DOCSLIB.ORG

Patrick Moore's Practical Astronomy Series

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Patrick Moore's Practical Astronomy Series Patrick Moore’s Practical Astronomy Series For other titles published in the series, go to www.springer.com/series/3192 Choosing and Using a New CAT Getting the Most from Your Schmidt Cassegrain or Any Catadioptric Telescope Rod Mollise Rod Mollise 1207 Selma Street Mobile AL 36604 USA ISBN 978-0-387-09771-8 e-ISBN 978-0-387-09772-5 DOI: 10.1007/978-0-387-09772-5 Library of Congress Control Number: 2008934774 © Springer Science+Business Media, LLC 2009 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by simi- lar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper springer.com About the Author Rod Mollise is an engineer by profession. He is also the author of numerous books and magazine articles on every aspect of amateur astronomy. Known to his fans as “Uncle” Rod Mollise, he is most well known for his books about catadioptric tel- escopes (CATs), which aim to help new CAT owners get past the inexperience and anxiety that often accompanies their entry into this wonderful hobby. In addition to his books and Internet sites, Rod’s writings can frequently be found in Sky & Telescope, Night Sky Magazine, Astronomy Technology Today, and many other pub- lications. Rod also finds time to teach astronomy to undergraduates at the University of South Alabama in Mobile. When he is not on the road attending and speaking at star parties, he shares a rambling old Victorian home in Mobile’s Garden District with his wife, Dorothy, two (four-legged) cats, and, at last count, 11 telescopes. v Acknowledgements Thirty-five years of using and loving Schmidt Cassegrain telescopes (SCTs) has taught me a few things about these wonderful telescopes, but I hardly know every- thing. This book would not have been possible without the assistance of many kind and generous members of the amateur astronomy community. The input from my online catadioptric telescope (CAT) user groups proved inval- uable from start to finish. These individuals have taught me far more about SCTs than I could ever have learned on my own. Special recognition is due these out- standing amateur astronomers: Bob Berta, Cal Beard, Matthias Bopp, Paul Cezanne, Steve Clayworth, John Clothier, Richard Edelson, “Poppa Fred,” Tanveer Gani, Steve Jaynes, Andrew Johansen, Leonard Knoll, Joe Kuhn, Jim Norton, Robert Piekiel, David Polivka, R. Richins, Dick Seymour, “Doc” Clay Sherrod, Rick Thurmond, Gord Tulloch, and many more. One of the greatest things about the SCT community is the close and supportive relationship that exists between telescope users and telescope makers. The following astronomy business pros provided me with the images and software I needed to make this book a reality: Paul Rodman (AstroPlanner); Michelle Meskill (Celestron); Steve Tuma (Deepsky Astronomy Software); Paul Hobbs (Meade); Terry D’Auray, Claire Kleffel, and Peter Moreso (Imaginova/Orion Telescopes and Binoculars); John Pem- berton and all the good folks at Orion Optics UK; and Greg Crinklaw (SkyTools). Finally, as has been the case with every book I have done for Springer, three people have earned my deepest appreciation. John Watson shepherded this one along in the early days, and without his efforts it would not have been published. Pat Rochford, my best friend, checked and proofread the manuscript, and without his hard work, it would not have been much good. Dorothy Mollise, my wife and always “the brightest star in this astronomer’s sky,” contributed the most of all. Without her love and understand- ing, it would not have been written. Thanks, y’all! vii Contents About the Author ................................................................................................. v Acknowledgements .............................................................................................. vii 1 Why a CAT? ................................................................................................... 1 2 What’s a CAT? ............................................................................................... 11 3 Inside a CAT ................................................................................................. 19 4 Which CAT? .................................................................................................. 41 5 Making Friends with a CAT ........................................................................ 113 6 Accessorizing a CAT..................................................................................... 129 7 First Light With a CAT ................................................................................ 165 8 Enjoying a CAT ............................................................................................ 195 9 Care and Feeding of a CAT .......................................................................... 223 10 Computerizing a CAT .................................................................................. 237 11 Taking Pictures with a CAT ......................................................................... 259 12 Hacking a CAT .............................................................................................. 291 ix x Contents 13 Keeping the Passion Alive ........................................................................... 313 Appendix 1 Telescope and Accessory Dealers and Manufacturers .............. 