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…
Installation Checklist
Just like my ‘Loading Checklist’, this checklist was created after I forgot to properly level my tripod. I had to remove my aligned telescope and mount in order to level my telescope and start building everything up again. So … My initial setup checklist Install tripod oriented due NorthInstall battery and splitter boxCover splitter box…
Loading Checklist
So I am the type of guy that when someone told me to make a checklist in order not to forget anything when I prepared for an evening out, I thought by myself … SURE! That was until the day I invited a friend and his son to come and have a look at the…
Resolution
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….
Focal Length
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…
Aperture
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,…
Reflector Telescopes
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…
Refracting Telescopes
Refractors, or refracting telescopes, are telescopes that use lenses as objectives to generate images. The objective lens refracts the incoming light to an eyepiece so the image can be seen. Larger aperture refracting telescopes are much more expensive, exponentially more expensive, than similar-sized reflectors. Therefore refractors are typically slimmer than reflectors. As the light does…
Telescope Add-ons
Having a telescope and a telescope mount is a nice start, but it is only that. A lot more is needed in order to be able to observe or image the night sky. I have categorized them into 3 groups according to how critical they are for an amateur astronomer. Not a perfect way to…