Paracorr-Newtonian for Visual and Imaging to f/3! Part 2

 
At top is a cropped image of the Pinwheel Galaxy (M101) by AstroBin user Luca Marinelli. All rights reserved. Imaged through Teleskop Service ONTC 10″ f/4 Newtonian with Tele Vue Paracorr Type 2 coma corrector and ZWO ASI1600MM Pro mono camera. At right is the Tele Vue Paracorr logo. At bottom are the placement and back focus diagram for the 3″ BIG Paracorr.

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.

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Paracorr-Newtonian for Visual and Imaging to f/3! Part 1

At left is the original Paracorr with the Parrot Mascot. “Strawberry Fields” was a set of stickers on Al Nagler’s backyard shed (built by Al, David, and grandpa Max!) that were used to illustrate how the Paracorr eliminates coma in the corners. Within “Strawberry Fields” are superimposed various versions of the Paracorr.
Paracorr and the Evolution of Newtonian / Dobsonian Telescopes
Chromatic aberration in a simple glass lens. In this exaggerated image, each color (wavelength) of light focuses a different distance behind the lens. (public domain image)
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.
 

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TELE VUE SCIENTIFIC PART 2
Doing Science with Tele Vue Optics

Tele Vue Optics has been the key to unlocking the limits of magnification.

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.

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Doing Science with Tele Vue Optics”

NP101: Imaging the Skies Over Colorado & New Product!

Horsehead and Flame Nebulae in Hα by SmugMug user Steven Schlagel. All rights reserved. Used by permission. Imaging details: the Tele Vue-NP101 APO (Nagler-Petzval) refractor (101mm, f/5.4) with a Nikon 810Da camera and narrowband Hydrogen-alpha filter were used to create this image. Exposure time was 3-hours total.

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. 

Horsehead and Flame Nebulae by SmugMug user Steven Schlagel. All rights reserved. Used by permission. Imaging details: the Tele Vue-NP101 APO (Nagler-Petzval) refractor (101mm, f/5.4) with a Nikon D810a DSLR camera for 6-hours.

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. 

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TELE VUE SCIENTIFIC PART 1
Doing Science with Tele Vue Optics

Tele Vue Optics’ science goes from solar to polar. Mosaic image adopted from ASTEP study by Crouzet et al. and PUNCH website. Images copyright their respective owners.

Tele Vue’s product quality, consistency, and reliability are well known in amateur astronomy circles. So, it shouldn’t come as a surprise that our top-tier optical performance also attracts the interest of professional astronomers looking for “off-the-shelf” solutions for their experimental needs. Tele Vue also provides researchers with the in-depth technical analysis necessary to determine if product integration is feasible or if custom solutions are required.

In this multi-part blog post we’ll explore some of the published science using our standard gear and take a look at a future science mission that called for a custom designed Tele Vue lens. Note that all the studies in the series, except the last one in this part, were produced with products bought off-the-shelf, same as you would receive from Tele Vue.

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Doing Science with Tele Vue Optics”

Tele Vue-NP101is: Imaging the Skies Over Southwest Florida

Rosette Nebula and NGC 2244 Cluster (Narrowband) by SmugMug user Linwood Ferguson. All rights reserved. Used by permission. Imaging details: the Tele Vue-NP101is APO (Nagler-Petzval) refractor (101mm, f/5.4), riding on an iOptron CEM70G mount, imaged with a ZWO ASI6200MM Pro camera, with ZWO Filter Wheel and Chroma 5nm narrowband filters. All subframes were 300s using these filters: Hα x 47, SII x 37, OIII x 31. (The OIII had a pretty strong gradient from the moon). Stacked and processed using PixInsight in roughly the Hubble Pallet with green shifted into blue and gold (star color shifted off magenta a bit). Finished off in Photoshop Lightroom Classic 10.0 (Windows).

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.

