Wondering what to get the astronomer in your life this holiday season?
Nov 21, 2017, 8:01 AM
For those who are struggling with what to get the astronomer in your life this holiday season, here are some tips that will put your concerns at ease.
I have evaluated and tested many products and I must say, throughout the last four decades, the number of choices have grown, while the costs of those choices have gone down.
Here are some savvy gift ideas that your loved ones will enjoy and will not break your budget this holiday season.
Every astronomer should have a pair of binoculars in order to get a good look at the sky, as well as other daytime events, like sporting events and nature viewing.
Binoculars are special devices that you look through with both eyes and are good for wide views of the night sky.
The main part of binocular basics is how to select the right pair. The most basic type of binocular is a 7×50. But what do those numbers tell us?
The seven is the power of the binoculars, meaning it has seven times the magnification of the human eye, while the 50 is the size of the lens on the front end measured in millimeters.
Binoculars that are 7×50 will provide a decent wide view of the night sky, with a field of view of some 7 degrees of the night sky, like 14 times the diameter of the full moon.
The larger the second number, the more light gathering power the binoculars have — and the more expensive they will be.
More powerful binoculars, like 10×70, are usually heavier and not that easy to use without a tripod.
My advice? Keep it simple and light, and your loved ones will love using the binoculars. There are so many choices out there, with decent products for less than $100 each.
Galileo used his crude-refracting telescope on the night of Jan. 7, 1610 to discover some of the main moons of Jupiter.
Refracting telescopes have a lens at the front end of the closed tube and usually have a starting diameter of 80 millimeters. That is just over three inches in diameter for the main lens.
This is your basic-sized refractor that comes with a few basic eyepieces.
The larger the millimeter size of the eyepiece, the larger the amount of glass and the lower the power of the telescope. Power of a telescope is measured by dividing the focal length of the eyepiece into the focal length of the objective lens.
The focal length of the objective is how long the tube is in millimeters, divided by the size in millimeters, which is listed on the lens.
For example, if your 80 millimeter diameter lens on your refractor has a tube length of 700 millimeters and you have 25 millimeter eyepiece at the other end, you divide 700 by 25 and you have 28x power of magnification.
The problem many people make with small refractors is that they think they will be able to magnify objects to 500 times or more and get good results.
You can only capture so much light with a 3 inch objective lens. You need a lot larger refractor to get decent high magnification.
However, I suggest no more than 50 power for each inch of the objective lens.
That is why, in my opinion, many low-cost refractor telescopes will not satisfy many people for long.
There are the classic, open tube telescopes with a polished mirror at the bottom of the tube.
These are generally available at low prices and may actually satisfy the need to gather more light for the money.
Reflecting telescopes of 6 inches or larger are available for less than $500 and provide some decent view of the night sky.
Many technology-savvy folks will want to have a telescope that is computer-controlled.
Whatever you choose, look at your budget and try and get the largest mirror or lens that you can afford. You want that item to grow with its owner and not be obsolete the minute they take it outside to view the great Arizona skies.
Get your very own November sky map here.