"The Sun Watchers" video is a comprehensive tour of the Big Bear Solar Observatory (BBSO). It provides insightful information about the 1.6m New Solar Telescope (NST) designed and manufactured by DFM Engineering, the instruments, the optics and the research capabilities and potential.
The NST and instruments at BBSO are designed and employed specifically for studying the activities and phenomena of the Sun. It is the most powerful ground-based solar telescope in the world.
"The Sun Watchers" video was produced by Astronomy Outreach Network.
Recent research and striking images have exposed new information about the events on the sun.
The telescope has captured extraordinary images of sunspots previously thought to be relatively calm that have proven to be quite tumultuous, three-ribbon solar flare events which are disturbances of the sun's magnetic field erupting charged material into space, and immense bubbling granules with magnetic flux rope explosions of energy.
The image detail is unprecedented because of the telescope's optical quality and capability to capture such data. The NST captures 100 images in 15 second bursts, correcting images in real time to get the sharpest images available.
Dr. John Varsik, Research Professor, of BBSO said, "The NST provides the highest resolution solar images that are now available. In solar physics, it's critical to get this resolution."
In "The Sun Watchers Video", Dr. Varsik and Stephen Edberg, Astronomer, discuss the importance of the information being derived from the NST and how we are learning to interpret the extraordinary data.
Sunspots are surprisingly active, compact, concentrated magnetic fields with some as large as Jupiter and lasting for weeks. With the NST, it was discovered that umbra, the structure of the central region of a sunspot, is very active and helps to understand sunspot dynamics.
Solar granules, regions on the sun where plasma rises to the surface like bubbles in boiling water, are another facet of study available because of the high resolution of the images from the NST. Analyzing granules with the NST at BBSO has led scientists to observe an emergence of a 6,000 mile long magnetic flux rope inside a granule while documenting and measuring the powerful resulting explosions as it bubbled to the solar surface.
The image quality and high-resolution detail is unprecedented. This detail quality is a direct result of the optics designed by the NJIT staff and the thermal control system designed by Dr. Frank Melsheimer.
The primary mirror for the NST uses a very thin 1.6m diameter segment of a much larger parabolic mirror. This allows an unobstructed aperture to reduce scattered light in the image. The University of Arizona Optical Sciences made the primary mirror.
Controlling the temperature of the primary mirror is a key design issue for this large-aperture solar telescope. While tracking the sun, the thin primary mirror is tilted enough to allow natural air convection to sweep turbulent air away and directly cool the primary mirror. Ventilation holes in the mirror cell aid this natural convection.
Dr. Melsheimer and the DFM Engineering staff designed and built a unique thermal control system, a closed-cycle, chilled-air system as part of the telescope mount to limit so-called "mirror seeing". The chilled air flows over the surface of the mirror sweeping away turbulent cells and directly cooling the primary mirror on the front surface and on the back surface. Even with the "air conditioning" of the primary mirror, after a day of observations the mirror must be cooled overnight to ensure that it is somewhat cooler than ambient in the morning. Controlling the temperature of the primary mirror is a key design issue for this large-aperture solar telescope. This system may be implemented in the future.
Claude Plymate, Telescope Engineer and Chief Observatory technician explained the significance of the structural components of the NST. One extraordinary feature of the NST is the balancing mechanism. The telescope mount is not passively balanced, but dynamically balanced by the TCS.
"Most telescopes go to great lengths to balance all the axes to eliminate forces on the motors and to run smoothly. However, there is a clever design incorporated here to allow the telescope to be permanently out of balance. Instead of counter weighting it, the design entails two screw jacks located on each side of the optical tube. Each of these screws compress onto a spring that actually carries the weight of the telescope on the spring," Plymate explained.
"So the telescope is actually floating on a spring suspension which carries the weight! The actual drive doesn't have to carry the stress of the weight," Plymate added. The two weights move up and down the long lead screw which is guided along a rack within the tubes. While these 2 force screws carry the out of balance load in DEC, a third screw positions the axis. HA is balanced by the two 900 lb. motorized counterweights that move as a function of telescope position. There is an entire counterweight motor chassis, second control computer, and program named TBController dedicated to balancing the telescope.
All weight calculations and the 3 DEC Yaskawa servo-motors are commanded by the DFM Telescope Control System software.
"This telescope is ideally suited to look at both infrared and ultraviolet ends of the spectrum where fine details of the solar surface will allow magnetic field study," Dr. Varsik said. " Ultimately, it's those magnetic fields, that when they get intense, lead to flares, coronal mass ejections and many events that actually affect a lot of our technology right now here on earth. The more we learn, the better we can protect our spacecraft which we are becoming increasingly dependant upon."
The Big Bear Solar Observatory (BBSO) is located in the San Bernardino Mountains of California. The observatory is built out into Big Bear Lake on a causeway so it is surrounded by water.
The water helps stabilize the atmosphere surrounding the observatory. This observatory site, coupled with the passive primary mirror cooling, and unobstructed light path allows for the superior quality of the images of the sun being collected that has proven to be essential for the primary interests of measuring and understanding complex solar phenomena.
The 1.6m New Solar Telescope (NST) unobstructed aperture solar telescope - designed and manufactured by DFM Engineering - was officially operational in October 2009. It is the largest of its kind in the world and making phenomenal solar discoveries possible in the science of astronomy.
For more information on the design, manufacture and installation of the telescope, please see NJIT Solar Telescope at BBSO posted in May, 2010 by DFM Engineering.
NJIT New Solar Telescope Manufacturing Documentation
NJIT New Solar Telescope Original Installation
BBSO Latest Halpha Images
"The Sun Watchers" video from Astronomy Outreach Network