REFRACTOR: Light is gathered by the front objective lens and travels to a focal point at the rear of the telescope and into the eyepiece. BACK TO TOP
REFLECTOR: Light is gathered by a primary mirror and reflected to a secondary mirror and into the eyepiece. BACK TO TOP
SCHMIDT CASSEGRAIN: (Combined Mirror-Lens System) This system uses a mirror-lens system to gather light; the light enters the front of the scope where it is 'corrected' by the front corrector plate (glass lens) and reflected off the primary mirror to the secondary mirror (which is in the center of corrector plate) and then to the eyepiece. BACK TO TOP
RITCHEY CHRETIEN: (A sub-set of a Reflecting Telescope) An RCT has a hyperbolic primary and a hyperbolic secondary mirror. The net effect is a flatter field view combined with a coma (color aberration) free image. It was invented in the early 1910s by American astronomer George Willis Ritchey (1864–1945) and French astronomer Henri Chrétien (1879–1956) (Cite: Wikipedia) BACK TO TOP
From the RC Optical Systems website, a well done illustration of the RC optical pathway of light in their telescopes
TYPES OF EYEPIECES AND THEIR RESPECTIVE LENS CONFIGURATIONS: Today, many eyepiece types are available and offer specific advantages which distinguish themselves from another. Most popular today is the Plossl eyepiece, which offers good eye relief through the use of multiple lenses (the distance your eye has to be to the eyepiece to see an object, the longer (greater distance) is usually better) and sharp images with a good field of view. The Nagler eyepiece is a high-quality, monster eyepiece that offers unprecedented field of view and uses multiple high-quality lenses to achieve this objective. BACK TO TOP
Experts estimate that the Sun will last about 10 billion years; currently, it is approximately 4.6 billion years old. Which means our Sun will last approximately 5.4 billion years from today. BACK TO TOP
Our Sun is comprised of many elements; however, hydrogen (71%), helium (27.1%), oxygen (.97%) and carbon (.40%) are the top 4 elements that make up the Sun. BACK TO TOP
The surface of the Sun is 9800°F (5400°C). BACK TO TOP
Solar winds are charged particles of both electrons and protons that are cast from the surface of the sun at velocities high enough to escape the Sun’s gravity and travel millions of miles from the Sun. The solar wind can be strong enough and carry enough charged particles to create the Aurora Borealis when these particles slam into the protective magnetic field of the Earth. Solar winds also carry enough energy to disrupt satellite communication and electrical grids due to the number of charged particles contained in the winds. BACK TO TOP
On average, the Sun is 93,000,000 miles from Earth. BACK TO TOP
The Sun does rotate; at the equator it rotates once every 24.47 days. Keep in mind that due to the rate at which the Earth rotates around the Sun, observational rotation from the perspective of the Earth is a little over 26 days. BACK TO TOP
The Sun orbits the Milky Way center at an estimated 486,000 miles per hour (about 135 MILES PER SECOND) BACK TO TOP
It has been long known that Sun spots have cycles of approximately 11 years of increasing activity. It is also known that an increase in Sun spots is also correlated with coronal mass ejections, solar flares and increased solar radiation. Records support that fact that temperature variations on Earth have closely correlated with both an increase and decrease in Sun spot activity. An event known as the Maunder Minimum during the 1630’s to the 1750’s was correlated with a low Sun spot activity and unusually low surface temperatures. Interestingly enough, in the past 100 years, there has been a steady increase in Sun spots with the highest amount occurring around 1955, this also correlated with higher Earth surface temperatures. BACK TO TOP
No, due to the size and mass of the Sun, it is not large enough to be a Supernova. Scientists have determined that to be a Supernova a star must have a mass of about 8 times that of our Sun. Stars the size of our Sun end their lives not in a blaze of glory, but rather become Red Giants prior to dying. In the initial stage our Sun will swell to many times its present size and will consume Mercury, Venus, and Earth. Once the Red Giant depletes its fuel, it begins to contract and the outer layers ‘puff off’ and eject most of their material into outer space (forming a Planetary Nebula). What is left of the core of the star then compresses to form a White Dwarf and once all heat is emitted into space, it becomes a Brown Dwarf, dead and floating in space. BACK TO TOP
Polar alignment- Polar alignment is the process of aligning your telescope with the North or South celestial pole. When we say polar alignment, we literally mean the MOUNT of the telescope. Take a look at this example from the Ocean Side Photo & Telescope website:
Notice how the stars seem to rotate around a central point VERY close to Polaris. Again, notice the Polar axis of the telescope, it is pointing at what appears to be the center point which all stars rotate around (contrary to popular belief, Polaris is very close to the North Celestial Pole but not exactly on the pole). If you align the axis of the telescope to the celestial axis then any object you point the telescope to, the telescope will follow the object in the same path as the axis of the Earth, allowing the object you look at in the scope to be followed by the scope’s field of view.
