IT people on vacation: what about the telescope?

Have you read post that observe the sky , seeing yourself and show your friends are interested in the topic. The logical next desire - to buy a telescope and look at the same beauty is already well to the naked eye. But this task is not as simple as it may seem, the choice depends on various parameters. Therefore, a post describing the various optical systems of telescopes, mounts, I think, will be useful.

Necessary demotivation and objects for observation To not felt sorry for the money spent, it is necessary to make a few discourages entry.

The Human Factor In the first place, we must understand that the amount and quality of beauty depends on your efforts. Astronomy does not belong to the entertainment of the "press a button and enjoy." It is necessary to think of ways to answer the following questions:

1. Budget. Location observations. Storage and transport. Where and in what form you are going to store the telescope? As transport to the place of the observations from the previous paragraph? How often? How to pack and on what type of transport to transport? the desired object of observation. Are there any types of objects that you really want to watch? Format observations.
   • Ask around friends, who have all of a sudden? View astroklubov presence in their city (in social networks or Astroforume ). Go to the evening of sidewalk astronomy, they spend a planetarium and stores selling telescopes.

     Technology surpassed human Secondly, we should not stir up a photo of the nebula with the Hubble Space Telescope, this you will not see. Unfortunately, the human eye can not accumulate the photons as a film or a matrix camera and night vision badly distinguishes colors. So what you will see in person, as a rule (there are exceptions!), Will look worse than the photo from the Internet. So I made a small list with illustrations will look like objects in the telescope. The list is sorted by simple observation and subjective beauty facilities.
     
     

     Moon The Moon - is one of the few objects that are visually more impressive than in the photo. The eyepiece moon is very bright, clear, visually very big, and very beautiful. It is best to observe the moon in the first and last quarters (ie, when about half of the visible disk). In this case, a boundary between light and shade (the terminator) is very well visible relief - craters different height roughness seas and other beauty. The moon - this is the easiest and visible object, which can be seen every month, is changing every day and never get bored. I took a photo Tver astrokluba and several edit it to create the most similar species:
     
     
     
     At high magnification, you can look at some beautiful landscape elements, such as Rainbow Bay:
     
     
     
     

     Planet The second type of access to facilities. Planet replace each other on a schedule, so this cycle is unlikely to get bored, but, alas, in amateur telescopes, they can be seen far worse than astrofoto, not to mention photos from observatories, interplanetary spacecraft and Hubble.
     
     Jupiter
     
     If you look closely, we see two bands on the disk. This photograph had their pririsovyvat have eyes the best dynamic range than that of a simple amateur astrofoto.
     
     Saturn
     
     Venus
     
     Mars
     
     Mercury and Uranus
     

     Multiple Stars The telescope has seen the color of stars. And if colored double star, it is very beautiful. The brightest representatives - Albireo in Cygnus and Cor Caroli in Canes Psah.
     
     
     
     Albireo, for a better perception of color may be slightly defocus the telescope.
     
     

     Open clusters Open clusters - this is the second type of objects that impresses more than their pictures. For the first time he saw Hee / Al Perseus telescope one of my friends remembered final "A Space Odyssey" - "Oh! It's full of stars! »
     
     The Pleiades
     
     
     Hi / Al Perseus Very nice two open clusters near:
     
     
     
     No, I still watch live better
     
     

     Globular clusters Here everything is sad. In amateur telescope globular clusters seen as dull spots, but if you're lucky with the conditions of observation, it still can be seen that they are formed by thousands and millions of stars.
     
     
     
     Big cluster of Hercules.
     
     

     Nebula Here everything is very sad. Due to the properties of the eye nebula, first, black and white, and secondly, very slightly visible, thirdly, we must go far beyond the city in the dark room to see them more or less visible.
     
     The Orion Nebula
     
     M57. Nebula "Ring" in Lira
     
     And do not say that you do not see anything here.
     
     

     Sun By purchasing a special filter, it is possible to look at the sun. In conventional filter visible sunspots, granulation (looks like a gridded surface).
     
     
     Prohodenie Venus, 2012, at the top of visible sunspots.
     
     NOTE: In the absence of a special filter, do not point the telescope at the sun. Perhaps meltdown or explosion set of eyepieces and irreversible blinding eye when you try to look through the eyepiece. Using the sooty glass cooking foil or other surrogates instead of a special solar filter is unacceptable!
     
