today. The central region is the base for the telescope pier. The surrounding is the base for the building’s foundation.

Feb 14 2016

Echelle Spectrograph Up and Running

Over the past few weeks, the high resolution spectrograph was down due to our working on installation of a new control PC and the replacement of the imaging fiber. The spectrograph is an Echelle design, utilizing a grating design that overlaps 50+ orders of spectra before then being split out into separate rows on an CCD image. The raw spectra image looks like a series of curved lines, but the software does its magic, sorts out which row is which and then reconnects them all into one long, high resolution spectra.

sol1

The wavelength calibration is done using a Thorium Argon lamp at the observatory. This lamp generates many well-known emission lines that the spectrograph software then uses to set wavelength values to the spectra of objects being studied. The ThAr spectrum is below with the spectral orders labeled and the identified emission lines wrapped in green boxes.

ThAr

Once the software has all this figured out, each row is calibrated for wavelength and intensity and is saved in a tremendous FITS file. Below is one small piece of that FITS file for our Sun, the region around 656.3nm, the Hydrogen-alpha line:

H Aplha

Compressed to fit the screen here is a spectrum of our sun (actually clouds above our observatory, because imaging the sun directly would be the last thing we’d want to do with this device!). The image has been saved from Shelyak Instruments EShel software and calibrated within VSpec software. Wavelengths are in ångströms. The violet side shows that we have to work on radiometric correction for the instrument…. in progress 😉

sol_eshel_2016-02-13

Sep 30 2015

Lunar Eclipse Wows All!

September 27th lunar eclipse was an awesome experience from Exeter, NH. Well over 100 people came to the observatory for a visit and a look through the telescopes while the eclipse was under way. At moonrise, I thought there was actually someone with a spotlight in the adjoining fields…. nope! That was the moon! It was BRIGHT! Bright enough to take this 5 second exposure of the fields and fog:

Fields and Fog with Full Moon

As the event ensued, we had a few cameras out there: one taking wide field shots of the event every 10 minutes or so, one taking closeup images with a 200mm telephoto, and some others roaming around. The following two images are of the event with the images stacked in PhotoShop. The moon’s dimming is very much evident here:

Wide field series of images of the eclipse.

This image shows the eclipse with deeper exposures. The stars become evident as the moon dims. Note to the lower right the light pollution from Boston, to our south. As with all photos in this blog, click on the images for higher resolution!

Wide field series with deeper exposures.

This series below is from the 200mm lens and follows the eclipse from full moon (no eclipse) to totality. Photoshop wass used to stack the images. Click for higher resolution.

Sept 27 2015 Lunar Eclipse Series

Sep 6 2015

The Observatory’s Summer Activities

School might get out in June, but the Observatory is a buzzing place with all sorts of activities while the students are away. The primary charge for us is completing the cleaning and maintenance work that needs to be done to keep all the equipment in top working order. This year, we also received a new optical tube assembly for the Kurtz Dome, necessitating some serious lifting and alignment procedures. Here is the list of activities done this summer to date (summer is not over just yet!):

