Celestron 21035 manual Seeing Conditions, Transparency, Sky Illumination

Page 15

Seeing Conditions

Viewing conditions affect what you can see through your telescope during an observing session. Conditions include transparency, sky illumination, and seeing. Understanding viewing conditions and the effect they have on observing will help you get the most out of your telescope.

Transparency

Transparency is the clarity of the atmosphere which is affected by clouds, moisture, and other airborne particles. Thick cumulus clouds are completely opaque while cirrus can be thin, allowing the light from the brightest stars through. Hazy skies absorb more light than clear skies making fainter objects harder to see and reducing contrast on brighter objects. Aerosols ejected into the upper atmosphere from volcanic eruptions also affect transparency. Ideal conditions are when the night sky is inky black.

Sky Illumination

General sky brightening caused by the Moon, aurorae, natural airglow, and light pollution greatly affect transparency. While not a problem for the brighter stars and planets, bright skies reduce the contrast of extended nebulae making them difficult, if not impossible to see. To maximize your observing, limit deep sky viewing to moonless nights far from the light polluted skies found around major urban areas. LPR filters enhance deep sky viewing from light polluted areas by blocking unwanted light while transmitting light from certain deep sky objects. You can, on the other hand, observe planets and stars from light polluted areas or when the Moon is out.

Seeing

Seeing conditions refers to the stability of the atmosphere and directly affects the amount of fine detail seen in extended objects. The air in our atmosphere acts as a lens which bends and distorts incoming light rays. The amount of bending depends on air density. Varying temperature layers have different densities and, therefore, bend light differently. Light rays from the same object arrive slightly displaced creating an imperfect or smeared image. These atmospheric disturbances vary from time-to-time and place-to-place. The size of the air parcels compared to your aperture determines the "seeing" quality. Under good seeing conditions, fine detail is visible on the brighter planets like Jupiter and Mars, and stars are pinpoint images. Under poor seeing conditions, images are blurred and stars appear as blobs.

The conditions described here apply to both visual and photographic observations.

Figure 5-3

Seeing conditions directly affect image quality. These drawings represent a point source (i.e., star) under bad seeing conditions (left) to excellent conditions (right). Most often, seeing conditions produce images that lie somewhere between these two extremes.

