The Goldendale Sentinel - Headlines & History since 1879

By Shelby Taylor
Reporter 

Observatory gets new telescope, undergoes major renovation

 

Contributed: Bob Yoesle

UP AND AWAY: The telescope at the Goldendale Observatory was lifted out of its building Thursday in preparation for major renovations to the Observatory.

Thursday, June 30, the telescope was removed from the Goldendale Observatory through the top of the dome via crane. The Observatory, having a long-standing history here in Goldendale, is undergoing its very first major renovation for the first time in 43 years.

The Goldendale Observatory is a well-known site, consistently attracting visitors from all over the world. The Observatory's location and reputation has been established through various historical events, including a total solar eclipse dating back to 1918, when the director of the Lick Observatory in San Jose, Calif., photographed an eclipse here in Goldendale. This data was attempted to be used in support of Einstein's theory of general relativity, though, as commonly believed, Einstein himself was never here.

More recently, upon its construction in 1973, Goldendale locals recall the total solar eclipse of 1979 with the Goldendale Observatory being straight in its path of totality. This event helped put the small town of Goldendale on the map, attracting more than 20,000 people. Though the site has been cherished for this bit of history, the structure received fresh attention from the Washington State Parks and Recreation, which decided to invest in a multi-phase $1.3 million upgrade of the facility.

"The telescope is one of the nation's largest public telescopes, and the work will update it to current state-of-the-art standards that include research-grade cellular optics and capacity for astrophotography," a Parks press release stated.

These upgrades have begun with the extraction of the large telescope, which should be back in service by fall.

Though beyond excited for the new upgrades to the structure, local resident Fern Williams recalls her experience of the 1979 eclipse here in Goldendale. "My family and I went to the Observatory early enough to watch the sun rise as it came up over the horizon. That was amazing. As the eclipse began to happen, photographers for newspapers had climbed on top of the roof of the Observatory with their big cameras to get the very best view." She described the craziness of the town, "There were cars parked along both sides of the road on Highway 97. It was an amazing sight for Goldendale. When we came downtown, it was just crowded with people. There were vendors selling small souvenirs and trinkets. It was truly amazing. Never in our lifetime never would we have seen anything like that. Everyone was so excited!"

Nostalgia will be a prominent feeling once the large telescope is upgraded, but the site's history will not be forgotten. The original 24.5in. x 5.5in., 200-pound mirror, ground by a homemade grinding machine in the '60s by the four founders of the Observatory, will be on display for public viewing. The new mirror will be just 1.5 inches thick, weighing just 35 pounds. Reducing the thickness of the mirror will contribute to decreased acclimation time, as thermal performance is exceptionally important with large telescopes.

As a telescope heats up or cools down, the components of the telescope expand and compress, affecting the telescope's optics. The original 200-pound pyrex glass took four hours to adjust to ambient temperature, with the new 35-pound mirror taking just 15 minutes.

Classically, very high tech materials that were less susceptible to expanding and contracting were used to compensate for thermal flux. But these materials, such as fused quartz and synthetic zerodur (a ceramic glass hybrid) are extremely expensive. Instead, the new mirror will be made of pyrex, as was the old mirror, but with a novel design.

"The new mirror is not a solid chunk of glass," says Observatory interpretive specialist Troy Carpenter. It looks like a snowflake with lots of nooks and crannies in it. A 3D printer creates the mold and then the molten glass is poured into it. The design only uses exactly as much glass as needed. This intricate design, called cellular optics, has trusses within the mirror matrix that create the rigidity required to prevent substantial differences under thermal loads. This eliminates the cost of high grade materials. "A mirror of that size with traditional materials and methods, would cost $18,000 - $25,0000, while zerodur costs up $100,000 - $250,000, depending on who made it," Carpenter adds.

The mirror will be provided by a Pennsylvania based optical company, which has previously only done business with The National Aeronautics and Space Administration (NASA) and The Defense Advanced Research Projects Agency (DARPA), and has also provided an educational discount.

In addition to the new mirror, the telescope upgrades will also include repairing the concrete pedestal and azimuth adjustment plate. It will be stripped of its thick, chipping paint and instead powder-coated with modern black matte light-absorbing material, increasing the contrast of the telescopes performance, provided a new drive control system, and additional small mechanical upgrades.

One important change being made is the design of the telescope. The original scope was a Classical Cassegrain, with the eyepiece located at the bottom of the telescope. This will be reconfigured to a Newtonian telescope, with the eyepiece located near the top of the scope. "For astronomy aficionados, this means the telescope will provide a more versatile, f/4.9 focal ratio than the current and excessively long f/14.5 ratio. The new focal ratio is what will allow the telescope to be used effectively for astrophotography," a Parks spokesperson writes.

The Cassegrain's long focal length was previously necessary due to its lack of optical correction, which was compensated for by having a long tube, giving the telescope an excessively long focal length of over 9,000mm. This results in a very narrow field of view, making it nearly impossible to take images, along with an extremely high magnification, making the image look quite dim and blurry.

The upgraded design of a Newtonian telescope will provide a shorter focal length of about 3,050mm, with the field being wider and brighter, allowing for astrophotography. This photography will be displayed online for educational and artistic uses, along with providing the capability for live video streaming from the telescope online.

In addition to the upgrades to the telescope, totaling about $50,000 alone, the remaining budget has already provided a new viewing deck, sidewalks around the facility, and the world's largest mass-produced solar telescope available.

Shelby Taylor

The old mirror, pitted from years of use.

The Observatory will remain open during the upgrades by utilizing the parks solar telescope for the 4 p.m. show, located in a smaller dome north of the building, and other portable telescopes for night shows starting at 8:30 p.m.

Visitors are encouraged to show up on time only, not between show times, as the facility is under construction. "By this time next year, we can honestly say the facility will have more space," Carpenter says. "We're hoping at least three times, enabling us to host larger groups, have interpretive materials and displays that will allow people to self-guide between shows, with a fully upgraded research specification telescope that will easily be one of the finest, if not the finest, public telescope in the world."

With the next total solar eclipse taking place next summer, on August 21, 2017, crowds can anticipate a fully upgraded, black matte with brass fixtures telescope.

 

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