astronomy

Goode Solar Telescope

Goode Solar Telescope is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Goode Solar Telescope rather than just read about it. In short: The Goode Solar Telescope (GST) is a scientific facility for studies of the Sun named after Philip R. Goode.

Key takeaways

Goode Solar Telescope belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Goode Solar Telescope to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Goode Solar Telescope from memory before moving on to harder problems.

Reference excerpt

The Goode Solar Telescope (GST) is a scientific facility for studies of the Sun named after Philip R. Goode. It was the solar telescope with the world's largest aperture in operation for more than a decade. Located in Big Bear Lake; California, the Goode Solar Telescope is the main telescope of the Big Bear Solar Observatory operated by the New Jersey Institute of Technology (NJIT). Initially named New Solar Telescope (NST), first engineering light was obtained in December 2008, and scientific observations of the Sun began in January 2009. On July 17, 2017, the NST was renamed in honor of Goode, a former, and founding director of NJIT's Center for Solar-Terrestrial Research and the principal investigator of the facility. Goode conceived, raised the funds, and assembled the team that built and commissioned the telescope, and it was the highest resolution solar telescope in the world (until the end of 2019) and the first facility class solar telescope built in the U.S. in a generation. The GST is capable of observing the Sun in visible to near-infrared wavelengths and features a 1.7-meter primary mirror in an off-axis Gregorian configuration that provides a 1.6-meter clear, unobstructed aperture. Adaptive optics correct for atmospheric schlieren in the solar image known as astronomical seeing.

Main telescope structure The f/2.4 primary mirror is a 1.7-meter off-axis section of a 5.3-meter diameter, f/0.73 concave parabola. It was cast from Zerodur by Schott and polished at the Richard F. Caris Mirror Laboratory Archived 2019-04-19 at the Wayback Machine of the University of Arizona. The figure error with respect to a parabola is 16 nm RMS. The secondary mirror, a concave ellipsoid, is mounted on a hexapod to compensate for thermal expansion and bending of the telescope structure keeping the mirror in its optimal position. A reflective, liquid-cooled circular field-stop in the primary focus before the secondary mirror limits the field of view to 120 arcseconds in order to reduce the solar heat load on subsequent optics. The GST is mounted on an equatorial mount made by DFM Engineering inside a ventilated dome resembling 5/8 of a sphere.

Adaptive Optics The Goode Solar Telescope deploys adaptive optical systems to mitigate image blur caused by atmospheric turbulence. With its single deformable mirror (DM), the CAO system has been routinely used since 2010 for the vast majority of observations and serves all post-focus instruments except CYRA. CAO is a classical adaptive optics system. It uses a Shack–Hartmann wavefront sensor that measures the average wavefront aberration over a field of view of 10 arcseconds and has a single DM with 357 actuators for wavefront correction. In 2016, the BBSO multi-conjugate AO (MCAO) called Clear with its three identical 357 actuator DMs enjoyed a successful first light trebling the corrected field of view by strongly reducing anisoplanatism. By 2020, Clear became a facility instrument, largely replacing CAO and holding lock as well as CAO ever did. Clear is the only MCAO system operating at any solar observatory, and is the only MCAO system with more than two DMs, day or night.

Instrumentation

Broad-Band Filter Imager (BFI)

The BFI is a filtergraph made of an interference filter and a digital CCD camera that samples the image of the Sun. The interference filter works as a band-pass filter that only transmits a selected color of the sunlight. Frequently used bands are 705.7 ± 0.5 nm (Titanium(II) oxide (TiO) spectral line, dark-red) and 430.5 ± 0.25 nm (G-band, blue-ish). The BFI camera captures 2048 × 2048 pixel images at a speed of 14 frames per second, covering an area on the Sun of 50,000 km × 50,000 km (70 arcseconds) in the TiO line, and 40,000 km × 40,000 km (55 arcseconds) in the G-Band. Despite adaptive optics, each frame suffers from atmospheric aberrations hindering diffraction limited image detail. In order to obtain diffraction limited resolution, bursts of about 100 frames get digitally analyzed to be formed into a single sharpened image (speckle-reconstruction).

Visible Imaging Spectrometer (VIS)

The VIS is an imaging spectrograph that, like the BFI, captures images of the Sun in narrow wavelength ranges. Instead of interference filters, however, VIS uses a Fabry–Pérot etalon to create a band-pass as narrow as 0.007 nm, tunable from 550 to 700 nm. VIS is frequently used to scan through the Fraunhofer lines at 656.3 nm (H-alpha), 630.2 nm (Fe), and 588.9 nm (Na). Per scan step multiple images frames are captured that also get processed for enhanced image detail.

Near Infra-Red Imaging Spectropolarimeter (NIRIS) A dual Fabry–Pérot imaging interferometer for the near-infrared from 1.0 to 1.7 μm.

Cryogenic Infra-Red Spectrograph (CYRA) A cryogenic Czerny-Turner spectrograph for the 1 to 5 μm regime.

Fast-Imaging Solar Spectrograph (FISS) A scanning echelle long-slit spectrograph.

Illustrations

Worked examples

Example 1 — a first encounter with Goode Solar Telescope

Start with the simplest possible case. Write down what Goode Solar Telescope claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Goode Solar Telescope before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Goode Solar Telescope ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Goode Solar Telescope

In research: Goode Solar Telescope appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Goode Solar Telescope in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Goode Solar Telescope is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2008 establishments in California, Reflecting telescopes, Solar telescopes, so understanding it makes those chapters shorter.
In everyday life: Look for Goode Solar Telescope outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Goode Solar Telescope in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Goode Solar Telescope means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Goode Solar Telescope out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Goode Solar Telescope in simple terms?

The Goode Solar Telescope (GST) is a scientific facility for studies of the Sun named after Philip R. Goode.

Why does Goode Solar Telescope matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Goode Solar Telescope?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Goode Solar Telescope.