Wednesday, September 9, 2020

Now Boarding at Gate 3

Heya folks!

  I was hunting around for what to write this morning, when I remembered that a friend had asked the fatal question.  "Hey Josh, what telescope should I get?"

  So, here's a post that's actually useful to the world at large, my buddy Pam specifically, and hopefully, you too.  

  "What telescope should I get?"  Oh MAN, you're about to buy both a starship and a time machine.  I'm gonna do the opposite of a recipe blog, and tell you the info FIRST, and then the details.

What a telescope does;

It magnifies things, but this is less important than gathering light.  Your eye, fully dark adapted, opens to about 7 mm.  The smallest telescope below is 76 mm.  That's a lot more light!  Once you've scooped up those photons, you magnify them.  Generally speaking, you'll be more concerned with the objective lens/mirror size than the actual magnification.  (Which is changed with the eyepiece.  So, in a telescope, you'll be able to swap out eyepieces, and even buy new ones.  The eyepieces are what determine the mags, but again, don't worry about that too much at the moment.)  

What you're looking for

  When I shop for a telescope, I look at two things:  1. The optical design, and 2. The Mount.  

The optical design roughly falls into three categories - the first is the classic Telescope telescope that's long, pirate-looking, and uses lenses to gather more light than your eye does.  That's called a refractor, using lenses to refract the light (bend it.)  

  The second is my favorite - the reflector.  Invented by Sir Issac Newton way back in the day, and still bears his name - the Newtonian Reflector, which uses mirrors to gather more light than your eye can, and then focus it for you using curved (parabolic) mirrors.  

  The third is a combination of the two, usually in a Schmidt-Cassegrain or Maksutov-Cassegrain design.  These are a little pricier, and frankly, I don't like them as much.  

The Mount also falls into three categories:  Altitude-Azimuth (up and down) on a tripod, Equatorial on a tripod (this tracks the motion of the Earth), and Dobsonian, which is a plywood version of the Alt-Az mount.  

  John Dobson created the Dobsonian style, and it's currently my favorite.  It allows for a great-moving scope made out of particle board and stovepipes, making sure all of the money is spent on the biggest and best optics possible.  Think of it as an old pickup truck with a big ol' race motor crammed under the hood.  Sure, it's not fancy, but MAN it's fast!  

  Dobs can also be home-built, to nice specs with nice materials and premium views. Here's a picture of one of my dobs - hand built by a buddy, actually, and SIGNED by John Dobson himself!  


  And they can get REALLY fancy.  I also have a variant of a dob design that costs more than several old pickup trucks, to reference that analogy again. 

Top Choice 
A 6" "dob" is an iconic configuration, and rightly so.  This one has a 2" focuser, too, allowing future upgrades for fancy eyepieces. It's portable, manageable, and will show you many things in the universe.  Now, they'll be small and faint - no color photos here, BUT - to actually see the rings of Saturn, or a star cluster that's billions of years old...now that's cool!


A Good Place to Start
A drawback of the hobby that almost did me in was the high cost of admission.  Although I haven't used this exact model, my first telescope was an 80mm Celestron similar to this one.  Things are small in the eyepiece - and you'll want to add some accessories.  But, this is a simple platform that can open up the skies for your inquiring mind to visit.  (Saturn will BARELY have rings with the included eyepiece, but the Moon will be awesome.)  


For a Few Dollars More
Yeah BUDDY!  This 8" dob is quite a "serious" telescope, and for under $500, you can see far, far away.  I regularly observe with an 8", and love it.  


Don't forget

 (And my brother got a $12 pair off eBay that gave my fancy ones a run for their money!)


What I recommend

  If you've got some money to burn, a 6" "dob" (Newtonian reflector mounted on a Dobsonian base) is an excellent scope to buy.  Another nice thing about reflectors - they avoid the bane of inexpensive refractors, which is chromatic aberration.  This is when a lens focuses red and blue light slightly differently, resulting in a halo of color around bright objects.  Mirrors don't have that problem.  

    If you don't, or are still wondering if astronomy is for you, a small refractor, or even a little tabletop "dob" would be a good choice.  Now, I haven't personally used this one, but it sure looks intriguing:  https://optcorp.com/products/celestron-cometron-firstscope-telescope

For sixty bucks, it seems worth a gamble.  


What I would avoid

Wobbly, spindly mounts, especially of the "EQ" (Equatorial) variety.  I love EQ mounts, but they have to be big, expensive, and heavy to work right.  Here's a video where I review a rig that costs about $800.  I use it all the time, and love it, but I wouldn't recommend it as a first scope.  

  I'm not a big fan of Newtonian reflectors mounted on tripods in this price range, but....more on that in a moment.  

What to expect

TEENY tiny "dots" and smudges.  Even through my premium gear, with the exception of the Moon, most things are gray smudges, and the scale of things is tiny.  Now, the light has been traveling since before the age of the Dinosaurs, and THAT'S cool.  But, you won't see color, you won't see (much) detail, and you'll have to learn the sky to figure out where you're looking.  It can be frustrating, but it's SO SO COOL.   

A word about binoculars

  A nice pair of binoculars should be in every observer's toolkit, be it your primary instrument or another horse in the stable.  Their effortless wide fields, and cruising along the Milky Way...wow!  Plus, their lenses gather much more light than your eyes can, so you'll see more, and farther.  Generally, stick to 10 power or below, and a range of 35-50 mm is a good target for the lens.  (A 10x50 model is ideal, and a 7x35 is excellent as well.)  

In closing

The best telescope is the one you have!  (Or the one you can afford.)  The sky can be enjoyed in so many ways, so definitely get out there and do some stargazing!  Keep in mind that the cheaper scopes can require a little more patience, and a $100 pair of binoculars will be much higher quality than a $100 scope.  That being said, the priority is to look at the sky.  

  Let me know if you have any questions, and of course, check out my YouTube channel, Astronomy with Josh!

Clear skies,
Josh 

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