Thirdway

It's done. Took 20minutes. I think ABs guide is very good, it's probably a bit too detailed. What I learned.

1. You definitely need a collimation cap. I just drilled a hole in the focuses dust cover.

2. Use two pieces of nice bright, dofferent coloured card for blanking the optics.

3. The initial setting up of the secondary with the cards in place is just, near as damn it, your still going to need to adjust for the next stage of lining the secondary and primary mirrors.

4. The hex screws in the secondary are all about, tighten, loosen, tighten, loosen over and over until you get the mirror clips framed.

5. The primary is easy to set up. Just turn one screw and see what happens, when you get close as you can, then start on the next screw with just gentle turns and see what happens. Mine was centred with one full turn of one screw and half a turn of the other.

6. I don't have a plate protecting the mirror! There isn't an Allen key in the tools that come with the scope to loosen the primary mirror locking screws. I ended up using a screwdriver which fitted the hex.

All of this is in AB s guide I just thought these were the points which made the difference.

That's colourful. I stuck a piece of white paper in front of the secondary and get an accurate, concentric pattern like the one shown. I'm trying to take in the next bit because none of the mirror clips don't seem to be in view?

I haven't touched anything as yet, the scope came like that. I'm glad you said its all out of wack, at least that gives me license to fiddle. I will have another read through your detailed instructions again.

Yes, looking down the Cheshire.

So the shiny bit and donut?

I see a large white area, then a smaller black area, a smaller white area. Within that final smaller white area is a black dot and the centre circle on the primary.

This is why it is difficult. When I look at the Shot glass video it's straight forward, then I look down the barrel of the Cheshire and it doesn't look much like the image in the video.

If I can understand which bit is supposed to go where I can figure it out.

So, in the photo I posted, what exactly is what? Is it secondary mirror position/tilt, primary position or are they all so far out I need to start from scratch.

It's annoying because I'm usually the 'go to' person when something technical rears it's head. It's not as if the process is particularly complex, align secondary mirror with eye piece and primary mirror with secondary mirror and there are half a dozen adjusting screws. Yet it still seems so obscure. I'm sure if someone showed me, it would make total sense and I would teach others.

I'm sure Astrobabes guide works well for a lot of people, but I just find it confusing. Can I use the Cheshire to get the secondary mirror aligned as well as the primary. Better still is there someone local who can teach me how to do this?

At present, looking through the cheshire this is the image I see.

http://db.tt/lCkS1N8g

Hi Damnut,

I already looked at all of them. No one uses a plain old Cheshire, they all use laser versions. I'm really wondering if the none laser collimator tool is even worth having if an old film cap does the same job? Seems like I bought a tool which has no real use? Probably should have splashed out for a decent laser.

Maybe it's just me. I read Astro baby's collimation page and it's left me more confused than ever.

I'm struggling to understand why I needed a fancy Cheshire tool, if I can do the set up with a film canister cap with a hole in it?

I'm I missing something? Can I just use the Cheshire without using the film cap?

On the side of the Cheshire is a hole with some shiny metal cut at 45 degrees. There is no mention of where this is placed in relation to the scope, or what it is used for. Perusing a few web sites they mention shining a light in the hole makes setting up very easy at night......errrr how?

I have inserted the Cheshire and had a look through it. I can see solid cross hairs and also a ghost of cross hairs that revolves if I turn it in the focus tube. Also the central image goes from white to black like looking through a polarising filter as the tool is turned.

I can see the primary mirror circle with a black circle adjacent to it, all inside another circle.

This is on my Skywatcher Dob 200.

Any help would be great.