In the last blog, we covered the history of the Newtonian reflector, its inherent aberrations, and how Tele Vue’s Paracorr enlarged the “sweet spot” of fast scopes to cover the entire field. We also compared the Paracorr – Newtonian combination against more “exotic” telescope designs for imaging. If you missed it, you can read Part 1 before continuing.
Which Paracorr to Use? Over the years there have been two optical versions of the Paracorr. The original Paracorr came in various mechanical designs which developed as we developed new eyepieces. For this BLOG, we’ll focus on the currently available three versions of the Type-2 Paracorr: 2″ Photo/Visual, SIPS, and 3″ Photo models. Performance improvement over the original Paracorr is most noticeable on all Newtonian/Dobsonian telescopes of f/4.5 and faster.
Paracorr and the Evolution of Newtonian / Dobsonian Telescopes
Invented from lenses used to make eyeglasses, refractors were the first telescopes when introduced in the 1600s. However, the early refractor builders could not avoid building scopes that displayed color fringes (chromatic aberration) around bright objects. It was Sir Isaac Newton (1642–1727) who figured out that white light is composed of different wavelengths that we see as colors. Each wavelength will refract (bend) by a different amount as it passed through the refractor’s objective glass. The longest wavelengths (red) refract less while the shorter wavelengths (blue) refract more. As a result, the red component of the image focuses behind the blue component. Pinpoint images and higher magnification were out of the question with these primitive scopes. Even after the cause of chromatic aberration was revealed, refractor builders didn’t have the glass types and manufacturing skills to counter it for another century. Sir Newton, however, had an idea to build a second type of telescope that avoided refraction: a reflector.
Paul Andrew has been an amateur astronomer since the age of 11. He is the founder and Honorable President of the South East Kent Astronomical Society in the UK. He’s had a number of his astrophotographs published — in particular, his solar images — in national newspapers and on websites as far afield as Russia. He’s been short-listed for the prestigious Insight Astronomy Photographer of the Year competition four times now. We’ve noted his high-quality solar images and discovered that many were made with our Tele Vue 2.5x Powermate in the imaging train. So, we present a selection of his work in this week’s blog.
As we close-out the year, we’d like to update you on what is going on “behind the scenes” at Tele Vue! From the arrival of the Apollo 11mm eyepieces to the ongoing GoodBuy 2019 Sale, and answering your questions in between, our employees in upstate New York are somewhat like Santa’s “elves” this time of year!
Over the years, we’ve seen conversational topics in online amateur circles that repeatedly crop up concerning the definition of apochromatic refractor, triplet vs. doublet design, and how glass designation might define performance. We expect these questions to continue to appear as new amateurs discover the hobby. So bookmark this blog post because here you’ll find notes on Tele Vue’s philosophy and build practices concerning our telescope line of 100% APO refractors.
Tele Vue has taken its collaboration with Tactical Night Vision Company one step further! We are happy to announce that we now offer their TNV/PVS-14 L3 Gen3 Un-Filmed White Phosphor night vision monocular plus accessories direct from Tele Vue.
Al Nagler Goes “Full Circle” on Night Vision
Back in 1971, while an employee of Farrand Optical Company, Al Nagler was given the task of designing an eyepiece for a spiffy-new, high-tech gadget designed by ITT Corporation: a night vision device. He designed an eyepiece to view the 40° field of view created by the image intensifier tube. Now, after almost 40-years of evolution, the latest generation night vision monocular that Tele Vue is selling uses an eyepiece at least inspired by Al’s Design — if not exactly the same!
On June 10th, Jupiter was closest to the Earth and rose at sunset — placing it in the sky all night long. The timing makes it well placed for observation throughout much of the summer. Currently, the planet is at its best for the year, at magnitude -2.6 with an angular diameter of 46-arc-seconds. It will “fade” slightly to a still very bright magnitude -2.1 and shrink to 36-arcseconds by the start of fall, where it will be in the west at sunset, setting just a few hours later. So, now is prime-time to view and image this gas giant planet, its famous Great Red Spot (GRS), and attendant giant moons.
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.
This year all eyes will turn to the Moon to mark the 50th Anniversary of the first Moon landing. The Moon is the natural first target for new amateur astronomers, yet all too often as observers become seasoned, the Moon becomes a nuisance that blots the stars from the sky. This week we explore the Moon through the eyes and talented hands of Michel Deconinck. As you will see, there is much to see in the monthly dance between shadow and light on the lunar surface.
Michel Deconinck is an artist in the South of France with a passion for astronomical watercolors. He is very involved with the international astronomical community and his artistic works have been published in magazines, scientific journals, and displayed at conferences and school events. His artistry is augmented with a background in nuclear physics, engineering and astrophysics.
This guest blog post is written by Phil Ressler, a longtime amateur astronomer who lives in Los Angeles, though his observing life began on the east coast. Phil is a veteran software industry executive, currently CEO of Sixgill, LLC.
I had never seen pinpoint or round stars — apart from observing our round Sun.
I’m old enough to remember when “pinhole” eyepieces with “soda straw” views defined what a telescope offered to the average amateur astronomer. More than anyone, Al Nagler, and more than any company, Tele Vue, changed that by opening up the sky and making it easier to explore through wider field viewing. Mr. Nagler and his company also showed us that a relatively rich field refractor could not only capably serve as an amateur’s sole telescope: it is the best telescope to own if you’re only having one. We can thank Al Nagler and Tele Vue for laying the foundation for the way visual astronomy is pursued today. Yet despite all that, until I tried a DIOPTRX™ on my 22mm Panoptic last year, I had never seen pinpoint or round stars — apart from observing our round Sun. I’ve been observing the sky through scope optics since 1961, my astigmatism never absent. For people like me, DIOPTRX™ is arguably Tele Vue’s most essential product, because it makes all of Al Nagler’s original work in eyepieces and refractors unmistakably worthwhile to the astigmatic viewer.
Privacy & Cookies Policy
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.