Telescope Field of View (FOV) Calculation

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…

Telescope Light Gathering Power: Calculation

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 Resolution (Resolving Power) Calculation

Resolving power, also referred to as “resolution” or “angular resolution”, is a measure of a telescope’s ability to differentiate between two closely spaced objects. Knowing the resolving power of a telescope allows astronomers to understand the capabilities of its optics. The resolving power is defined by a combination of factors, including the diameter of the…

Telescope Magnification (Magnifying Power)

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…

Telescope Focal Ratio: Explanation (F Ratio & F-Number)

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…

Telescope Focal Length: Explanation

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…

What Is A Telescope Aperture? Explanation and Size Comparison

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…

How Does a Telescope Work? Functions of Optical System

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 James Webb vs Hubble Space Telescope

The James Webb Space Telescope and Hubble Space Telescope were both designed by NASA to study the composition and characteristics of our universe. Both of these telescopes have unique characteristics, allowing them to accomplish different objectives.  Size & Dimensions of James Webb vs Hubble Space Telescope The James Webb Space Telescope’s (JWST) primary mirror diameter…

History of The Chandra X-ray Observatory

The Chandra X-ray Observatory (CXO) is a space telescope, designed by NASA in the 1990s. Chandra’s mission is to observe x-ray emissions from high-energy regions of the universe, such as the remnants of collapsed stars, galaxy clusters, and black holes.  History of The Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously called the Advanced…

What is Collimation in Telescopes?

Collimation is the process of aligning all components in a telescope to bring light to its best focus. Most manufacturers collimate telescopes before shipping, but they often require recollimation to achieve the best image. When a telescope is out of collimation, celestial objects may appear blurry.  What Are the Types of Collimation in Telescopes? There…

What Can You See With A Telescope?

With a telescope you can see planets, stars, galaxies, constellations, meteors and much more. This article is a guide for astronomers and astrophotographers who are enthralled by the limitless space filled with countless stars. It doesn’t require specialized training or extensive sessions. Simply get a telescope with a suitable lens, or a camera, wait until…

The History The Kepler Space Telescope

The Kepler Space Telescope was designed by NASA to study exoplanets using the transit method. It was first proposed in 1994 and renamed in 1996, after German astronomer, Johannes Kepler, who is known for his discovery of laws of planetary motion. Kepler was developed by NASA’s Ames Research Center and the Ball Aerospace & Technologies…

The History The Compton Gamma Ray Observatory

The Compton Gamma Ray Observatory (CGRO) was a space observatory that studied gamma rays, the most energetic form of electromagnetic radiation. It was launched into space on April 5, 1991, and operated until its deorbit on June 4, 2000. CGRO was a collaboration between NASA and several international partners, and it was the second space…

Spitzer Space Telescope

NASA’s Spitzer Space Telescope, initially known as the Space Infrared Telescope Facility, was the fourth and final of NASA’s Great Observatories. Launched on August 25, 2002, Spitzer was NASA’s primary infrared light observatory, allowing astronomers to study the universe in critical parts of the electromagnetic spectrum of light. History of the Spitzer Space Telescope NASA…

The History of Galileo Galilei’s Telescope

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 History of James Webb Space Telescope

The James Webb Space Telescope (JWST) was developed by NASA, in partnership with the European Space Agency (ESA) and the Canadian Space Agency (CSA). It was named after James E. Webb, who served as a NASA administrator and played a key role in the Apollo program. The concept for the JWST was first proposed in…

The History of Optical Telescopes

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…

History of Space Telescopes

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…

Contribution of Telescopes in Scientific Development

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 History of 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…

How to See Kemble’s Cascade With A Telescope?

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…

How to See the Winter Hexagon With A Telescope?

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,…

How to See the Variable Stars With A Telescope?

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…

How to See the Pleiades With A Telescope?

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…

How to See the Hyades Star Cluster With A Telescope?

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…

How to See The Total Eclipse of the Moon With A Telescope?

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…

How to See the Summer Triangle With A Telescope?

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…

How to See the North Star (Polaris) With A Telescope?

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…

How to See the Big Dipper With A Telescope?

The Big Dipper 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 and…

How to See a Lagoon Nebula With A Telescope?

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…

How to See The Ring Nebula With a Telescope?

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…

How to See The ISS With A Telescope?

The International Space Station (ISS) is a space laboratory where astronauts stay for a period of time and do experiments. It moves around the Earth at around 300 miles up and at 17,000 mph. It has several parts like the solar array wings working as power stations, rooms and laboratories for the astronauts, and all…

How to See Comets With A Telescope?

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…

How to See Binary Stars With A Telescope?

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…

How to See the Orion Nebula With A Telescope?

The Orion Nebula, also familiar as M 42 is easy to spot and visible to unaided eyes. It is one of the brightest Nebula in the night sky with a magnitude of 4. It is located in the Orion constellation and includes stars, ionized gas, and dust. This diffuse nebula extends across a 1° region…

How to See Andromeda With A Telescope?

The Andromeda galaxy is the nearest galaxy to the Milky Way located at 7.7° northwest of Mirach. This is the only galaxy you can see with bare eyes without any optical aid. However, it appears as a faint misty patch on a moonless night at a short distance from the band of the Milky Way….

