First Light: Research telescope debut to coincide with Hubble anniversary

April 25 will mark the 25th anniversary of the world-famous Hubble Space Telescope, and the George Observatory will celebrate with a debut of their restored 36-inch Gueymard Research Telescope, the largest specialized Cassegrain telescope open to the public, and the only one that chooses to use an eyepiece.

The Gueymard Research Telescope, a 36-inch Ritchey—Chretien Cassegrain.

The Gueymard Research Telescope, a 36-inch Ritchey—Chretien Cassegrain.

“You can see the images with your own eyes instead of on a computer screen like other telescopes,” George Observatory Director Peggy Halford said. “It gives you a much more personal experience.”

A Ritchey—Chretien design, the telescope features hyperbolic primary and secondary mirrors which sharpen the image, eliminating the fuzzy edges around its center, what is known to astronomers as an off-axis coma. With optics this precise, the telescope brings to the naked eye the phenomena of deep space.

A couple of years ago, astronomers at the George began to notice the quality of images in the Gueymard was degrading. Views were clearer in the smaller, though still research-grade, 11-inch refractor attached to the Gueymard. While they knew something was wrong, they didn’t expect the adventure they would embark upon to restore it to its original power.

Amateur astronomers remove the primary mirror from the Gueymard Research Telescope.

Amateur astronomers remove the primary mirror from the Gueymard Research Telescope.

When they removed the primary mirror, the equivalent of “checking under the hood,” they found environmental pollutants built up in microscopic divots and fissures left on its surface after its original grind 50 years ago. Optical technology has come a long way since then; imperfections in contemporary optics are virtually absent, Halford said. The George acquired the telescope from Louisiana State University, where it had stood in swamp-like conditions another 25 years prior to its installation in Brazos Bend State Park. Time and humidity had taken its toll.

The Museum sent the delicate 500-pound mirror to a coating company that did the simple things first — a bath and a new reflective coating — to try to refurbish the mirror, but the coating refused to stick, and they knew they would need to bring in the big guns.

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The wooden container the George employees used to ship the hyperbolic mirror.

It took a three-month fundraising campaign, Save Our Scope, to raise the money to hire Master Optician James Mulherin to resurface the element. Halford is proud to report the campaign took much less time than she anticipated, given the surprising amount of support from the public.

February 2014, the George again sent mirror away, this time to Mulherin, and a year an a month later, the project was complete. Mulherin took a trip to the George to help install the element, and he sat down to explain the particulars of the resurfacing project and what he does at his business, Optical Mechanics, Incorporated.

One of two specialists in the nation who do this kind of work, Mulherin came highly recommended from amateur astronomers who dropped his name to Halford at star parties when they learned of the George’s difficulty with the Gueymard. What was tough for the astronomers was a piece of cake for Mulherin.

“It was a fairly routine job,” said Mulherin, whom universities and aerospace companies regularly hire for their optical needs. “There was no real challenge.”

Mulherin did mention, however, that he had to work around the hole in the middle of the mirror, where a steel hub goes through to hold the mirror in place at the bottom of the telescope. Normally a glass plug is installed during the grinding phase, but there was too much difference in the composition of this 50-year-old glass and that of contemporary optics, he said, so he had to work around it.

Using specialized equipment to move the delicate, but massive, hunk of glass, Mulherin’s company stripped the aluminum finish and ground down the old surface to remove the imperfections in the element. The opticians then re-shaped the mirror’s hyperbolic curvature, shining light through the glass at different stages to check their progress. Finally, Mulherin coated the surface with enhanced aluminum to increase reflectivity.

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The George will debut the repaired Gueymard April 25, coinciding with the 25th anniversary of the Hubble Space Telescope.

The result was a total restoration of the optics, but volunteers still had to put the mirror back into place. The replacement, including the removal of the cement blank used to counterbalance the telescope while the mirror was out, along with cleaning the housing, took Tracy Knauss, Dana Lambert and Chris Randall 10 days straight, working from noon to 10 p.m.

