Telescopes have such a big magnification that it is very hard to point them directly to a specific point in the night sky. The field of view is just too small. Point your telescope up anywhere you want and when you look through the eyepiece, you’ll just see a bunch of random stars and will…
Headlamp
Obviously, astronomy is a hobby that we practice outside and at night. So how do we get around in the dark? With a little light of course. And the easiest type of lamp to use is a headlamp. It keeps our hands free to operate the equipment, and we can point the lamp where we…
Angled eyepiece for polar finder-scope
Polar aligning a telescope mount, is not difficult once you know what you are doing, but it is a very annoying task. It requires us to kneel, sit or lay down on the ground in order to be able to look through the polar finder scope. I am rather tall, and not that flexible. That…
Bob’s Knobs
I persuaded myself to purchase a little add-on for my telescope. It is not really on the ‘must-have’ list, but it is a very, very ‘nice-to-have’ if you have a reflector: I upgraded my telescope with Bob’s Knobs. As I mentioned earlier, in order to make sure the mirrors of my reflector are correctly aligned,…
Eyepieces
Eyepieces are small lenses that need to be attached to telescopes in order to see the generated image. They have two important characteristics that determine directly the performance of a telescope: The eyepiece focal length combined with the telescope effective focal length determines the magnification the telescope generates.The eyepiece apparent field of view is the…
Apparent Magnitude
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…
Field of View
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…
Bathinov Mask
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…
Brightness
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…
Magnification
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…