Robert Jr.'s Forum - Okay, when you have a telescope, its really just a spyglass on a 3 legged post, but having a mount in place lets it move around and see the stars! But, mounts can be VERY expensive, it depends on the type and size of the mount:
Alt. Az. Versus Equatorial Alignment- If you have seen a based model telescope in stores for Christmas, chances are it was an Alt. Az. Mounted telescope.
Here is how to tell the difference:
Meade Wedge
First, notice the position of the fork ‘arms’ of the mount, for the Alt. Az., the forks are perpendicular to the ground. While the fork arms for the Equatorial mount are ‘pointing’ at the celestial pole (North Star) and the entire base of the telescope is mounted on a ‘wedge’ which allows the telescope to positioned and aligned to the celestial pole.
It is the wedge that allows Alt. Az. Mounts to be modified and become equatorial mounts. So, what’s the big deal? The truth of the matter is that for visual observing, an Alt. Az. Mount is all you need to observe anything in the sky; however, if you wish to get into astrophotography, you will need a wedge for your Alt. Az. Scope to take serious pictures and have the best chance of keeping your targeted object in the field of view. Sure, you CAN take images with the alt.az. mount but this would require either very short duration images to avoid star motion or an expensive camera rotator. Need a camera rotator? Check out the Pyxis Rotator for more information. Why? It’s the motion of the mount; an Alt. Az. Mount moves in a ‘stair-step’ fashion in order to keep the objects in the field of view.
Equatorial Imaging Mounts (also called German Equatorial mounts)– High cost, very high precision mounts that can be robotically controlled making them ideal for remote imaging. It should be noted that an equatorial wedge from the example above can be remotely controlled but the precision of the wedge and an equatorial mount can be dramatically different with the obvious advantage to the ‘true’ equatorial mount.
So, what exactly are we talking about when we mention German equatorial mounts? Here are some examples:
ASA Direct Drive Mount - $18,000
Paramount ME - $14,500
Fork Mounted Equatorial Mount on Wedge
Alt. Azimuth Mount
Takahasi EM 200 - ~$5,000 (Discontinued)
.JPG)
Astro-Physics Mach1 GTO Mount ~ $7,000
Surely there are other mounts available, but these are some examples of what the market offers for serious CCD imagers.
©2010 The Lozano Observatory
True Motion of an Alt. Azimuth Equatorial mount motion tracks natural star motion
This stair-step motion is quite different from the equatorial mount that moves in a smooth arc due to its alignment with the polar axis.
2012 Theory - I think The 2012 Theory is a rumor gone bad. I'm 99.99% sure 2012 will NOT be the end of the world. Just because the Mayan Calendar ends in the year 2012 means NOTHING TO US!! Maybe it was just 2 guys writing the calendar and they looked at each other and said "why are we still doing this? Who cares how long this calendar is, I'm tired and want to go home!!" BACK TO TOP
WHAT IS MEANT BY THE MERIDIAN?
The meridian is an imaginary line dividing the sky into East and West portions. Here is how it works; stand facing the North star and raise your arm drawing an imaginary line beginning at the horizon just below Polaris and continue this line over your head and all the way to the southern horizon. As you can see, over the course of the night stars that began on the east side of Meridian will travel to the west side of the Meridian. This motion is important to telescopes because stars on either side of the Meridian require different commands from the telescope control system. Perhaps you have heard of a Meridian flip. What this means is that when stars move from one area of the sky drops the Meridian, the telescope will not be able to follow the stars without hitting the telescope mounting pier.