Changes to the width of the mirror required volunteers to adjust the secondary mirrors after the installation of the main element — no small task. Installation and adjustments of the precision optics continued from 8 a.m. to 10 p.m. Monday, and again Tuesday from noon to 10 p.m.

“I wanted to stick an eyepiece into it and it work,” Halford said, but collimating the telescope, or aligning the elements with accuracy, required much more time.

Mulherin said he felt at home at the George during the course of the project, and happy to help.

“I feel like I’m part of the community,” he said. “When I started, we were all amateur astronomers, and I found I was more interested in optics than astronomy.”

About the telescope, he said, “It’s amazing to me that it still works.”

Halford hopes for clear skies April 25, but if conditions turn cloudy, she said, “We’ll just show it off.” The George will observe regular Saturday hours from 3 to 10 p.m. for the event.

First Light & 25th Anniversary of the Hubble Space Telescope Celebration
Saturday, April 25
3:00 p.m. – 10:00 p.m.
April 25 will mark the 25th anniversary of the world-famous Hubble Space Telescope, and the George Observatory will celebrate with a debut of their restored 36-inch Gueymard Research Telescope, the largest specialized Cassegrain telescope open to the public, and the only one that chooses to use an eyepiece. 

This week at the George Observatory: Perseids Punch Through Supermoon on August 12

If you follow astronomy websites, you’ve probably noticed that every month or so there’s an article about a meteor shower happening. There are meteors showers frequently throughout the year. Some showers are more active than others depending on various factors. This August one of the most reliably active showers, the Perseids, will take place. 

The Perseids, sometimes called The Tears of St. Lawrence, occur when the Earth passes through a debris field created by comet 109P Swift-Tuttle. This year, the meteor shower peaks Tuesday night (August 12) through early Wednesday morning. Besides being one of the most active showers (in 2013 it averaged 109 meteors an hour), the Perseids also have a very broad peak. Meteors can be seen as early as July in some circumstances. 

The early meteors which are the first ones to hit the earth’s atmosphere, tend to be the brightest ones with the longest tails.These are called “Earth-grazers” and those are the ones we will be looking for the evening of August 12-13 here at the George Observatory.

This year, the shower will be taking place during another “Supermoon,” occurring August 10. While not at its closest point, this means the Moon will still be very close and bright on August 12. Normally, this would not be an ideal night for observing meteors since the Moon will flood the sky with light.

Our astronomers like to joke that “Moon” is a four letter word. 

But don’t fret! The Moon won’t rise until 9:30 p.m. that night and, with our high tree-line here at the George Observatory, it won’t start affecting viewing until at least 10 p.m.  Also, even after the Moon rises, the brightest meteors will still shine through. 

In 2011, the Perseids peaked on a full Moon and people still saw an average of over 50 meteors an hour. This year the Moon will be a waxing gibbous (progressing from the full moon to the new moon).

The George Observatory will be open on Tuesday, August 12 from 5 p.m. until 2 a.m. for  meteor shower viewing. 

Event tickets are $5 per person.  Our Discovery Dome will also be available for $3 per person.  

Seeing Stars with James Wooten: The Perseids are back August 12!

Star Chart August 2014

This star map shows the Houston sky at 10 pm CDT on August 1, 9 pm CDT on August 15, and dusk on August 31. To use the map, put the direction you are facing at the bottom. The Summer Triangle is high overhead. This consists of the brightest stars in Cygnus, Lyra, and Aquila. Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to his left. From the Big Dipper’s handle, ‘arc to Arcturus’ and ‘speed on to Spica’ in the southwest. Watch Mars close in on Saturn this month. The Great Square of Pegasus rises in the east, heralding the coming autumn.

This month, Mars is in the southwest at dusk this month. Mars continues to fade a little each night as Earth continues to leave it farther behind. Still, Mars rivals the brightest stars we see at night.

Saturn is also in the south southwest at dusk. Mars passes 3.4 degrees south of Saturn on August 25. 

