Welcome to 2022! In this posting, we’ll examine how the pandemic impacted amateur astronomy this past year and review our most popular social media posts from 2021.
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.
For the amateur astronomer, “diamond,” “ruby,” “emerald,” and “pearl” evoke poetic descriptions of eclipses, stars, clusters, comets, and nebulae. They are also the traditional gemstones for the anniversary years of 10 (diamond), 15 & 40 (both ruby), 20 (emerald), and 30 (pearl). With over 40-years of experience designing and building astronomical products —many in production for decades — we have a few “gems” of our own celebrating notable anniversaries this year. In this blog post, we take a look at current production products that are celebrating anniversaries. Among these products are five Sky & Telescope “Hot Product” awardees (those awards only started in 1998 🙂 ).
For Tele Vue, January 2020 began optimistically: our Apollo 11mm Commemorative eyepiece had started shipping in mid-December and we innocently opined on this blog that the year would be best remembered for “20/20 vision” puns. Our usual round of winter telescope shows and star parties began with David Nagler jetting off for the late-January European Astrofest in London and Al Nagler debuting a 67mm converter for our 55mm Plössl eyepiece at the Winter Star Party in February. David Nagler visited the studio at OPT Telescopes in Carlsbad, CA to discuss The Future of Visual Astronomy for an early-February Space Junk Podcast. In March we were looking forward to the “2020 Messier Marathon” and the arrival of Spring in the latter half of the month. Instead, COVID-19 precautions shut us down from March 20th — the first full day of spring — to May 26th. Thankfully, we all returned to work healthy, but the new concept of “social distancing” put an end to any chance of in-person appearances for the rest of the year.
With the strange year of 2020 behind us, we now choose to look back at the positive. In 2020 we managed to publish 34-postings covering a variety of topics. In this week’s blog we’ll examine our most popular stories for the year based on reader raw page views.
Tele Vue Optics was founded by an amateur astronomer, Al Nagler, and it is no surprise that amateur astronomers have been drawn to fill the ranks of Tele Vue employees. In this week’s blog, as part of an ongoing series, we meet one of the amateur astronomers at Tele Vue.
Our newest employee is a telescope builder and avid astrophotographer who has been busy imaging the night sky with a Tele Vue-85 and Canon DSLR since he started at Tele Vue. “Satesh” as he goes by, graduated with a Masters in Mechanical Engineering, from City College of NY. Al Nagler, who also graduated from City College with a Physics degree, but just a “few” years before Satesh, has enjoyed having a fellow alumnus on our team.
In his own words, Mahendra describes his journey into amateur telescope building.
Astronomy was not always a specific interest of mine, it was always space exploration in general. When I learned that there are amateurs that build their own telescopes, that all changed because I felt as if space had become a bit more accessible to me. Being an aspiring engineer at that time, the idea of building something as elegant as a telescope was more appealing than buying one. An extra challenge I had was that I had absolutely no experience with amateur astronomy or telescope making and when I say absolutely, I mean I had never looked through a telescope. Luckily there is a wealth of information online about telescopes and mirror making and I read so much that I became confident that I could do it.
I approached mirror making as smart as I could. To prevent astigmatism, I decided not to grind the mirror by hand. Instead, I made a fixed-post grinder that was driven by a hand crank and this ensured that the mirror’s surface was ground symmetric about its optical axis. I documented the process in a handwritten journal in case I encountered any problems during Ronchi testing. I could refer back to my notes and see what caused the problem. That paid off because I encountered almost every problem I read about; zones, under correction, over correction, turned down edge, etc. I fixed all of them and finally, I had a parabolized 6-inch F/6.5 mirror uncoated. I quickly assembled the mirror into the optical tube. In October 2014, I looked through a telescope for the first time when I finally tested my mirror on the sky by observing the moon and star testing on Sirius. The mirror was still uncoated and I hadn’t made the Dobsonian mount as yet. I pointed the scope by propping it up on a chair. By the end of 2014, the mirror was coated and the mount was complete. The entire process took almost a year, from building the mirror grinder to completing the scope.
It was March 19th of this year when we published a blog post, Shelter in Space, inspired by an image posted to flickr by Los Angeles based amateur Bill Allen. At the time we wrote:
Getting out in the desert for astrophotography is definitely sheltering in space.
We encountered the above phrase, this week, in the caption of an image of the Christmas Tree Nebula, made with our Tele Vue-85 APO refractor. We felt it apropos for our hobby as it succinctly conjures the connection between amateur astronomy and our current moment in world history.
Toward the end of the blog we opined:
As a strategy to avoid “cabin fever,” one local New York City television station has urged people to get outside and connect with the natural world — while maintaining social distance. Not an easy task during the day, but an easy prescription to take for amateur astronomers doing their night-time viewing and imaging.
During the course of that week, New York State had been putting out proposals for limiting the number of employees working in non-essential businesses. The proposals first called to limiting staff to 75%, and as the week wore on it evolved to 50% and then a draconian sounding (for the time) 25%.
The next day, Friday, March 20th, the first full day of Spring — exactly 7-months ago — we found out that social distancing under the stars was not enough: New York State had ordered 100% closure of non-essential businesses statewide for the foreseeable future. So, we hastily announced on this blog that we would be Closed Due to Covid-19 Until Further Notice. The news headlines at the time and the uncertainty of the duration of the closing was a jarring development for our staff and some wondered how this would impact the hobby when and even if we re-opened our doors.
Tele Vue Optics was founded by an amateur astronomer, Al Nagler, and it is no surprise that amateur astronomers have been drawn to fill the ranks of Tele Vue employees. In this week’s blog, we meet one of the amateur astronomers at Tele Vue.
Jon is a Chicago native born and raised. Before joining Tele Vue Optics, he worked for 8-years on the retail side of amateur astronomy, splitting his time between 20/20 Telescopes outside Chicago and Woodland Hills Camera & Telescopes in Los Angeles. In this blog post we interview Jon about the “many hats” he wears at Tele Vue headquarters.
One role you’ll often find Jon fulfilling is quality control on Tele Vue eyepieces. Unlike other manufacturers, that may inspect a representative sample (or none at all), every single Tele Vue eyepiece is checked before going out the door. You might assume that inspecting and boxing dozens of eyepieces a day is tedious. But not for Jon. “I find it therapeutic,” he says while inspecting a 55mm Plössl for cosmetic defects under the glowing fluorescent ring of a magnifier lamp. He eschews the built-in magnifier on the lamp because he feels he sees more just holding the eyepiece close to his eye.
The year 2020 holds some big product anniversaries for our company. Tele Vue was founded in 1977 by Al Nagler, originally to sell his television projection lenses (hence the name “Tele Vue” to match the abbreviation “TV” — read “Tele Vue: What’s in a Name?” blog post). In 1980 Al introduced Tele Vue to the amateur astronomy market with its inaugural range of four Plössl eyepieces (26mm, 17mm, 10.4mm, and 7.4mm). Additional models followed over the years until the final five focal lengths were released 25-years ago (1995).
With the positive reception of the Plössl eyepieces (hailed as “the sharpest I’ve ever used” by Astronomy editor Richard Berry) Al Nagler had the confidence to then bring to market his ground-breaking 82° Nagler eyepiece. This eyepiece used principles from Al’s work a decade earlier on an optical probe for an aircraft landing simulator. So began the era of “spacewalk” viewing forty years ago. (See slide show in “I Thank My Lucky Stars!” blog post.)