This guest blog post is by Tele Vue-85 owner Chris Owen. Chris is a physician in Orange County California, where he lives with his wife and 3-year old son. You can see more of his images on AstroBin.
I got started in astronomy in the 1990s while I was still in High School. I spent cold clear winter nights in Northern New York learning the basics together with my father on an 8″ Schmidt Cassegrain. I remember trying to manually guide my first prime focus images of M42 with the 2,000mm focal length SCT, shooting 35mm film in 10°F temperatures. The results were predictably flawed and after I went off to college the scope and gear were put away. I went west after finishing school and my astronomy interest faded away under the light polluted sky of Southern California.
20-years later my wife decided to surprise me with a telescope for our first Christmas and called my father for advice. He had since discovered the advantages of wide-field refractors and he answered without hesitation: I found a Tele Vue-85 under the tree for Christmas 2015. The crisp, high contrast image struck me on my first terrestrial views through the little scope. Before long I had an iEQ35 pro mount, starshoot autoguider, a Canon T5i and some halfway decent shots of the great nebula that had eluded me on those cold nights years ago.
I shoot now from my backyard in coastal Southern California. Last year I made the transition to narrowband imaging and a cooled CMOS imager (ASI1600M Pro). These images are from my first season with the new imager.
The Tele Vue TRF-2008 0.8x Reducer/Flattener gives a perfect field on the APS-C sensor and focusing is easy. The narrowband filters cut through the light pollution and the wide field/low power of the ’85 means I don’t have to worry about the seeing here, which varies a lot with the marine air mass.
The wide field is also nice for mosaic shots. A panorama from the Horsehead to M42 fits into just 3 fields of view with enough overlap to stitch the frames without too much artifact. I use the mosaic wizard in Sequence Generator Pro to set up the shots and shoot over several nights.
I use Astro Pixel Processor to process and stack the subs. It has a very powerful mosaic tool which can normalize values and create seamless compositions from lots of subs over many nights.
For final processing I try to use the “tone mapping” technique developed by J-P Metsavainio. The narrowband data gives tremendous latitude for color interpretation and level and curve adjustment to determine the final overall feel of the image. It is a constant struggle to maximize the detail in the data without introducing noise, artifact or over-processing. With each image I gain new appreciation for the artistry of master imagers like J-P. The Tele Vue-85 at the heart of my set-up makes it easy to soak up more data and continue my efforts.
About the Tele Vue-85
With an 85-mm APO (Doublet) objective and 600-mm focal length, this f/7 refractor offers a combination of optical performance and airline portability that delights amateur astronomers, birders, and reviewers alike. Resolving close double-stars, viewing lunar detail, viewing deep sky, and photographic uses were reported in Sky & Telescope as: “Truly awesome! …Incredible!…the view almost blew me off my chair!…” The conclusion, “…an extremely powerful, compact instrument capable of delivering stunning images of the universe.” Maximum field-of-view is 4.4° (with our 41 -mm Panoptic [mobile site] at 14.6x or 55-mm Plössl [mobile site] at 10.8x) allows use as a self-finder. Optional Nagler 3-6mm Planetary Zoom (mobile site) yields 100x – 200x in this scope for obtaining optimal planetary observing power to match the seeing conditions. The addition of the TRF-2008 0.8x Reducer/Flattener (mobile site) converts the Tele Vue-85 to 480mm f/5.6 for flat field, fast photography with any camera that accepts a T-Ring. See more info on the Tele Vue-85 page (mobile site).
Taking advantage of the Tele Vue-85’s ability to work as a high-end, prime, telephoto lens, Chris also provided us with these birding images.
To learn more on using the Tele Vue-85 or our other small APO scopes for birding please visit our Birdscope website.
Hands-on with the Tele Vue-85 (mentions in prior blog posts)