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.

KJR_3611

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. 

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!

You saved our ‘scope at the George Observatory! And this is how it happened.

CliffsNotes: Thanks to all of you, we have done exactly what S.O.S. intended, and we saved our ‘scope!

HMNS is proud to own the largest telescope in the country that is open to the public on a regular basis, the Gueymard Research Telescope. Many of you have come and enjoyed the night skies and looked through this amazing telescope at the George Observatory. But it needed some well-deserved TLC this past winter.

SOSYou saved it!

The donations to repair the Gueymard telescope ranged from pennies to $10,000, and came from families, individuals, children, companies and foundations!

Special thanks go to Dr. Reggie DuFour, who launched the campaign with a generous $10,000 donation. We are also extremely grateful to major donations from The George Foundation and The Henderson-Wessendorff Foundation. We were also given a generous donation from elementary students at Shady Oak Christian School, who sent us over the top with their $1,800 donation, which was collected from their annual fun run.

Why is the Gueymard telescope so important to us — and to you?

On a clear night, it is incredible to be able to see with your own eyes the many wonders of the universe. There are other, larger telescopes, but they are far away and they are only available to scientists who apply for time and get their projects approved. These large ‘scopes use cameras which are then fed to an indoor area where scientists “look” with their computers. Here at the George Observatory, we think there is something very personal and magical about using your own eyes to look at Saturn or Jupiter or a galaxy far, far away.

The 36-inch Gueymard mirror and dome were purchased from LSU in advance of the 1989 opening of the George Observatory. LSU had owned and operated the ‘scope for 25 years in highly humid conditions, very similar to the ones in Brazos Bend State Park. Brazos Bend is a swamp and grassland, but it is also located conveniently about an hour away from light-polluted cities in and around Houston.

The unique relationship with Brazos Bend guarantees us a safe, dark place to view the skies. Most telescopes are put on top of mountains or out in dry deserts where the weather conditions allow for more nights of clear skies. When Halley’s Comet returned in 1986, thousands of visitors lined up at the park wanting to see the comet. We knew then, if not before (and certainly now), that there is a high interest level in everything astronomical in Houston.

We believed that because the mirror had already lived in a swamp for 25 years, it should continue to do well in similar conditions. This was true for a long time. However, several years ago we noticed that we really couldn’t see as well with the large scope. The mirror was becoming cloudy. In 2011, it was determined that the mirror surface had lost all reflectivity. After extensive research and phone consultations, the mirror was sent to Marian Schafer at Galco Electronics in Mesquite, TX. Galco, which is well-equipped to put coatings on mirrors, was selected based on its good reputation and, in part, its  Dallas-area location – which allowed our volunteers to transport the mirror, saving shipping costs.

Mirrors are supposed to be shiny. This one was not.

SOS 1Starting in December 2011, Marian stripped, cleaned, baked and held the mirror under a vacuum five times to try to remove contaminants from inside thousands of small microscopic fissures found on the surface and interior of the mirror. In addition, there are numerous other bubbles throughout the glass mirror that can be seen with the naked eye. Galco used a sub layer of chrome as a binder and then put a final coating of aluminum. When this coating failed, titanium was applied as the binder in order to block leeching contamination.

It was understood that if the titanium was put on, the only way to remove it would be to regrind the mirror. The titanium coating failed, and did not bond to the mirror surface. This first attempt helped us to determine exactly what needed to happen next with the mirror.

SOS 3Time to hit the grind.

The next step to fix the telescope was to bring in an independent expert on a Ritchey–Chrétien designed telescope like ours. James Mulhernin, from Optical Mechanics Inc. (OMI) was flown here from Iowa. Mulhernin determined the composition of the glass as excellent quality Pyrex, and also determined that the microscopic fissures were artifacts from when the mirror was originally made almost 50 years ago. Over time, pollution and microscopic “gunk” in the fissures prevented a coating from sticking to the mirror.

