Newbie collimation issues

[DOBGUYNORTHWEST]

Hi all, so I got my Skywatcher 200p Dob a few days ago and received my laser collimator in the post today, I also made my own collimation cap.

So the issue I'm having is with the secondary mirror. As far as I know I've followed astro babys steps exactly. Yet all 3 primary mirror clips are not visible.

Have I gone wrong somewhere or is this not an issue? (my laser from the collimator is reflecting off the secondary, onto the primary into the target circle. And the reflection off the primary into the collimator is on target too)

Any help would be appreciated, I've been scratching my head for several hours now!

[DOBGUYNORTHWEST]

Here's a cropped picture easier to see

Sent from my D6603 using Tapatalk

[beamer3.6m]

Put the collimation cap in the eyepiece and make sure the secondary is centered.

Then use the laser to get the primary sorted.

That's it.

On my 130pds the mirror clips are low profile so very hard to see if not impossible.

The best test is to take it outside and do a star test.

[DOBGUYNORTHWEST]

Thanks for the advice, it seems everything is aligned. I was just unsure about all 3 mirror clips being not all being visible, I'll do a star test as soon as all this horrible cloud has cleared  Thanks again!

[ronin]

Have you V blocks or similar to check the laser collimator?

The beam has to be straight down the axis of that, equally if it were not I think you would get different results each time you removed and replaced it.

Basically making sure all possible bits are correct. Had a few where the collimator was out.

[BritAngler]

I have the f5 version (yours is f6) and on my scope the primary mirror clips are never all visible, it's just a quirk of the scope. Use the collimating cap to get the secondary mirror circular and centred, then use your laser (or better still, a Cheshire) to align the primary mirror as per Astro Baby's tutorial.

[DOBGUYNORTHWEST]

I have the f5 version (yours is f6) and on my scope the primary mirror clips are never all visible, it's just a quirk of the scope. Use the collimating cap to get the secondary mirror circular and centred, then use your laser (or better still, a Cheshire) to align the primary mirror as per Astro Baby's tutorial.

Ahh this is a relief, I thought I'd completely messed up somehow.

[Moonshane]

it looks like you need to rotate your secondary a little to me but hard to tell from the pics.  the clips are a red herring really. other than holding the mirror in the tube, all they are is a guide as to where the edge of the primary is in relation to the secondary. some scopes don't even have clips.

[brantuk]

I agree with Moonshane - it looks like the mirror needs rotating a little because the image of the secondary doesn't look perfectly round. That said - it's only a little off. I have the f-5 version of the 200P and all three mirror clips are visible.

If a star test reveals out of shape stars and the airy rings are not perfectly round and concentric that that would confirm it for me. Possibly there's a bit too much tilt on the primary also - if it was square on to the secondary the laser will hit the center of the laser's target. Hth

[laudropb]

Have to agree with ronin. I started out with a laser and it was well out of collimation. Eventually I got a Cheshire and have never had any problems since.

[sidelight]

IF you can see some of the clips but not all then your secondary is out, you should be ale to see, or not all the clips equally (and not seeing equally is going to be difficult to say the least  ).  I found I have to use a cap as the extra length the cheshire and adapter introduced reduced the amount of the primary I could see reflected in the secondary so I couldn't see the clips.

[DOBGUYNORTHWEST]

Managed to get a star test in last night with an hour or so break in the clouds, would not focus at all.

Its not properly collimated so gonna spend tonight on it, I think the spider veins might be out so will measure up them!

I'll get there eventually!

[Charic]

Visually align the secondary first, use the collimation cap for better eye alignment to the focuser axis. That secondary mirror should look round and concentric to/with the inside edge of the focuser tube.

Once central, any tilt that may be required is added at this stage in order to align to the primary , making those clips visible. Make sure the focuser tube is fully wound inside to align the secondary. If you still cant see the three primary clips, withdraw the focuser tube slightly to give yourself more field of view through the focuser. 

It just takes time and patience, even if you have to do it over and over again, just take your time.

And you mention no focus? Underneath the focuser is a grub screw tension adjuster, adjust the tension, then check that when you rotate the wheels, the focuser  tube extends and retracts!

If this is a NEW Dob, as in your the first to own it, unless its been dropped, its unlikely that the spider or anything is that bad. Don't go adjusting too much right at the start.

Do your star test ( doesn't focus? Why not! ) adjust the  focus tension setting..........Align the secondary, Find those clips, good to go ( hopefully )

keep at it, but also get some sleep in-between. You will succeed!

[DOBGUYNORTHWEST]

Visually align the secondary first, use the collimation cap for better eye alignment to the focuser axis. That secondary mirror should look round and concentric to/with the inside edge of the focuser tube.

Once central, any tilt that may be required is added at this stage in order to align to the primary , making those clips visible. Make sure the focuser tube is fully wound inside to align the secondary. If you still cant see the three primary clips, withdraw the focuser tube slightly to give yourself more field of view through the focuser.

It just takes time and patience, even if you have to do it over and over again, just take your time.

And you mention no focus? Underneath the focuser is a grub screw tension adjuster, adjust the tension, then check that when you rotate the wheels, the focuser tube extends and retracts!

If this is a NEW Dob, as in your the first to own it, unless its been dropped, its unlikely that the spider or anything is that bad. Don't go adjusting too much right at the start.

