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.
The above portrait of the Horsehead and Flame nebulae is stunning. Created in Hydrogen-alpha light, this monochrome image is filled with wispy tendrils, puffy molecular clouds, dark lanes, and glowing gas. It really brings out the interplay of shockwaves and ionizing radiation at work in this region of the much larger Orion Molecular Cloud Complex.
You can compare this image with the color one below of the same region. The red hues are dramatic, but we lose a sense of the “sculpting” that is taking place in the gas and dust.
The Horsehead (Barnard 33) and Flame Nebulae (NGC 2024) are separated by the bright blue supergiant star Alnitak (center-left in the above image), the easternmost star in the “Belt” of constellation Orion. Like a giant neon sign, the “Flame”, below Alnitak in the image, is “lit up” by ultraviolet light from the star. The flame-like appearance is enhanced by dark “branches” of light-absorbing gas in the nebula. As for the Horsehead, its appearance is due to the three-star system Sigma Orionis “above” the “horse” (bright star along a line through the horse’s neck and head). It causes hydrogen gas to glow behind a dark concentration of dust that has the distinctive appearance of a horse’s head.
The lead-off image of this post is certainly an eye-grabber! It is one of the most unique interpretations of the Rosette Nebula (NGC-2237 or Caldwell 49) in Hubble Palette filters we’ve seen. Most striking, the usual Hubble Palette aquamarine color surrounding the central cluster is cobalt blue! The typical outer ring of yellows and burnt ochre now has a deep-orange hue. This color manipulation was done while maintaining the filamentary wisps and dark protostar Bok Globules in the nebula, along with a jet-black sky background. The resulting dimensional quality of this image draws the viewer from the ruddy edges of the nebula into the blue-colored center and then out the “back” aperture of the structure.
In the middle of the Covid pandemic, stuck at home, I decided to resurrect an interest in astronomy, and in particular astrophotography.
This image is from a great collection of Tele Vue NP101is images posted by Linwood Ferguson on SmugMug. At the top of this SmugMug page is stated the motivation for his astro imaging: “In the middle of the Covid pandemic, stuck at home, I decided to resurrect an interest in astronomy, and in particular astrophotography”. In this blog, we present a gallery of Linwood’s NP101is images.
Mauri Rosenthal’s Tele Vue 2.5x Powermate solar images appeared in our Here Comes the Sun! blog last December. Imaging from just 10-miles (16-km) from New York City, it was reasonable to expect that his flickr and Instagram walls featured images of the Sun, Moon, and Planets. To our surprise, we also saw some images of deep-sky objects (DSOs), taken with a Tele Vue-85, from the same light-polluted location. We were intrigued at how he was able to get such reasonable results from his poorly situated location and asked if he’d relate his experiences in this blog.
It turns out we’d found the right guy for the job. Mauri wasn’t a “typical” amateur astronomer/imager: he actually teaches Urban Astrophotography in New York City, under the auspices of the Amateur Astronomers Association of New York. His instructor’s biography, on a recent class registration page, describes Mauri’s motivation as follows:
Surprised by the image quality achievable with small telescopes from his yard in Westchester County, Mauri has been developing deep expertise in Ultraportable Urban Astrophotography and is on a mission to use new technology to extend the access of city-dwellers to the wonders of the night sky.
In this guest blog post, we asked Mauri about his overall experience and how Tele Vue Optics contributes to the enjoyment of his hobby.
We’re quite impressed with Frank Wielgus’ exquisite collection of wide-field, deep-sky images on SmugMug. Photographed with a Tele Vue-NP127is APO refractor, the attention to image capture and software craftsmanship is evident in his collection of galaxies and nebulae. His images have often been selected as winners in the Amateur Astronomers Association of Pittsburgh’s Kevin J. Brunelle Photography Contest.
In his guest blog Frank shows and tells us the story of his astrophotography.
I started astrophotography in the early ’90s using film. It was a Pentax camera with screw mount lenses, piggybacked on an SCT using slide film. Boy, I’m glad those days are gone! I have recently started using those lenses again on a wide field DSLR set up. I then moved to imaging through the SCT. At some point, I wanted to up my game in quality, and for me, that meant a refractor.
