How stupid!

[Stardaze]

I’ve accidentally touched the surface of my secondary mirror with the palm of my thumb whilst collimating. I can see that there’s a mark on it. What’s best to wipe it off? Trying to remain calm whilst extremely annoyed with myself! The paper blocking off the primary fell flat and as I delved in to sort that out 🤬

[Stardaze]

Just found this... I’ll kick myself again and leave it for now.

 

[johninderby]

Get yourself some of this stuff. Great for cleaning optics and will get the marks off your mirror. 

https://www.firstlightoptics.com/astronomy-optics-cleaning-protection/baader-optical-wonder-fluid.html

More info

https://www.baader-planetarium.com/en/downloads/dl/file/id/110/product/1661/cleaning_and_maintenance_of_optics_a_short_instruction_guide.pdf

https://www.baader-planetarium.com/en/blog/cleaning-cdk-17-mirror-with-baader-optical-wonder/

Edited May 30, 2020 by johninderby

[Stardaze]

1 hour ago, johninderby said:

Get yourself some of this stuff. Great for cleaning optics and will get the marks off your mirror. 

https://www.firstlightoptics.com/astronomy-optics-cleaning-protection/baader-optical-wonder-fluid.html

More info

https://www.baader-planetarium.com/en/downloads/dl/file/id/110/product/1661/cleaning_and_maintenance_of_optics_a_short_instruction_guide.pdf

https://www.baader-planetarium.com/en/blog/cleaning-cdk-17-mirror-with-baader-optical-wonder/

Thanks John. I’m having a right mare realigning the secondary. I wasn’t happy with it, but I’m a couple of hours into it and still can’t quite get it right....grrrrrr! 
It does state for not cleaning Newtonian mirrors. I’ll try it, what’s the worst that can happen...

Edited May 30, 2020 by Stardaze

[DaveL59]

1 hour ago, johninderby said:

Get yourself some of this stuff. Great for cleaning optics and will get the marks off your mirror. 

https://www.firstlightoptics.com/astronomy-optics-cleaning-protection/baader-optical-wonder-fluid.html

More info

https://www.baader-planetarium.com/en/downloads/dl/file/id/110/product/1661/cleaning_and_maintenance_of_optics_a_short_instruction_guide.pdf

https://www.baader-planetarium.com/en/blog/cleaning-cdk-17-mirror-with-baader-optical-wonder/

surely that's for lenses and not mirrors?

I'd have thought the usual method of remove, wash in soapy water and rinse with distilled is all that's needed. OK it means taking the secondary out and recollimating afterwards but at least it won't harm the coatings.

[johninderby]

Baader gives instructions for cleaning newt mirrors with the fluid. 

[Stardaze]

12 minutes ago, johninderby said:

Baader gives instructions for cleaning newt mirrors with the fluid. 

A little bit on a cloth and be very careful 😆

[Stu]

Personally I would always err on the side of caution and stick with slightly soapy warm water, and gently dragging a cotton wool ball over the surface whilst it is under water. Rinse with de-ionised water.

[Ricochet]

25 minutes ago, johninderby said:

Baader gives instructions for cleaning newt mirrors with the fluid. 

Yes, the instruction is to remove the mirror and soak it in Baader Wonder fluid. I guess you could spray the fluid over the whole surface of the mirror to let it soak rather than the usual method where the mirror is submerged in water. Perhaps this is actually easier for a secondary mirror which is attached to a spider.

I have had Wonder Fluid on a mirror before and my experience is that it will clean them with no damage that I can see to the mirror, but if you just clean a spot, you can see the outline of where the fluid was until it is completely cleaned using the normal method. 

@Stardaze Hold off from cleaning yours for a couple of minutes. I'll dig out my old secondary and see if spraying to soak works.

[Carbon Brush]

The Baader fluid will be good for dissolving finger grease, as it contains some alcohol.

Isopropanol. Neat or 70/30 with water will be good. This is a popular virus killing chemical.
Be wary if the 70/30 mix has been made with tap water, rather than deionised. 

Either of the above might avoid the need for any contact cleaning.

Given some carefully placed tissues to catch spills, you might avoid removing the secondary.

Last time I cleaned an absolutely filthy fly stained primary, I used soak and soapy water first. There was no choice.
But on the final step, while it was vertical for draining, a squirt of Baader fluid worked really well to help draining with all but zero surface tension. 

David.

[Ricochet]

33 minutes ago, Ricochet said:

@Stardaze Hold off from cleaning yours for a couple of minutes. I'll dig out my old secondary and see if spraying to soak works.

