How To Calculate Area Of Field Of View In A Camera On A Telescope

If you own a telescope to view the stars from your backyard you'll need to know its FOV.

This is an important characteristic that will enable you lot to see more when you lot look up at the nighttime sky.

What, exactly, is FOV?

FOV stands for Field Of View. It's measured in degrees. While yous might recall that this is the same as the telescope's magnification, it'southward non – but the ii features are linked.

Magnification makes stars or planets announced larger, only FOV is merely how much heaven y'all'll exist able to see. And so, with that in listen, let'southward take a look at FOV and how you tin can calculate information technology for the all-time views of the sky.

Contents

• 1 How Magnification And FOV Are Continued
• 2 Why FOV Is So Important
• 3 Telescope FOV Calculator In Google Sheets
• four How To Find FOV On Binoculars
• five How To Calculate FOV On A Telescope
• 6 Apps That Aid You Calculate FOV
• vii How To Summate Degrees In The Sky?
• viii Related Questions
  • eight.1 What are arcminutes and arcseconds?
  • 8.2 How can you measure 180 degrees in the sky?
• nine Conclusion

How Magnification And FOV Are Connected

Basically, when yous choose the magnification for your telescope, this will affect your FOV. This is because the more than magnification y'all use, the smaller your FOV will be – and that means you lot'll be able to come across fewer stars in the sky.

Information technology'due south like to stepping right in front of a painting on the wall. The more than yous "zoom into it," the more than you'll see the office right in front of you but y'all'll run into less of the rest of it.

Nevertheless, when you step back, y'all're able to take information technology all in. In a similar way, when you view the stars in the nighttime sky a greater FOV will help you lot make connections in what y'all're seeing much better.

Why FOV Is So Of import

There are many expert reasons why you should know how much FOV your telescope will requite you.

For starters, if you're star hopping with the utilise of a star nautical chart you'll need to be able to find the brightest stars in order to find others in the nighttime sky but without knowing your telescope'southward FOV you won't be able to see what stars volition be visible to you.

You might also notice information technology easier to go lost. Again, it's well-nigh zooming in likewise much then that you lot don't run across a lot!

FOV is especially important to know if you want to encounter a galaxy or cluster of stars because these celestial objects aren't super-clear or brilliant. That means that it can be difficult to know if your FOV is focused properly or not when viewing them.

To adapt your focus, you lot'll demand to focus on some other, brighter, star. If your FOV is larger, this means you'll be able to see more than stars so that y'all can utilize them to better your focus.

Telescope FOV Reckoner In Google Sheets

How To Find FOV On Binoculars

FOV is not simply something you demand to know when using a telescope – you should as well know your FOV when you utilise binoculars.

Luckily, you can easily see what FOV your binoculars have just by checking the second set of numbers that are usually listed on your binoculars next to i of the eyepieces. This number is also usually underneath the objective f size and magnification number.

So, if you encounter this on your binoculars: "9.2/500 ft/130m," the first number refers to the FOV. The other two basically mean that if you had to use your binoculars from a distance of 130m, you'd run across 500 feet of its height and width.

Not all binoculars will clearly country the FOV. This means you'll accept to work information technology out for yourself. You can do this with the two numbers that are provided on your binoculars. So, if you lot're only given "500ft/130m," so you'll have to accept the first number and dissever information technology by 52.4.

This will give you the FOV in degrees. Note: if your binoculars don't give you the first measurement in feet but rather in meters, you volition demand to separate that number by xvi. That will give y'all the FOV.

How To Calculate FOV On A Telescope

If yous own a telescope, yous'll need to calculate the FOV a little differently. It's worth begetting in mind that when you modify your telescope's eyepiece, this will change your magnification and also the FOV. This tin can, therefore, make calculating the FOV a flake more complicated.

The first stride you need to practise is to find your telescope's focal length. The adept news is that this is easy to find – you can locate it online. The eyepiece you're using on your telescope will as well have a focal length you'll demand to know when calculating the FOV.

