Dob view

[wookie1965]

Took my 10" Celestron Starsense out before turned it on M13 wasn't a great view but thought only 9.45pm not dark enough

Went to Albireo looked through the eyepiece (25mm) I could only see a blue and a yellow line adjusted the focus made no different could this be collimation please. 

[Spile]

No it sounds like focus issue to me. The blue and yellow components are very wide and should be easy prey for your telescope.

[NGC 1502]

7 hours ago, wookie1965 said:

Went to Albireo looked through the eyepiece (25mm) I could only see a blue and a yellow line adjusted the focus made no different could this be collimation please. 

Best check for collimation is to view a bright star at high power. For a 10”, 200x is ok.  Slightly defocus until you see diffraction rings. They look like several rings within each other. They should look concentric, not skewed to one side.

VERY IMPORTANT-  keep the defocussed star central in your eyepiece view.

 

[wookie1965]

6 hours ago, Spile said:

No it sounds like focus issue to me. The blue and yellow components are very wide and should be easy prey for your telescope.

All the stars looked like streaks I tried racking the focuser one way and the other did not make any difference, M13 looked like a grey blob not sharp which I know this can easily do.

[wookie1965]

10 minutes ago, NGC 1502 said:

Best check for collimation is to view a bright star at high power. For a 10”, 200x is ok.  Slightly defocus until you see diffraction rings. They look like several rings within each other. They should look concentric, not skewed to one side.

VERY IMPORTANT-  keep the defocussed star central in your eyepiece view.

 

I tried that on Albireo not on purpose but I racked the focuser in and out and never got any rings. 

Could it be pinched optics.?

[NGC 1502]

24 minutes ago, wookie1965 said:

I tried that on Albireo not on purpose but I racked the focuser in and out and never got any rings. 

Could it be pinched optics.?

What magnification were you using?   Pinched optics usually give a triangular diffraction pattern. This can be quite subtle depending on the degree of pinching. Don’t expect a sharp cornered triangle. Pinched optics are usually caused when the mirror is restrained in the mirror cell.

 

[wookie1965]

6 minutes ago, NGC 1502 said:

What magnification were you using?   Pinched optics usually give a triangular diffraction pattern. This can be quite subtle depending on the degree of pinching. Don’t expect a sharp cornered triangle. Pinched optics are usually caused when the mirror is restrained in the mirror cell.

 

I changed the springs on the Primary  so I thought perhaps I had tightened something up too tight I had a 25mm in first then tried a 15mm  lastly a 10mm they all gave me different size streaks.

 

[The60mmKid]

If you are seeing stars as lines, especially since you just swapped out the springs on your primary mirror cell, I think your mirrors must be significantly out of collimation. Not to worry, though--the collimation process isn't too challenging once you get used to it, and it is discussed on many threads here.

[The60mmKid]

Oh, and I'd leave the second alone for now until you're confident that you need to adjust it. The main suspect is the primary since you just changed those springs. If the position of the secondary was fine before, it may still be fine.

[wookie1965]

1 minute ago, The60mmKid said:

If you are seeing stars as lines, especially since you just swapped out the springs on your primary mirror cell, I think your mirrors must be significantly out of collimation. Not to worry, though--the collimation process isn't too challenging once you get used to it, and it is discussed on many threads here.

Just wanted confirmation I am conversed with collimation I did think I had done it obviously I need to redo it thanks

[The60mmKid]

Just now, wookie1965 said:

Just wanted confirmation I am conversed with collimation I did think I had done it obviously I need to redo it thanks

😎👍 Please let us know how it goes. Best wishes!

[wookie1965]

1 minute ago, The60mmKid said:

😎👍 Please let us know how it goes. Best wishes!

I will thank you, I've never seen stars like it before and this is my 3rd reflector had a 6",8" and now the 10" with this being the 10" when I flocked it I just flocked up to the the spider so I know that's not been moved. 

I can check the secondary with my con-centre makes adjusting that easy then it's just the primary. 

I will screw the bolts all the way in then back them off two turns they will all be near enough the same length so shouldn't have any problem collimating it. 

[Peter Drew]

Sounds to me to be more likely a mechanical-optical issue rather than focusing or collimation.  It's possible that the stronger springs have distorted the mirror cell, how free is the primary mirror in the cell?    🙂

[The60mmKid]

9 minutes ago, wookie1965 said:

I will thank you, I've never seen stars like it before and this is my 3rd reflector had a 6",8" and now the 10" with this being the 10" when I flocked it I just flocked up to the the spider so I know that's not been moved. 

I can check the secondary with my con-centre makes adjusting that easy then it's just the primary. 

I will screw the bolts all the way in then back them off two turns they will all be near enough the same length so shouldn't have any problem collimating it. 

Agree with @Peter Drew... Given what you've shared here, it now seems less likely to me that it's purely a collimation issue.

[wookie1965]

Secondary position which looks bang on to me. 

Edited September 5, 2023 by wookie1965

[wookie1965]

Collimated I hope what do people think. 

[wookie1965]

A better view and enlarging shows the donut in the exact middle 

Edited September 5, 2023 by wookie1965

[wookie1965]

3 hours ago, Peter Drew said:

Sounds to me to be more likely a mechanical-optical issue rather than focusing or collimation.  It's possible that the stronger springs have distorted the mirror cell, how free is the primary mirror in the cell?    🙂

I checked the mirror cell just in case could not get a piece of paper under any of them started to undo them, on the second clip I visibly saw a wave on the mirror like the tension had been took off it.

I have checked all 6 clips and can get a piece   of paper under each one just like checking spark plugs with a feeler gauge.

Checked collimation again just a tad out adjusted that so now I am ready for testing tonight.

[wookie1965]

Can anyone check my pictures please and let me know what you think.

[Peter Drew]

The pictures look good enough, there's no way that collimation at that level would produce the issue reported

[John]

There wasn't a cable of some sort crossing the aperture of your scope somewhere above the top of your scope by any chance ?

I've accidently observed stars when telephone wires have happened to be in their direction and have seen long diffraction lines caused by the wires.

[Spile]

This is where you need to be:

I'm seeing mainly rotational error so I'd loosen the centre bolt, rotate, tighten and tweak fine adjustments (three outer bolts) as necessary.

Edited September 6, 2023 by Spile

[bosun21]

On 05/09/2023 at 06:11, wookie1965 said:

All the stars looked like streaks I tried racking the focuser one way and the other did not make any difference, M13 looked like a grey blob not sharp which I know this can easily do.

That’s collimation error. Out of focus doesn’t create streaks on any reflector I’ve owned.

[wookie1965]

13 hours ago, John said:

There wasn't a cable of some sort crossing the aperture of your scope somewhere above the top of your scope by any chance ?

I've accidently observed stars when telephone wires have happened to be in their direction and have seen long diffraction lines caused by the wires.

It was the washing line lol 

[wookie1965]

32 minutes ago, Spile said:

This is where you need to be:

I'm seeing mainly rotational error so I'd loosen the centre bolt, rotate, tighten and tweak fine adjustments (three outer bolts) as necessary.

Thank you for that I knew last night it still needed a tweak I will get the concentre on it later after my hospital appointment.