WHAT IS THE TERMINATOR OF THE MOON?
The terminator of the Moon is the division between light and dark areas, or sunlight shining on one side of the Moonl darkness covers the other side. It is easy to visualize the terminator specially during different phases of the Moon. One side of the Terminator can be 250° Fahrenheit but the dark portion can be -200°F.
WHAT IS THE ECLIPTIC?
The Ecliptic is the great circle that is the apparent path of the Sun among the constellations in the course of a year;
DO THE PLANETS ALWAYS FOLLOW THE SAME AREA OF THE NIGHTTIME SKY?
Each of the planets in the solar system follow what is known as the Ecliptic, or the angular direction that the sun travels relative to our planet. An easy way to locate any of our solar system planets is to pay attention to the daytime sky and the position of the sun. When nighttime comes look roughly in the direction that the sun traveled through the sky during the day and you will be able to locate any of the planets that are visible for that time of the year. Keep in mind that the way you can tell a star from a planet is the planets do not blink or twinkle, they shine bright with almost no differing in their magnitude.
ASTRONOMY ACRONYMS:
What does all this terminology mean?
Find out what they all mean!
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A/D |
Analogue to digital a device that converts a continuous quantity to a discrete digital number. The reverse operation is performed by a digital-to-analog converter |
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AFOV |
Apparent field of view eyepiece's apparent field of view is the angular diameter, expressed in degrees (°), of the circle of light that the eye sees. It is analogous to the screen of a television (not the picture seen through it). |
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APO |
Apochromatic - is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses. |
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ASCOM |
Astronomy Common Object Module (set of common mount interface standards) -http://ascom-standards.org/About/Index.htm |
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ATM |
Amateur telescope making (or manufacture) |
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Astronomical Unit (measure of interplanetary distances) - The average distance of the Earth from the Sun ~ 93,000,000 Miles |
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AVI |
Audio video interleaved (file format) a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback. |
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BMP |
Bitmap (a picture file type) an image file format used to store bitmap digital images, especially on Microsoft Windows and OS/2 operating systems. |
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bps |
bits per second (data transfer rate) |
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CAT |
Catadioptric is one where refraction and reflection are combined in an optical system |
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CCD |
Charge-coupled device is a device for the movement of electrical charge |
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CMOS |
Complementary metal oxide semiconductor - a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits. CMOS technology is also used for several analog circuits such as image sensors, data converters, and highly integrated transceivers |
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DOB |
Dobsonian telescope (not really an acronym) is an alt-azimuth mounted newtonian telescope design |
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DRAM |
Dynamic RAM - a type of random access memory that stores each bit of data in a separate capacitor within an integrated circuit. Since real capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory. |
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DSC |
Digital Setting Circle (eg Argo Navis) Setting circles consist of two graduated disks attached to the right ascension (RA) and declination (DEC) axis of an equatorial mount |
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DSO |
Deep sky object - referring to any Nebula, cluster or Galaxy in the night sky. |
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ED |
Extralow dispersion - glasses are particularly used to reduce chromatic aberration, most often used in achromatic doublets. |
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EFR |
Emerging flux region (on our sun) - An area on the sun where new magnetic flux is erupting. |
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EP |
Eye piece - a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is so named because it is usually the lens that is closest to the eye when someone looks through the device. |
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EQ |
Equatorial intersection of the Earth's surface with the plane perpendicular to the Earth's axis of rotation and containing the Earth's center of mass |
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ET |
Ephemeris time can in principle refer to time in connection with any astronomical ephemeris |
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FAQ |
Frequently asked questions |
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FIR |
Far infra red - Far infrared (FIR): 15 - 1,000 µm |
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FL |
Focal length it is the distance over which initially collimated rays are brought to a focus |
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FLI |
Finger Lakes Instrumentation Co.- http://www.flicamera.com/ |
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FMC |
Fully multi coated Coated optics will have a less shiny, even dark appearance when looking into the barrel or tube. |
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FOV |
Field of view - the (angular or linear or areal) extent of the observable world that is seen at any given moment. |
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FTP |
File transfer protocol - a standard network protocol used to copy a file from one host to another over a TCP/IP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server |
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FUV |
Far ultra violet -An invisible band of radiation at the upper end of the visible light spectrum. With wavelengths from 10 to 400 nm, ultraviolet starts at the end of visible light and ends at the beginning of X-rays. |
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GCVS |
General catalogue of variable stars - a list of variable stars. Its first edition, containing 10,820 stars, was published in 1948 by the Academy of Sciences of the USSR and edited by B. V. Kukarkin and P. P. Parenago. |
