What Are These Telescope Features Called?

I’m thinking about saving up for a high-quality backyard telescope. I’m specifically looking for two features, but I don’t know what they’re called in the telescope industry (I want to know the right search terms to look for when I shop).

1: Some sort of interactivity, possibly via a phone app and a Bluetooth connection (or something). I select Saturn on my map/app, a motor turns the device to Saturn. I select Betelguese on the device, the motor turns it to Betelguese.

2: A motor that turns the device such that my quarry remains in view, relative to the rotation of the Earth.

And if anyone has any recommendations for a quality machine with a price tag of < $700 or so, please let me know.

What you’re looking for is a GoTo mount.
It will both find and track whatever object you want.

Number one is usually called a simple go-to capability. There is no scientific name.
Number two is an equatorial mount with drive. You will usually get #2 if you get #1. It is possible to track with an alt-azimuth mount as well, and if you use it for simple skygazing it is OK.

$700 will be a serious stretch. You standard makes are Celestron and Meade. You might squeeze one in at $800.

Never mind.


^ $350, give or take.

Sorry, underestimating, but as I added in an edit above, not by much. A 6 inch Celestron can be had with computer controlled go-to for about $800 US.

OK, that is seriously cheap. But a 4" reflector is going to be a disappointing buy. There is not much up there that is going to be easily visible in that.

Thanks for the heads up. What do you recommend as a good starting point, reflector wise? Nine inches?

Looks like I’m going to have to save up for a while longer.

Nothing beats aperture. If you can, find a local amateur astronomy/star gazing club and attend a viewing night. You can get a feel for what is possible and what might meet you expectations. I picked on the $800 6" very quickly as what I might consider a starter size. But YMMV.
I own a very very old Celestron 8. (No computer anything) and have had some fun with that. Dobsonians have been the rage for many years as cheap light buckets, but computer control is not something they generally do. Dobsonans require you to do all the legwork, but they reward that with great views for the money. The trouble with a 4" computer controlled scope is that it will automatically point itself to something in the sky that it is incapable of dragging enough light in to show you. Especially if there is even a hint of city lights in the sky.

You came sooooo close to saying that name three times. Nobody needs that!

I was quite deliberate in not saying it a third time!

Phew! Good man.

Worth mentioning the value versus the hope with nearly any telescope for sky gazing. Turning your telescope to Betelguese will yield a view that is basically no different to what you will see with the naked eye. (OK, so long as you know where to look.) It is reddish pinprick of light in the sky, and a reddish brighter pinprick in the scope. Stars are impossible to make into anything other than a point of light (well no until you are into insane scientific endeavours with professional facilities. Betelguese was the first star to ever have its disk resolved.) Double stars (ones that orbit one another) are a bit of fun, but the novelty wears off.

The things to look for are planets - well the easy four - Venus, Mars, Saturn, and Jupiter, and then extended objects. Galaxies and gas nebulae. Those just need light grasp. You will never see colour, but you can have fun seeking out the various well known objects for yourself, and nothing beats the experience of seeing with your own eye any of these objects. It might just be a smudge of light in the sky, and nothing compared to the pictures one see from the HST and its brethren, but you are looking at the real actual thing. That makes it real. :slight_smile:

Everyone should have this experience.

I have an older model of that exact telescope and I can second this.

The other issue that I had is that, in the cheaper model Celestrons, the vibration from the tracking motor is sufficient to blur the image, particularly when you’re looking out at Jupiter and the moons. I will note that mine is now 10+ years old and it’s possible that they’ve fixed/improved that problem.

One of these times, I’m going to get around to making a Dobsonian with a homemade goto drive (probably powered by an Arduino). What I envision would be something that you could just plop down with a reasonable guess of which way is north, and an approximately level base, and then it would use its internal clock and a best guess of latitude and longitude to aim to the three brightest stars available. Then you’d manually aim it exactly at those stars, and it would use that data to refine its position and orientation, and thereafter function as a goto drive.

Just to make sure, I Googled, “Betelguese pronunciation,” and was told: a) It’s actually spelled Betelgeuse, and, b) it’s pronounced like the Michael Keaton character, but then Google said it was the brightest star in the constellation “OH-ree-on,” so whatcha gonna do? :crazy_face:

This is a GoTo mount. I have been told they are expensive, a hassle to set up, and overall disappointing. What I use instead is a phone mount. There are hundreds of sky viewing apps that can get the object close enough to fine-tune with a viewfinder.