319 Appendix 2 Internet Resources, Software, and Books for CAT Users .......... 323 Index ...................................................................................................................... 329 CHAPTER ONE Why a CAT? Since you’re reading this, I’m guessing you have made an exciting decision: You want a telescope. Specifically, you want a telescope for looking at the sky, a telescope that will open the depths of space to your gaze and allow you to visit the Moon, the planets, and all the strange and distant wonders of our magnificent universe. And you are not looking for just any telescope, either, but for a Schmidt Cassegrain telescope (SCT), whose full-color advertisements fill the pages of astronomy magazines. In our consumer culture, most of us have become wary of high-pressure ads from manufacturers who promise the Moon and deliver little. Luckily, that is not the case when it comes to SCTs. Sometimes, the advertising does contain hyperbole, but Schmidt Cassegrains really can deliver the Moon—and the stars, too. SCTs, like anything else, are not perfect, but when all is said and done, the Schmidt Cassegrain may be the most versatile, technologically advanced, and easy-to-use telescope ever sold to amateur astronomers. Since SCTs were first offered at prices the average person could afford way back in 1970, they have dominated the amateur astronomy telescope market. Don’t believe that? Take a stroll around the observing field of a local astronomy club during the next star party. Chances are a majority of the telescopes there will be SCTs. Fancy advertisements alone simply could not account for the enduring popularity of Schmidt Cassegrains. Something good is going on. Not that an SCT (Plate 1) looks much like a telescope of any kind to novice astronomers. Catadioptric telescopes (CATs, for short), which are telescopes that use both lenses and mirrors, do not much resemble the telescopes we are used to seeing in the movies or on television. The eyepiece is where it “ought” to be, at the end of the tube, and that tube is perched on a tripod, but that is where the similarity ends. The tube is short and fat, looking more like a beer keg than a respectable R. Mollise, Choosing and Using a New CAT, 1 DOI: 10.1007/978-0-387-09772-5_1, © Springer Science + Business Media, LLC 2009 2 Choosing and Using a New CAT Plate 1. (SCT) An 8-inch Schmidt Cassegrain tele- scope set up at a dark site and ready for an evening of deep space voyaging.” Credit: Author telescope. It is not just attached to a tripod, either. It is sitting on a complicated- looking “mount” festooned with myriad lights and switches. The SCT looks different enough in beginners’ eyes to be positively frightening, maybe scary enough to make a new astronomer who just wants a good look at the craters of the Moon turn tail and run. Appearances can deceive, however. The SCT is at heart an uncomplicated telescope. Despite its looks, its basic operation is easy to understand, and it is actually one of the most user-friendly scopes ever made. And, it is not just user friendly. A beginning amateur astronomer may start out just wanting a look at the good old Moon but will soon find the faithful SCT can take even a novice observer way beyond our cosmic neighborhood—maybe even as far as the daunting depths of the universe inhabited by the mysterious quasars. Although nothing in the design of the SCT is astoundingly innovative, its basic lay- out is extremely sound and features good optics in sizes sufficient to take even a tyro a long, long way from home. Capability is just the beginning of the SCT story,
Load more

Recommended publications
  • The Wide Field Cassegrain: Exploring Solution Space Peter Ceravolo Ceravolo Optical Systems [email protected]
    The Wide Field Cassegrain: Exploring Solution Space Peter Ceravolo Ceravolo Optical Systems www.ceravolo.com [email protected] Abstract This article illustrates the use of an internal aperture stop in a high speed, wide field Cassegrain optical system. The astrograph features a well corrected and uniformly illuminated focal plane. Opto-mechanical design and manufacturing issues are also discussed. 1. Introduction Of all the conventional astronomical telescope Aperture Stop designs used in amateur astronomy the Cassegrain is the least likely to be considered a candidate for wide field imaging applications. This perception is a hangover from the era of visual observing where minimizing the central obscuration was critical to preserving image fidelity. The resulting long focal length, slow telescopes did not lend themselves to photography. The central obscuration in reflector astrographs need not be so constrained since ground based amateur instruments never achieve diffraction limited performance, primarily due to poor seeing, image sampling limitations and tracking errors. Cassegrain astrographs with a large obscuration (50% of the aperture diameter or greater) and a fast primary will permit a relatively short overall focal length, a wider field of view and more uniform focal plane illumination. While the larger obscuration does reduce system through put, the light loss can be compensated for with longer exposures. Figure 1, internal stop Cassegrain astrograph In addition to the benefits of a larger obscuration, allowing the aperture stop position to move from the primary mirror to a more central location in the Cassegrain optical system offers the potential to achieve very wide fields of view in a fast system 2.