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GEM |
German Equatorial Mount - a mount for instruments that follows the rotation of the sky (celestial sphere) by having one rotational axis parallel to the Earth's axis of rotation[1][2]. This type of mount is used as mounts for telescopes, satellite dishes, and cameras. The advantage of an equatorial mount lies in its ability to allow the instrument attached to it to stay fixed on any object in the sky that has a diurnal motion by driving one axis at a constant speed. |
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GLP |
Green laser pointer - 532 nm green laser wavelength is obviously superior to a 650 nm red laser wavelength. And unlike a red laser, the green beam itself can be seen in mid-air in dark conditions, not just the laser beam dot. This allows the green laser pointer to be used for pointing to star constellations (skypointing). The green laser beam dot can be seen at much greater distances than with a red laser pointer. |
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GMT |
Greenwich mean time is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. It is the same as Coordinated Universal Time (UTC) |
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GPS |
Global positioning system |
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GRS |
Great red spot (on Jupiter) - is a persistent anticyclonic storm, 22° south of Jupiter's equator, which has lasted for at least 180 years and possibly as long as 345 years or more.[65][66] The GRS rotates counterclockwise, with a period of about six Earth days[67] |
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HA (or Ha) |
Hydrogen alpha (light spectrum) is a specific red visible spectral line created by hydrogen with a wavelength of 6562.8 Å. |
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Hb |
Hydrogen beta (light spectrum emission line) filter transmits only hydrogen-beta light to your eye, allowing you to see objects that only emit this wavelength. |
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HDRI |
High dynamic range imaging - a set of techniques that allow a greater dynamic range of luminances between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods. |
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HF |
High frequency - radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred metres). |
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HST |
Hubble space telescope |
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IC |
Index Catalogue -a catalogue of galaxies, nebulae and star clusters that serves as a supplement to the New General Catalogue. It was first published in 1895, and has been expanded to list 5,387 objects, known as the IC objects. |
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IR |
Infra red (light) is electromagnetic radiation with a wavelength between 0.7 and 300 micrometres, which equates to a frequency range between approximately 1 and 430 THz.[1] IR wavelengths are longer than that of visible light, but shorter than that of terahertz radiation microwaves. |
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JPG/ JPEG |
it is the most common format for storing and transmitting photographic images on the World Wide Web. It is a method of lossy compression for saving photographic images. |
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ISS |
International Space Station |
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LMC |
Large Magellanic cloud is a nearby irregular galaxy, and is a satellite of the Milky Way.[3] At a distance of slightly less than 50 kiloparsecs (≈160,000 light-years), the LMC is the third closest galaxy to the Milky Way |
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LPR |
Light pollution Filters decrease sky glow caused by artificial lights and enhance deep sky objects. They decrease sky glow but they also decrease the brightness of stars. |
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LRGB |
Luminance Red Green Blue LRGB imaging allows you to combine a deeper black-and-white image with a color RGB image to bring out more detail than the RGB would have alone. |
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LSB |
Low surface brightness (ie, dim!) |
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LST |
Local sidereal time a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. Just as the Sun and Moon appear to rise in the east and set in the west, so do the stars. |
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LV |
Lanthanum Vixen eyepieces use eight lenses in a proprietary five-group design to achieve a uniformly very wide 65 degree apparent field of view |
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M |
Messier Catalog - a set of astronomical objects catalogued by the French astronomer Charles Messier in his "Catalogue des Nébuleuses et des Amas d'Étoiles" ("Catalogue of Nebulae and Star Clusters"), originally published in 1771, with the last addition (based on Messier's observations) made in 1966.[1] Messier created a list of non-comet objects that frustrated his hunt for comets. |
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MCT |
Maksutov-Cassegrain telescope a catadioptric telescope design that combines a spherical mirror with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly "spherically symmetrical". |
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mW |
milliWatt, = 0.001 W |
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NGC |
a well-known catalogue of deep sky objects in astronomy. It contains 7,840 objects, known as the NGC objects. The NGC is one of the largest comprehensive catalogues, as it includes all types of deep space objects |
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NPB |
Narrow pass band filter These filters allow only the bright pair of emission lines of Oxygen III, the Hydrogen Beta emission line, and wavelengths between H-beta and the OIII lines to get through. |
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OAG |
Off axis guider allows you to guide your telescope through the same optics by use of a diagonal which splits the image to allow the user to see the guide star while imaging. |
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OIII |
Oxygen III filters - have a narrow passband centered on the 4959Å and 5007Å emission lines of doubly ionized oxygen where emission nebulas radiate strongly. |
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OTA |
Optical tube assembly of a telescope |
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PAE |
Pointing Accuracy Enhancement (feature of GoTo mount) |
