Dobsonian telescopes are modified Newtonian reflector telescopes popularized by John Dobson in 1965. Amateur astronomers prefer Dobsonian telescopes for their large aperture, low cost, and portability. Dobsonian telescopes use a concave mirror as the objective lens to collect and focus light from distant objects. Dobsonian telescopes are available in sizes ranging from small portable models…
A reflecting telescope works by using mirrors to gather and focus light from the cosmos, providing detailed images of distant celestial objects. The primary mirror, which is concave in shape, captures the light, which is then focused onto a smaller area. A secondary mirror, positioned at a 45-degree angle, redirects the focused light towards the…
The diffraction limit is the highest angular resolution a telescope is able to achieve. This limit refers to the theoretical maximum if nothing besides the size of a telescope’s light-collecting area affects the quality of the images. This limit is a direct consequence of the nature of light waves. When light waves encounter an obstacle…
The field of view (FOV) in a telescope defines the extent of the observable universe that is visible through the eyepiece at any given moment. Knowing the FOV allows astronomers to determine the ideal eyepiece for a specific observation. There are two distinct types of FOV: the apparent field of view (AFOV) and the true…
The light gathering power (LGP) refers to the telescope’s ability to collect light. Knowing the LGP of a telescope is important because the more light a telescope can gather, the better its ability to observe faint objects in the night sky. The LGP is measured in terms of the area of the telescope’s aperture, usually…
Telescope magnification, often referred to as “power” or “telescope zoom,” defines how much a telescope can enlarge the appearance of distant objects. Magnification is the factor by which a telescope amplifies the size of an object compared to its size as seen with the naked eye. A telescope’s magnifying power is determined by dividing the…
Focal ratio, also known as the “f-number,” “f-ratio,” or “aperture ratio,” defines the relationship between the focal length of a telescope and the diameter of its primary optic. The focal ratio is calculated by dividing the telescope’s focal length by the diameter of the aperture. Knowing the focal ratio is crucial as it serves as…
Focal length is the distance between the objective lens or mirror of a telescope and the point where incoming light converges to form an image. Knowing the focal length allows observers to comprehend key aspects of a telescope’s performance. To calculate the focal length of a telescope or lens, measure the distance from the lens…
Telescope aperture is the size of the primary optical element. Knowing the aperture of a telescope allows observers to understand the light-gathering ability and resolution. For amateur telescopes, apertures range from 50mm to 130mm in diameter. Knowing the aperture diameter size also allows telescope users to understand the focal ratio and focal length. These values…
A telescope works by collecting and focusing light from distant objects. The objective gathers and bends light. The objective is either a lens, in refractor telescopes, or a mirror in reflector telescopes. Light is then focused into the eyepiece, which magnifies the image, enabling detailed observation of distant celestial bodies. Atmospheric conditions significantly impact the…
The Hubble and James Webb Space Telescopes represent different eras in space observation technology. Hubble was launched in 1990 and observes primarily in visible and ultraviolet light. James Webb, launched in 2021, focuses on infrared wavelengths. James Webb’s 6.5-meter mirror dwarfs Hubble’s 2.4-meter mirror, allowing it to collect more light and detect fainter objects. James…
Chandra X-Ray Observatory: Launch Date, Mission, Discoveries, Location NASA launched the Chandra X-Ray Observatory on July 23, 1999 aboard Space Shuttle Columbia. Chandra is a sophisticated space-based telescope designed to detect X-ray emission from hot regions of the universe. The observatory orbits Earth at an altitude of approximately 139,000 km in a highly elliptical orbit….
