Telescopes

Anyone have experience with telescopes for casual viewing of the moon/planets/etc? My wife and I were tossing out the idea of buying a telescope to play around with. I Googled "best telescopes 2020" and this one peaked my interest:

https://www.highpointscientific.com/apertura-ad10-10inch-dobsonian-telescope-ad10

I don't think we need all the motorized bases with preprogrammed viewing objects. I just want to see something, and quickly look at it.

Any suggestions from someone who owns a telescope?

 

I own a Celestron NexStar 8. It's got the goto and auto alignment features.

Dobsonian telescopes are great scopes. If all you want to do is look at stuff, it might be nice to have auto guider just to help you find the cool stuff. You can use Star Walk or another app to help you find objects too.

I'm looking at a newer scope that's in the 14" range with a camera. Because I want to image, I will need tracking as well. Usually, you take multiple images and then stack them.

 

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Ok scratch the Apertura Dobsonian 10"... did NOT realize they are like as big as a person. Was just browsing pictures and noticed one next to a couch and it was like just as big as the couch, ha ha. Will need to refine my search to something a little smaller. I'll check out the Celestron Nexstar 8 as @ian408 mentioned.

 

These bad boys are massive.

If I recall correctly, @LeftCoastNerd has a Dobsonian that he carries in the back of this truck. He's also a good source of information on telescopes.

 

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Drop down to an 8" Dobsonian, much easier to handle. An f/8 will be about 6 feet long, and weigh about 2/3 what the 10" does. If you go with a faster (optically) scope, such as a f/5 or f/6, it will be shorter. The downside to that is, less maximum magnification for small or very distant objects. A 6" would still give you some great viewing, an f/8 would be about 5 feet long and 1/2 the weight of the 8".

You might want to look at refractors for your first telescope. The main reason is that mirror type scopes have to be collimated occasionally, meaning the mirrors have to be properly aligned. Refractors don't have a mirror. Seems like when you're a noobie looking for a first scope, there's a lot you need to know in order to find what's best for you.

Refractors come in three main types; the most basic is a simple two-lens with minimal coatings. I wouldn't even consider one, that's your garden variety "toy" telescope that kids get for Christmas. Generally poor optics.

Then comes the achromatic. It will have better coatings which help decrease reflections, add clarity, and decrease what is called "chromatic aberration". When light is bent by a lens, the component colors bend at different angles, creating a small "halo" around the image, usually a red or blue one. Achromatic telescopes can eliminate one and decrease the other. Achromats have gotten very good in the last few years.

The best are apochromatic refractors. They use three lenses, and can pretty much eliminate chromatic aberration. Downside is that they are heavier, and way more expensive than a good achromat.

You can get a decent achromat for $400 or so, if you're just going to observe. That's just the scope, you'll need a mount to hold and aim it. Again the focal ratio is important. Higher f/-number means longer scope, and more magnification, at the expense of a slightly dimmer image. An f/7 to f/9 is a good visual scope.

I have an Apochromatic refractor, and two Schmidt-Cassegrain telescopes. The Schmidt-Cass is a folded optic telescope, has two mirrors. The primary mirror is the big one at the rear, is either concave or parabolic; there is a hole in the middle of it; The light reflected from the primary bounces back toward the front, where there is a convex or parabolic mirror that captures the light from the primary, focuses it some more, and reflects it don through the hole in the primary, to the eyepiece. A fairly long focal length can be made into a very short telescope. Schmidt-Cassegrain scopes have a native f/10 focal ratio and are very good for deep space, dim objects, as well as planetary and lunar. Bright images, lots of potential magnification. Consumer-size scopes run from 5" to 14" diameter primary mirrors. Schmidt-Cass can get really expensive.

Two main types of mount. Altitude-Azimuth is the simplest and least expensive. It's a simple yoke or dovetail mount that holds the scope on the tripod (which may or may not come with the mount). Alt-Az is simple: Altitude is the up/down motion, Azimuth is the side/side.

