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. 

The stars at night are big and…. falling: Geminid Meteor Shower Returns December 13!

Of the many meteor showers that occur throughout the year, the Geminid Meteor Shower in December may be the most reliably active. This meteor shower occurs when the Earth passes near 3200 Phaethon, a Palladian Asteroid. The Geminids were first observed in 1862. The shower gets its name because they appear to originate in the Gemini constellation. 

Under ideal conditions, one may see as many as 50-100 meteors an hour. The meteors from this shower are also especially bright, and many astronomers believe that the shower is intensifying every year. The shower should peak around 9:00 p.m. on Saturday December 13th. That’s good news because most of the other significant showers, like the Perseids, peak after midnight. With no Moon until after midnight, we should be able to see a lot of meteors (weather permitting of course). 

The George Observatory will be open Saturday, December 13th until midnight for viewing the shower. Tickets for viewing the shower are $5 and include access to our telescopes.  That night, we’ll be able to view several star clusters and nebulae with our scopes. Jupiter should rise in time to be viewed as well. We’ll also have our Discovery Dome available for $3. 

If you can’t make it out to the George, you can still view the shower anywhere with dark skies.

 

 

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.  

We’ll weather the weather: George Observatory’s dome gets a makeover

Editor’s note: This post is part three of our three-part series on how you helped us save our telescope at the George Observatory. Read part one here, and part two here.

In our Save Our ‘Scope (S.O.S.) campaign, much of our focus was on replacing the mirror in the telescope. This was the first and most obvious thing we realized we needed to fix. However, just as important as the telescope and the mirror (which allows us to see the wonders of the universe) is the dome which protects the telescope and the hydraulic lift floor that allows us to take multiple visitors to look through the ‘scope. 

We have an amazing elevator-type floor that allows us to take many people up to the telescope at the same time. The telescope complex weighs 10 tons, so it will not move anywhere. The floor allows us to let short children and people in wheelchairs still look through the massive telescopes. Historically, most large telescopes have a single chair which lifts the astronomer up to the eyepiece, as you can see in the image of Percival Lowell below.

As computers and imaging have evolved, now most observatories attach a camera to the eyepiece holder and then run a cable to the building downstairs so the astronomer can use a computer to “look” in the telescope. This is pretty convenient (air conditioning and snack foods, anyone?), but it doesn’t allow someone the very personal experience of looking at something amazing in space with their own eye. The George Observatory does have cameras that scientists use when we are not open to the public. We will always use an eyepiece for the public observing.

The next big item to address was the dome itself. Steel in the Houston climate gets much abuse. Most large observatories are placed in deserts or on top of mountains in very low humidity conditions. However, this is not necessarily where many people are located, so we are committed to regular maintenance to keep the dome in good condition. 

Here are the before shots of the dome:

Scope Blog 3 7It wasn’t easy to fix, and we needed to accomplish this before the summer heat set in.

Scope Blog 3 8 Scope Blog 3 6Here is the after shot. The dome is ready to protect the newly refurbished mirror as soon as it comes home! 

Scope Blog 3 9 Scope Blog 3 10