Collimation is the alignment of the optical elements of a telescope, ensuring that light travels accurately through the optical path to bring celestial objects into sharp focus. Knowing how to collimate a telescope is crucial for optimal astronomical observations. To collimate a telescope, start by consulting the manual as different types require specific approaches, especially…
What is a Kepler space telescope? Kepler space telescope was a NASA observatory launched in 2009 to search for exoplanets outside our solar system. William J. Borucki led the mission. Kepler orbited the Sun 225 million kilometers from Earth. The telescope observed 150,000 stars using a 0.95-meter mirror and 42 CCD camera. Kepler detected 2,600+…
The Compton Gamma Ray Observatory was a space-based observatory launched by NASA on April 5, 1991. It weighed over 15 tons, making it the heaviest payload ever flown at the time. The observatory operated in a low Earth orbit at an altitude of 450 km for nine years until June 4, 2000. Compton Gamma Ray…
The Spitzer Space Telescope was NASA’s infrared observatory launched in 2003. Spitzer operated for 16 years, detecting light from cool objects like distant galaxies and exoplanets. Its 85 cm mirror and cryogenic cooling enabled groundbreaking infrared astronomy discoveries. Spitzer’s mission aimed to explore the cosmos in unprecedented infrared detail. Spitzer made numerous groundbreaking discoveries during…
How Did Galileo’s Telescope Impact History? Galileo Galilei was the first to point a telescope skyward, changing the course of telescope history. After news of Hans Lippershey’s telescope spread, Galileo quickly created his own with stronger magnification. This allowed him to be the first man to peer into the cosmos, essentially founding modern astronomy. When…
The James Webb Space Telescope is the largest and most advanced space observatory ever built. It features a 6.5-meter primary mirror and operates in the infrared spectrum. JWST conducts infrared astronomy to investigate the origins of first stars and galaxies, planet formation, and exoplanet atmospheres. The telescope’s instrument suite includes four main instruments: Near-Infrared Camera,…
What is an Optical Telescope? An optical telescope is a telescope that uses lenses or mirrors to collect and focus light from distant objects, such as stars, galaxies, and planets. The light is magnified and projected into an eyepiece or detector, allowing astronomers to study the objects in detail, from a great distance. Who Invented…
The history of space telescopes dates back to the early 20th century when scientists began to propose the use of telescopes, orbiting in space, to observe the universe. Throughout history, telescopes have led to significant advancements in our understanding of the universe. Who Designed the First Space Telescope? Astronomer Lyman Spitzer, considered the father of…
Throughout history the innovation of telescopes allowed us to explore the universe and led to countless scientific advancements and discoveries. These discoveries have improved our understanding of the universe. The history of telescopes shows a 400 years of improvements and innovations of telescopes that changed the scientific world. How Have Telescopes Contributed to Astronomy? Telescopes…
The first documentation of a telescope appeared in the Netherlands in 1608. This instrument was a staple in the Scientific Revolution, bringing numerous inventors to create their own with variations and improvements. As telescopes have advanced throughout history, as have their magnification, clarity and overall abilities. When Was the First Telescope Designed? The first recorded…
Kemble’s Cascade is an asterism in the constellation Camelopardalis featuring more than 20 stars, with the open cluster NGC 1502 at one end. This star pattern is an unofficial arrangement of stars known as an asterism and is not one of the recognized constellations in the night sky. HIP 18505 is the star in the…
Finding the Winter Hexagon will give you a fresh viewpoint on the winter night sky. It is made up of six brilliant stars that surround the constellation of Orion in the southeast (as seen from the northern hemisphere). The Winter Hexagon is an excellent naked-eye target in January and February. Going clockwise in the hexagon,…
Variable stars are crucial for testing our theories of stellar development, from bloated red giants nearing the end of their lives to binary stars engaged in deadly gravitational dances. They play a significant role in stellar astrophysics. However, extrinsic variables and intrinsic variables are the two basic categories of variable stars. Intrinsic variables are stars…
The Pleiades or the Seven Sisters (M45) is an open star cluster that originated from a huge cloud of dust and gas around 125 million years ago. The stars of M45 are so bright for the high rate of fusion at the cores. However, they are located in the constellation Taurus having a distance of…