Equatorial is the other kind, which uses counterweights to balance the scope on a mount which uses Declination and Right Ascension axes. Right ascension mimics the normal rotation axis of the Earth, and when properly set up and aimed at an object, RA is the only thing that needs to be adjusted to keep the image in the view. More complex, much more expensive than Alt-Az mounts. The Dobsonian you were looking at uses Alt-Az. Mounts can be totally manual, or fully automated. One of the automated mounts is called a "go-to" mount. After an initialization procedure when you first start to use it each night (has to be repeated if the telescope location is moved even a couple of feet) called "alignment", it has a hand controller which has a memory database loaded with up to 15-20K objects. All you do is select one, the scope goes to it. For beginners and very casual observers, I think the manual is just fine. I have three equatorial mounts, two of which are go-to, and one is manual.

I could keep going on what to look for, but the main thing is to take your time and shop, read as much as you can find on telescope types, the advantages and disadvantages of each, along with mounts and tripods. Then come the eyepieces. You can sink as much money in half a dozen good EP's as you can in the telescope itself.

1st pic is my refractor, a f/5.9 William Optics 3 inch apochromatic, next to my Edge 8", which is a Schmidt-Cassegrain design, both on computerized go-to equatorial mounts. This was at a star party at the Green Bank, WV Radio Observatory, home of the world's largest steerable radio telescope. The dish measures 2.3 acres in area.

2nd picture is my 6" Schmidt-Cassegrain on a manual EQ mount. I was shooting the Solar Eclipse of 2017 from Clemson, SC, where it was over 2-1/2 minutes of totality.

3rd picture is the recent Comet Neowise, made with the 3" refractor. The camera in both pictures is a Nikon D3400 DSLR. The gold streak at the top of the image was the ISS passing through my field of view, I got lucky.

4th picture is the main dish Radio telescope at Green Bank. The picture was made from a mile away, the telescope is over 375 feet tall.

5th picture is the "Diamond Ring", the first flash of light at the end of totality as the moon moves out from in front of the Sun. Timing is critical; as soon as this appears, looking at the Sun is as bright as if the entire disc were uncovered, and it can burn your retinas if you are observing, or burn out the light sensor in the camera. This image is shot without a filter; all other pictures of the partial eclipse must be shot with some sort of light reduction filter.

 

Awesome feedback. Thanks for taking the time to write this all out. I'll start researching more about the refractors but sounds like the sweet spot for a beginner may be a refractor with achromatic lenses.

 

I pulled the trigger on a 14” Meade. I also picked up a camera, ASi294. Looking for a wedge also but none seem to be available.

I’m a little nervous tho because Meade filed for bankruptcy last year and just recently had another action filed against it. This stems from a suit filed by Orion against Both Celestron and Meade’s parent companies alleging price fixing.

I know it will be at least a couple weeks but dang, I’m excited. Mostly about imaging.

 

Are you talking about the ACF Schmidt-Cass? That's a nice scope. I haven't bought much telescope-related stuff in a year or so. I'd really like to get a dedicated CMOS color cooled astro camera, just haven't felt like coughing up the money. It'll be a ZWO when I do, though. I have an ASI 200 as a guide camera, but most of the astrophotography I've been doing is unguided single-image stuff. I'm retired now, been hoping to have time to learn more, but the skies around here have been lousy all Spring (pollen) and Summer (rain).

 

LX200. Yes.I'm looking forward to it. I joined the local astro group and plan on attending an imaging event here in the next week or two-assuming it doesn't get cancelled as there are several fires burning in the area.

 

How much power do you need to see the rings of Saturn clearly?
I am able to see a slight blob using my 40x spotting scope

 

Probably something like a 6-8 inch Schmidt and a good eyepiece.

Edit: I found this article.

 

Still waiting on the scope to show up. In theory, today or tomorrow but I’m not holding my breath.

I signed up for a meet-up group but apparently, the avatar I use is not good enough and my application was denied. They claimed it was for “security reasons”. Ha ha. Oh well.

On a more positive note, the camera showed up today!

 

Fires in California are burning pretty close to the the iTelescope.net's Sierra Observatory.

 

https://www.sierra-remote.com/telemetry-quick-view.html

 

I visited the site today and I'm not sure what the status is. There are a couple of photos from yesterday that looks like things are mostly OK. Other data isn't current but that could easily be because only essential power is available.

Hope everything is OK.

 

How to see Uranus (without using a mirror):
https://www.space.com/uranus-neptune-skywatching-september-2020.html

 

https://youtu.be/008BPUdQ1XA