Mulhernin’s newer technology will allow us to re-grind the mirror and prevent any of these old issues from coming up again in the future. This is indeed great news for us here at the George Observatory.

SOS 4The mirror was shipped to OMI and is currently being serviced. Reports are all very positive.

While the mirror is gone, we can still use the amazing 11-inch refractor with near-perfect lenses mounted on the side of the big telescope. But that’s another story as to how we removed a 458-pound mirror and can still remain open on Saturday nights!

Stay tuned for more updates on the repair progress, and start looking forward to the 25th Anniversary celebrations in October here at the George Observatory.

Save Our ‘Scope: A Gueymard fundraising update & why telescope mirrors matter

If you didn’t already know, we’re in the process of raising money to repair the Gueymard telescope at the George Observatory in the Save Our ‘Scope campaign. And thanks to you, we’ve raised over $65,000 of our $80,000 goal through donations ranging from $1 to $5,000 — and we’re grateful for every last one of ‘em.

But what’s the big deal? I mean, you can totally just buy a new mirror at Target or something, right? Well, in a word: nope.

Telescopes are amazing pieces of equipment – dauntingly large (the Gueymard weighs 10 tons) and yet incredibly delicate. If the mirror in a telescope warps just a few centimeters, it can vastly distort the images you see. Therefore, it’s extremely important to keep these machines in tip top condition.

Eye see you

Think of telescopes as an extension of your eyes. We can’t see things far away very well. When you look at the sky at night (and it’s dark enough) you see tons of tiny specks of light – some are stars, some are planets, others are galaxies, or even galaxy clusters. The light can travel for thousands (or millions or billions) of light years. The light heads right into your eye, onto your retina, and sends a message to the brain that says, “Hey, that’s neat, a speck of light.”

However, due to the distance involved, we can no longer appreciate the scale or detail of the images. The further away an object is, the smaller the space it takes up on the retina.

Telescopes fix all of this so that a bright, detailed image can reach your eye as it captures more light and then focuses and magnifies it.

Light-bending lenses

Lenses bend light waves, either causing them to converge (focusing light) or diverge (spreading out light). Glass lenses were used in the creation of the first telescopes, called refracting telescopes.

In this model, light passes through the objective lens, which collects the light, causing it to converge on the eyepiece where it is then magnified. These images would become distorted, however, as different wavelengths of light bend at different angles and focus at different points.

Mirror, mirror on the wall

So, how do you solve a problem like bent light? In a word: mirrors. With reflecting and compound telescopes, the light doesn’t pass through the objective lens. Instead, it is reflected (via concave mirror) back to a smaller mirror, directing the light to the eyepiece where it is magnified. Ta-da! Beautiful, clear images of faraway objects.

The cool thing here is that the larger your mirror, the more light you capture, giving you higher resolution images with better detail.

The bigger, the better?

If your goal is to capture as much visible light as possible, then yes, bigger is better. But this comes with special problems too. Mirrors can get heavy – very heavy. Think about it: our Gueymard telescope mirror is 36 inches in diameter, and some mirrors can be several hundred inches in diameter. Now that’s a lot of mirror! All of this weight can change the shape of the mirror so that, over time, they sag and no longer properly focus light to another point.

Oh, honey

This issue can be solved with honeycomb mirrors. No, they’re not made by bees. Rather, they’ve been influenced by the structure of a honeycomb. This allows the face of the mirror to be well supported, while reducing the weight of the mirror up to 80 percent.

Now that you’re (sorta) a telescope expert, come see the big stuff at the George Observatory in Brazos Bend State Park! Houston’s really lucky to have this observatory in its backyard, so to speak, since the Gueymard is the largest telescope in the country open to public viewings.

Can you spare a George for the George? We’d greatly appreciate if you pitched in to help save our ‘scope. Your efforts ensure that Houstonians can continue to stargaze through the most incredible telescope they’ll ever get to use for many years to come.