    [Show full text]
  • Comets in UV
    Comets in UV B. Shustov1 • M.Sachkov1 • Ana I. G´omez de Castro 2 • Juan C. Vallejo2 • E.Kanev1 • V.Dorofeeva3,1 Abstract Comets are important “eyewitnesses” of So- etary systems too. Comets are very interesting objects lar System formation and evolution. Important tests to in themselves. A wide variety of physical and chemical determine the chemical composition and to study the processes taking place in cometary coma make of them physical processes in cometary nuclei and coma need excellent space laboratories that help us understand- data in the UV range of the electromagnetic spectrum. ing many phenomena not only in space but also on the Comprehensive and complete studies require for ad- Earth. ditional ground-based observations and in-situ exper- We can learn about the origin and early stages of the iments. We briefly review observations of comets in evolution of the Solar System analogues, by watching the ultraviolet (UV) and discuss the prospects of UV circumstellar protoplanetary disks and planets around observations of comets and exocomets with space-born other stars. As to the Solar System itself comets are instruments. A special refer is made to the World Space considered to be the major “witnesses” of its forma- Observatory-Ultraviolet (WSO-UV) project. tion and early evolution. The chemical composition of cometary cores is believed to basically represent the Keywords comets: general, ultraviolet: general, ul- composition of the protoplanetary cloud from which traviolet: planetary systems the Solar System was formed approximately 4.5 billion years ago, i.e. over all this time the chemical composi- 1 Introduction tion of cores of comets (at least of the long period ones) has not undergone any significant changes.
    [Show full text]
  • Uncle Rod's Used CAT Buyer's Guide
    Uncle Rod’s Used CAT Buyer’s Guide 10th Edition (2013) Rod Mollise Would You Buy a Used CAT from this Man? A Chaos Manor South Production Table of Contents Introduction 4 Before the SCT 5 Celestron C8 Orange Tube 7 Celestron Pacific White/Blue C8 11 Meade 2080 14 Celestron Super C8 17 Celestron Super C8 Plus 19 Super Polaris C8 20 Meade LX3 22 Celestron Powerstar C8 24 Meade LX5 26 Celestron Ultima 8 28 Takahashi TSC 225 33 Meade LX6 35 Meade Premiere 38 Celestron Classic 40 Return of the 2080 42 Meade LX200 Classic 43 Meade LX50 and LX100 47 Celestron Ultima 2000 50 Celestron Celestar 54 Meade LX10 57 Celestron Fastar 8 61 Celestron Celestar Deluxe 63 Celestron NexStar 5/8 65 Celestron NexStar GPS 69 Meade LX90 75 Celestron CG Series GEMs 79 Celestron CI-700 82 Celestron CGE 84 Celestron GP-C8 87 Meade LXD Series GEMs 89 Celestron ASGT CG 5 92 Meade LXD 75 95 Celestron C14/C11 98 Celestron C5 102 Meade 2040/2044 107 Meade 2045/2045D 110 Criterion Dynamax 6 114 Bausch and Lomb 4000 115 Quantum 4/6/8 117 Uncle Rod’s Used CAT Buyer’s Guide 2 Celestron C90 123 Meade ETX 127 Meade 7-inch MCT 134 Intes MK66/67 136 Questar 3.5/7 140 Criterion Dynamax 8 145 Bausch and Lomb 8000/8001 147 Celestron Compustar 149 Used Buyer’s Checklist 153 Uncle Rod’s Used CAT Buyer’s Guide 3 Introduction Been a long time coming, muchachos. The 10th Edition of the Used Guide, that is.