As an aside, individual stars aren’t much to write home about. Betelgeuse is going to look about the same magnified or unmagnified. Galaxies, planets, and nebulae are where the action is. An affordable refractor will get you good views of Mercury, Venus, Mars, Jupiter, Saturn, and of course the Moon. Anything fainter than that, and you’ll want a reflector.

For this purpose I use an equatorial mount. Because they’re expensive, and I don’t take photos, I use an unmotorized one. It’s cheaper and sufficient for what I need. When you start viewing, you center the mount on Polaris. Once you find your object, it’s just one knob twist to keep up with Earth’s rotation. (Compare with up-down, right-left adjustments on something like a Dobsonian reflector).

But there are many people who say you don’t need to spend all that money. Buy a Dobsonian, get the biggest aperture you can, and the image size/quality compensates for the less graceful mount.

(A Dobsonian is just a generic term for reflectors that trade off large aperture for a klunky mount. The hope is you can get some good early use with the klunky mount, then re-mount it to an equatorial when you get more serious).

For beginners, the Moon and inner planets are really the spectacular low-hanging fruit that you can see in a refractor. You’ll exhaust those pretty quick… even quicker right now, since they’re not easily viewable. So a large-aperture Dob gives you a shot at seeing galaxies, clusters, nebulae, deep-space stuff and even take photos of it.

Back when I was active in the hobby, I could keep a Dob on target just by nudging it with my knees. Yeah, with an alt-az, you have to move it in two dimensions at once, but you get used to it.

I’ve been out of the hobby for a long time, so I’m probably a bit out of date. But it is worth summarising some of the history.
Dobsonian should refer to the design developed and popularised by John Dobson. He had a specific intent - make viewing of the astronomical sky accessible to everyone. In an age when “proper” telescopes emphasised precision parts, equatorial mounts, obsessive accuracy of optical components, he went the other way. Make it cheap, easy to make in anyone’s garage, and most of all, deliver good views to the naked eyeball.

His design was nothing more than a wooden box with a relativity thin, but big, mirror mounted via simple sliding bearing into another box that itself rotated on Teflon pads on a sheet of wood. But he developed it over the years and to the surprise of the established amateur telescope making community these cheap light buckets delivered on the promise.

Now the basic design is a mainstay of available telescopes, and sits alongside other more traditional telescope designs. It has also formed the basis of much more advanced and feature filled (and vastly more expensive) offerings.

It is possible to make a tracking Dobsonian mount, and I remember in the early days when the amateur telescope making community began to embrace the idea there were a number of clever designs that provided anything up to an hour of basic equatorial movement with careful layout of bearing surfaces and little more than an electric clock motor and threaded rod. The success of these designs depends a bit on your latitude. Computer controlled alt-az is possible, but there is a point where you cease to be meeting John’s original objective of cheap accessible sky viewing. IMHO a true Dobsonian should deliver a cheap fun light bucket. Additional funds should go into more aperture.

Equatorial mounts were initially the thing because you can track the sky with only movement in one axis. If you have computer controlled motor drive on both axes you can of course track the sky with an alt-az mount. The only downside is that the field of view rotates over time, so photography becomes impossible unless you rotate the camera, and that means another computer controlled motor. But computer control is now near free. No modern scientific telescope built will be on an equatorial mount. The sheer size of modern devices would make that impossible anyway. A less commonly mentioned issue with mounts is the amount of sky they afford easy view of. This depends upon your latitude, the size of the telescope tube, and overall balance of the design. Alt-az can win big here.

Hobby level telescope are a mix. You see alt-az mount scopes, equatorial mounts, both with and without motor drive and computer control. You can argue the value proposition forever.

Worth mentioning, if you use a basic telescope, you can use a smartphone sky view app as a pushto guider. For Android the SkEye app is designed for purpose. Strap your phone to the scope and it will tell you how to point it at whatever you need, at least within range of being able to visually pick it up. That plus a good sized simple Dobsonian might bring about the most joy for the dollar.

A GPS, compass, and accelerometer that can be integrated with an Arduino is like $15. It shouldn’t be necessary to point it at all, or even level it. No need for an internal clock, either.