GAWD thank you for this. I've been wondering how much to defocus, 'cause if i go WAY out it seems like I'm just seeing my primary. I understand now. Just used a star test tonite to correct my collimation, and it worked rather well actually :D
High magnification and seeing make a big difference too, no?
@luftim the inner ring or center hole is the reflection of the back of the secondary mirror in the primary mirror of a reflecting telescope; at some point of defocus you can also see the secondary mirror spider vanes radiating outwards from it. You don't see the hole/ring in a refractor because that type of telescope has no central obstruction/secondary mirror.
very cool and informative video. good job man. (or woman as the case may be) i am setting up my meade 8 inch tonight, and this was a subtle reminder to follow this simple yet very important procedure.
when i looked at a star last night though my telescope, i was able to zoom enough so that the star was covering the whole sight. it seemed to be bubbling like in this video, but did not have any black hole in the middle. was wat i was seeing the actual star engulfing? or was it an illusion from the focus of my telescope or even the atmosphere?? somone please answer
@masegta1 my guess is that you "zoomed in" too much so that the bubbling part occupied your whole field of view (it's not actually zooming, it's adjusting the focuser for focus as you zoom by switching eyepieces). Not good! There has to be some contrast between the center hole and the bubbling part or else you won't be able to center the first on the latter.
@masegta1 ohhh okayy thanx. ill try again tonight and see if i can see the center hole to show properly. i just got my first telescope this christmas so im very new at this:P
@masegta1 this explains it :) What you have is a refracting telescope (100% lens based). In my vid I'm using a reflecting telescope (mirror based). Mine has a central obstruction (due to the secondary mirror) which causes the black hole in the center of the image - that is normal for this type of telescope. In an unobstructed telescope such as yours you will see just the bubbling part with no hole. You won't need to worry about collimating a refractor as it's much more robust than a reflector.
@AndyFlash0f Miscollimation may be caused for instance by transporting the telescope over bumpy roads, you don't have to actually touch the mirrors. The larger the aperture the often the need to collimate. 10-12 inch owners are usually advised to check collimation every observing session.
Thank you for this ideo mate! I just watched another austrailian fellow showing how it's done with what looked like an Orion Laser colminator, but after buying my 10" Dob I didn't think about the colmination, so I was very pleased to find out I could do it the old school way (now that I know there is an old school way in the first place LOL) which is GREAT, it will get me going at least till I get a laser colminator. Are the lasers better, or is this way better setting it up to your vision? IC.
@IcechickenSr I also have a laser collimator but use it only to align the secondary mirror. The primary mirror's alignment must be very accurate (within 1-2 mm error). Lasers themselves are usually miscollimated so you get poor results in centering the primary mirror. Even if you use a laser you have to fine tune by doing this star collimation at the end. This is especially critical for planetary viewing (high power). Otherwise you won't get the best picture.
Thanks so much for this. My first time star-testing my telescope and I experienced similar images to your video and like you said... the books display perfect images so it had me worried there was something wrong with my collimation. Thanks again!
So what I am looking for here is the dark dot should be centered in the ring? I assume the scope is pointing at a star near the zenith and you are changing the focus? Since the star is moving then it is not tracking. I have read the manual on my CPC800 and I am about to try to collimate it. Thanks for showing me what I should be seeing!
GAWD thank you for this. I've been wondering how much to defocus, 'cause if i go WAY out it seems like I'm just seeing my primary. I understand now. Just used a star test tonite to correct my collimation, and it worked rather well actually :D
High magnification and seeing make a big difference too, no?
artao5 8 months ago
can someone explain to me what the ring is?? i still dont understand :S
luftim 1 year ago
@luftim the inner ring or center hole is the reflection of the back of the secondary mirror in the primary mirror of a reflecting telescope; at some point of defocus you can also see the secondary mirror spider vanes radiating outwards from it. You don't see the hole/ring in a refractor because that type of telescope has no central obstruction/secondary mirror.