The Hyades Star Cluster is the closest cluster to the solar system containing myriads of stars some of which can be observed with the unaided eye. It is located at a distance of 150 light-years away from us. The four brightest stars Gamma Tauri, Delta 1 Tauri, Epsilon Tauri, and Theta Taur makes a V…
Imagine when Earth comes between the sun and the moon and the shadow of the earth falls on the moon. This darkens the moon and it happens only when the moon is full. The outer lighter shadow is called the penumbra, and the darker core is called the umbra. Penumbral shadow is hard to detect…
Sometimes stargazing does not need to memorize all the constellations because like the Summer Triangle, the best star patterns to observe are not always constellations but asterisms. An asterism is a pattern of stars not included in the official 88 constellations. The Summer Triangle is an asterism, made of 3 bright stars Vega, Deneb, and…
Polaris, the North star is located in the constellation named Ursa Minor. It is very close to the north celestial pole of the earth. It is very easy to identify from the northern horizon using the little dipper as a reference. It seems like all the stars and constellation orbits Polaris throughout the year. But…
The Big Dipper constellation is a group of stars belonging to the constellation Ursa Major or the Big Bear. It is easy to spot on any dark night in the Northern Hemisphere. The Big Dipper with its neighbor the Little Dipper can be seen rotating around the North star Polaris throughout the year. In summer…
The Lagoon Nebula is an emission nebula with an active area of star formation full of gas and dust. It is located in the constellation Sagittarius around 5000 light years away. We can see the glow of the embedded star cluster NGC 6530. It has a luminosity of magnitude 6 that makes it a nice…
M57 (The Ring Nebula) is a planetary nebula located in the Lyra constellation at a distance of 2,300 light years from the earth. The shell of gas was produced by a red giant that has to evolve away. The expansion rate of this nebula indicates that it is 10,000 years old. Quick Guide to Observe…
The International Space Station (ISS) can be observed through a telescope, offering a captivating viewing experience. The ISS is one of the brightest objects in the night sky, with a maximum magnitude of -5.9, making it an ideal object for telescopic observation. To view the ISS successfully, a telescope with an aperture of at least…
Comets are a mixture of ice, frozen gasses, dust, and rocks. Scientists think that comets are the debris from materials that formed the solar system initially around 4.6 billion years ago. Comets follow elliptical orbits around the sun. The more it gets closer to the sun, the faster it is pulled in. Some comets fall…
Telescope has revealed the interesting fact that all stars are not alone. Sometimes they are accompanied by one or other multiple stars and form star systems. Double stars that are bound gravitationally are called binary star systems. According to the research around 85% of the stars of the Milky Way are in binary pairs unlike…
The Orion Nebula (M42) is a bright and visible nebula that can be seen with the naked eye under dark skies, but is best viewed with a telescope for more detail. Even a small telescope with a diameter of 60mm can reveal the nebula’s faint, misty shape, while larger telescopes with a diameter of at…
The Andromeda Galaxy is a distant celestial object. Andromeda can be viewed from Earth using a telescope of the right size. Even amateur astronomers can enjoy a stunning view of Andromeda with a moderate-sized telescope, specifically one with an aperture of 6-8 inches (15-20 cm). This size is ideal for gathering enough light to reveal…
The Milky Way is our home galaxy. Milky way is a barred spiral galaxy that stretches approximately 100,000 light-years in diameter. You can view the Milky Way through a telescope, but it’s impossible to see the entire galaxy structure at once due to its enormous size. A telescope allows for a more detailed view of…
A galaxy is referred to as the collection of dust, gas, hundreds of billions of stars, and their planets which are held together by gravity. A galaxy is the most distant object you can see with your telescope. They appear with different shapes and colors and we can see the combined glare of all the…
A nebula is a cloud of gas and dust composed of Helium, Hydrogen, and other ionized gasses. They become visible from Earth due to the interaction of gas with other materials or supernova explosions. However, it is possible to see a nebula with a telescope. Typically a nebula looks gray though the view improves with…
Photo: The Dogstar (Sirius A) and its Pup (Sirius B) Sirius, also known as the Dog star, is the brightest star in the sky found in late winter and spring. It has a tiny companion named Sirius B known as Pup which is basically a white dwarf star. Both of them make a binary star…