Venus remains in the morning sky, although it now begins to approach the Sun more and more. Look east at dawn for the brightest point of light there; only the Sun and Moon outshine Venus. Venus remains a morning star for almost all of 2014.

Jupiter emerges from behind the Sun into the morning sky by late August. Venus is about 1/5 of one degree from Jupiter at dawn on August 18th. (Both are low in the east at dawn). 

The Big Dipper is left of the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ and then ‘speed on to Spica’; those stars are in the west at dusk.  Leo, the Lion, is setting in the west at dusk.

Antares, brightest star of Scorpius, the Scorpion, is in the southeast, with the ‘teapot’ of Sagittarius behind it. The Summer Triangle is high in the east. The stars of summer are here. By late evening you can look for the Great Square of Pegasus rising in the east, indicating that fall is approaching.

Coming to an observatory near you, August 12: The annual Perseid meteor shower peaks next week, late Tuesday/early Wednesday (August 12-13).  As usual, we see more meteors towards dawn because that’s when we rotate into the meteor stream. 

The George Observatory is open 7:00 p.m. August 12 until 2:00 a.m. August 12-13 for the shower. 

 

Moon Phases in August 2014

1st Quarter: August 3, 7:50 p.m. 
Full: August 10, 1:10 p.m.
Last Quarter: August 17, 7:26 a.m.
New: August 25, 9:12 a.m.

Click here to see the Burke Baker Planetarium Schedule.

On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement. 

Clear Skies!

The great balancing act: Stabilizing telescopes at the George Observatory

Editor’s note: This post is part two of our three-part series on how you helped us Save Our ‘Scope at the George Observatory. Read part one here.

Many have asked us how we are still using the large research dome at the George Observatory while the 36-inch mirror is in Iowa getting fixed. The simple answer is that we are continuing to use the 11-inch refractor, which is mounted on the side of the 36-inch telescope. The refractor has near-perfect lenses and is an incredibly high quality instrument in and of itself. The 36-inch mirror is best used for deep space objects, and the 11-inch refractor is best used for closer objects like we find in our solar system. Together, they work in tandem to make a remarkable team to view near and far.

The entire telescope grouping and mount weight approximately 10 tons. The 36-inch mirror weighed almost 500 lbs with the mirror and the center hub that holds it in place.  Because everything is so perfectly balanced, the motor to run the telescopes is approximately the size of a sewing machine motor. This delicate balance is also what keeps the telescope working properly. When we removed the more than 500 lbs. for the primary and secondary mirrors, the entire system was totally out of balance.

We were advised that glass is the same density as cement by our mirror expert.  With this piece of information and the help of Tracy Knauss, Paul Halford and Chris Randall, a plan was devised to make an exact replacement of the glass mirror out of cement. Paul located the materials and then Chris took over the project. He had scales and tools at his home and handily went about making the cement mirror.

First, Chris started with some rebar and a 36-inch sonotube.  

SOS Cement mirrorThen Brazos Bend State Park provided a fork lift to get it out of the truck.

SOS Cement mirror 2

SOS Cement mirror 4Then we had to get the 500-pound blank inside the building and placed underneath the dome so that it could be lifted three stories up into the dome and then installed.

SOS Cement mirror 6Here is the cement mirror blank installed in the real mirror cell.

SOS Cement mirror 9Finally, Tracy and Chris installed the cement blank into the back of the telescope casing where the real mirror will eventually be. By replacing the weight almost exactly, only a very few adjustments had to be made so that it was back in balance and able to support the 11-inch refractor again. 

With Jupiter, Mars and Saturn so prominent right now, this is the best ‘scope for viewing until the 36-inch returns to the George Observatory.

Save the Date: The George Observatory’s 25th Anniversary Celebrations
October 10, 2014: Members and donors event 
October 11 & 12, 2014:  Anniversary weekend. The Observatory will be open  from dusk until 11 p.m. Come look through the newly refurbished 36-inch Gueymard telescope that you helped save!