Gear

Exit Pupil In Same Telescope

What is an Exit Pupil, and Why is it Important?

Understanding exit pupil can help you when using your telescope and shopping for eyepieces and binoculars. Exit pupil is an important but underappreciated topic in astronomy. Everyone is familiar with the concept of an entrance pupil. This is the black circle in the middle of your eye, the visible aperture through which light enters.  In…
Eye Relief

Eye Relief: A Handy Guide for Astronomy 

Eye relief is the distance between your eye and image in your eyepiece. Often eye relief problems can be mitigated with an eyecup. Those who wear glasses when they observe may want adjustable eye cup eyepieces.  In general, longer eye relief makes an eyepiece easier and more comfortable to use, but there are some exceptions. …
Are Eyepieces Interchangable?

Are Telescope Eyepieces Interchangeable?

Telescopes need eyepieces to work. Eyepieces come in three sizes; 0.965”, 1.25”, and 2”.  Telescopes usually have focuser sizes that are 2”, but they often come with an adapter for 1.25” eyepieces, so most 1.25” and 2” eyepieces will fit into most telescopes. 0.965” size focusers are generally only found on vintage or very low…
Satrun by Mike Ducak

Which Is the Best Eyepiece for Viewing Saturn?

Saturn, the jewel of the solar system. Every amateur astronomer remembers their first view of the ringed planet, and for good reason. Nothing quite prepares you for just how much it looks like Saturn.  I’ve had more than one person accuse me, half-seriously, of putting a Saturn slide in my telescope. If you have a…
DIY Telescope Cover

DIY Telescope Cover: 3 Ways to Protect Your Scope 

If you have a permanent place to mount your telescope, perhaps an installed pier or a covered porch or gazebo you may be able to leave your scope assembled with a good cover.  I often travel to observe and I can use my cover to protect the scope when I am done observing for the…
Can I store my telescope outside

Can You Store A Telescope Outside?

Storing your telescope away from dirt, dust and moisture will extend the useful life of your telescope. There are great ways to store a telescope outside to make it easier to use it more frequently.  You can store a telescope outside in a weatherproof outdoor structure like an observatory, unheated garage or shed. Choose a…
Hybrid Eyepiece

Are 2-Inch Eyepieces Better?

Acquiring a 2-inch eyepiece is a big deal for many newcomers to astronomy. But are these hefty, big-barreled oculars truly superior to their 1.25” cousins?  A 2-inch eyepiece is a tool which is well-suited for some tasks, and not so well for others. After fifteen years in this hobby, I still do the bulk of…
Parfocal and Non Parfocal Eyepieces

What Are Parfocal Eyepieces?

Parfocal eyepieces are 2 eyepieces that maintain focus when you change from one to the other. This is done by creating lenses that keep the focal point on the same plane. Parfocal eyepieces allow you to change magnification without refocusing your telescope.  Learning to get good focus is one of the first challenges faced by…
DSLR camera and t-ring provide 55mm of the required spacing

What is Back Focus in Astronomy? (With Pictures)

Back focus is a term that causes much confusion among newcomers to astrophotography. This is because when people talk about back focus, they often mean different things: the back focus on a telescope, the required back focus for accessories such as field flatteners, or the flange focal distance of DSLRs and astro cameras.  When we…
Computer Controlled Telescope

How Much RAM Do You Need for Astrophotography?

Modern astrophotography requires a computer. Computers play a key role for performing various functions in this increasingly automated hobby.   It might come as a surprise to some that you can’t just connect a camera to your telescope and snap a detailed photo, as you would photograph a bird or a sunset.  For image capture and…