How to See the Milky Way With A Telescope?

The Milky Way is a common spiral galaxy with a visible diameter of 100-200 thousand light years. It has 4 main spiral arms having 100-400 billion stars in each of them and our solar system is located in Orion’s arm. You can see the other side of the Milky Way even with unaided eyes. From…

How to See Galaxies With A Telescope?

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…

How to see a Nebula With A Telescope?

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…

How to See Sirius With A Telescope?

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…

How to see The Sun With A Telescope?

Planets and the moons are not the only things astronomers intend to observe in the sky. Stars are always mysterious that can reveal dramatic detail even with a 4-inch telescope. The sun is the nearest star to us and also the only night sky object that may cause harm to our eyes. Observing the Sun…

How to See Titan With A Telescope?

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…

How to See Asteroids With A Telescope?

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…

How to See Pluto With A Telescope?

Pluto is mostly known as a dwarf planet. You cannot see Pluto with a small or low-powered telescope. Only a large aperture telescope with high magnifications and show you its appearance. It is situated at the very edge of the solar system. It is not a shiny object having a magnitude of 14.4. To observe…

How to See Neptune With A Telescope?

Neptune is the eighth and the last official planet from the sun. A Neptunian day is only 16 hours, but it orbits around the sun in about 165 earth years.  Neptune is an icy gas giant composed of hot icy materials like water, ammonia, and methane. It has 14 moons. It also has five main…

How to See Uranus With A Telescope?

Uranus is the coldest planet in the solar system. It takes 82 earth years to orbit the sun once. The most interesting fact about Uranus is its axial tilt at about 98 degrees which means Uranus orbits the sun on its side. Uranus has two sets of rings just like Saturn. It also has 27…

How to See Saturn With a Telescope?

Saturn is a gas giant and 6th in position among all planets from the sun. It is well known for its rings made of ice particles and rocky debris and dust. Amazingly, Saturn has 80 moons among which Titan is the largest. Saturn is the second largest planet in the solar system and it takes…

The History of The Hubble Telescope

The Hubble Space Telescope was designed by NASA in the 1940s. After nearly 50 years of planning, the telescope was launched into orbit on April 24, 1990. This telescope has made over 1.3 million observations to collect data on the expansion, age and composition of our universe. History of the Hubble Space Telescope NASA began…

Telescope vs Telephoto Lens Comparison

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…

Telescope vs Spyglass Comparison

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…

Telescope vs Periscope Comparison

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…

Telescope vs Binoculars Comparison

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…

Telescope vs Microscope Comparison

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…

Telescope vs Monocular. What is the difference?

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…

Telescope vs Spotting Scope

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…

How to See Jupiter With A Telescope?

The biggest gas giant in the solar system, Jupiter is 319 times more massive than earth. The part we see through a telescope is mostly its clouds composed of ammonium hydrosulfide (brown) and ammonia (white). The appearance of Jupiter changes over time due to the growth in storms, changes in the color of cloud belts,…

How to See Meteor Shower With A Telescope?

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 Telescopes

With Zhumell you get precision-crafted and field-tested optics for the most affordable price. So even if you’re starting as an amateur astronomer, you don’t have to settle for entry-level products. Zhumell customers enjoy astronomy in rich, colourful detail – the kind of detail that only high-performance optics can produce. Zhumell designs telescopes for discerning, price-conscious…

About Zhumell Reflectors

For serious stargazing, the highly adaptable Newtonian design provides the best value. The reflectors range from an extremely powerful 12″ Deluxe Dobsonian reflector to a simple yet portable 76mm Newtonian on a portable Alt-Azimuth mount. If you can easily access reasonably dark skies and want to add excitement to your observing program, check out Zhumell’s…

Zhumell Z130 Reflector

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…

Zhumell Z114 Reflector Telescope

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…

Zhumell Z100 Reflector Telescope

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…

Zhumell Z12

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. …

Zhumell Z10

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…

Optical Aberrations in Telescopes

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…

What is Distortion in Telescopes?

Distortion is an optical aberration, resulting in a difference in magnification across your field of view. This aberration does not affect optical focus but causes your image to appear curved. What Causes Distortion? Distortion is caused by light hitting curved lenses. Because the lens is curved, light travels a different distance from the edge to…

What is Field Curvature In Telescope?

Field curvature is an optical aberration caused by a difference of curvature in the focal planes. Because of this, the lens is unable to focus the edges and center of the field at the same time, resulting in a curved distortion. What Causes Field Curvature? Field curvature is caused by a difference in the lens…

What is Astigmatism in Telescopes?

Astigmatism is an off-axis optical aberration caused by the obliquity of focal planes. This results in rays of light meeting at different focal points, distorting the image. What Causes Astigmatism? Astigmatisms are caused by optical defects or rays of light hitting the telescope obliquely. Telescopes have two perpendicular planes; the tangential and the sagittal. Astigmatism…

What is Comatic Aberration (Coma) in Telescope?

Comatic Aberration, also called Coma, is an off-axis optical aberration, meaning it has a greater effect as it nears the edge of the field. This results in a blurred tail around the object you’re viewing. What Causes Comatic Aberration? Coma is caused by the deviation of light rays in lenses or mirrors. This causes rays…