JamesAstro2002

Update: If anyone was curious about what this could be, it was down the the belt. I had to take it off, flip it around and adjust the tension again and the clicking was gone. Glad the drop didn't cause any damage!

Just gathered a few more test frames, that weird coloured blob seems to be moving across the frame?!

Now another bright blob around Vega has just popped up! These are some nasty looking reflections, but I don't know what's causing them.

L_0009_ISO400_120s__20C.CR2

Luckily enough, tonight is a decent clear night so I've been able to do a test run. Stars are looking nice and round all the way to the corners now, so you were correct, thanks a lot alacant!

Do you have any idea what that odd looking thing is under the bright star? I'm guessing some sort of reflection. Looks like I have a slightly twisted spider vane as well.

Hi people,

So I've been a bit of a fool and managed to drop my entire HEQ5 Pro mount head on my foot (Ouch). I was carrying it upstairs 'attached' to the tripod so I could make some adjustments to the DEC axis since there was a slight amount of play. So I set the tripod down and bam, the head rolled off and landed right on my foot. Silly me didn't realise the head screw wasn't done up all the way!

So I gave it a test to make sure it was okay, got the hand controller out and moved it in both RA and DEC and it seemed fine.

Then I decided to proceed with what I was going to do in the first place, adjust the worm gear engagement for DEC since there was a bit of play. After following astro baby's guide, I can hear this awful clicking sound when rotating the DEC axis a certain direction. I've attached a video below to show what I mean:

Any help on this would be greatly appreciated, I really hope I haven't messed it up too bad.

Cheers,

James.

Yeah I know. But the clouds rolled in quickly so I only had time to quickly look at polaris out of focus. I did briefly view the star in focus but it still looked to have that fringing on the edge, but the clouds soon rolled over so I couldn't tell properly.

I thought that the out of focus star test for collimation was supposed to look the same in the edges as it does the center ? It looks to me like the dark circle has shifted slightly when at the edge of the frame.

And I've already cut off some of the focusser, looks like it may need a little more cut off as you suggested, though.

Hopefully I'll get a longer patch of skies tonight so I can actually test the stars in focus. I just assumed that the out of focus star test looked bad at the edges - but we'll see.

Thanks for helping out :).

Well this is not the result I hoped for 😕

star test at the centre:

And at the edge:

3 minutes ago, alacant said:

I'd be satisfied with that

Great. Now I just need to wait for the sun to set, cross my fingers and toes the weather forecast is correct for once and the sky will be clear.

Thanks again for helping out.

Not sure why the image didn't attach in the previous message, but here it is.

28 minutes ago, alacant said:

That will do, but since we're trying to sort out misshapen stars, maybe we could perfect it?

1/4 turn more on the secondary centre screw should have the secondary dead inline with the focuser. Whilst you have it loose, get those Cheshire cross hairs dead centre of the primary donut reflection; ATM they're at about 10 o'clock given the orientation of your photos. Now the easy -but most important- bit.; adjust the primary to coincide perfectly with those cross hairs.

But before we go over the top, let's take a while to read the common collimation myths.

How's the sky? Don't get it too perfect or the clouds are sure to roll in!

Sure.

Okay, I've adjusted it again, this looks better to me, not sure if it's perfect..

41 minutes ago, alacant said:

Or the Cheshire is making the focuser sag...  Or the Cheshire isn't square in the focuser... It's what sw focusers do.

Anyway, take the secondary up the tube -clockwise on the centre bolt of the spider- about 1/2 turn and recollimate with the Cheshire at the position you would normally focus. I wouldn't go any further until you have feedback from the camera frames.

Okay, thanks.

Does this look any better?

Yeah, true.

As I was doing the collimation with the cheshire, I noticed that as I reeled out the focusser, collimation slowly went out!

This is with the focusser all the way in:

And all the way out:

I'm guessing this is due to some tilt in the foccuser or something?

6 minutes ago, alacant said:

OK, but I don't think the mirror clips were the problem. More, the limitations of the cc.

Good luck anyway.

Right. Have you got any other ideas in mind I could try before getting out under the skies for a test?

Thanks for taking your time to help me out so far.

1 hour ago, alacant said:

That's exactly how it should be.

Perfect.

 

Oh right, okay. Thank you. Hopefully there should be a patch of clear skies tonight so I can give it a test.

Hopefully this shows what I mean. No matter how loose I make the screws, the clip will always drop down and rest on the surface of the mirror. Which I'm guessing is wrong, seeing as you said I should be able to slide a sheet of paper between the clip and the mirror.

4 hours ago, alacant said:

Ah, I think I see what you mean.

They are loose, yes? IOW, they are not held against the mirror by the retaining screws? You can move them easily? If so, that's it; the screws do not hold the retaining clip tightly, allowing the clips to move and there is a gap so that the sheet of paper can fit between the clip and the mirror...???

Yeah the clips still touch the mirror, I could only slide a sheet of paper between the clips and the mirror if I lift them up, otherwise they fall back and just rest on the mirror's surface. I'll just send some pictures to show you what I mean.

3 minutes ago, Uranium235 said:

As for the mirror clips, there should be just enough room to slip a fag paper between the clip and the mirror... so get down the corner shop and grab a pack of rizla..lol 

Okay, cheers 😂. Though, I'd have to wait another year until I'm old enough to legally buy them, lol. 

Actually, I just thought. Could I take off the black plastic bit on top of the clips, then put them underneath so they act as a spacer so the clips won't touch the mirror? If that makes sense, lol.

5 minutes ago, alacant said:

Remove them completely. Replace and wiggle them as you tighten. Stop when you feel contact then back off.

Thanks. Just tried that, but still, they fall back and touch the mirror.

12 minutes ago, alacant said:

No. At least a sheet of paper's clearance. 

HTH

So I just tried looseing the clips more, but no mattter how much I loosen them they still come in contact with the mirror. Almost looks like there should be a spacer to raise the clip so it doesn't come it contact with the mirror.

4 minutes ago, alacant said:

No. At least a sheet of paper's clearance. 

HTH

Oh okay, thanks.

I'm still thinking that my star shape problem is because of the mirror being pinched. Do the clips need to be touching the mirror or not ? Because I have loosened them but they still touch the mirror. 

2 hours ago, alacant said:

Hi

Yeah. The SW focuser is hopeless. If it doesn't tilt, it slips. The best way we found is with one of the older built-like-a-tank- 62mm rack and pinion focusers. A drop in replacement to any sw baseplate. OK, no fine focus but hey, it it just works.

Cheers

Yeah, the focuser can be a pain at the best of times, lol. Guess I just have to play by it's strengths.

That focusser does look a bit of a tank!

11 minutes ago, Adam J said:

I have done the same, I still have issues. I think that nothing short of a moonlight focuser will totally solve it. 

The other thing is that the secondary mirror can shift about if you have not got the spiders sufficiently tight (just dont distort the tube!). 

Adam

Yeah, a moonlight would be great.

Hmm, interesting. They seem perfectly tight to me already, though.

1 minute ago, Adam J said:

Similar two element design, to prevent that issue you need a three or even four element corrector. 

Oh right, okay. I've tapped an extra thumbscrew into the focusser as well, so I would've thought that would help with any tilt that may occur.

1 minute ago, Adam J said:

Its probably tube droop on the focuser causing tilt and that is variable according to the direction that the scope is pointing in. The color fringes on the stars towards the edges are inherent to the Baader Field Flattner as it suffers from some degree of radial CA.  

Okay, thanks for the response. I should probably mention i'm using the Skywatcher Coma Corrector.