208 of 246 people found the following review helpful
Not The Best Choice For a Beginner,
This review is from: Celestron 21061 AstroMaster 70AZ Refractor Telescope (Camera)
If you are into astronomy, and you want to purchase a first telescope, you might want to consider another. I have bought this scope, and was really excited to use it. When I set it up outside on my porch to observe Venus, I found something that made my totally regret ever buying this telescope. As the planet moves across the sky due to the earth's rotation, you have to unlock the handle bar that makes the telescope pivot. When you go in to tighten it again, the telescope tends to move out of alignment. You have to hold the telescope upright to make it go into the correct position. When I finally managed to do that, the image I got was horrible. Venus was all blurry and very difficult to make out. When I looked at the moon, there was this red and purple halo surrounding it. This is due to the refractor telescope. The lens in the telescope is used to focus the light into a single point. It doesn't really work that way. It focuses the red light and the blue light in different areas. Also, the finder scope tries to trick you into buying something that looks high tec. it has a little red dot in the middle so you can point it at the stars. The thing is as you move you head, the red dot doesn't do you much good. The AZ in the products name is the kind of tripod they use. The AZ mount as I mentioned before is strictly used for cameras, not for telescopes. In fact, the locking of the movements is a very large disaster as I said before. When you buy a beginner telescope, you want a tripod you can depend on. Look for the telescopes that have a EQ in the name. The EQ tripod system is a lot easier to use.
Scrap what I said in this last paragraph. The mid to higher end celestron telescopes give excellent views. The AZ kind of mount is only good if you have something like a dobsonian, in which the telescope moves slow with no jerky movements. Overall, just get the EQ. It is a acceptable refractor optics wise, but the mount must be 10 bucks. The eyepieces are also quite cheapy. If you don't want to bust the bank, but still get good views, I recommend the AstroMaster accessory kit that is about 40 bucks. It will be a wise investment for the beginner.
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Showing 1-4 of 4 posts in this discussion
Initial post: Dec 14, 2013 2:39:20 PM PST
Thanks for the advice, gold! I went to u tube and educated myself!
In reply to an earlier post on Jan 30, 2014 9:04:51 PM PST
M. Kettler says:
Having used both AZ mounted refractors and EQ mounted reflectors, I have to take exception to your claim that an EQ reflector is categorically much better for a beginner. Which is better depends more on what you want to do with it, and which compromises you want to make. Learn about both and make your own choices for your own situations.
Reflectors do result in images that are generally free of color fringing (chromatic aberration), however they have problems of their own.
You've portrayed the upsides of an EQ reflector well, but let's look at some downsides:
Reflector telescopes require periodic collimation, which isn't that difficult but can be frustrating the first time you do it. They require cool-down periods if you move them from inside to a cooler outdoor night, as their open tubes are prone to tube currents.
Is the generally better image quality a good tradeoff for the periodic adjustments and cooldown periods?
Also Reflector telescopes are not free of image problems. They are somewhat prone to a different kind of image distortion, called coma, which looks a bit like stars streaking out to the edges. This isn't a big problem in reflectors, but is more prevalent in lower f ratios (and so is chromatic aberration in refractors).
Furthermore, Reflectors portray an inverted and backward image. While not an issue for astronomy, it makes them relatively useless for terrestrial viewing (birds, nature, etc) unless you buy an image correcting prism. Getting an erect image out of a refactor is not difficult, so if you have dual interest, they can do a bit of both (with limits).
I would also say that EQ mounts aren't the be-all end-all of mounts. Yes, they make it easier to track the stars. However, they require more set up (you *must* align the RA axis to face north, or it won't track stars), and the curved motions make it difficult for beginners to get aimed at what they want. EQ mounts also have a counterweight on them to balance the scope, adding considerable extra weight to the setup. My Orion 130ST EQ reflector weighs 24lbs assembled. Mounted, it is large, heavy and awkward to move around, despite being a short-tube design. Is the setup, initial aiming and weight worth the trade-off for better tracking? Maybe, if you want to look at an object for extended periods. If you want to free-form hunt-and-seek, you would be better with an AZ, or dobsonian mount.
There's a reason there's a lot of telescope designs out there... budget is part of it, but also there are many different ways people use them.
In reply to an earlier post on Mar 23, 2014 11:19:49 AM PDT
This is of course startling to the amateur, because it's hard to see the apparent motion of the stars with the naked eye even over a couple of hours.
For any medium or high powered viewing EQ mounts are superior to AZ mounts, it is as simple as that.
As for refractors vs. reflectors in the bargain price range reflectors outperform refractors. Chromatic aberrations in cheap refractors are much worse than coma in cheap reflectors.
Posted on Feb 22, 2015 7:16:21 PM PST
Scrap the last paragraph? The review was only one paragraph long!
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