What objects you can photograph does not only depend on how good your equipment is or how much light pollution you can filter out.  It also depends on their apparent magnitude, how bright the object as seen from Earth: Very bright stars far away can be harder to see than dimmer objects nearby. Vsauce has…

The field of view (FOV) is the size of the circle of the sky you can see through the eyepiece of a telescope. The Maths FOV is dependent on the apparent field of view of the eyepiece, and the magnification of your setup.  It is calculated by dividing the eyepiece FOV by the magnification of…

Focusing a telescope is important DUH. But when you take images, especially long exposure images, it is critical. Focusing can be done by pointing your telescope to a distant star or planet, and focus your telescope manually until you are happy with the result. Or you use a little tool called a Bathinov mask. If…

The apparent magnitude of objects in the sky determines their brightness when we see images of them through a telescope.  No money in the world can buy you more brightness when looking at objects in the sky.  The brightness of an object when looking through a telescope is what it is.  There is a cheap…

The light captures through a telescope needs to go somewhere.  Astrophotographers capture light using a camera and astronomers observe the night sky through an eyepiece.  Both a camera and an eyepiece have their own focal length.  It is only by combining the focal length of the telescope and the focal length of the eyepiece or…

The f/ratio or focal ratio of a telescope is the ratio between the telescope’s focal length and its aperture. This seemed like a weird combination of specifications, but an f/ratio is a great way to quickly get a first impression of the capabilities of a telescope: A lower f/ratio indicates a larger aperture relative to…

The resolution of a telescope of its ability to distinguish small details on an object (moon crater details), or the ability to distinguish closely located objects from each other (double stars). The resolution of a telescope is directly proportional to its aperture and is measures in arcseconds.  An arcsecond is a 3600th of a degree….

If the aperture is the most important spec of a telescope, the focal length is probably the second most important one.  The focal length of the telescope is the distance between the main, light-gathering lens or mirror and the point where the image comes into focus. But just like aperture, focal length on its own…

The aperture of a telescope is the diameter of its main, light-gathering lens or mirror.  A bigger aperture means collecting more light and hence having sharper and brighter images that show more detail. This makes aperture, from all the specifications you will find on a telescope, the most important one.  Whatever you plan to do,…

Reflectors, or reflector telescopes, are telescopes that use reflective mirrors as objectives to generate images.  Light is reflected from the primary mirror onto a secondary mirror that will lead the light to an eyepiece so the image can be seen. Large primary mirrors are much cheaper to make than large lenses and hence reflectors typically…