EQ mount for beginner?
Posted 08 March 2011 - 12:27 PM
Posted 08 March 2011 - 03:12 PM
Posted 08 March 2011 - 04:29 PM
Posted 08 March 2011 - 04:37 PM
Posted 08 March 2011 - 04:55 PM
If the answer is NOT "I want a mount that tracks the target" then you may find little benefit in a GEM mount.
There ARE some benefits, but they may not be worth the (not all that really) extra complexity.
First, GEM mounts are EASY to use. It doesn't SEEM like that would be the case, but they are.
The initial setup consists of setting the tilt of the polar housing (the main housing of the mount) back so that it is at an angle to the ground for your latitude. Most have scales, and even if these scales are not all that accurate, they will get you close enough for motorized tracking.
Once you have that, you only need to point it at the North Star (not as accurate as a polar alignment, but good enough for tracking).
When you have it set up, you train your telscope on a target, lock the levers on the two axises, flip a switch, and the mount starts tracking the target.
Now, if you want to use a manual GEM to LOCATE targers, that is an entirely different ball game. Here, the mount has to be set up carefully and the setting circles have to be adjusted. You may have to do things like shim the OTA to remove Cone Error.
All of this can be done, and in fact 30 years ago, if you used a GEM, it was pretty well required for using the setting circles to locate objects.
There is a simple joy to this, similar to flying a plane using dead reckoning. I enjoy both activieies, but the fact is that if I am serious about navigation, I use electronic aids, and if I am serious about finding targets, I use a go-to scope.
But I know HOW to use setting circles, and it can be tedious to learn.
So, it really depends on your desires. If you just want a mount that tracks the sky, a simple GEM will do (though I would recommend a CG4 or CG5, or Vixen Polaris/SP/GP).
If you want a manual mount that can also be used to locate targets, depending on the telscope, one of these might work (the Polaris actually has quite good setting circles), but if the scope is a longer focal lenght scope, you may want to move to a GM8 because these mounts have large, usable setting circles.
Otheriwse, I would go with a Go-to mount. They have gotten very inexpensive, and you have both motors already built in.
You don't NEED to use the Go-To. Most have a way to quickly get them tracking
That way, you have motors for moving the mount and never have touch a knob, which almost always induces shaking.
So, using an EQ mount is pretty easy if you just want tracking.
Using an EQ mount to FIND things has a learning curve.
You don't NEED a Dec motor on an EQ mount, but by the time you add one, you might do better just bying a Go-to mount.
Posted 08 March 2011 - 08:43 PM
The truth is that the learning curve is steeper on an EQ mount because of the need to polar align and the motion in both axes, which is somewhat counter-intuitive to folks used to "up-down, left-right." Unless a beginner was truly interested in AP or in starting with a truly high end scope I would tend to steer them to a model that does not come with an EQ mount. I really hate the thought of someone trying this hobby, getting frustrated by the more complex demands of the |EQ mount and leaving it in the garage to gather dust.
Posted 09 March 2011 - 08:06 AM
Posted 09 March 2011 - 08:22 AM
Posted 09 March 2011 - 09:44 AM
Posted 09 March 2011 - 06:55 PM
Posted 10 March 2011 - 12:23 AM
The difference between using this, and a manual Alt-Az is, once you find an object, on the Alt-Az mount you have to continually tweak both directions to keep your object in view. On the EQ, you only have to tweak one (realistically, you have to tweak the dec to make up for poor eyeballing). In the end, I added an RA motor to do automatic tracking.
For some reason, I like having my reflector on the EQ2. I've since bought an Alt-Az for my refractor. Logic would probably say that most people would flip the two setups. Both with fit on either, though, so I have the flexibility to do what I want.
One note....this isn't true for all EQs, but mine can be set so that it's actually working as an Alt-Az. I used it that way for several sessions until I got the mount figured out and started to understand how the EQ worked.
Posted 10 March 2011 - 10:16 AM
To the beginner question though. Almost all beginner scope/mount combinations are under mounted. I wouldn't recommend less than an EQ-3 for almost any scope. Even a short 80mm refractor or 90mm Mak will have some focusing jitters on an EQ-2. Not a frustration that a beginner needs.