Dome cleanings: Just after students graduate, the first order of business is to give each dome a thorough cleaning. Observatories maintain a low level of sweeping, as this kicks up a lot of dust and makes the optics a real mess. In spring, the optics are thoroughly sealed in plastic bags, the cobwebs and pollen and dusted down from top to bottom, then the whole dome is vacuumed and wet-wiped.
Batteries in the various components are replaced: there are little button batteries here and there for little things like ROM backups, and bigger things like illuminated reticles for the finder scopes.
We installed the new 16″ ACF SCT telescope in the Kurtz Dome. The Takahashi refractor and the Celestron SCT were removed first. The mount saddle was configured for two optical tubes and was turned 90 degrees, so that required realignment. That done, the new 16″ OTA was put into place and counterbalanced. It is one heavy OTA at 75 pounds. The weights need to be in proper position to prevent too much stress on the mount’s drive systems. Once balanced, the whole system needed to be reconfigured for the larger tube using software that knows the extent to which the tube can travel without smacking into the pier. That would not be good!
The Robotic Observatory had a complete software upgrade. Those who know me, know one of my mottos: if it is working, DO NOT upgrade anything. I hold to this as much as possible, but there are times when things are working, but the software manufacturers have control over us. In this case, the license for our internet-accessible server/control system was expiring, and they would not allow a simple renewal without software upgrade. Alas! Upgrading that required upgrading everything. The status now with the software is that the automated focusing software is not compatible with the other pieces. We focus by hand for now. That said, there are other gremlins in the system:
- The electronic focuser was getting stuck. A little dismantling and some lubrication fixed that. We had a solid run last night without any focuser issues.
- No focuser issues means that we must have had something else going on… nothing is perfect. Yes, the shutter on the CCD imager was getting stuck! After 40 flawless images, the images started to show the bright stars with vertical blooming down each column. This means that the shutter was remaining open as the CCD downloaded the images by pushing the pixel charges down to the readout registers. Sigh. The camera needs to be dismantled and diagnosed now. That is on the to-do list.
New tripods were ordered for the portable telescopes which have a few benefits: They allow easy polar alignment; They can be adjusted for height (not all students are very tall); They are lighter, easier to carry around; They are much more stable than the piers we used to use.
The spectrographic system in the Alden Dome has checked out perfectly.
The Heliostat has checked out perfectly, though I am beginning to think about getting the mirrors a new aluminum coating.
Tested a home-made grism (a diffraction grating system: grating + prism = grism) with a DSLR camera on the 16″ telescope. Results are encouraging and might be awesome to use with winter Astronomy 392 classes.

Aug 18 2015

New Visual Telescope for the Observatory

The observatory took delivery of a new 16″ f/8 ACF Schmidt-Cassegrain telescope this summer. It has been installed, collimated and tested out on a recent clear night. This telescope joins the list of instruments available for swap in the Kurtz Dome. With a 16″ aperture, it has the largest light gathering power of all the instruments at the observatory and also the highest resolving power. We cannot wait until Saturn and Jupiter are in our skies! Stay tuned for information about open houses and other observing opportunities. http://www.twitter.com/PEA_Obs

The new 16″ telescope just after installation with Dr. Ward and Dr. Adams.

On the evening of the 16″ first light. We were able to enjoy nice views of M-16, M-13, M-57 and more.

Aug 9 2015

Time for Meteors!

The Earth is headed through two meteor streams at this time, both pretty abundant in meteor activity, or just sheer quantities of meteoric dust. Peaking on August 12-13, the Perseid shower is one of the best known. The shower comes from the debris from comet 109P/Swift-Tuttle. It has many bright meteors and plenty of fireballs. It has often reached numbers over 100+ per hour and is well worth staying up for. Like most meteor showers, we see more meteors when the observer is on the side of the planet that is facing into the stream. This is when we are facing the morning side of night…. i.e. after midnight. So, bug spray, warm drinks, and a sleeping bag are the tools of choice. No need for an observatory. No need for binoculars. No need for lighting. Get away from the town and city scene. Get into the dark country skies, lie down, look up!

If that were not enough, the second shower (remember there are two) is the Southern Delta Aquarid which \gives us some 10-20 meteors per hour. It is a good season for meteors!

Jun 21 2013

June 2013 Exeter Astronomy Education Conference

It is that time again! I will be hosting another astronomy education conference starting this weekend! The weeklong meeting will allow astronomy educators from around the USA to discuss and try various methods of teaching modern astronomy and astrophysics. Topics that have been covered in detail in the past:

CCD Imaging: photometry, color work, narrow band filters, astrometry, guiding, installation, design.
Observatory design, construction and maintenance.
Available software for astronomy, science, data reduction, learning and labs.
Required topics in astronomy.
Best practices in astronomy education, pretesting, post-testing, assessment.
Teaching astronomy in difficult situations: limited budgets, light pollution, late nights out.

It is always a fun time, and generates a ton of communications following the event. This year, we are once again full. We even had a wait list! Stay tuned for more information as the week progresses.

ExeterAstro

Astronomy at Phillips Exeter Academy

Tag Archives: astronomy