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Many people mistakenly believe they need a high-magnification home telescope to see crisp, detailed images of planets and celestial bodies. After all, the planets and galaxies are far away, and the higher the magnification, the better, right?
Unfortunately, it is more complicated, like most things in astronomy!
Several crucial factors can impact the performance of the magnification power of your home telescope. Viewing conditions like light pollution, atmospheric turbulence, wind speeds, and air temperature all impact how well your telescope can magnify the image of a celestial body.
While it is true that with higher telescope magnification, you can zoom in more on your target, it also results in more pronounced interference from atmospheric turbulence. So, what should be the ideal magnification?
A good magnification for a home telescope depends on many things, including the state of the atmosphere and brightness and the size of the object being observed. The magnification of your home telescope should be between 4 to 50 times the size of the telescope aperture for best viewing.
In this article, we will take a detailed look at how magnification works and how you can use it to your advantage while observing the universe through your home telescope.
Let’s get started, shall we?
What is telescope magnification?
The magnification of a telescope indicates how many times bigger an object looks through the eyepiece compared to its size when viewed with the naked eye. For example, if an object appears fifty times as big through your telescope’s eyepiece as it does with your naked eye, the magnification is 50x.
As you can imagine, telescope magnification plays an important role in your stargazing experience.
However, no one angular magnification will produce universally good results. You must adjust the magnification according to the conditions for the best results.
Playing around with the magnification settings on your refractor telescope allows you to control the image quality better and enhance your experience.
Factors affecting magnification for a telescope
The magnification power of both reflector and refractor telescopes is affected by many factors, including the size of the objects you want to see and the atmospheric conditions.
Some of the factors that can influence how much magnification you can use include the following:
- Light pollution in the area
- The temperature of the air
- The turbulence of the atmosphere
- Speed of wind
With higher magnification, you can zoom in better on your target, narrowing your field of view. Ideally, this should translate into a closer and brighter image revealing good details.
However, the situation can be drastically different than what you might expect. For instance, atmospheric turbulence can ruin the image quality, and you lose details if you use a higher magnification.
How to calculate magnification of your telescope lenses?
The magnifying power of your telescope is directly related to the physical aspects of your lens or mirror, including:
- The telescope’s aperture
- The focal length (FL) of the telescope lens
- The FL of the eyepiece lens
It is quite straightforward to calculate the magnifying power of your backyard telescope if you know the focal lengths of the ÷primary mirror or primary lens and eyepiece lens. The formula to calculate the magnifying power is as follows:
Magnifying power = The telescope lens FL ÷ The eyepiece FL
Let’s understand this by taking an example. If your telescope lens has an FL of 2000 mm and the eyepiece lens has an FL of 50 mm, the eyepiece magnifies the object 40 times or 40x.
While discussing the magnification of your telescope, you should remember one crucial aspect of even a small telescope. In a home telescope like this best-seller Gskyer Home Telescope, the FL of the telescope lens is fixed.
So, if you want to change the useful magnification, you must use primary mirror or lens with different focal lengths.
Importance of magnification in a telescope
Telescope magnification is a crucial aspect of telescope design and usage, as it allows observation of a wide range of celestial objects, from distant galaxies to nearby planets.
Telescope magnification is achieved by using lenses or mirrors in a reflector telescope to gather and focus light waves, allowing you to see details that would otherwise be invisible to the naked eye.
Here are a few ways magnification can affect your stargazing experience with your refractor telescopes.
Magnification allows for detailed observation of celestial objects
One of the primary uses of magnification in a telescope is for observing celestial objects like faint stars and nebulae that are too far away to be seen with the naked eye.
Magnification allows you to see distant celestial objects, galaxies, double stars, and nebulae in much greater detail, allowing you to admire their beauty and learn more about the universe.
It also allows observing objects too faint to be seen without it, such as galaxies like the Andromeda galaxy and distant quasars.
Higher magnification allows for greater resolution
Resolution refers to the ability of a telescope to distinguish small details in an object. The higher the telescope magnification, the greater the resolution and the more detail can be observed.