     

     Other With some luck and skill, you can watch the planes flying past, the ISS (four rows of solar panels is quite distinguishable), lanterns and so on.
     
     Also pay attention to the plug "eyepieces", the shipped Stellarium. If you enter the parameters of the telescope and eyepiece, Stellarium will show the size of the object in the eyepiece.
     
     

     Materiel To objectively talk about telescopes, it is necessary to understand what telescopes are and what the advantages and disadvantages of.
     
     

     Definitions Aperture The focal length Aperture heat setting Adjustment
     

     Optical telescopes scheme
      
     
     
     
     Refractor Advantages:
     

     1. Minimum maintenance. Factory adjustment is maintained over the years, the tube is closed from dust and moisture. Extremely fast thermal stabilization. Aperture works completely (no elements blocking the part of the aperture in the pipe), a large contrast of the image
        1. Chromatic Aberration to achromatic price for apochromat. Do not come in large aperture (larger lens is very difficult and expensive to make). 150 mm is already very expensive, large aperture almost never. The length of pipe (can be a disadvantage)  
           
           
           
           Reflector Advantages:
           
           1. The absence of aberrations, excellent image quality. The cheapest millimeter aperture - with increasing aperture reflectors more and more in relation to other schemes. short time thermal stabilization, which, however, increases with the size of the telescope.
              1. The secondary mirror with holders "eats" part of the aperture. Stretching of the yield characteristic "Ray" star on astrofoto. Open the tube. Over time, the mirror is polluted with dust. The need for adjustment. After transporting the alignment of the reflector can lose, and it needs to be rebuilt. Fortunately, the experience is a matter of a few minutes.  
                 
                 
                 
                 Katadioptrik Максутова, the inventor of one of the most popular schemes mirror-lens telescopes - Maksutov-Cassegrain scheme.
                 Advantages:
                 
                 1. Compact. The shortest telescopes. Closed pipe keeps the mirror from dust. The absence of aberration.
                    1. Less contrast image for the area of ​​the central screening aperture does not work completely. The most expensive millimeter aperture. A great time thermal stabilization.

                       Prybars mount - is an adapter between the telescope and tripod. From it depends on how comfortable you will be observed as weights with a carry, and how much will shake the telescope for observations.
                       In basic design of the mount is divided into alt-azimuth and equatorial.
                       
                       
                       Alt-azimuth Advantages:
                       

                       1. A simple, easy, weight lifting. We do not need additional training to observations.
                          1. The object should be accompanied by two axes. The object turns slowly into view, it complicates astrophotography. As a rule unsuitable for observation area zenith.
                             
                             
                             Equatorial Advantages:
                             
                             1. object is simply to accompany the manual, even for a budget mounts have a place to mount the simple motor, which greatly facilitates the maintenance of the object. There are no problems with the availability of the zenith. The field of view remains fixed, it's good for astrofoto.
                                1. The mount is more complex and difficult, the structure includes a very heavy counterweight. The mount requires additional operations before observations and after them.
                                   • In the simplest version of equatorial mount equipped with analog or digital motor to follow an object. Aiming is done by hand. A more complex version - it drives on both axis of the mount, allowing to direct the telescope at the object from the remote (if available port from a laptop with the appropriate software) and follow it automatically. The most difficult option - computerized mount with the base objects, capable of self-induced on the object and to accompany him. The most advanced mount can be equipped with GPS / GLONASS and compass for fully automated preparation for observation.
                                     

                                     Precautions What mistakes you can make when choosing a telescope?
                                     Purchase telescope hypermarket too greedy Newton corrector Short-refractors-achromats
                                     

                                     selection logic
                                      If you have a clear idea of ​​their desires and limitations, the choice will not be very difficult. There are a few common scenarios that may be mentioned.
                                     
                                     

                                     Balcony sightings in the city To monitor the balcony is important compact telescope. Therefore, on a limited budget are preferable on an azimuthal mount refractors - refractor at most of the pipe will stick out, and with azimuthal mount is easier to handle. If a lot of money, you can think about katadioptrike on motorized mount. In any case, do not chase much aperture of 100-150 mm for the city is enough. However, these tips are advisory, I am quite successfully operated on the balcony of a reflector on an equatorial mount, because when choosing a telescope I wanted a large aperture without chromaticity on a limited budget, and has been planned for the purchase of a drive mount.
                                     
                                     
                                     
                                     
                                     P.S.