Collimation Collywobbles

[F1Bird]

I have had a Celestron Astromaster 114EQ for a year or so now and thus far have had no issues with focus. However, I got an 8mm BST eyepiece for Christmas which I cannot focus! I think its that the higher magnification is emphasising the fact that the collimation is out but I would welcome some educated opinions. When I look at a bright star totally out of focus I see a dark ring surrounded by a bright disc and the 4 spikes of the spider vanes (I think this is what you are supposed to see when you do this). However, my understanding is that the circles should be concentric but mine is rather lopsided. When I try to focus I get to a point where I cant get it any sharper and at this point can see the spot of light which is the star but it has a flare (for want of a better word) coming out of the side. When there are multiple stars in the view they all have flares in the same direction. Is this my collimation? If it is my collimation then can anyone offer any advice as to how I should approach this? I have been told that collimation of my particular scope is a nightmare due to a Bird-Jones lens or some such thing which I don't understand! I have seen people advise taking the scope apart and removing bits to make the process easier but this is WAY beyond my capabilities! I have seen the tutorials about collimation and think I understand the basic process but am just wondering how the process needs to be adapted to allow for the structure of my scope. Thanks!

[CodnorPaul]

Yes that's definitely collimation - sounds quite a bit out as well.

My best advice would be to find a local astro group and find out when they have a beginners night, or an observing night, and take it along for someone with experience of collimating to show you the ropes.  I am sure they would be only too willing to help

[Charic]

I have had a Celestron Astromaster 114EQ for a year or so now and thus far have had no issues with focus. However, I got an 8mm BST eyepiece for Christmas which I cannot focus! I think its that the higher magnification is emphasising the fact that the collimation is out but I would welcome some educated opinions. When I look at a bright star totally out of focus I see a dark ring surrounded by a bright disc and the 4 spikes of the spider vanes (I think this is what you are supposed to see when you do this). However, my understanding is that the circles should be concentric but mine is rather lopsided. When I try to focus I get to a point where I cant get it any sharper and at this point can see the spot of light which is the star but it has a flare (for want of a better word) coming out of the side. When there are multiple stars in the view they all have flares in the same direction. Is this my collimation? If it is my collimation then can anyone offer any advice as to how I should approach this? I have been told that collimation of my particular scope is a nightmare due to a Bird-Jones lens or some such thing which I don't understand! I have seen people advise taking the scope apart and removing bits to make the process easier but this is WAY beyond my capabilities! I have seen the tutorials about collimation and think I understand the basic process but am just wondering how the process needs to be adapted to allow for the structure of my scope. Thanks!

F1Bird.........Hi, ..........Don't worry. Its only a problem for folk who wish to use a laser beam to align the mirrors. If you read this guide several times first, you`ll realise that its really not that difficult.

 http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

It just looks difficult. The simple  collimation cap can be made from the dust cover that covers the focuser. A small bit of tape to cover the hole afterwards if you so desire.  But basically, you look down into the focuser assembly without any eyepiece in place and you should see the secondary mirror. It should appear to be round in shape and central to the focuser tube, disregarding everything else. If that is ok, then the next thing to check is that you can see the 3 primary mirror clips from the same view. Once that is ok, the dust  collimation cap just helps to keep your eye central to the focuser, and you should be able to see everything that I've just described, but described in the most simple terms, but the guide is correct. Part one about adjusting the vanes you may be able to ignore, because I think the vanes are fixed on your scope. You wont break anything, but if you align anything wrong, you just start again.

[paulastro]

As you're in Lancashire, I suggest you pop along to The Astronomy Centre nr Todmorden any Saturday evening (non-members are welcome any Saturday) where you will receive a warm welcome and your scope will be in A! collimation in no time.  Ask to speak to Peter (Drew) and he will show you how to collimate it yourself in the future if you ever need to. If you google TAC Todmorden there is a location map and lots of other information.  Look forward to seeing you perhaps.

PS No need to ring first, just pop along.

[Peter Drew]

As Paulastro says, come on down, we'll sort it out for you. 

[itmo]

That "flare" is error we know as "coma". the tail points away from the point which is optically centered. You will always see some coma with newtonians but the middle of the field of view should be coma free. 

[proflight2000]

On my old Newt I used to use the lid from an old 35mm film cannister with a hole made in the middle of it to look through to the mirrors. It is one of those things that people are weary of wanting to try, but once you get the hang of it, it really is quite simple and will become second nature. Going to the meeting sounds perfect if you are not happy at the moment to have a go.

[F1Bird]

Thanks so much for the offers of help but unfortunately I have no transport so coming to see you is not an option. I'm going to have to grit my teeth and have a go myself! As the spider vanes are fixed on my scope will this mean that the secondary mirror wont need tweaking or does that make no difference? I've read through the collimation guide (and a few others) and adjusting the secondary mirror is the most baffling bit so if I don't need to do it I'll be much happier!