It’s time to revisit the Sun! This nearby yellow-dwarf star is entering middle-age and is showing some spots! Here we have a selection of solar images, taken from around the world, made with Tele Vue Barlows and Powermate image amplifiers.
In this installment, we travel to Kitt Peak in the Arizona-Sonoran Desert to “speckle” binary stars and finally learn what the impressive-sounding Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne group does! (If you missed our prior Tele Vue Scientific installments, you can click to read Part 1 and Part 2).
Introduction Often practiced by amateur astronomers doing planetary work, “lucky” imaging was invented by professional astronomers to try to “freeze” distortion of starlight passing through our planet’s turbulent atmosphere. This is done by taking many short exposures of a target, instead of one long one. Amateurs usually align and stack the best quality photos to create an image. Professionals use their data to perform speckle interferometry involving complex math. Speckle interferometry is useful in refining the orbits of close binary stars. The introduction to a 2014 paper, “Kitt Peak Speckle Interferometry of Close Visual Binary Stars,” explains how this works.
The resolutions of conventional visual binary observations were seeing limited until Labeyrie (1970) devised speckle interferometry as a way to circumvent seeing limitations and realize the full diffraction-limited resolution of a telescope. The light from a close binary passing through small cells in the atmosphere produces multiple binary star images which, if observed at high enough magnification with short exposures (typically 10 to 30 milliseconds), will “freeze” out the atmospheric turbulence and thus overcome seeing-limitations. Although the multiple double star images are randomly scattered throughout the image (often superimposed), their separation and position angle remains constant, allowing these two parameters to be extracted via Fourier analysis (autocorrelation).
The paper says that this technique, made practical with the introduction of the CCD camera, resulted in an order of magnitude improvement in binary star data measurement over visual observations. Speckle interferometry then became the preferred technique for characterizing close binary stars.
In the last installment, our scientific path went from “polar to solar.” (If you missed it, please go back and read Tele Vue Scientific Part 1.) In Part 2 of this multi-part blog post on the use of Tele Vue gear in science, we reveal Sneakey research with Tele Vue Powermates and how a compact Tele Vue-NP101is telescope proved once again that lights are “all askew in the heavens.” All this research was done using our standard gear with products bought off-the-shelf — the same as you would receive from Tele Vue.
According to a recent Solar Activity Update by the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center, “Solar activity picked up at the end of November into early December, 2020, as several sunspot groups emerged or rotated onto the visible disk”. The update continues: “Solar activity is anticipated to slowly increase over the upcoming years towards the predicted solar maximum peak around July, 2025.” This is great news for observers of our nearest star! At times this year, there had been month-long sunspot “droughts” with no or few sunspots on the solar disk.
The return of Sun as a target of interest has led to a sudden uptick in Solar image postings to social media these past few weeks.
Images from the 2019 Mercury Transit made with Tele Vue gear have now been posted to social media. We present here the best (with permission) and note that Tele Vue Powermate™ amplifiers “shone” in the creation of most. Not only does Powermate™ help fast, modern scopes achieve a focal length suitable for imaging the tiny planet, but some high-end, drawtube-side, narrow-band filters requires a Powermate’s telecentric operation to create parallel rays for best image contrast. (See Daystar application of Rear-Mounted Filter page).
The “ice giant” planet Uranus was in opposition on October 28th. That means that the Sun, Earth, and Uranus all lined up together at an instant in time on that date. Uranus is on the same side of the Sun as the Earth, so the planet was closest to Earth and brightest for the year and in the sky all night long. If you missed it: don’t worry. The slow-moving planet will remain at least 3.7″ of arc in diameter and at magnitude 5.7 for the next month.
If you’re suffering from the cold northern winter like we are at Tele Vue headquarters in upstate New York, you’ll instantly be “warmed” by these “hot” solar images made by Jordi Sesé Puértolas from his balcony in Barcelona, Spain. These photos appear to show a blazing inferno on the “surface” of the Sun. However, science tells us this is not fire we are seeing but hot plasma (ionized gas) and gas in the wavelength of Hydrogen-α light.
On the 23rd, the “ice giant” Uranus will be visible all night, as it rises when the sun sets (hence it is opposite the sun). It will also be at its largest for the year: a diminutive 3.73″ of arc. Due to its distance and close-to-circular orbit, Uranus doesn’t vary that much in brightness over time. It will reach magnitude 5.7 from mid-October through early November before slightly fading to magnitude 5.9 in late March 2019. This makes it a naked-eye target in dark skies and easy to locate in a binocular or finderscope.
We’ve noticed a proliferation of close-up plane images on Instagram made using Tele Vue Powermate™ image amplifiers. What is amazing about these images? They are taken from the ground with the plane at jet-aircraft cruising altitude. This is the imaging side of the hobby of “plane spotting.” It is sort of like bird watching — but the “bird” is much bigger and potentially much further away: in the stratosphere!
While imaging a bird can be serendipitous, the modern plane spotter has the advantage of free online flight-tracking software, such as FlightRadar 24 and FlightAware, to predict what aircraft are approaching their location. Aircraft identification, route, speed, altitude, and heading are just a click away. This software has also made its way to the ubiquitous smartphone. Thus, unlike birding, plane spotters can anticipate targets to observe in advance. This gives the spotter time to prepare for encounters with common and rare aircraft — like the Antonov An-225.