Viewing the Sun through a telescope can be a fascinating experience, but it’s crucial to prioritize safety to protect your eyes from potential damage. Looking directly at the Sun through a telescope without the appropriate protective equipment is extremely dangerous and can cause severe damage to the eyes, including permanent blindness. Concentrated sunlight can burn…
Titan is the largest among 83 moons of Saturn and the second largest natural satellite in the solar system. Titan is the only moon that has a dense atmosphere. This is also known as the only object in space that has surface liquid. A small beginner telescope can spot them easily. Quick Guide to Observe…
We see night sky objects through a telescope because they reflect sunlight. Asteroids do the same thing which means it is possible to view them from the earth through a suitable telescope. In fact, sometimes it becomes indistinguishable from the stars though the distances between the asteroid and stars from the earth are different. Asteroids…
Pluto is a distant dwarf planet. Pluto can be seen with a telescope under specific conditions and with the right equipment, although it is not visible to the naked eye or with binoculars. Telescope with a significant aperture of at least 8-10 inches (20-25 cm) in diameter is required to spot Pluto. This size ensures…
Neptune is the eighth and farthest known planet from the Sun. Neptune can be seen through a telescope. Telescope with an aperture of at least 8 inches (20 cm) and a magnification between 100-200x is recommended to achieve the best view of Neptune. Neptune appears as a small, blue-green dot or disk when viewed through…
Uranus is the seventh planet from the sun. Uranus can be seen with a telescope, transforming it from a faint star-like object into a distinct celestial body. With a small telescope of around 60 mm (2.4 inches) in aperture, one can resolve the disk of Uranus and distinguish it from background stars. Moderate magnification between…
Saturn is the sixth planet in our solar system. Saturn can be viewed with a small telescope. A telescope with a diameter of 2 inches can reveal Saturn, while a larger 3-inch telescope with 50x magnification can distinctly show Saturn’s iconic rings. Binoculars with 40x magnification can provide a glimpse of the rings, but a…
The Hubble Space Telescope is a renowned space-based observatory orbiting Earth at an altitude of 340 miles. Launched on April 24, 1990, aboard the Space Shuttle Discovery, Hubble has dramatically altered our view of the universe. The telescope features a 2.4-meter primary mirror and two solar arrays generating 2,800 watts of power. Hubble has made…
Getting started in astrophotography, you may be wondering which optical device is best for you. Telescopes provide a narrow and detailed view of objects in space, which makes them ideal for astronomy. Telephoto lenses provide a wider, less detailed view, which makes it easier to locate and capture imagery. Telescopes vs Telephoto Lenses for Astrophotography…
Telescopes and spyglasses are optical devices used for viewing distant objects. While telescopes are used for astronomy, monoculars are typically used for viewing terrestrial objects. While you can use spyglasses for basic astronomy, the magnification is much weaker than that of a telescope. How Strong is the Magnification of Telescopes vs Spyglasses? Because telescopes are…
Telescopes and periscopes are optical instruments used to view objects that we cannot see with the naked eye. Telescopes allow us to view extremely distant objects within your line of sight. Periscopes are used to view objects not directly in your line of sight and have much weaker magnification. When Should You Use Telescopes vs…
Telescopes and binoculars are optical instruments used to view distant objects. While telescopes are used for astronomy, binoculars are typically used for viewing objects on earth. You can use binoculars for basic astronomy, but the magnification is much weaker and won’t provide as much detail. Depth Perception of Telescopes vs Binoculars One major difference in…
Telescopes and microscopes are both optical instruments but have very different purposes. Telescopes are used to view extremely distant objects, like celestial bodies. Microscopes are used for viewing very small objects, like bacteria. How Are Telescopes and Microscopes Used? Telescopes magnify large and distant objects, making them best suited for astronomy. Microscopes magnify small and…
Telescopes and monoculars are optical devices used for viewing distant objects. While telescopes are used for astronomy, monoculars are typically used for viewing objects on earth. While you can use monoculars for basic astronomy, the magnification is much weaker than that of a telescope. Magnification of Telescopes vs Monoculars Because telescopes are used for viewing…