This number will be constitute on the eyepiece barrel or top. The average focal length range you'll find in eyepieces is between 3mm and 40mm, just it'll be much larger for your telescope.

Now, you need to calculate the eyepiece magnification by dividing the telescope's focal length (such equally 650mm) with the eyepiece'south focal length (such as 40mm). Using these numbers as an case, your magnification would be around 16x.

The side by side footstep you need to exercise is calculate your True Field Of View. Okay, brace yourself considering this is a flake more than complicated.

Eyepieces have an Apparent Field Of View measurement that'southward basically the number of degrees of sky the eyepiece would exist able to show you if you placed information technology in front end of your eye without using a telescope.

Simply, the True Field Of View is how many degrees of sky y'all'll see when yous use the eyepiece with your telescope. To find that number, you'll take to divide the Apparent FOV by the magnification.

You might battle to find the eyepiece's Credible FOV then you'll need to enquiry information technology. If yous nonetheless tin can't find information technology despite your best efforts, it's a proficient idea to choose an apparent FOV of 50 degrees every bit this is a general i.

Apps That Aid You Calculate FOV

If you don't desire to calculate FOV yourself, in that location are websites and apps that can assistance you, so bank check these out.

• Sky At Night FOV Calculator: This website folio enables you to punch in all the information you need, such as the type of telescope you lot own or camera brand, in order to calculate your FOV.

• Stellarium: This app is a valuable i for astronomy enthusiasts. It can help you calculate the FOV for your astrophotography hobby, such as by allowing you to put in your DSLR camera sensor data and lens specifications, but you'll demand to install the Oculars plugin.

• FOViewer Deluxe: This app is available on Android phones. You lot can use it to figure out the magnification of your telescope and eyepiece combination, and yous can also view FOV superimposed on well-known celestial objects.

How To Calculate Degrees In The Sky?

If you lot notice out that your telescope can offer you lot 10 degrees of FOV, what does that really hateful for yous when you indicate information technology to the heaven? To put degrees into a better perspective, it's worth knowing that you tin can apply your fist to understand the idea of degrees better.

Basically, when you put your fist at arm's length in front end of yous and position your fist and then that information technology could rest on the horizon in front of you, the top of your fist width is approximately 10 degrees. Hither are other means you can brand sense of degrees with the utilise of your fingers.

• When you stretch your pollex and piffling finger of the same hand then that they are equally far autonomously as possible, the distance from the tip of your thumb to the tip of your finger is 25 degrees.
• When you stretch your index finger and your little finger so that they're as far apart as possible, this distance is xv degrees.
• Concord iii eye fingers of one hand together. The altitude from one end to the other is five degrees.
• When at arm'south length, the width of the tip of your trivial finger is about i to 1.5 degrees, as ABC Science reports.

The above examples can aid you when you search for celestial objects in the heaven.

For instance, if you're looking for something that'southward just 1 degree from where Jupiter is located, yous can put the tip of your pinkie adjacent to Jupiter and you'll run across how far the object is, which will help you to locate it.

What are arcminutes and arcseconds?

When you're dealing with angles that are less than one caste, these are measured in arcminutes. Every degree is divided into sixty parts, and these are called arcminutes.

How can you measure 180 degrees in the heaven?

Start at the horizon. From there to the indicate directly overhead you, this is 90 degrees. And then, from i horizon indicate through the place overhead (known equally the zenith) and all the way across to the opposite point of the sky is 180 degrees.

Determination

Finding your telescope's FOV is a valuable calculation to aid you figure out how much of the sky you'll exist able to see when you look up at nighttime.

In this commodity, nosotros've looked at how y'all tin can summate the binocular and telescope field of view so that y'all'll have a ameliorate idea of how much you'll be able to see in the night sky, in degrees.

We've likewise included hand measurements yous tin can use to help you lot make better sense of what those degrees mean.

Source: https://astronomerguide.com/telescope-field-of-view/

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