    [Show full text]
  • J'/ 7 ~,J,,F42~OD'/ 4~Z T 0014- AL4 '4 N 444 4 V-~ V~'4,,/C4D4 ;/L X' 3* ''(N I /I -- -K
    4'T,4 "~ J, itI' ~ " 4 4~~~~~~t f"- N'. 4 tV34 '' '4~~~~~~~r "''',) m/4' - 4 / .,~~~~t 4f {'NW ' I, '~ / . 4 4'~~~~~-' ~~~~-"" ' ' A '' " I \ ' o A4 j'/ 7 ~,j,,f42~OD'/ 4~z t 0014- AL4 '4 N 444 4 v-~ v~'4,,/C4D4 ;/l x' 3* ''(N I /I -- -K . 2 . /-, -, 1 '> 97 (; ' '-I' -4 )-' Ni\iS ,L -I-' "1/ iT h 'i l I .=.,, ca ec~- fr ain ivsoOd* .: 25 C , '-A- ", ---.- a a en .- -_ . - ; . - - '1 (N, -< I' 4 -I --. N ?- j -. Thspprpeet h veso h uhrs adde o eesr .I ~rf~c :";athethe vieio oddr Spce ight Cenbitr o: NASA r 7-ref e.'th viGods th~ar ddSpace', Fligt . enter. .. orN-/- " -- -' -- I / -I- _ . - " . -,t -" , *-*- . : TABLE OF CONTENTS Page LIST OF ATTENDEES 3 FOREWORD 6 INTRODUCTION TO SPACELAB/SHUTTLE 8 ASTRONOMY PAYLOADS 12 I. A Very High Resolution Spectrograph for Interstellar Matter 15 Research - E. Jenkins and D. York, Princeton University Observatory 2. Schmidt Camera/Spectrograph for Far Ultraviolet Sky Survey 20 G. Carruthers and C. Opal, Naval Research Laboratory 3. UV Telescope with Echelle Spectrometer - Y. Kondo and 25 C. Wells, Johnson Spacecraft Center 4. Small Infrared Cryogenic Telescope - R. Walker, Air Force 29 Cambridge Research Laboratory 5. Two EUV Experiments - S. Bowyer, University of California 33 at Berkeley 6. Ultraviolet Photometer - A. Code and R. Bless, University 39 of Wisconsin 7. Schwarzschild Camera - A. Smith, Goddard Space Flight Center 43 8. Three Rocket-Class Payloads for Spacelab - C. Lillie, 49 University of Colorado 9. Additional Payloads 57 ASTRONOMY MISSION STUDIES - W. Scull, Goddard Space Flight Center 60 SMALL INSTRUMENT POINTING SYSTEM (SIPS) - C.
    [Show full text]
  • The Maksutov Revolution
    EQUIPMENT ROUNDUP If you’re looking for optical quality in a small package, consider one of these fine telescopes. /// BY STEVE EDBERG The Maksutov revolution Among the telescopes available today, the Maksutov- Cassegrain (or Maksutov, for short) ranks fourth in popularity. Russian astronomer Dmitri Maksutov (1896–1964) invented the optical design in 1944. Dutch astronomer A. Bouwers, who may have preceded Maksutov, independently developed the design. What we now call the because their slower (larger f number) Maksutov telescope is a hybrid optical sys- optics don’t require as large a secondary tem using both mirrors and a lens to pro- mirror. All other qualities being equal, a duce images at the focus. Such systems are smaller secondary mirror means that the called catadioptric. The more common viewed images will have higher contrast Schmidt-Cassegrain telescope is also a cata- than through telescopes with larger second- dioptric system. ary mirrors. Contrast in the viewed image The primary difference between the two depends heavily on scattered light, and a is the corrector lens found on the “sky” end smaller secondary scatters less light. of the telescopes. Whereas a Schmidt- One concern with Maksutovs can be Cassegrain uses a thin lens shaped with a their optical alignment, or “collimation.” complex curve, the Maksutov lens is thick The corrector lens and the secondary mirror and has matching spherical curves ground attached to it must be aligned perfectly with into it. The lens is a thick shell of glass, the primary mirror or the final image will which conveniently minimizes spherical be degraded. Collimation is not easily aberration and provides sharp images.
    [Show full text]
  • Placeyour Essential Source for Astronomical
    Market Your essential source for Place astronomical products ACCESSORIES ACCESSORIES ACCESSORIES Foster Systems Serving astronomers and observatories worldwide ! WeatherAlert ew Weather Monitor N •Rain/Snow alert •Cloudy/Clear sky alert •Dewing alert Configurable •Wind Speed alert From $299 •USB and ASCOM compliant Visit us at www.fostersystems.com SkyandTelescope.com January 2010 87 JJan_8pgs.inddan_8pgs.indd 8787 111/17/091/17/09 88:27:08:27:08 AMAM ACCESSORIES ACCESSORIES ACCESSORIES With Hubble 5-star Artificial Star(s) telescopes are truly easy to test and collimate! $29.95 SHIPPED WORLDWIDE www.hubbleoptics.com We Make Your Part! Custom astronomy parts machined to YOUR specifications. One-of-a-kind adapters and accessories in aluminum, brass, titanium, stainless steel. Try our free Cost Estimator at www.preciseparts.com 305 253-5707 [email protected] Custom Parts for Astronomy Worldʼs Best DEW CONTROL SYSTEMS •Top Quality build •Effective •Systems for every budget NEW FireFly Heaters Low Power, High Quality, Very Competitively priced. 1.25” Heater.......... $25.00 2” Heater............... $26.00 3” Heater............... $28.00 Are you 8 4” Heater............... $29.00 PETERSON EQUIPPED? 5” Heater............... $30.00 For over 50 years, your source for j GET-A-GRIP™ Ergonomic 8 6” Heater............... $31.00 handles make your big camera quality Japanese optics Meade feel many pounds ~ 7/8” Heater............ $35.00 lighter. $71.99/pair k EYEOPENER® Get all the 9/10” Heater.......... $39.00 Planetary Orthoscopics 2" eyepiece aperture that you paid 9 for. Increase light reaching your 11” Heater............. $40.00 Wide-Field Konigs pupil by up to 65% while eliminating vignetting.
    [Show full text]
  • The World of Celestron Sport Optics
    CONTENTS CHOOSING A BINOCULAR 3-5 Welcome To The World UPCLOSE 6-8 Of Celestron Sport Optics TRAVELER 9 OUTLAND 10 This catalog introduces you to the extensive selection of sport optics OUTLAND LX 11 products that has earned Celestron a well-deserved reputation for providing ULTIMA DX 12 products with optical excellence and outstanding design at an affordable NOBLE 13 price. Celestron is also recognized as a world leader in the design and REGAL LX 14 OCEANA 15 manufacturing of high-quality computerized and non-computerized SKYMASTER 16 telescopes that are used by all levels of amateur astronomers. In keeping OPTIVIEW 17 with this reputation, we only offer binoculars and spotting scopes that are VISTAPIX 18-19 manufactured to meet our rigorous and uncompromising standards. CHOOSING A SPOTTING SCOPE 20-21 Celestron optical instruments deliver excellent resolution and contrast. MINI ZOOM 22 Our binoculars and spotting scopes combine the highest quality precision ULTIMA 23 optics and the most modern, user-oriented design features to produce ULTIMA ED 24 visual instruments that perform exquisitely year after year. Celestron sport MAKSUTOV SPOTTING SCOPES 25 REFRACTOR SPOTTING SCOPES 26 optics products offer versatility in viewing any subject of interest to you, C5 SPOTTING SCOPE 27 be it a sporting event, wildlife, bird watching, scenic views in nature, travel, VISTAPIX IS70 28 sailing — even the far reaches of the night sky. Inherent in the design of SPECIALTY OPTICS 29-35 all of these products is our mission to provide the highest quality optical POWERSEEKER 30-31 products at a competitive price. NEXSTAR SLT 32-33 EXPLORASCOPE 34 SKYSCOUT 35 All Celestron Binoculars Are Covered By ICON DESIGNATIONS A NO-FAULT LIFETIME WARRANTY Look for one or more of the following icons as a quick reference guide for the intended use of each binocular and spotting scope line.
    [Show full text]
  • Chinese Co. Owes $40M for Telescope Monopoly, Jury Told - Law360
    12/3/2019 Chinese Co. Owes $40M For Telescope Monopoly, Jury Told - Law360 Portfolio Media. Inc. | 111 West 19th Street, 5th floor | New York, NY 10011 | www.law360.com Phone: +1 646 783 7100 | Fax: +1 646 783 7161 | [email protected] Chinese Co. Owes $40M For Telescope Monopoly, Jury Told By Dorothy Atkins Law360, San Jose (November 21, 2019, 9:45 PM EST) -- A Chinese telescope seller should pay $40.3 million for suppressing competition and for its “complete and total domination” of the telescope market, a California company told a federal jury during closings of an antitrust trial Thursday, while the Chinese seller said there’s no evidence it engaged in a price-fixing conspiracy. Orion Telescopes & Binoculars’ counsel, Noah Hagey of BraunHagey & Borden LLP, told eight men and one woman sitting on the jury that Ningbo Sunny Electronic Co. Ltd. conspired with another telescope distributor to fix the price of consumer telescopes, eventually pushing Orion out of the market. If the jury doesn’t find in its favor, Orion will likely go out of business within the year, Hagey said. “The market has been taken over,” he said. “When they get rid of Orion, they’ll have complete and total domination of it. And that was their goal.” Hagey’s comments came during closing arguments of a weekslong trial in San Jose, California, over Orion’s claims that Ningbo Sunny violated the Sherman Act and Clayton Act by forming a monopoly over the domestic consumer telescope market between 2013 and 2018. Orion’s suit originally named Synta Technology Corp.’s U.S.
    [Show full text]
  • Griffith Observer Cumulative Index
    Griffith Observer Cumulative Index author title mo year key words Anonymous The Romance of the Calendar 2 1937 calendar, Julian, Gregorian Anonymous Other Worlds than Ours 3 1937 Planets, Solar System Anonymous The S ola r Fa mily 3 1937 Planets, Solar System Roya l Elliott Behind the Sciences 3 1937 GO, pla ne ta rium, e xhibits , Ge ologica l Clock Anonymous The Stars of Spring 4 1937 Cons te lla tions , S ta rs , Anonymous Pronunciation of Star and 4 1937 Cons te lla tions , S ta rs Constellation Names Anonymous The Cycle of the Seasons 5 1937 Seasons, climate Anonymous The Ice Ages 5 1937 United States, Climate, Greenhouse Gases, Volcano, Ice Age Anonymous New Meteorites at the Griffith 5 1937 Meteorites Observatory Anonymous Conditions of Eclipse 6 1937 Solar eclipse, June 8, Occurrences 1937, Umbra, Sun, Moon Anonymous Ancient and Modern Eclipse 6 1937 Chinese, Observation, Observations Eclips e , Re la tivity Anonymous The Sky as Seen from 6 1937 Stars, Celestial Sphere, Different Latitudes Equator, Pole, Latitude Anonymous Laws of Polar Motion 6 1937 Pole, Equator, Latitude Anonymous The Polar Aurora 7 1937 Northern lights, Aurora Anonymous The Astrorama 7 1937 Star map, Planisphere, Astrorama Anonymous The Life Story of the Moon 8 1937 Moon, Earth's rotation, Darwin Anonymous Conditions on the Moon 8 1937 Moon, Temperature, Anonymous The New Comet 8 1937 Come t Fins le r Anonymous Comets 9 1937 Halley's Comet, Meteor Anonymous Meteors 9 1937 Meteor Crater, Shower, Leonids Anonymous Comet Orbits 9 1937 Comets, Encke Anonymous
    [Show full text]
  • Download Paper
    Lens systems for sky surveys and space surveillance John T. McGraw University of New Mexico Mark R. Ackermann Sandia National Laboratories Peter C. Zimmer Go Green Termite University of New Mexico ABSTRACT Since the early days of astrophotography, lens systems have played a key role in capturing images of the night sky. The first images were attempted with visual refractors. These were soon followed with color- corrected refractors and finally specially designed photo-refractors. Being telescopes, these instruments were of long-focus and imaged narrow fields of view. Simple photographic lenses were soon put into service to capture wide-field images. These lenses also had the advantage of requiring shorter exposure times than possible using large refractors. Eventually, lenses were specifically designed for astrophotography. With the introduction of the Schmidt-camera and related catadioptric systems, the popularity of astrograph lenses declined, but surprisingly, a few remained in use. Over the last 30 years, as small CCDs have displaced large photographic plates, lens systems have again found favor for their ability to image great swaths of sky in a relatively small and simple package. In this paper, we follow the development of lens-based astrograph systems from their beginnings through the current use of both commercial and custom lens systems for sky surveys and space surveillance. Some of the optical milestones discussed include the early Petzval-type portrait lenses, the Ross astrographic lens and the current generation of optics such as the commercial 200mm camera lens by Canon. We preview our astrograph designs for commonly available CCD detectors. 1. INTRODUTION Telescopes are usually built to address specific scientific questions, with angular field of view and image resolution being the usual primary design parameters.
