How To Collimate a Telescope Without a Laser

Collimation it's always a bit scary for  beginners even before buying a telescope.   You may be fear the collimation because of  the myths you read all over internet however   those negative feelings will only lead you  to a misconception of the reality which is   that collimation it's not a monster at all. You  may also be tempted to blame collimation when   you see the views are not so good with the  Dobsonian telescope however 99% of the   problems don't come from bad collimation but  from other sources therefore to help you and   to demystify the collimation process I will show  you how I collimate my dobsonian telescopes in   a quick and easy way and using a very basic  language. The collimation tool I love and I   use every time therefore I recommend  you to use it it's the CONCENTER RAY. This tool is very easy to use, similar  to the collimation cap however having   this concentric circles at the bottom it will  turn your collimation process much easier much   simpler and very accurate. You have the links  of all the materials I use at the description   below and if you don't have a CONCENTER or you  don't want to buy it right now I suggest you   to use a simple collimation cap but buy one,  it's inexpensive and it's worth it. It's true   you can make one at home but in my opinion  isn't worth it because the collimation cap   is so inexpensive that buying a brand new one, you  will make sure that is very precise. Now let's see   how I collimated my 8" Dobsonian telescope  using the CONCENTER of course and a simple blank   sheet of paper. You will see in a moment why.  Collimation it's just the alignment of the   telescope Optics. The light had come from the  sky entering the telescope from the top bumps   on the bottom in the primary mirror which is  slightly curved, projecting it as a cone to   the secondary mirror at the top and then it will  reflect to the focuser where we have our eyes or   a camera therefore to align everything and have  a nice image we start by the secondary mirror   and this mirror has four knobs: one at the middle  that hold and pull the secondary mirror outwards   and three more knobs around it which will push  the secondary mirror downwards and all these four   knobs acting as two opposite forces when very  well tightened will keep the secondary mirror   stiff and quiet in its place. Important tip: if  you only loosen the three knobs it will happen   nothing to the mirror however if you unscrew the  middle knob all the way out the mirror will fall. The solution is simple: every time you play with  a Middle Screw, hold the secondary mirror with   the other hand, of course without  touching the mirror surface ever.   And here's another tip: make sure you work this  part with the tube horizontally positioned. That   way you avoid major problems until in the future  you have the confidence to work at the top. Now   let's insert a piece of white paper behind the  secondary mirror and then look through the cap or   the CONCENTER. The goal is to get the secondary  mirror Centered to the focuser and here the   CONCENTER tool shine bright because with those  concentric circles it turns your job much easier.   Important tip: forget the small Central Donut for  now. This is a common mistake people often make but   to Center the secondary mirror you don't need to  focus your attention in the donut. Pay attention to   this image, it's all right, it's fine, everything is  concentric and that was the goal so with that tip   in mind and to reach this concentric image in your  eyes you need of course to play with a secondary   mirror and that's when most people mess it all. To make it easy remember your body is on vertical   but the tube is not so that means when you're  looking through the collimation tool what you   are watching is at the left the top, at the right  the bottom Direction and up and down position   Okay now if you need to adjust your image to  the left or to the right you need to play with   the central bolt. That means if you loosen the central  Bolt the secondary mirror will move to the right   but if instead you tight the central Bolt the  secondary mirror will move to the left. Remember   when you tighten the central bolt you will need  to loosen probably the three other screws. While   doing that adjustment you should also play with the  secondary mirror rotating it up and down which is   called the rotation but also adjusting the Tilt.  Those are all the movements that you need to do   in order to get the secondary mirror aligned. What I  usually do is when I see that it's aligned I quickly   tight the three other knobs to keep it all close  to the alignment and then make small adjustments   to those knobs, tightening them very well, that's  another mistake people often do, they fear to tight   the secondary mirror knobs and then they lose  collimation using the telescope of course, that's   all metal no problem at all, tightening them very well.  You want everything to be well tightened. These are   not the clamps of the primary mirror so tighten  very well. This was the harder part, now just make   tiny adjustments until you have everything fine  however if the secondary mirror is not centered   in a focuser after this process you may have  tilt in the focuser. Sometimes it happens and   it happened to me with my 8" Dobsonian telescope  and I solved that taking out the focuser and using   a piece of foam as a shim but be careful and make  sure it is really a focuser tilt and not you just   centering the secondary mirror in the wrong way. Important tip: in my images you can't see because of   the reflection but there's a shadow which is  not concentric. It's the only thing that will   be not concentric and it's to be like that. It's  the secondary mirror Shadow and if you did well   the alignment it should be pointing towards the  opposite side of the focuser. Now let's go to the   primary mirror. Now unlock the Locking knobs of  the primary mirror at the bottom and play with   the three collimation knobs at the bottom also  to get the donut Centered. There are 6 knobs at   the bottom: three of them are locking knobs and  usually are white. In other telescopes they are   different, though, and usually the thinner ones like  for instance in my 6 inch virtuoso telescope which   by the way it's the telescope I mostly recommend  to beginners and that you can buy in Astro Art   Finland our astronomical partner. Although it's  much easier than collimating the secondary   mirror, to collimate the primary mirror takes a  bit more of time and it's much easier in smaller   telescopes where you can be watching through the  collimation cap while your right arm can reach   the collimation knobs. You may find with time  that is very satisfying to adjust the donut in   the primary mirror. When everything is aligned you  get like a boost of dopamine.When it's done tight   the Locking knobs well tightened but softly and  keep checking the collimation tool because those   locking knobs change the collimation. Be aware  about that. You may also need to fine-tune a bit   the secondary mirror, the first alignment. But don't  be a perfectionist, this is to enjoy.And now that   you know how to properly collimate your telescope  in a simple way you should check this video over   here to know different upgrades that you can  do to your telescope and improve your views

Channel: Dobsonian Power

Views: 109,329

Keywords: newtonian, reflector, dob, dobson, telescope, telescopio, teleskop, astronomy, astronomia, eyepiece, equatorial platform, stargazing, starhopping, astrophotograpy, orion, skywatcher, explore scientific, zhumell, apertura, televue, telescope tips, telescope mods, geoptik, EAA, baader, 8inch, 12inch, Electronically Assisted Astronomy, StellaLyra, Tiago Ferreira, dobsonian telescope 8 inch, dobsonian telescope 12 inch, dobsonian telescope 8, dobsonian telescope 12, 10 inch dobsonian, 6 inch dobsonian

Id: kwzqizxAXdY

Length: 8min 50sec (530 seconds)

Published: Tue Feb 28 2023