For example, a telescope with less magnification may only show a distant galaxy like Andromeda as a small, faint smudge.
In contrast, a telescope with greater magnification can reveal details such as individual stars and spiral arms.
The craters on the Moon and other surface characteristics can be visible with a high-magnification telescope. You can also see the moons of planets like Jupiter if you have a high-magnification telescope with high optical quality.
Magnification affects the field of view
As you zoom in on a celestial object using a reflector telescope, you narrow your field of view. Magnification can affect the field of view, which is the area of the night sky that can be seen through the telescope at one time. The higher the magnification, the smaller the field of view.
It can make it difficult to locate and track certain objects, especially faint objects spread out over a large area of the night sky.
For example, if you use a telescope with lesser magnification to view a faint galaxy, you will see a large area of the night sky at once, making it easier to locate a fainter galaxy.
However, if you use a higher telescope magnification, the field of view will be smaller, and it may be harder to locate that galaxy.
Proper magnification can enhance the viewing experience
If your magnification settings are adjusted properly, you can make your stargazing experience more enjoyable.
For example, if you observe a celestial body with too small a magnification, you might miss many details.
On the other hand, locating a planet or a nebula at a very high magnification can also be difficult. The image can be very unstable and blurry with faint diffraction rings if the magnification is too high.
Correct magnification can eliminate distortion and aberrations
One of the biggest issues when observing distant objects such as the Orion nebula or distant galaxies is the disturbances due to the atmosphere. As light is refracted when it travels through the atmosphere, it can cause artifacts in your image.
If the magnification is too high, more light distortions due to differences in refractive indices of the layers of the atmosphere can create an unstable image.
A lower magnification can eliminate this by stabilizing the image and allowing you to observe more details. You can use an aluminum tripod for additional stability when using high magnification.
Magnification can affect the brightness and clarity
Magnification can also influence the brightness and clarity of the image.
Brightness
As the magnification of the telescope increases, the image becomes smaller, and the light is spread over a larger area. It often results in a dimmer image. You will observe that as you zoom in more and more into a celestial body, you will lose much light.
So, if you are trying to see a particularly dim object in the sky, you are better off using a lesser magnification than a higher one.
Clarity
Theoretically, high magnification should make the image appear clearer. However, it also magnifies any aberrations or distortions in the optical system. The combined effect is a less sharp and clear image.
Choosing your magnification is crucial if you want a clear image with much detail.
Proper magnification can make it easier to find and track objects
A lesser-magnification eyepiece can make it easier to find an object in the sky. The field of view is larger, and the object will appear brighter. It allows you to scan a large sky area and find the object you are looking for.
Once an object is located, switching to a high-magnification eyepiece can make it easier to track and study bright objects in more detail.
A reflector telescope mount with a motorized tracking system can also make tracking objects easier as they move across the sky. It allows you to maintain a steady image of the object in the eyepiece, even as the Earth rotates.
Celestron Computerized Telescope
Good magnification for a home telescope
In light of what we have seen above, it becomes clear that choosing the right magnification for your home telescope is essential. If you choose the wrong magnification, it can result in poor-quality images, ruining your experience.
As we saw earlier, the FL of your telescope lens is fixed. So, when it comes to the ability of your small telescope to adjust magnification, you need eyepiece lenses with small and long focal length.
Here is how you can calculate a home telescope’s lowest and highest magnification.
Minimum useful magnification
To calculate the lowest magnification at which your home telescope will be useful, multiply the aperture of the main lens (in inches) by 3 or 4.
For instance, if you have a telescope with an aperture of 5 inches, the lowest possible useful magnification would be 15x or 20x. Going lower than this is not advisable as you would lose many details.
Besides, you can see a large portion of the sky with this lesser magnification. In other words, less magnification will give you a wider field of view, allowing you to scan for celestial objects like galaxies and nebulae.
