The choice of a telescope is difficult for a beginner. Even as a beginner is for me a telescope under 300 euros but out of the question. Here are already too many low-end telescopes from Vorweihnachtsaktionen the discount chains in German cellars around unused. A very helpful guide is here buying guides telescopes in 4 steps with 100 product launches: Select Astronomical Telescopes. Knowledge - types - choice - models.
Pros and Cons at Meade ETX 125
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+ Telescope Maksutov by making technical reasons readjustments optics unnecessary. Especially Newtonians must be readjusted regularly.
+ As opposed to lens telescopes no fringing.
+ For a 5 inch mirror very lightweight and thus portable device with just 11 kg total weight (of which 4.5 kg tripod) and lightest device of the device class with opening of 127mm.
+ Significantly lichstärker than the lowest entry level in reflecting telescopes with only 90-100mm aperture (width) of the mirror. The larger the aperture, the brighter the image (important to dark in comparison to planets deep sky to see objects at least partly).
+ Very good quality in order to easily adjust the telescope to a well-functioning (!) GoTo function at startup can. The telescope must not be horizontally positioned by the user (electronic level integrated) are more oriented to the north (electronic compass installed). In addition, one must no time manually (built very accurate clock) every time you start to re-enter.
+ The only (known to me unit) with 127mm opening at the back 2 connections for 1 and 2 eyepiece via a screw adapter for a prism (2 eyepiece) or a camera. This is so only when Celestron Nexstar SE 4, however, has only 102mm aperture and thus is considerably fainter than the ETX 125.
+ Clamping of the electric drive can be easily converted to manually with a lever. For terrestrial observations very suitable if you want to pan quickly without motor / must, for example, airplanes, animals etc .. This is also handy if the batteries are unexpectedly blank when outdoor use (and that can happen quickly). Then you can still align manually. Disadvantage: somewhat reduced stability.
- The batteries can be changed only if unscrewing the mirror mount. However, this is not quite as bad, since the mirror is easy and you, the device must decompose in tripod mount and in outdoor use, where you need batteries as a rule anyway. It's quick and easy.
- Cheap prism / mirror, which cost quite sure of light (not 100% reflection)
- If the tube has to be steeply upward (fairly common occurrence), the prism comes in 2nd slot on the bottom, so that further pivotal movement is no longer possible. One must here remove the prism / camera and can no longer access a 2nd photograph (the 1st sitting the eyepiece).
- Lack of support on the telescope to GoTo computer. This dangling freely on a spiral cable down (if you do not keep it in his hand).
- The red dot finder can only be switched on via the control box GoTo menu and only there the time will light in the viewfinder, be adjusted. This is awkward. A small switch on the viewfinder would be easier, as is done for example in the Celestron NextStar telescopes.
- Mechanically for the price range solid, but in absolute terms, with significant compromises subject here (!). For more severe (which are often, unfortunately, the high end) eyepieces / Barlow lens or even a DSLR (this is therefore not recommended) restlessness. The same applies to the relatively light = transportable tripod especially at higher magnification bem stargazing.
- Only simple screw clamping (standard in this price range) of the eyepieces in the tube. Slight instability and sub-optimal centering of the eyepieces into the sleeve. Zoom eyepieces that need to be rotated, do not hold the right place. The Okularhülsen easily scratched.
Building
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The construction of the telescope itself is very simple. The well-made stainless steel stand is easily unfolded and screwed a plate between the struts to increase stability. Then you can use 8 AA batteries in the stand cover. The actual mirror mount is placed and bolted quickly and easily with 2 screws. Here comes a low weight of the mirror in good stead. Then you have to adjust the viewfinder, which is attached to the mirror, with 2 screws (only for the 1st time!), Which is very easily achieved by using the instructions. There is then the GoTo control, a small hand-held computer with a display, connected to a socket. It turns it on at the telescope and must then once entering the exact time, and select a location from a small (!) List, which is the location of the next. That's it for now.
GoTo
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As the advertising promises, you really need to calibrate the telescope to automatically adjust later planets and stars can hardly knowledge. I keep a fully automated alignment with a small camera built for not needed. You should invest in a more intense look the money prefer. The calibration runs at ETX like this:
1. unit simply place it on the ground with the largest possible field of vision.
2. The Tubusklemmung solve (simple lever in the ground) and the tube until it stops counterclockwise and determine the clamping. The device Nordet then independently a (you do not have to view to the north).
3. Thereafter, the ETX selects 2 stars from that anfährt it rough and urges, to center the brightest here visible within each star in the middle with the hand control. A star is actually getting much brighter than all the others in another environment. This selects the GoTo already like this (here it shows as a beginner that stars are not equally bright). It is important then only to provide him with the arrow keys for manual control as precisely as possible in the middle of the field of view. This is not always the same and not to take more hand control!
I can start as 20 objects from the GoTo in succession and they were all using the supplied 26mm eyepiece in the visual field.
Image Quality
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The picture is, if you do not exceed 120-150x magnification, very sharp. In the picture is quite dark and dull with missing details. The focus knob must only be turned very carefully and the image wobbles strongly at higher magnifications, so precise focusing is difficult. Terrestrial I have 4 km away can still see on a path landing corvids. The included 26mm eyepiece is usable, but not really good and but has only moderate field of view (50 degrees). Here's another eyepiece with 30-31mm and possible 68-70 degree field of useful eg Baader Planetarium Hyperion eyepiece Aspheric 31mm. This or the Standardokular go very well with the sun, moon, deep sky and terrestrial. When planets then you need another eyepiece, eg 13mm, eg Baader Planetarium Hyperion eyepiece 13mm, since these are otherwise very sharp, but also very small in the frame. The Okularwahl at high magnifications is highly dependent on the visibility conditions. If these are not really good (especially with not really dark places in the city) is at 13mm end. You can not do what you want.
Sun, Moon and planets large (Saturn, Jupiter) are beautifully observed. Many deep sky objects are for the ETX too faint (it remains dark, where they should be actually).
Autostar
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In addition to the GoTo function that needs every beginner, so astronomy no frustration, since you hardly find small and faint objects, explains the computer at all controlled objects every single time. This makes astronomy really fun because you do not just leaves any objects. Even for beginners, making it the fully automatic calibration with a built-in (simple) camera actually dispensable.
Astrophotography
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For photography of planets (Jupiter, Saturn, Mars, Venus), Moon and Sun well suited. The main problem, precisely to center a planet in the camera (not easy as working with high magnification), is considerably simplified, that the ETX already back has a dual-port, where a switch quickly between eyepiece (for centering) and can switch camera. Since the above objects are bright, the performance of the ETX enough. Particularly suitable and software is the brand new Celestron Celestron camera NexImage 5 Digital Camera planets camera (5 megapixels, Built-in IR cut filter). You simply insert the back.
Resumee
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For beginners well suitable telescope Price class-related weaknesses. The compromise of easily transportable and mechanical sensitivity = must make one. Simply built up and ready for use and also for beginners useful GoTo function without necessary knowledge of star names. Good explanations from GoTo computer that make practical astronomy exciting. Who more deep-sky objects will see (nebulae, galaxies, etc.), should select the telescope larger, preferably with a 8 '' mirror. Then there is also mechanically stable.