topaz84 1 year ago
@topaz84 ok.. i understand. but the ring, is it light from the star right? i mean the star is a sun right.. so the ring is light from the sun (star)
luftim 1 year ago
very cool and informative video. good job man. (or woman as the case may be) i am setting up my meade 8 inch tonight, and this was a subtle reminder to follow this simple yet very important procedure.
novelist10 1 year ago
when i looked at a star last night though my telescope, i was able to zoom enough so that the star was covering the whole sight. it seemed to be bubbling like in this video, but did not have any black hole in the middle. was wat i was seeing the actual star engulfing? or was it an illusion from the focus of my telescope or even the atmosphere?? somone please answer
masegta1 1 year ago
@masegta1 my guess is that you "zoomed in" too much so that the bubbling part occupied your whole field of view (it's not actually zooming, it's adjusting the focuser for focus as you zoom by switching eyepieces). Not good! There has to be some contrast between the center hole and the bubbling part or else you won't be able to center the first on the latter.
topaz84 1 year ago
@masegta1 ohhh okayy thanx. ill try again tonight and see if i can see the center hole to show properly. i just got my first telescope this christmas so im very new at this:P
masegta1 1 year ago
@masegta1 what telescope is it?
topaz84 1 year ago
@topaz84 umm im not really sure, it just says astronomical telescope on the front of the box
but it says the focal length: 700mm
diam:60mm
and coated lens.
and the eye peice i used said SR4mm
but thats all i know about it
masegta1 1 year ago
@masegta1 this explains it :) What you have is a refracting telescope (100% lens based). In my vid I'm using a reflecting telescope (mirror based). Mine has a central obstruction (due to the secondary mirror) which causes the black hole in the center of the image - that is normal for this type of telescope. In an unobstructed telescope such as yours you will see just the bubbling part with no hole. You won't need to worry about collimating a refractor as it's much more robust than a reflector.
topaz84 1 year ago
i need to collimate just for the first time or,if not,what cause the des-collimation?i mean i didn't touch the mirrors :/
AndyFlash0f 1 year ago
@AndyFlash0f Miscollimation may be caused for instance by transporting the telescope over bumpy roads, you don't have to actually touch the mirrors. The larger the aperture the often the need to collimate. 10-12 inch owners are usually advised to check collimation every observing session.
topaz84 1 year ago
@topaz84 ok,thx
AndyFlash0f 1 year ago
@AndyFlash0f defapt multumesc
AndyFlash0f 1 year ago
@AndyFlash0f cu placere :)
topaz84 1 year ago
Thank you for this ideo mate! I just watched another austrailian fellow showing how it's done with what looked like an Orion Laser colminator, but after buying my 10" Dob I didn't think about the colmination, so I was very pleased to find out I could do it the old school way (now that I know there is an old school way in the first place LOL) which is GREAT, it will get me going at least till I get a laser colminator. Are the lasers better, or is this way better setting it up to your vision? IC.
IcechickenSr 1 year ago
@IcechickenSr I also have a laser collimator but use it only to align the secondary mirror. The primary mirror's alignment must be very accurate (within 1-2 mm error). Lasers themselves are usually miscollimated so you get poor results in centering the primary mirror. Even if you use a laser you have to fine tune by doing this star collimation at the end. This is especially critical for planetary viewing (high power). Otherwise you won't get the best picture.
topaz84 1 year ago
Thanks so much for this. My first time star-testing my telescope and I experienced similar images to your video and like you said... the books display perfect images so it had me worried there was something wrong with my collimation. Thanks again!
hreasons 1 year ago
Cam prea slab seeingul pentru colimare :).
tarfin 2 years ago
So what I am looking for here is the dark dot should be centered in the ring? I assume the scope is pointing at a star near the zenith and you are changing the focus? Since the star is moving then it is not tracking. I have read the manual on my CPC800 and I am about to try to collimate it. Thanks for showing me what I should be seeing!
real1hagar 2 years ago