Maximum useful magnification
As a rule of thumb, you can calculate your home telescope’s highest useful magnification by multiplying the aperture (in inches) by 50. So, for a telescope with a main lens with an aperture of 7 inches, you should aim for a maximum magnification of 350x.
Although you can theoretically go much higher than this by using a higher FL eyepiece, it will generate a bad-quality image. If your lens aperture is smaller, you will have a much better viewing experience with a lesser magnification than a higher one with an equatorial mount.
When to use low and high magnification
Now that you can calculate your telescope’s lowest and highest useful magnification, let’s talk about when to use which magnification.
Low magnification
Low magnification or low power on a telescope is used for wide-field observations, such as large astronomical objects like galaxies, nebulae, and star clusters. It allows you to see a larger portion of the sky at once, which can be useful for finding and locating celestial objects.
Reducing the magnification also allows for greater light-gathering ability, which can be especially useful for observing faint objects.
So, if you want to see distant galaxies or nebulae, it is better if you stick to the lower magnification values on your telescope than go up the magnification ladder.
Furthermore, if you want to observe larger objects in our solar system, like planets and the Moon, it is better to stick to lesser magnification as you will get a better image.
Similarly, reducing magnification is the way to go if you want to see famous constellations.
High magnification
High magnification or high power can be used for observing small and faint celestial objects such as comets, asteroids, and distant galaxies. These objects are often difficult to see at low magnifications, but high magnification can reveal their details and structure.
Increasing the magnification is also a great way to observe deep-space objects such as globular clusters, planetary nebulae, and small galaxies.
High magnification can be challenging, requiring a steady mount, good atmospheric conditions, and a telescope with high-quality optics. Additionally, you may need to adjust the focus frequently as the atmosphere and temperature change.
So, if you want to explore the celestial objects of the deep skies, you will need a telescope with good optics.
Check out the Celestron – NexStar 130SLT Computerized Telescope, which has a huge 130 mm aperture high-quality optic system. Click here if you want to read a complete review
This telescope model has two eyepieces with focal lengths of 25 mm and 9 mm and an objective lens with an FL of 650 mm.
Celestron – NexStar 130SLT Computerized Telescope
Zoom magnification
Zoom magnification on a telescope refers to the ability to adjust the magnification over a range of values.
It is typically achieved using a zoom eyepiece, allowing you to adjust the magnification by twisting a ring or moving a sliding mechanism.
Zoom magnification is useful for observing various celestial objects, as it allows the observer to quickly and easily adjust the magnification to suit the observed object.
For example, when observing the Moon, you might start with a low power to view the entire Moon and then use the zoom magnification to increase the magnification and observe specific features such as craters, mountains, and valleys.
It is also useful for observing binary stars, as it allows you to adjust the magnification to suit the separation of the stars. It can be useful for determining the stars’ relative brightness, color, and distance.
Barlow lens
A Barlow lens is an optical device placed in a telescope’s eyepiece holder to increase the telescope’s magnification. It works by effectively increasing the telescope’s FL and increasing the eyepiece magnification.
It is typically a simple doublet or triplet lens that fits into a telescope’s eyepiece holder. These lenses come in different magnifications, such as 2x, 3x, and 5x, meaning that factor will increase the eyepiece’s magnification.
For example, if you use a 25mm eyepiece with a 2x Barlow lens, the effective magnification of the eyepiece will be 50mm.
The biggest advantage of using a Barlow lens is that it increases the telescope’s magnification without purchasing additional eyepieces. They increase your eyepiece collection’s versatility and can be more cost-effective than buying multiple eyepieces.
Additionally, Barlow lenses can also correct for some optical aberrations and increase the image quality at high magnifications.
However, it is worth noting that using a Barlow lens will decrease the field of view and increase the vignetting. Additionally, the quality of the Barlow lens will also affect the image quality, so it’s important to use a high-quality lens for the best results.
You may also like to read this in-depth article about Barlow Lens vs. Eyepiece (Magnification Battle) to learn about these great telescope accessories.
Factors to consider when choosing the right magnification for your home telescope
Choosing the right magnification for your stargazing session is equally important as picking the right telescope. The right magnification can enhance your viewing experience even with low-end, less sophisticated equipment.
On the other hand, if you pick too low or too high magnification, you might have a poor experience even with a high-end telescope.
When choosing the right magnification for your home telescope, you should consider the following factors.
Aperture
The aperture of a telescope refers to the objective diameter that gathers light. The telescope’s aperture plays a crucial role in determining its magnification, affecting its light-gathering ability, resolution, and image quality.
A large aperture allows a telescope to gather more light, which can be useful for observing faint objects like distant galaxies and double stars. It also allows you to observe details on brighter objects like the Moon and planets.
Having an objective mirror or lens with a large aperture also allows for a greater resolution, which means that the telescope can resolve finer details on the observed objects.
It is particularly useful for observing small and faint objects such as comets, asteroids, and binary stars.
Aperture alone does not determine the magnification of the telescope; rather, it works in conjunction with the FL and eyepiece. A large aperture allows the telescope to gather more light.
The ratio of FL and the aperture is called focal ratio. Lower focal ratio telescopes show brighter images of distant objects like nebulae and galaxies.
So, even if you have a high magnification lens but with a smaller aperture (smaller area), then you are limited with the magnification you can achieve. If you want to have the best viewing experience, you want to invest in a telescope that has a wider aperture.
As a rule of thumb, the best magnification you can get with the same aperture lens is about four to fifty times the aperture when measured in inches.
Focal length
The focal length of the primary mirror or objective lens and eyepiece lens determine the telescope’s true magnification. As we have seen earlier, the magnification of your telescope can be calculated easily by dividing the main lens’s FL (in inches) by that of the objective lens.
So, the higher the FL of your objective lens, the better. As you can’t change the focal length of the objective lens, it makes the most sense to purchase a telescope with a longer FL. You can have multiple eyepieces to get to the magnification level you desire.
Alternatively, you can use a Barlow lens to finetune your magnifying power.
However, you must remember that having a high FL lens with a smaller aperture is useless. If you decide to get a home telescope, you should get one with an aperture of at least 2.8 inches (70mm) and a focal length of at least 23.5 mm.
This combination should give you a minimum and maximum usable magnification value of 11x and 140x, respectively.
Eyepiece
The focal length of your eyepiece determines the magnifying power of your telescope. Besides, as eyepieces are smaller and cheaper, you can collect multiple with different focal lengths to get to the magnification value you want.
A general rule of thumb is that for observing wide-field objects such as galaxies, nebulae, and stars, a low-magnification eyepiece with a long focal length is the best.
It is typically in the range of 25-32 mm. These eyepieces will give you a wider field of view and allow you to see more of the sky at once.
They are also good for observing large solar systems, objects like the Moon, and planets like Jupiter and Saturn’s bright and dark rings, where a wider view and low power are more beneficial.
A bigger magnification eyepiece with a shorter FL is best for observing small, faint objects such as comets, asteroids, and distant galaxies.
These eyepieces have a focal length of 8-15 mm. They will give you a narrower field of view and allow you to see finer details on the object you are observing.
Quality of optics
The quality of the optics in a telescope plays a crucial role in determining the magnification of the telescope. Optics refers to the lenses and mirrors used in a telescope to gather light at the focal plane.
High-quality optics such as a secondary mirror will allow a telescope to achieve a bigger magnification without sacrificing image quality.
Good quality lenses and mirrors will be free from optical aberrations, such as chromatic and spherical aberrations, which can cause distortion and loss of sharpness in the image.
High-quality optics will also have a high transmission of light, transmitting more light to your eye, resulting in a brighter and clearer image.
On the other hand, low-quality optics can cause a loss of image quality at high magnifications. Low-quality lenses and mirrors may have optical aberrations, which can cause distortion and loss of sharpness in the image.
They also may have a lower transmission of light, meaning less light reaches the eye, resulting in a dimmer and less clear image.
Viewing conditions
Viewing conditions play a crucial role in determining the magnification of a telescope. The quality of the viewing conditions will affect the amount of light that reaches your eye, affecting the image quality and the level of magnification that can be used.
Under good viewing conditions, such as clear skies and steady air, a telescope can achieve high magnifications without any problems. The image will be stable and clear, allowing you to see fine details on the observed object.
In these conditions, a telescope can be used at high magnifications to observe small, faint objects such as comets, asteroids, and distant galaxies.
Under poor viewing conditions, such as turbulence and high wind speeds, it can be difficult to use high magnifications. The image will be unstable and distorted, making it difficult to see fine details on the observed object.
In these conditions, it is best to use lower magnifications to get a stable and clear image.
Choosing the right eyepiece
Choosing the right eyepiece for a home telescope depends on the focal length and the desired magnification. It is also important to consider the eyepiece’s field of view and eye relief.
A wider field of view allows for more of the sky to be seen at once, while a longer eye relief allows for more comfortable viewing.
Eyepiece focal length
The ideal eyepiece focal length for a home telescope depends on the specific telescope and the desired viewing experience. You should start with a lower power eyepiece (longer FL) for wide-field viewing and high power eyepiece (shorter focal length) for detailed observation of specific objects.
For a short focal length telescope, a longer focal length eyepiece (about 25mm) will provide a lower magnification, wider field of view, and longer eye relief.
On the other hand, for a telescope with a longer focal length, a short focal length eyepieces (about 9mm) will provide bigger magnification and a narrower field of view but with shorter eye relief.
A good starting point is to have a variety of eyepieces with different focal lengths, such as 25 mm and 9 mm, to allow for different magnifications and fields of view.
As you become more experienced, you can add more eyepieces with different focal lengths to your collection.
Eyepiece design
The eyepiece design can also affect the field of view. Some eyepiece designs, such as Plossl and Kellner, have a wider field of view, while others, such as Orthoscopic and Erfle, have a narrower field of view.
The eyepiece design can also affect eye relief or the length of the eyepiece.
Some eyepiece designs, such as Plossl and Kellner, have longer eye relief, while others, such as Orthoscopic and Erfle, have shorter eye relief. Longer eye relief eyepieces are more comfortable to use.
Eyepiece brand
Several high-quality eyepieces are available for your home telescope. Here are a few brands that are worth their value:
Celestron
Celestron is a well-known brand among telescope manufacturers and offers a wide range of eyepieces with different focal lengths and designs.
Check out this great Celestron eyepiece collection.
Orion
Orion is a respected brand that offers a range of eyepieces with different focal lengths, including some designed for high-power observation.
You can check out Orion 08890 1.25-Inch Premium Telescope Accessory Kit that offers great value for your money.
Orion 08890 1.25-Inch Premium Telescope Accessory Kit
Tele Vue
Tele Vue is a premium brand with high-quality eyepieces, excellent optics, and a wide field of view.
Check out the Tele Vue 3-6mm Nagler Zoom 1.25″ Eyepiece, which is a great companion for any home telescope.
Tele Vue 3-6mm Nagler Zoom 1.25″ Eyepiece
Recommended magnification for different objects
Different celestial objects require different magnification values to be seen properly with a home telescope.
You might want to experiment with the magnification on your telescope, but here are a few good starting points.
Moon and planets
A magnification range between 50x to 100x per inch of aperture is a good starting point for the Moon. For planets such as Jupiter and Saturn, a magnification of around 100x to 200x per inch of aperture is a good starting point.
Star clusters and nebulae
For star clusters, a magnification of around 20x to 50x per inch of aperture is a good point to start exploring with an equatorial mount.
For nebulae, a magnification of around 20x to 40x per inch of aperture is a good starting point.
Galaxies and quasars
Start with a magnification of around 20x to 40x per inch of aperture if you are trying to observe galaxies and around 20x to 40x per inch of aperture for quasars.
Remember that the minimum magnification may vary depending on the atmospheric conditions, the eyepiece quality, and the telescope’s quality.
Comets and meteors
Comets and meteors are distant objects that need bigger magnification. A magnification of around 20x to 50x per inch of aperture is a good starting point for comets.
For meteor showers, start with a magnification of around 20x.
Deep-sky objects
Deep-sky objects like galaxies, the Orion nebula, and star clusters can be seen with a magnification of around 20x to 40x per inch of aperture.
Magnification and image quality
Although magnification is an important aspect of telescope use, it is important to keep in mind that the image quality of a telescope also plays a pivotal role in determining the overall viewing experience.
A greater magnification does not always mean a better image even with an equatorial mount. The magnification level should be balanced with the aperture and focal length of the telescope and the atmospheric conditions.
Here are a few factors that magnification can influence, improve or deteriorate your viewing experience.
Resolution
The effect of magnification on the resolution of reflector telescopes is a complex issue, as the resolution of a telescope is determined by a combination of factors, including the aperture, focal length, and quality of the optics.
In general, increasing the magnification of a telescope will increase the apparent resolution of an object. Still, there is a limit to how much magnification can be used before the resolution is degraded by atmospheric turbulence and the telescope’s optics.
Contrast
Contrast is the difference between the intensities of bright and dark parts of your image. The effect of magnification on contrast can be quite complex as it depends on several factors.
Increasing the magnification of a telescope will decrease the overall contrast of the image even in an equatorial mount, as a greater magnification results in a smaller field of view, making it harder to see faint details.
Brightness
Magnification also affects the brightness of the image it generates.
Increasing the magnification of a telescope will decrease the image’s overall brightness. As the magnification increases, the same light is spread over a smaller area, resulting in a dimmer image.
The effect is known as the “exit pupil effect” and is related to the size of the telescope’s objective lens or mirror and the eyepiece’s field of view.
Field of view
The effect of magnification on a telescope image’s field of view (FOV) is straightforward: as the magnification increases, the field of view decreases.
The FOV is the sky’s area visible through the telescope’s eyepiece. When observing an object at high magnification, the FOV is smaller, making it harder to locate and track an object or to see faint details.
What can I see with a 1000x magnification telescope?
A 1000x magnification telescope could provide very high magnification, but several factors will determine what you can see at this level. Some factors that will determine the level of detail you can see include:
- The aperture
- The quality of optics
- The atmospheric conditions
With 1000x magnification, you would see a great deal of detail on the Moon and Jupiter and some details on Saturn and Mars.
You may also like: How Big of a Telescope Do You Need to See Saturn’s Rings?
Maintenance of magnification
Maintaining the magnification of a telescope requires proper care and maintenance of its components. Here are a few tips on preserving good magnification using a telescope.
Cleaning optics
Cleaning the optics on a telescope is important in maintaining the magnification and image quality. Blow off any loose dust or debris from the lenses and mirrors using a blower bulb or compressed air.
Use a solution of mild dish soap and water to remove smudges. Avoid excess water and use a dry cloth to remove any remaining moisture.
Collimation
Collimation is aligning the telescope’s optics, including primary lens and secondary mirror, to ensure that the image is sharp and clear.
You can use a collimation tool such as a laser collimator or a Cheshire eyepiece to check the alignment of the primary and secondary mirrors.
These tools project a beam of light into the telescope and allow you to see the alignment of the optics.
Storage
Most backyard telescopes are sensitive pieces of equipment that need care during storage. The ideal location to store your telescope is dry, dust-free, and secure. You should store your telescope at or near the prevailing temperature outside.
Ideally, you should store your telescope in an observatory, but a basement can also suffice in a pinch. Just make sure the place has no excess moisture or dust.
Takeaway: Get a closer look at the celestial world with the right telescope magnification
A telescope is a great way to explore the mighty universe and appreciate its complexity and vastness. You can see galaxies, nebulae, and planets in great detail using the right magnification.
You might need to experiment with your telescope to find the perfect magnification that produces crisp and clear images. A large aperture and high-magnification telescope can help you uncover the mesmerizing world of celestial bodies.
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