Do your star test ( doesn't focus? Why not! ) adjust the focus tension setting..........Align the secondary, Find those clips, good to go ( hopefully )

keep at it, but also get some sleep in-between. You will succeed!

Thanks, so here's what I've done over the past few hours and wanted to check with the more trained eyes of this forum.

1. The Spider veins are perfect, like you said.

2. Then the alignment of the secondary. Which to my eyes and the astrobaby guide looks right.

3. Aligning the secondary with the primary. Which looks right to me, managed to get all 3 primary mirror clips visible this time.

4. Alignment of the primary mirror using laser comillator.

Looking from the bottom of the scope up to the collimator all seems to be well & on target after tweaks.

This is where my problem starts, when I look down the opening of the telescope & onto the primary mirror, the laser point is not in the exact centre of the target. Probably only a millimetre or so out. (sorry for the strange angle photo down the tube, only way I could get the laser & target to appear)

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[beamer3.6m]

Collimation is something which can tear your hair out if you over think it.

Questions:

1. Is the secondary in correct position

2. Does the laser hit the target in the laser window.

If yes to the above (assuming the laser was collimated) then go outside and enjoy.

Or... Over think it, redo it all again and miss the clear skies by looking down instead of up.

[buikimaging]

Hi there.

Dont get frustrated :-)

We have the same lasercollimator as you have and we don't use it anymore.

Why?

The thing itself isnt collimated properly. when you put it in your sighttube of your scope and watch where the laserpoint goes when your turn the lasercollimator round.

Not the lasercollimator gives you problems but the 2" to 1 1/4" gives some problems as well.

These things have slob and not the slightest.

These things make everything worse.

What loudrob suggested is the only right thing to do.

Collimation cap and Cheshire.

Your secondary is still offcenter in photo 1

Fix this first.

What we can see is that the secondary is slightly rotated.

Left upper space (yellow) is smaller then right under.

This is caused by rotation of the secondary.

This mirror is adjustible with rotation and tilting in all directions.

The difficult thing is to keep the rotation of the secondary mirror in the same place when adjusting the tilt.

Thats the hardest thing.

When done give us a sign.

[Charic]

1mm out...............SEND THE SCOPE BACK ITS FAULTY!

No really, thats good what you have achieved so far, and by CAREFULL manipulation of the adjusters, you will find the dead centre of the centre spot, and that laser spot will dissappear into that hole on the target face!

If you leave everything as I see it from the images you provide, pop in a 2xBarlow? The Barlow diffuses the laser beam, so it does'nt need collimating for this task! The diffused laser beam illuminates the primary surface creating a SHADOW of the centre spot which is reflected back onto the laser's target face. As long as the shadow circles the hole on the target of the laser tool, you have a collimated telescope? A Star test will confirm.

It looks good from the images supplied, try the Barlow!

[mdstuart]

Looking at your pics I would say your collimation is now on...ignore the laser c....go out and look at the pole star...focus to a nice dot and shout YES...

[DOBGUYNORTHWEST]

Thank you all for the help! Made the adjustments to the secondary @buikimaging suggested. I'll be putting a Cheshire on my Christmas list for sure! Now to wait for a clear night for a star test!

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[Andy Mitchell]

That laser collimator looks a lot like mine, and like most cheap laser based ones, the beam wasn't aligned well enough at the factory. So using it "out of the box" will make things worse. There are a couple of holes in the side of tube filled with something rubbery, you can pick that stuff out and then adjust the laser diode so it points accurately. Don't worry about it for now as...

The not being able to achieve focus might not be a collimation issue, in your photos you have both the extension tubes fitted. Did you use the same combination with an eyepiece? You shouldn't fit both or you will never get in focus at infinity. Fit just the one that matches your eyepiece size. I've heard some say Skywatcher "helpfully" ship their telescopes with both pre-fitted to confuse people who are new to the hobby.

[Charic]

Andy Mitchel, Good spot!

The most likely cause, apart from focuser tension?

[John]

Right from your 1st photos I've been thinking that the scope is pretty nearly in collimation. If there is further adjusting to do, it's fine tuning rather than anything more significant.

If you can't bring the scope to focus on a star, the moon etc it's not collimation, it's something else. The difference between the state of collimation that your scope looks to be in and perfect will deliver slightly sharper images and slightly better contrast, thats all.

Andy Mitchell above may have hit on the real issue here. It's a common mistake with Skywatcher scopes and nothing to do with collimation.

[buikimaging]

Just wait until the weather clears up and do a star test. Bring the scope out of focus and try to make a photo or even peak to a normal eye peace. You will see almost the same as what you see trough your collimation cap.

Its a bit difficult to what you are looking at when its out of focus but move your eye a little in front of the eye peace and you will see what i mean. You can also try to make a picture. Sometimes its much more easy to see of every thing is right. if its still not alligned all you have to do is do some adjustments on the primary mirror but dont mess with the secondary else your one step back. When done be sure to fix the primary mirror so it wont move. The scope needs a good bang to get it out of alignment. We allign once every 4 months or so and then most of the time its the primary witch need a little adjustment.

When you want a good cheshire look for a 2" version this reduce the chance of slob by using a adapter on a smaller one. Good luck.