First collimation with a Cheshire

[Albenn]

With the weather being the way it is and all that, I decided to try my hand at collimating my new scope with my equally as new deluxe cheshire combination tool using the Astro Baby guide. At least I'll get to look at something through my scope

Now, I don't know if this is true for all scopes or just my particular model, but when I place the Cheshire in the focuser at a depth that allows me to evaluate the position of the secondary and tighten the eyepiece holder screws to keep it there, I find I can rock the cheshire in the focuser which changes the viewing axis and therefore the relative position of the secondary as viewed through the cheshire. However, when I fully insert the cheshire and just let it sit on the focuser rim, the secondary is spot on centre and is a nice circle.

The primary mirror was not centre to the target reflection so I thought I'd have go at getting it aligned. I was pleasantly surprised at just how easy it was to get the primary aligned! I think the ease of this alignment is due to the fact that with the Heritage 130P you can easily reach the 'twiddly' end of the tube.

Is this 'rocking' of the cheshire normal, or was I using it incorrectly in the first place:iamwithstupid:

[jimmyjamjoejoe]

It should always be inserted all the way to the hilt. If you can't see the whole secondary then rack out the focuser a bit, if you still struggle, then make a collimation cap for that part of collimation and use the cheshire for the rest.

Well done for taking the plunge though, far less scary than people make out isn't it?

[JamesM]

Hi Alan, I have seen on numerous videos regarding collimation that many people use an 'eyepiece centering adaptor' which you can view here. I would add that it is not an essential piece of kit in order to perform good collimation, but it is a useful addition to ensure that the cheshire is centred in the middle of the focuser and of course can be used to secure eyepieces without fiddling for a little screw to hold them in position.

James

[Albenn]

It should always be inserted all the way to the hilt. If you can't see the whole secondary then rack out the focuser a bit, if you still struggle, then make a collimation cap for that part of collimation and use the cheshire for the rest.

Well done for taking the plunge though, far less scary than people make out isn't it?

Thanks for advice Jimmyjamjoejoe. I thought that may be the case. That explains why the secondary 'snapped in' to alignment under the fuzzy xhairs when I fully inserted the tube.

I really was surprised how easy it was! I believe that if you read up and get as much of an understanding not only of the process itself but what is actually going on and why it happens then it helps when you go 'hands on'.

Even if you can't be bothered to understand it all and just want to collimate, I think if you take a methodical approach then you shouldn't go far wrong. Assuming of course that something isn't damaged!

Like my wife always says to me "I don't need to know how my car works to drive it"

[Albenn]

Hi Alan, I have seen on numerous videos regarding collimation that many people use an 'eyepiece centering adaptor' which you can view here. I would add that it is not an essential piece of kit in order to perform good collimation, but it is a useful addition to ensure that the cheshire is centred in the middle of the focuser and of course can be used to secure eyepieces without fiddling for a little screw to hold them in position.

James

Thanks James. I didn't know such a piece of kit existed but I want to keep my collection of 'things that I must have to use my scope' down to a minimum but I will have a look at it.

[Ally8446]

Hi guys. Got my first scope back in January this year and very quickly discovered it required collimating. So armed with my trusty laptopamabob I Googled 'how to collimate a reflector telescope'. When the results appeared I swear my heart stopped for a second. THEY WANT ME TO DO 'WHAT'!!!!!!!!!!. OMG and all the rest. Purchased a cheshire collimating tool, made my own collimation cap..............Eh voila, its a breeze. Even took my primary out, it needed a centre dot (surprised Celestron don't do this considering its impossible to collimate without one). Got every bit of knowledge I needed from SGL. Top forum !!!!!!!!!!!

[Albenn]

Hi Alan, I have seen on numerous videos regarding collimation that many people use an 'eyepiece centering adaptor' which you can view here. I would add that it is not an essential piece of kit in order to perform good collimation, but it is a useful addition to ensure that the cheshire is centred in the middle of the focuser and of course can be used to secure eyepieces without fiddling for a little screw to hold them in position.

James

James. I've just had a look at that adaptor but it is to convert a 2" focuser to accept a 1.25" tube. The scope I have is already 1.25" but thanks for the heads up anyway:icon_salut: