A Guide to Telescopes
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Sky-Watcher Skyliner-300P Flextube Auto Sky-Watcher’S Latest Dobsonian Telescope Can Track the Stars So That the Views Through Its Huge Aperture Stay in the Eyepiece
AUGUST 09 FIRST LIGHT: AN IN-DEPTH LOOK AT THIS MONTH'S HOTTEST NEW PRODUCT SKY-waTCHER Skyliner-300P FlexTube Auto Sky-Watcher’s latest Dobsonian telescope can track the stars so that the views through its huge aperture stay in the eyepiece. Paul Money takes a look VITAL STATS hen John Dobson MDF rocker base here, like the plug it into a power pack, neither created the telescope setup of some other Dobsonians. of which are supplied. > PRICE £1,099 design that bears his This is no doubt to ensure that the The Skyliner’s 1,500mm of > APERTURE 305mm (12 inches) name, he would scarcely have 300P’s axis motors stay accurately focal length collapses down to > FOCAL LENGTH 1,500mm; f/5 imagined how it would evolve installed. Instead, you just lift the just under a metre thanks to its > OpTICAL DESIGN Newtonian thanks to Sky-Watcher. First, tube assembly onto the rocker telescopically extending trusses, reflector > FINDER 9x50 straight-through the company came up with the base and the main job’s done. All making it extremely portable for > EYEPIECES 25mm, 10mm; FlexTube collapsible truss tube, that’s left is the 9x50 straight- such a large instrument. We were 1.25-inch fit which greatly improved through finderscope to assemble impressed to find no collimation > FOCUSER Crayford; 1.25- & 2-inch fit portability. Now it has added and the hand controller to install. issues, even after repeated setups. > MOUNT Motorised Dobsonian auto-tracking motors to the The 300P comes with two And with its tracking motors, we > WEIGHT 40kg FlexTube design, taking the eyepieces, a 25mm and 10mm could take decent images of the > SUPPLIER Optical Vision Dobsonian on its next great 1.25-inch fit that give 60x and Moon and planets, despite the > www.opticalvision.co.uk leap forward. -
A Guide to Smartphone Astrophotography National Aeronautics and Space Administration
National Aeronautics and Space Administration A Guide to Smartphone Astrophotography National Aeronautics and Space Administration A Guide to Smartphone Astrophotography A Guide to Smartphone Astrophotography Dr. Sten Odenwald NASA Space Science Education Consortium Goddard Space Flight Center Greenbelt, Maryland Cover designs and editing by Abbey Interrante Cover illustrations Front: Aurora (Elizabeth Macdonald), moon (Spencer Collins), star trails (Donald Noor), Orion nebula (Christian Harris), solar eclipse (Christopher Jones), Milky Way (Shun-Chia Yang), satellite streaks (Stanislav Kaniansky),sunspot (Michael Seeboerger-Weichselbaum),sun dogs (Billy Heather). Back: Milky Way (Gabriel Clark) Two front cover designs are provided with this book. To conserve toner, begin document printing with the second cover. This product is supported by NASA under cooperative agreement number NNH15ZDA004C. [1] Table of Contents Introduction.................................................................................................................................................... 5 How to use this book ..................................................................................................................................... 9 1.0 Light Pollution ....................................................................................................................................... 12 2.0 Cameras ................................................................................................................................................ -
The Blue Planet Report from Stellafane Perspective on Apollo How to Gain and Retain New Members
Published by the Astronomical League Vol. 71, No. 4 September 2019 THE BLUE PLANET REPORT FROM STELLAFANE 7.20.69 5 PERSPECTIVE ON APOLLO YEARS APOLLO 11 HOW TO GAIN AND RETAIN NEW MEMBERS mic Hunter h Cos h 4 er’s 5 t h Win 6 7h +30° AURIG A +30° Fast Facts TAURUS Orion +20° χ1 χ2 +20° GE MIN I ated winter nights are domin ο1 Mid ξ ν 2 ORIO N ο tion Orion. This +10° by the constella 1 a π Meiss λ 2 μ π +10° 2 φ1 attended by his φ 3 unter, α γ π cosmic h Bellatrix 4 Betelgeuse π d ω Canis Major an ψ ρ π5 hunting dogs, π6 0° intaka aurus the M78 δ M , follows T 0° ε and Minor Alnitak Alnilam What’s Your Pleasure? ζ h σ η vens eac EROS ross the hea MONOC M43 M42 Bull ac θ τ ι υ ess pursuit. β –10° night in endl Saiph Rigel –10° κ The showpiece of the ANI S C LEPU S ERIDANU S ion MAJOR constellation is the Or ORION (Constellation) –20° wn here), –20° Nebula (M42,sho ion 5 hr; Location: Right Ascens a region of nebulosity ° north 4h Declination 5 5h 6h 7h 2 square degrees th just 1,300 a: 594 and starbir Are 3 4 5 6 0 1 2 0 -2 -1 he Hunter 2 Symbol: T 0 t-years away that is M42 (Orion Nebula); C ligh Notable Objects: a la); NG C 2024 laked eye as a tary nebu e M78 (plane visible to the n n la) d. -
Web Suppliers of Telescope Building Parts and Materials
Appendix I Web Suppliers of Telescope Building Parts and Materials No endorsement or recommendation is provided or implied. The organizations listed are here because they were found in other such lists or advertisements or were personally known to someone. Those for whom e-mail addresses were available were notified that they would be listed. Those for whom there were no e-mail addresses or whose e-mail was not deliverable were sent regular letters with the same information. If there was no response to notification, the listing was removed. Quite a few listed organizations submitted additions or changes to their list of products. References to items specific to astrophotography and to Dobsonians were, for the most part, avoided. Likewise, references to subjects other than building telescopes, such as star charts, were avoided. If you are searching for some particular item or for something that will serve for a particular item you are advised to look under a variety of related categories. There is very little standardization of nomenclature in telescope design. For exam- ple, “used” usually means “buys and sells used parts and complete scopes.” Rings and mounting rings probably are overlapping categories. Diagonals, mirrors, and secondary mirrors probably all mean the same thing. Some of the listed organizations produce or distribute items useful to us telescope makers but with a much wider/different selection of clients. In dealing with them it would be useful if you are particularly clear as to the intended use. Some produce items for other industries and are set up to supply materials in large quantities. -
407 a Abell Galaxy Cluster S 373 (AGC S 373) , 351–353 Achromat
Index A Barnard 72 , 210–211 Abell Galaxy Cluster S 373 (AGC S 373) , Barnard, E.E. , 5, 389 351–353 Barnard’s loop , 5–8 Achromat , 365 Barred-ring spiral galaxy , 235 Adaptive optics (AO) , 377, 378 Barred spiral galaxy , 146, 263, 295, 345, 354 AGC S 373. See Abell Galaxy Cluster Bean Nebulae , 303–305 S 373 (AGC S 373) Bernes 145 , 132, 138, 139 Alnitak , 11 Bernes 157 , 224–226 Alpha Centauri , 129, 151 Beta Centauri , 134, 156 Angular diameter , 364 Beta Chamaeleontis , 269, 275 Antares , 129, 169, 195, 230 Beta Crucis , 137 Anteater Nebula , 184, 222–226 Beta Orionis , 18 Antennae galaxies , 114–115 Bias frames , 393, 398 Antlia , 104, 108, 116 Binning , 391, 392, 398, 404 Apochromat , 365 Black Arrow Cluster , 73, 93, 94 Apus , 240, 248 Blue Straggler Cluster , 169, 170 Aquarius , 339, 342 Bok, B. , 151 Ara , 163, 169, 181, 230 Bok Globules , 98, 216, 269 Arcminutes (arcmins) , 288, 383, 384 Box Nebula , 132, 147, 149 Arcseconds (arcsecs) , 364, 370, 371, 397 Bug Nebula , 184, 190, 192 Arditti, D. , 382 Butterfl y Cluster , 184, 204–205 Arp 245 , 105–106 Bypass (VSNR) , 34, 38, 42–44 AstroArt , 396, 406 Autoguider , 370, 371, 376, 377, 388, 389, 396 Autoguiding , 370, 376–378, 380, 388, 389 C Caldwell Catalogue , 241 Calibration frames , 392–394, 396, B 398–399 B 257 , 198 Camera cool down , 386–387 Barnard 33 , 11–14 Campbell, C.T. , 151 Barnard 47 , 195–197 Canes Venatici , 357 Barnard 51 , 195–197 Canis Major , 4, 17, 21 S. Chadwick and I. Cooper, Imaging the Southern Sky: An Amateur Astronomer’s Guide, 407 Patrick Moore’s Practical -
RASC Choosing and Using a Telescope for Astronomy
of binoculars accompanied by a good rainbow, obscuring fine detail. The objective astronomy guide like the Royal Astronomical lens in achromat refractors is commonly made Society of Canada’s Observer’s Handbook or of two or more lenses of different glass types to Beginner’s Observing Guide is all you need to begin help correct this problem, Choosing understanding the night sky. known as chromatic aberration. This most and Using a TELESCOPE READINESS TEST commonly manifests itself as faint fringes of colour “Space is mostly empty and you can find a around objects like the whole lot of nothing with a telescope” --- Moon or Jupiter, but it is Richard Weis, former President of rarely fully cured except in RASC-Calgary Centre. Telescope very expensive If you can do the following, then you are ready apochromat refractors. for Astronomy to make full and rewarding use of a telescope: Advantages: Refractors, by default, have a Find and name four circumpolar totally clear aperture. No central obstruction constellations causes light to be scattered from brighter to For many people, the words ‘astronomy’ and Find and name three constellations seen in darker areas. Thus, contrast is good in ‘telescope’ are inseparable. Many newcomers to the southern sky in each of the four seasons refractors. Refractors are often chosen as the the hobby of astronomy mistakenly believe that Find and name - (a) 4 double stars (b) 4 premier instruments for planetary and double- it is important to get a telescope as quickly as variable stars (c) 5 star clusters (d) 5 nebulae star observing. Refractors are also low in possible. -
Dobsonian Telescope
30˚E 15˚E OWNER’S MANUAL DOBSONIAN TELESCOPE ZHUMELL Z12 DELUXE DOBSONIAN REFLECTOR TELESCOPE 0˚ 15˚W 75˚W 60˚W 30˚W 45˚W Zhumell customers know that there are plenty of ways to experience the world. They also understand that, however you choose to explore it, the best experience is one that fully immerses you in the world’s most striking details. That’s where our optics products come in. We strive to put high-performance products in the hands of our customers so that they can experience the world up close, with their own eyes. With Zhumell, you get field-tested, precision-crafted optics at the best possible value. So even if you’re just starting out as an amateur birder or astronomer, you don’t have to settle for entry-level products. Zhumell customers enjoy life’s pursuits, hobbies, and adventures in rich, colorful detail- the kind of detail that only high-performance optics can produce. At Zhumell, we design our binoculars, telescopes, and spotting scopes for discerning, price-conscious users who are uncompromising on quality. If you’re looking for accessibly priced optics that will bring your world within reach, you’re looking for Zhumell. Enjoy the dob. 2 ENJOYING YOUR ZHUMELL DOBSONIAN TELESCOPE 1. Caring For Your Telescope i. Warnings ii. Cleaning and Maintenance iii. Collimation 2. Specifications 3. Parts List 4. Telescope Assembly i. Base Assembly ii. Optical Tube Assembly 5. Donsonian Telescope Basics i. 1.25-inch Eyepieces ii. 2-inch Eyepieces iii. Altitude and Azimuth iv. Focusing the Image v. -
Orion® Intelliscope® Computerized Object Locator
INSTRUCTION MANUAL Orion® IntelliScope® Computerized Object Locator #7880 Providing Exceptional Consumer Optical Products Since 1975 Customer Support (800) 676-1343 E-mail: [email protected] Corporate Offices (831) 763-7000 89 Hangar Way, Watsonville, CA 95076 IN 229 Rev. G 01/09 Congratulations on your purchase of the Orion IntelliScope™ Com pu ter ized Object Locator. When used with any of the SkyQuest IntelliScope XT Dobsonians, the object locator (controller) will provide quick, easy access to thousands of celestial objects for viewing with your telescope. Coil cable jack The controller’s user-friendly keypad combined with its database of more than 14,000 RS-232 jack celestial objects put the night sky literally at your fingertips. You just select an object to view, press Enter, then move the telescope manually following the guide arrows on the liquid crystal display (LCD) screen. In seconds, the IntelliScope’s high-resolution, 9,216- step digital encoders pinpoint the object, placing it smack-dab in the telescope’s field of Backlit liquid-crystal display view! Easy! Compared to motor-dependent computerized telescopes systems, IntelliScope is faster, quieter, easier, and more power efficient. And IntelliScope Dobs eschew the complex initialization, data entry, or “drive training” procedures required by most other computer- ized telescopes. Instead, the IntelliScope setup involves simply pointing the scope to two bright stars and pressing the Enter key. That’s it — then you’re ready for action! These instructions will help you set up and properly operate your Intelli Scope Com pu ter- ized Object Locator. Please read them thoroughly. Table of Contents 1. -
Atmospheric Refraction: a History