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PE |
Periodic error - Error in precise gearing of a circular gear of a telescope mount due to slight manufacturing error, it is typically a predicable and repeatable error. |
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PEC |
The process of applying a computer model to correct periodic error so gearing on a telescope precisely matches the movement of the sky, producing smooth guiding of a telescope. |
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Pn |
Planetary nebula - an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life.[1] |
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QEE |
Quantum Efficiency (CCD Camera type) a quantity defined for a photosensitive device such as photographic film or a charge-coupled device (CCD) as the percentage of photons hitting the photoreactive surface that will produce an electron–hole pair.[1] |
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RA |
Right ascension astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system |
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RC |
Ritchey-Chretien a specialized Cassegrain telescope designed to eliminate coma, thus providing a large field of view compared to a more conventional configuration. An RCT has a hyperbolic primary and a hyperbolic secondary mirror |
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RCOS |
RC Optical Systems was founded in the mid 1990s with the goal of manufacturing the highest quality astronomical telescopes possible. http://www.rcopticalsystems.com/index.html |
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RGB |
Red green blue - red, green, and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors |
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SBIG |
Santa Barbara Instrument Group http://www.sbig.com/ manufacturer of High Quality CCD Camera |
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SCT |
Schmidt-Cassegrain telescope a catadioptric telescope that combines a cassegrain reflector's optical path with a Schmidt corrector plate to make a compact astronomical instrument that uses simple spherical surfaces. |
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SD |
Super-low dispersion A special glass used for lens making, whose refractive index varies lightly according to the wavelength of light. Chromatic aberration, especially, is easier to correct using low dispersion glass |
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SLR |
Single lens reflex (camera) a camera that typically uses a semi-automatic moving mirror system that permits the photographer to see exactly what will be captured by the film or digital imaging system |
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SMA |
Super modified achromat |
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SMC |
Small Magellanic cloud a dwarf galaxy[3]. It has a diameter of about 7,000 light-years[4] and contains several hundred million stars.[5] It has a total mass of approximately 7 billion times the mass of our Sun. |
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SQM |
Sky Quality Meter (brightness reading) measures the brightness of the night sky in magnitudes per square arcsecond. |
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SV |
Super view fully multicoated optics with blackened edges to minimize light reflection and maximize contrast and light transmission. Usually referring to eyepieces |
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SXV |
Starlight Xpress - a specialist supplier of cooled CCD cameras for low noise imaging applications. http://www.starlight-xpress.co.uk/ |
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TEC |
Telescope Engineering Company began in 1994 as a distributor/subcontractor of optics and optical materials. http://www.telescopengineering.com/ |
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TFOV |
True field of view - is the angle of sky seen through the eyepiece when it's attached to the telescope. The true field can be approximated using the formula: True field = Apparent field / Magnification |
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TMB |
Thomas M. Back (of TMB Optical Co) optical designer Thomas M. Back, who passed away unexpectedly in late 2007 http://www.tmboptical.com/ |
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TOA |
Triplet arthroscopic apochromat (Takahashi design) ultra-premium FPL-53 ED (Extra-low Dispersion) glass is positioned between two low-dispersion crown glass elements to produce images of very high quality. |
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UHC |
Ultra high contrast filter passes three nebula emission lines...the two doubly ionized oxygen lines (496 and 501nm) and the H-beta line (486nm)...while blocking light pollution and sky glow. |
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UO |
University Optics http://www.universityoptics.com/ |
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USB |
Universal serial bus (data transport) is a specification[1] to establish communication between devices and a host controller (usually personal computers), developed and invented by Ajay Bhatt while working for Intel.[2][3] |
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UT |
Universal time a timescale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time (GMT), i.e., the mean solar time on the meridian of Greenwich, and GMT is sometimes used loosely as a synonym for UTC. |
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UTA |
Upper tube assembly (of truss Dobs) |
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UV |
Ultra violet (light) electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 10 nm to 400 nm, and energies from 3eV to 124 eV. It is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet |
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WO |
William Optics- http://www.williamoptics.com/
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Modern Constellation Acronyms
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Abbreviation |
Constellation |
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And |
Andromeda a spiral galaxy approximately 2,500,000 light-years (1.58×1011 AU) away[4] in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224 |
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Ant |
Antlia is one the constellations named by Nicolas Louis de Lacaille during the mid eighteenth century, designed to chart the southern hemisphere. Antila represents the air pump |
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Aps |
Apus a faint constellation in the southern sky, first defined in the late sixteenth century. Its name means "no feet" in Greek, and it represents a bird-of-paradise |