Telescopes are designed to view celestial bodies and spotting scopes are typically used for viewing wildlife. While they may look and sound similar, they have distinct differences in usage, view and portability. How Are Telescopes and Spotting Scopes Used? Telescopes are used to observe objects in space while spotting scopes are used to view objects…
Jupiter is one of the brightest objects in the night sky. Jupiter can be observed with a telescope to discern its disk and atmospheric details. A telescope with a lens diameter of at least 60mm is sufficient to reveal Jupiter’s disk, major cloud bands, and up to four of its largest moons: Io, Europa, Ganymede,…
Meteors are basically dust and rocks that float at thousands of miles per hour through our solar system. On their way, if they strike the earth’s atmosphere, they burn up and make a long streak across the sky. Sometimes earth encounters them in large numbers making Meteor showers. Meteor showers are formed by debris from…
Zhumell is an optical company that produces telescopes. The company was founded in Duluth, Minnesota and moved to Omaha, Nebraska after being purchased by Hayneedle in 2006. Zhumell offers a relatively small selection of telescopes compared to their competitors, but they have established a reputation for popular models such as the Zhumell Z130. Zhumell has…
The Zhumell Z130 is the largest and most capable of the three Zhumell tabletop Dobsonians, which places it in a bit of an awkward position both mechanically and price-wise. It features a 130mm parabolic primary mirror, a high-end feature not usually found in telescopes of this size. The parabolic mirror removes visual defects like spherical…
The Zhumell Z114 has great build quality and optics. It is extremely portable. It is recommended for beginners who are just starting out and intermediate astronomers who would like a telescope to scan the sky for just a few minutes. The great thing about the Zhumell Z114 is the low price. For just 150$, you…
The Zhumell Z100 Portable Reflector Telescope features a 100mm parabolic primary mirror, a high-end feature that’s very uncommon in telescopes of this size. The parabolic mirror removes visual defects like spherical aberration, providing noticeably sharper views. The primary mirror and all other optical surfaces are coated with Zhumell’s high-reflectivity coatings. You can count on more…
The Zhumell Z12 Dobsonian telescope features a massive 12” parabolic primary mirror that captures a substantial amount of light and produces crisp, bright images free of visual defects like spherical aberration. You will also get two fully multi-coated eyepieces: a 2” 30mm eyepiece for wide field views and a 1.25” 9mm eyepiece for higher magnification. …
The Zhumell Z10 Dobsonian telescope features a 10” parabolic primary mirror that captures a substantial amount of light and produces crisp, bright images free of visual defects like spherical aberration. You’ll also get two fully multi-coated eyepieces: a 2” 30mm eyepiece for wide field views and a 1.25” 9mm eyepiece for higher magnification. With the…
Aberrations are defects in optical systems caused by the deviation of light. This can be a result of either a limitation in your design or a defect in your optics. Every telescope experiences some degree of aberrations, but by selecting the right telescope, you can reduce or eliminate specific aberrations. What Are the Types of…
Distortion in optics modifies images produced by optical systems, causing information loss about observed objects. Aberrations like spherical aberration, coma, astigmatism, and chromatic aberration introduce errors into images. Radial, tangential, and angular distortions affect images distinctly. Lens design and shape are primary factors contributing to optical distortion. Curved lens elements introduce distortion by varying magnification…
Field curvature is an optical aberration that affects the ability of a telescope to bring a flat object into focus on a flat image plane. It can cause distortion, reduced image sharpness, and other aberrations, impacting the overall quality of the images produced. Field curvature in telescopes can be corrected using various methods, such as…
Astigmatism is an optical aberration causing distorted or blurry images. Lens or mirror curvature irregularities result in light rays focusing at two different points instead of one. Corneal astigmatism occurs when the corneal surface curves unevenly. Optical professionals measure the astigmatism axis in degrees. Astigmatism correction employs cylindrical lenses, mirrors, and prisms. Cylindrical lenses refract…
Coma aberration is an optical defect in lens designs that causes off-axis point sources to appear distorted with comet-like tails. Imperfections in lens components, asymmetry in optical systems, and non-uniform refractive indices contribute to this image-degrading effect. The coma coefficient measures distortion severity, ranging from 0 to 1, with 0.5 representing moderate to severe distortion….