Atmospheric refraction: a history Waldemar H. Lehn and Siebren van der Werf We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of uniform density up to a sharp upper transition to the ether, at which the refraction occurred. Alhazen and Witelo transmitted his knowledge to medieval Europe. The first accurate measurements were made by Tycho Brahe in the 16th century. Finally, Kepler, who was aware of unusually strong refractions, used the Ptolemaic model to explain the first documented and recognized mirage (the Novaya Zemlya effect). © 2005 Optical Society of America OCIS codes: 000.2850, 010.4030. 1. Introduction the term catoptrics became reserved for reflection Atmospheric refraction, which is responsible for both only, and the term dioptrics was adopted to describe astronomical refraction and mirages, is a subject that the study of refraction.2 The latter name was still in is widely dispersed through the literature, with very use in Kepler’s time. few works dedicated entirely to its exposition. The same must be said for the history of refraction. Ele- ments of the history are scattered throughout numer- 2. Early Greek Theories ous references, many of which are obscure and not Aristotle (384–322 BC) was one of the first philoso- readily available. It is our objective to summarize in phers to write about vision. He considered that a one place the development of the concept of atmo- transparent medium such as air or water was essen- spheric refraction from Greek antiquity to the time of tial to transmit information to the eye, and that vi- Kepler, and its use to explain the first widely known sion in a vacuum would be impossible. -
Appendices A
Appendices A. List of mathematical symbols 449 A. List of mathematical symbols Chapter 2 Table A.I. List of symbols for Chapter 2 Symbol Meaning Where defined A Aperture stop Fig. 2.6 aI, a2" . Coefficients for the definition of a centered surface Eq. (2.13) aE, bE, CE Positions of the Ramsden disk in a refracting Fig. 2.8 telescope b Distance from the pole of MI to the final image Fig. 2.11, in a 2-mirror telescope Fig. 2.12, Eq. (2.65) b Normalized value of b Eq. (2.87) C Beam compression factor Fig. 2.8, Eq. (2.39) C Curvature of a surface = 1/r Eq. (2.13) (see surface number v) Cl Velocity of light in wavefront propagation Fig. 2.3, Eq. (2.11) D Effective diameter (aperture) of a system; diame- § 2.2.6 ter of the entrance pupil (DAXh Axial beam diameter of M2 in a 2-mirror telescope Eq. (2.93) (DTOTh Full diameter of M2 in a 2-mirror telescope Eq. (2.93) d Axial distance between a given surface of a system Fig. 2.11, and the next surface (see surface number v) Fig. 2.12, Eq. (2.37) E, E' Entrance, exit pupil of a system Fig. 2.6 F, F' Object, image focal point of a system Fig. 2.1, Fig. 2.2 j, l' Object-side, image-side focal length of a system Fig. 2.1, Fig. 2.2 450 Appendices Table A.2. List of symbols for Chapter 2 (continued) Symbol Meaning Where defined J{, J~ Image-side focal lengths of M I , M2 in a 2- Eqs. -
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. -
Instruction Manual
Instruction Manual Maksutov Telescope 90/1250 OTA English version 10.2014 Rev A Reproduction of part or all of the contents of this document in any form is expressly prohibited other than for individual use only. All text, images and labels are property of Nimax Gmbh. The Omegon® Maksutov Telescope 90/1250 OTA Congratulations on the purchase of the new Omegon® Telescope Maksutov 90/1250 OTA. This telescope tube is suited for both terrestrial and astronomical use. It is compact and easy to carry around; it can also be used as a tele-objective or a high-power telescope. You can even use it to take photos with a DSLR camera (not included). 1. Included parts. Besides the telescope tube we have included a finderscope, a finderscope bracket and a soft carry case. 2. Getting started. It is very simple to get started. Here is how the telescope works. The telescope aperture (lens) should be pointing to the object being observed. The light comes through the aperture lens, to the mirror on the back and is then reflected to the small secondary mirror on the telescope lens. There it is reflected again and so brought to the eyepiece. The eyepiece can be used in two positions – top (#5) or back (#6) – see below. At the focuser one can use accessories. Different accessory combinations give different results, such as different image magnifications. All this will be explained in detail on the next pages. 2.1. Knowing your telescope. 1- Optical Tube; 7- Finderscope adjustment screw; 2- Dovetail adapter for telescope mount or tripod; 8- Focusing knob; 3- Finderscope adjustment screw; 9- Flip-Mirror System; 4- Finderscope; 10- DSLR Camera (not included); 5- Top eyepiece holder; 11- T-ring adapter (not included); 6- Back eyepiece holder; 12- Eyepiece (not included).