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Aqr |
Aquarius |
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Aql |
Aquila |
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Ari |
Aries |
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Aur |
Auriga |
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Boo |
Bootes |
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Cae |
Caelum |
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Cam |
Camelopardalis |
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Cnc |
Cancer |
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CVn |
Canes Venatici |
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Cma |
Canis Major |
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Cmi |
Canis Minor |
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Cap |
Capricornus |
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Car |
Carina |
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Cas |
Cassiopeia |
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Cen |
Centaurus |
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Cep |
Cepheus |
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Cet |
Cetus |
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Cha |
Chamaeleon |
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Cir |
Circinus |
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Col |
Columba |
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Com |
Coma Berenices |
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CrA |
Corona Australis |
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CrB |
Corona Borealis |
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Crv |
Corvus |
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Crt |
Crater |
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Cru |
Crux |
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Cyg |
Cygnus |
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Del |
Delphinus |
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Dor |
Dorado |
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Dra |
Draco |
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Equ |
Equuleus |
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Eri |
Eridanus |
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For |
Fornax |
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Gem |
Gemini |
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Gru |
Grus |
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Her |
Hercules |
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Hor |
Horologium |
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Hya |
Hydra |
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Hyi |
Hydrus |
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Ind |
Indus |
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Lac |
Lacerta |
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Leo |
Leo |
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Lmi |
Leo Minor |
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Lep |
Lepus |
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Lib |
Libra |
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Lup |
Lupus |
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Lyn |
Lynx |
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Lyr |
Lyra |
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Men |
Mensa |
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Mic |
Microscopium |
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Mon |
Monoceros |
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Mus |
Musca |
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Nor |
Norma |
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Oct |
Octans |
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Oph |
Ophiuchus |
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Ori |
Orion |
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Pav |
Pavo |
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Peg |
Pegasus |
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Per |
Perseus |
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Phe |
Phoenix |
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Pic |
Pictor |
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Psc |
Pisces |
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PsA |
Piscis Austrinus |
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Pup |
Puppis |
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Pyx |
Pyxis |
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Ret |
Reticulum |
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Sge |
Sagitta |
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Sgr |
Sagittarius |
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Sco |
Scorpius |
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Scl |
Sculptor |
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Sct |
Scutum |
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Ser |
Serpens |
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Sex |
Sextans |
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Tau |
Taurus |
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Tel |
Telescopium |
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Tri |
Triangulum |
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TrA |
Triangulum Australe |
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Tuc |
Tucana |
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UMa |
Ursa Major |
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UMi |
Ursa Minor |
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Vel |
Vela |
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Vir |
Virgo |
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Vol |
Volans |
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Vul |
Vulpecula |
Telescope Basics
The basic operation of the telescope is to collect light, magnify this light and focuses it on a specific point. During the process of collecting light and the combination of lenses or mirrors magnifies the image. By itself, the telescope can't magnify the image any more than what is present without the eyepiece. Take out the eyepiece and look through the slot where the eyepiece is suppose to be, you will see a large, out of focus image. DO NOT EVER ATTEMPT TO LOOK AT THE SUN WITH A TELESCOPE, IT WILL DAMAGE THE TELESCOPE AND BLIND YOU INSTANTLY!!! You MUST use a solar filter to view the Sun. It is the eyepiece's job to magnify an image for you to see. Pick a 15mm eyepiece and you will have a close up view of what ever you are looking at switch to a 32mm and you have a much wider view and much less magnification.