    [Show full text]
  • Astronomy July 2014
    IMAGER PROFILE With remote observatories in GERALD Namibia and the Alpen foothills, this Austrian imager can lock his lens RHEMANN on any comet or nebula he likes. text and images by imaging from Gerald Rhemann near and far My first encounter with astronomy wasn’t until 1986. Intrigued by the frequent media reports about the return of Halley’s Comet, I decided to have a look through a big telescope myself. I trav- eled to the western suburbs of Vienna — the capital city of Austria and my hometown — where the historic Kuffner Observatory and its 10.6-inch (270 millimeters) refract- ing telescope live. But what I saw through the eyepiece dis- appointed me. Even through this big refrac- tor, Comet 1P/Halley appeared as nothing more than a foggy patch — no evidence of the impressive tails that shone through in photographs. Still, Halley aroused my inter- est enough that a couple of years later, in 1989, I purchased a telescope and mount. I wanted to make images that captured the For several months, the author (pictured above) had same level of detail I had seen in photos of the opportunity to remotely control an astrograph that comet, detail that the eye alone can’t located in Nerpio, Spain. With it, he captured IC 2177, the Seagull Nebula in Monoceros (right). see. Plus, because I was the owner of a pho- This image had 21.9 total hours of exposure — the tography shop, I had ready access to all the longest of any object the author has ever captured. other stuff I needed — cameras, lenses, a (ASA 8-inch f/2.9 hyperbolic astrograph, FLI PL darkroom, and experience.
    [Show full text]
  • Front Back Cover 2.Qxd
    TELESCOPE PRODUCT GUIDE 2005/2006 ABOUT CELESTRON TABLE OF CONTENTS C14 • Rosette Nebula • Image courtesy of Richard Hedrick Celestron. Over 40 Years Of Telescope History The history of Celestron dates Celestron takes pride in its reputation for innovation.These back to 1957 when it was innovations, which have changed the landscape of amateur founded and incorporated as astronomy, began with the introduction of the first commercially Valor Electronics by Mr.Tom available Schmidt-Cassegrain telescope. Below are some of the Johnson, an electrical engineer notable innovations Celestron has introduced over the years*. and avid amateur astronomer. • 1966 — Introduced the first commercially available Mr. Johnson’s passion for Schmidt-Cassegrain telescopes. telescope making became the • 1969 — First to have an entire line of Schmidt-Cassegrain basis for the future of his company. The name of the company was soon telescopes; the now famous C6, C8, C10, C12, C16, changed to Celestron. In 1980, Celestron was acquired by the Swiss firm and C22. Diethelm Ltd. In 1998 Tasco International, a large global marketer and • First to offer commercially available Observatory Class Telescopes, distributor of telescopes binoculars and other the C16 and C22. sport optics products, purchased Celestron • First to offer commercially available Schmidt Cameras from Diethelm. In June of 2002, Tasco Intl. in the late 1960’s. ceased operations and as a result three • Popularized the Cold Camera in the early 1970’s. members of Celestron’s senior management • Popularized piggyback photography. purchased Celestron. This acquisition initiated a new era for Celestron and began the • 1979 — Popularized the Maksutov-Cassegrain optical design implementation and realization of long-term in astronomy with the introduction of the C90 Astro for $495.
    [Show full text]