Ever since I first acquired Tele Vue Plössls in the early ’90s, I have always admired Tele Vue products. Quality, design, and locality of service were important considerations for me. For these reasons, the NP127is was a dreamed-for acquisition for a number of years. So when the opportunity arose and with the prompting of a good friend, I acquired one. I remember being blown away by the quality. Now stars look like stars and the sharpness with flat field are incredible things to see. Barring any unusual circumstances, this scope and I are in it together for the long haul.
Brian Paczkowski has been employed by NASA/Jet Propulsion Laboratory in Pasadena, California since 1983. Some of his work includes the Galileo Mission to Jupiter and the Cassini Mission to Saturn. He is currently the Europa Clipper Science Manager.
Every clear night he images with his Tele Vue-76 installed at a remote observatory located at Dark Sky New Mexico (DSNM). He dedicates his Instagram wall of astroimages, “to my love of astrophotography.”
Located in the northern regions of Ursa Major and 12-million light-years from Earth, the two prominent galaxies in Brian’s image are Bode’s Galaxy (M81) and The Cigar Galaxy (M82). They are joined by NGC 3077 (an elliptical galaxy slightly further away) in the upper-left corner. All three are gravitationally interacting members of the M81 Group of Galaxies. This wide-field image shows foreground dust in our own galaxy covering the starscape.
In the close-up crop below, the intervening dust is not emphasized in processing. The yellowish core of M81 indicates an older population of stars while the red “spots” are from glowing hydrogen gas excited by ultraviolet light from newly formed young giant stars.
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.
Even though we’re past the point of closest approach and opposition, Mars continues to loom large in the sky and is higher each night at the same time. In the northern hemisphere, the nights are coming sooner and lasting longer. Until mid-November, Mars will appear bigger than at any opposition until 2033!
You can use the excellent Mars Mapper 2020-2021 web app (mobile version) on the British Astronomical Association website to identify features on the planet when you observe or image it.
If you’d like to try your hand at imaging the planet, study the next sections carefully as they contain image processing tips from top Martian imagers on the Internet.
We were struck by the neon-like colors produced by Murray Parkinson’s imaging through our Tele Vue-NP127is APO Refractor using different combinations of Hydrogen-alpha (Hα), doubly ionized oxygen (OIII), and ionized sulfur (SII) filters. His Porpoise Nebula image below looks like it is leaping out of the page! Others agree: he provided the cover and inside cover spread images for Nightfall October 2017 (a journal of astronomy in South Africa). He tells us “I love my two Tele Vue refractors. Only wish you made a 12-inch refractor … .” This week’s guest blog post is a gallery of his work from suburban Sydney, Australia.
“When I became interested in astrophotography, I quickly learned that the quality of the optics was crucial to achieving high-quality results. Only the very finest telescope designs can deliver round, pinpoint stars across the entire frame. I chose the Tele Vue-NP127is partly because of the reputation of Al Nagler and partly because of trust in products made in the USA. I also had a lot of trust in the salesperson who looked after me at BINTEL in Sydney. He always gave excellent advice on what to buy.
“Without a doubt, the versatility of the Tele Vue-NP127is stands out in my mind. The telescope delivers true astrograph performance when imaging at multiple focal lengths. It also delivers brilliant views when used visually and is light enough to transport to a dark sky location on a car camping trip. I still love visual observing and appreciate a telescope that can deliver on all accounts.
The Porpoise Nebula in Canis Major
“This faint Oxygen III nebula is catalogued as Sharpless 308 in the constellation of Canis Major and is commonly called the Gourd Nebula, but I am one of those people who see a Porpoise first, or I am fonder of porpoises than gourds anyway. The nebula is classified as a Wolf-Rayet bubble and originates from the star located close to the centre of the frame.
“When I was a young boy in the early 1970s, my stepfather took me to see a movie at a drive-in theater in the country. At the end of the movie, I stepped outside the car and looked up to behold the summer Milky Way overhead. This was the first time I had seen the Milky Way from a dark location and I was overwhelmed with awe. To this day, I still experience awe, swooning at the beauty of a starry night when I am lucky enough to camp somewhere truly dark.
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