Eyepieces
A Telescope requires that an eyepiece be placed in the appropriate slot in order to view objects. Think of your telescope as a giant as zoom lens, alone, without an eyepiece it is pretty much useless. In this example the telescope is the lens and the eyepiece would be a camera body. There are many different types of eyepiece currently available for various applications. For instance, there are wide angle, long eye relief, barlow, zoom, high power and illuminated eyepieces. Illuminated eyepieces have a tiny cross hair target in their center for precisely centering objects. Most commonly these type of telescope eyepieces are used during the alignment procedure for the telescope. These eyepieces can also be used to assist in the alignment procedure by a observing stars and noticing which way the Star moves which will then allow the astronomer to correct the limit of the telescope. Obviously, different eyepieces have different applications for telescopes.
Many astronomers prefer high power eyepieces for observing planets and star clusters. One limitation to high power eyepieces is that they are dependent on the sky conditions and are most useful during nights were the sky is very clear and there is little wind. As you increase the magnification of the telescope the distortions you receive from magnification are dramatically increased when you use a high-power eyepiece, it is no different than trying to focus in on a distant object with a video camera or camera. Personally, it is quite rare for me to use an eyepiece that is below 10 mm(189X power magnification on my 12"LX90). My preferred eyepiece is a 26mm eyepiece which produces a 73X magnification, not too much and not too little but for me just right. After my alignment I usually switch to the 15mm Plossl which is 126X for visual viewing. If I plan on imaging I stay with the 26mm so if there are any problems with the GOTO accuracy of my scope I will have a better chance of locating my object with the wider view of the 26mm.
The wide angle eyepieces offer a dramatic field of view especially for those who are new to the hobby. And variable adjustment (zoom) eyepieces offer the ability to have a wide angle view as well as the ability to zoom in on an object.
Some eyepieces offer a dramatic increase in magnification of the object or they may offer a wider field of view to make viewing easier. There are even eyepieces that are available for people who wear glasses so that they don't have to take off their glasses to look through the eyepiece. These eyepieces have a feature which is called Long eye relief which means that a person who looks through this eyepiece does not have to press their eye right up against the eyepiece, they can look at the eyepiece just by getting within an inch or so from the opening
Focal Length
F Number, What does this mean?
The f-number is the focal length divided by the "effective" aperture diameter. It is a dimensionless number that is a quantitative measure of lens speed, an important concept in photography. An f/4 telescope is 'very fast' and an f/11 scope is 'slow'. Lower f numbers allow for shorter exposure times and a generally larger field of view. THINK OF IT THIS WAY: A fast (f/4 number) is like your pupils when they are dilated you gather light in your eye much more than when you are in bright light. In bright light your pupils are constricted which is analogous with a slow (f/12) number; think of it this way and you will be ahead of the curve when choosing a scope / camera setup.
GOTO Telescopes
One of the best things that has happened to astronomy in the last 20 years has been the development of the GOTO telescope. Telescopes with this type of system are able to automatically move from object to object with incredible accuracy and speed provided that they are aligned correctly.
SHORT ANSWER: GOTO telescopes are designed to automatically be able to move from deep sky object to deep sky object based on location information you enter into the telescope. Do you want to see the Crab Nebula? Just enter Messier 1 in the menu and press GOTO the telescope will automatically move to the Crab Nebula!