15

Page 14 Page 16
Image 15
Page 14 Page 16
Contents Travel Scope Table of Contents Page Travel Scope Setting up the Tripod Moving the Travel Scope Manually Attaching the Telescope Optical Tube to the TripodInstalling the Diagonal & Eyepiece Installing the FinderscopeAligning the Finderscope Calculating Magnification FocusingGeneral Observing Hints Determining Field of ViewCelestial Coordinate System Motion of the Stars Lunar Observing Hints Observing the MoonObserving the Planets Observing the SunStar Hopping Observing Deep-Sky ObjectsLyra Seeing Seeing ConditionsTransparency Sky IlluminationRub in circles Care and Cleaning of the OpticsTravel Scope Specifications Reiseteleskop Inhaltsverzeichnis Achtung Abb -1 Travel Scope Aufbau des Stativs Manuelle Bewegung des Travel Scope Aufsatz des optischen Tubus des Teleskops am StativInstallation des Zenitspiegels und Okulars Installation des SucherfernrohrsAusrichtung des Suchers Finderscope Berechnung der Vergrößerung FokussierungAllgemeine Hinweise zur Beobachtung Ermittlung des GesichtsfeldsDas Himmelskoordinatensystem Bewegung der Sterne Empfehlungen zur Mondbeobachtung MondbeobachtungBeobachtung der Planeten Beobachtung der SonneStarhopping Beobachtung der Deep-Sky-ObjekteRingnebel Sicht BeobachtungsbedingungenTransparenz HimmelsbeleuchtungPflege und Reinigung der Optik Spezifikationen des Travel Scope Telescopio para viajes Índice Advertencia Figura 1-1 Travel Scope Vea la Figura Cómo ensamblar el trípodeMovimiento manual del Travel Scope Conexión del tubo óptico del telescopio al trípodeInstalación de la lente a 90º y el ocular Instalación del telescopio buscadorAlineación del telescopio buscador Cálculo del aumento EnfoqueConsejos generales para las observaciones Cómo se determina el campo visualFigura El sistema de coordenadas de los cuerpos celestesFigura Movimiento de las estrellasSugerencias para observar la Luna Observación de la LunaObservación de los planetas Observación del SolSalto de estrellas Observación de cuerpos celestes en el cielo profundoLira Vega Visión Condiciones para la observaciónTransparencia Iluminación del cieloCuidado y limpieza de las lentes ópticas Especificaciones del Travel Scope Longue vue de voyage Manuel de l’utilisateur Table des matières Avertissement Longue vue de voyage Installation du trépied Fixation du tube optique du télescope au trépied Déplacement manuel de la longue vue de voyageInstallation du renvoi coudé et de l’oculaire Installation du chercheurAlignement du chercheur Calcul du grossissement Mise au pointConseils généraux d’observation Établissement du champ de visionLe système de coordonnées célestes Mouvement des étoiles Conseils d’observation des planètes Observation de la LuneObservation des planètes Observation du SoleilLe Star Hopping cheminement visuel Observation d’objets du ciel profondLA Lyre Véga Visibilité Conditions de visibilitéTransparence Luminosité du cielEntretien et nettoyage des éléments optiques Spécifications de la longue Telescopio da viaggio Indice analitico Avvertenze Figura 1-1 Travel Scope Facile vedere la Figura Approntamento del treppiediSpostamento manuale del Travel Scope Collegamento del tubo ottico del telescopio al treppiediInstallazione del diagonale e dell’oculare Installazione del cannocchiale cercatoreAllineamento del cannocchiale cercatore Calcolo dell’ingrandimento Messa a fuocoSuggerimenti generali per l’osservazione Determinazione del campo visivoIl sistema di coordinate celesti Movimento delle stelle Suggerimenti per l’osservazione dei pianeti Osservazione della LunaOsservazione dei pianeti Osservazione del SoleStar Hopping Saltare da una stella all’altra Osservazione di oggetti del cielo profondoLira Visibilità Condizioni di visibilitàLimpidezza Illuminazione del cieloCura e pulizia dell’ottica Dati tecnici del Travel Scope 01-09 REV

21035 specifications

The Celestron 21035 is a high-quality, versatile telescope that caters to both novice and experienced astronomers. This reflector telescope is part of the AstroMaster series, known for its ease of use, excellent optical performance, and sturdy construction. One of its standout features is the 70mm aperture, which allows for bright and clear images of celestial objects. The larger the aperture, the more light the telescope can gather, making it ideal for viewing the Moon, stars, and even some of the more distant planets in our solar system.

One of the key technologies integrated into the Celestron 21035 is its fully coated glass optics. The objective lens and the eyepieces feature multiple layers of coatings, enhancing light transmission and delivering sharper images with improved contrast. This optical design ensures that both the colors and details of celestial objects are rendered accurately, which is crucial for astronomical observation.

Ease of setup is another highlight of the Celestron 21035. The telescope comes with a pre-assembled mount and optical tube, allowing users to get started with minimal effort. The simple, intuitive design is perfect for beginners who want to dive into stargazing without being overwhelmed by complicated setup processes. The lightweight and portable nature of the telescope makes it easy to transport, whether you are going to a local observatory or simply heading to your backyard for some nighttime exploration.

Additionally, the Celestron 21035 features an adjustable, full-height tripod that provides sturdy support, minimizing vibrations and maintaining stability while observing. The mount is manually operated with slow-motion controls, enabling precise targeting of celestial objects. Users can easily track their target as it moves across the sky, enhancing the viewing experience.

For those who enjoy astrophotography, the Celestron 21035 offers the option to attach a smartphone or a camera, allowing you to capture stunning images of the night sky. The telescope's versatility is further highlighted by its compatible eyepiece sizes, providing users with the ability to swap in different magnifications based on their interests.

In summary, the Celestron 21035 is an excellent choice for anyone looking to explore the wonders of the universe. With its robust optical performance, user-friendly design, and impressive features, it serves as a reliable tool for amateur astronomers and seasoned stargazers alike. Whether you’re observing lunar craters or distant galaxies, the Celestron 21035 promises an enjoyable and enriching experience under the stars.
Top Page Image Contents