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Our Virtual NEAF 2021 Videos

Northeast Astronomy Forum (NEAF) 2021 — “the World’s Largest Astronomy & Space Expo” — is in the history books after streaming 10-hours of material on April 10th.  Tele Vue provided seven unique videos for the event and we’d like to thank all who tuned in and showed their support in the chat!

Each of our videos answers a question from one of our blog readers. If you want to review them, they’re all linked below and cued up to the question being answered. 

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Virtual NEAF 2021: Your Questions Answered!

Due to the continuing COVID-19 crises, the Northeast Astronomy Forum (NEAF) — “the World’s Largest Astronomy & Space Expo” — will be a “virtual,” online-only affair for the second year in a row. However, that is not all bad: it allows people from around the world —  who might normally not travel to New York — to experience this special show. It’ll be FREE too!

Last time in this blog we asked for your Tele Vue product questions which would be answered on videos and played at the virtual NEAF on April 10th. The response was tremendous! Though time and slots were limited, we were able to produce seven videos for the show. Each video provides a “front-row” seat to the answer from David and Al Nagler. Below you can view a 1-minute “sneak peek” video of what to expect.  

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Virtual NEAF 2021: Send Us Your Questions!

Activity in the Tele Vue NEAF booth over the years.

For a second year, unfortunately there is no actual NEAF to attend. So once again stuck in the virtual world, we thought we might be able to create a bit of the sense of what goes on in our booth at a real NEAF. We hope to whet the appetite of those that have never been and let those experienced NEAF-goers do what they’ve done for us since the first NEAF in 1991… keep us talking about how Tele Vue products can satisfy their needs!

As our “home” show, we normally pack-up every Tele Vue product for display at NEAF. It’s a wonderful chance for people to get their hands on our equipment and really see and feel the care and quality we put into our products. While we’ll miss that personal interaction the most, the other valuable aspect of coming to visit us at NEAF is that you can ask us your questions and we can show you the answer.

With your help, we can do just that!  We thought rather than listen to Al or David ramble on about esoteric product details on a video, let’s do what we do best at NEAF. We answer hundreds of your questions from eyepiece recommendations to DIOPTRX™, Night Vision, our Imaging System, even product philosophy and manufacturing questions — you name it! This is your chance to ask us your questions and we’ll respond in the video just as we would at NEAF.

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This Weekend: Messier Marathon 2021!

By the 1970s amateur astronomers had noticed that all 110 Messier objects (a list of notable objects in the northern skies visible in small scopes) could be observed at low northern latitudes over the course of a night in mid-to-late March. Hence, the phrase “Messier Marathon” was invented to describe the attempt at locating and verifying observance  of each object on the list over the course of a single night.

The first page of a typical Messier Marathon check sheet under red light. Messier objects in the background taken with Tele Vue-60is by James Burnell. All rights reserved. Used by permission.

Sheltering in Space
Last year, on March 11, we published our “2020 Messier Marathon!” post on this blog. We noted the best dates to observe based on latitude and lunar phase, and discussed the type of gear to use for the event. We pointed out that the Saguaro Astronomy Club, in Arizona, was one of the oldest organized Marathons and they offered awards in various categories for completing the list. It turned out to be our last blog post during “normal” times that year: COVID-19 social-distancing and lock-down orders, which we had only heard about, suddenly swept through our region. The Saguaro Messier Marathon and many star parties were ultimately canceled that year and it continues into this year.

M33 The Photon Sucker (Triangulum Galaxy) by Astro Bin user Tom Peter. Copyright Tom Peter. Used by permission. Tele Vue-NP127is and Tele Vue-85 combined exposures. This is one of the first few objects in the traditional Messier Marathon list. Of course, in your scope, without the benefit of 15-hrs of exposure, this will look like a blurry little black & white smudge!

The Messier Marathon did and will go on again, “run” by solitary observers “sheltering in space.” In fact, due to COVID-19 there may be MORE Marathoners than ever as the hobby of amateur astronomy has taken off during these socially distant times. See this recent report from CBC Canada that features our dealer All-Star Telescope in Alberta: Amateur astronomy lifts off during the pandemic.

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