DETAILED ANSWER:
One of the best things that has happened to astronomy in the last 20 years has been the development of the GOTO telescope. Telescopes with this type of system are able to automatically move from object to object with incredible accuracy and speed provided that they are aligned correctly. When I first began his hobby many years ago the most frustrating part was the amount of time that it took me to locate objects in the sky. I have to admit that because of this frustration and actually left the hobby for about 10 years.
For parents who are looking to buy their children telescopes this would be the biggest thing that I would advise them to do; buy a telescope with an integrated GOTO system! Because children are prone to distraction and a short attention span it is really in the best interest of the child and parents to give them a tool that will allow them to discover the universe quickly and accurately. Most of the GOTO systems are very accurate but some more than others require precise alignment or the problem not being able to find the object you were looking for will become an issue.
Here is how most of the systems work; the manufacturer has developed models of the entire sky and has written an algorithm into the telescope to adjust for different times of the year and zip code locations. Based on the information that he put into the telescope such as the zip code and the time alter telescope needs to know is which direction is north and it needs to have two stars in different locations in the sky to build the necessary algorithm to know exactly where the other stars or targets are at the time you wish to view them. It sounds very simple and one would think that a computer would have no problem developing a model that would tell them exactly where deep sky objects are located based on your input information that is actually a little more difficult than that. Not only does the telescope have to develop a model based on where it currently is in order to move to the next target accurately, it needs to be able to keep up with the rotation of the earth or in this case against the rotation of the earth in order to keep the object you are viewing in the eyepiece. There is an example: a point my telescope at Polaris and level the amount so the telescope knows that it's starting position is roughly north and level (here is where the model begins its calculations). The telescope doesn't care where it is because anywhere in the northern hemisphere this is the most basic information that it requires to begin working. I enter the current time including whether it is daylight saving time or not, the step is very important because even if you are off by one hour you will not be able to correctly align the telescope. I'd then tell the telescope in which zip code it is currently in so at this point the telescope has a rough idea of where everything is but is still not precise enough. In order to make the alignment more precise and will need to and at least two different stars so the telescope will know exactly where it is on the surface of the earth. Many different manufacturers have various ways in which to achieve this portion of the alignment but this method is specific to the Meade brand of telescopes. For this example it will choose vague and as my first alignment Star, I locate vague in the telescope menu and press GOTO and the telescope moves to where it thinks Vega should be based on the information I have already input into the telescope. I center Vega in the eyepiece by using the telescope control and press enter (now the telescope has one precise location to configure its calculations). I choose my second star, in this case Alkaid, which is the last star in the handle of the big dipper and a press GOTO, telescope again moves to the location it believes the stars should be in and again I center the star using the hand control from this telescope. When I press Enter, the telescope is able to complete its model of the entire sky and tell me you have aligned the telescope correctly based on the stars that I have input. If I have successfully aligned telescope with models that it creates will allow me to observe any object in its database accurately and went to use what I want to observe from the menu it will automatically move to the object and center it in the eyepiece.
Telescope Aperture
Aperture is the size of the main optical lens of the telescope. It can be specified either in inches or millimeters. 'Light Gathering' is how much light an optical system can gather is a function of the area of the aperture, so that light gathering ability varies with aperture size.
Remote Observing
The ability to view objects with a telescope located in another part of the country or world! Many new services are available that offer users the ability to image with professional level telescopes and high quality cameras. Many amateur astronomers are now able to connect their telescopes to the internet via programs like Maxdome II, a telescope and observatory control program that allows users to access their equipment anywhere they have access to the internet! the creation of Internet based telescopes offers many new users the ability to create incredible images without even owning a telescope. Personally, I have been able to increase the amount of time than I spend imaging and viewing stars based on my access to my telescopes using Maxdome II and I highly recommend this program.
Declination and right ascension
Similar to how latitude and longitude are used to determine locations on the surface of the earth, declination and right ascension are essential for astronomers to be able to locate objects in the sky. It is helpful to think of declination as latitude on Earth. Long ago astronomers decided the
More to Come soon!! Check back in early August!