Having tried this, it will get rid of a finger print quite nicely. However, Baader's instruction:

Quote

Afterwards, wipe the mirror dry and clean with a lot of clean Kleenex-tissues, which have also been moistened with cleaning fluid.

doesn't really work. If you moisten the tissue even the smallest amount, then some cleaning fluid is left on the mirror, which has to evaporate off. Badder also say:

Quote

 it dries off without leaving any residue, striae or color hue on the coating! 

Which is true if you look at the mirror face on, but from a shallow angle I can see lots of small purple dots and streaks where the fluid was.

A standard wash with a final deionised rinse gives a better result I feel.

[Stardaze]

I’ve lost the will to live right now. Still can’t quite get the primary lined up.... so close...

Fresh head later then and I’ll think about the cleaning. Thanks for all of your advice.

[Ricochet]

Just the final step of collimating the primary? Assuming that you're using a tool where you have to look through the focuser to see the result, then you can always get a second person to slowly turn one of the knobs while you look though it. If you don't have anyone to help then try to identify which direction a particular knob moves the doughnut and then just concentrate on adjusting in that one direction. to get it roughly right. When that axis is roughly right, test a second knob. In theory you should be able to collimate without needing to move the third knob, but a small tweak on it at the end might be easier.

[Stardaze]

18 minutes ago, Ricochet said:

Just the final step of collimating the primary? Assuming that you're using a tool where you have to look through the focuser to see the result, then you can always get a second person to slowly turn one of the knobs while you look though it. If you don't have anyone to help then try to identify which direction a particular knob moves the doughnut and then just concentrate on adjusting in that one direction. to get it roughly right. When that axis is roughly right, test a second knob. In theory you should be able to collimate without needing to move the third knob, but a small tweak on it at the end might be easier.

I bought a concentre and the mirror wasn’t quite right. The fine tune at the end with the 3 knobs is relatively straightforward. Struggling getting the holder aligned whilst getting the tilt absolutely perfect. Trying to press back on the sprung base whilst tilting the mirror. Keep getting it ever so slightly off-centre.

Anyway, my back is in a mess after being bent double for 4hrs - didn’t want to admit to that length of time 😂

Edited May 30, 2020 by Stardaze

[Stardaze]

Well, I can’t leave it.. so stood in a good que in search of deionised water..

Edited May 30, 2020 by Stardaze

[Stardaze]

Got it all washed and is absolutely fine. Still struggling getting the holder far enough in to line up. Still doesn’t seem far enough in but look how much gap there is. Can this be correct? Is the focuser not aligned properly?

[Stardaze]

And here.. I feel such a pleb today, it’s taken all day! Feels like the holder needs to be quite far out?

[johninderby]

Not far off. 🤔

the mirror looks a tiny bit too far down and the mirror needs rotating a bit.

[Stardaze]

4 minutes ago, johninderby said:

Not far off. 🤔

the mirror looks a tiny bit too far down and the mirror needs rotating a bit.

Just can’t seem to move the holder upwards (as above) and tilt it to be concentric. So annoying, spent all day at it. Don’t think I’ve found anything so tedious that has stumped me before. My back is I bits leaning back and forth so going to have to call it a day. Does yours protrude so much John?

[johninderby]

Not quite as much.

Just slacken off all the adjusting screws a turn and tighten the central bolt to move the mirror up the tube while holding the mirror holder.

Edited May 30, 2020 by johninderby

[Stardaze]

3 hours ago, johninderby said:

Not quite as much.

Just slacken off all the adjusting screws a turn and tighten the central bolt to move the mirror up the tube while holding the mirror holder.

So does the collimation shop open this week.. I’m really quite embarrassed about it. Had another play and can get it ever so close. It is almost like the holder sits too far out on the screw. Ah well, I’m in the bad books tonight as haven’t done much else today so I’ve packed it all away and might look at it again next weekend 😂

[johninderby]

Ah those “simple” jobs that you waste a whole day on. 🙄🤬

[Stardaze]

8 minutes ago, johninderby said:

Ah those “simple” jobs that you waste a whole day on. 🙄🤬

I was wide awake at 6, so thought “an hour tops before the girls get up.” Even took a book down to read when I was done. I’m not normally this useless...honest 😂

My back is in tatters, I’ve a sore finger and a blurred eye.. all through trying to align a mirror 🙄

Edited May 30, 2020 by Stardaze

[johninderby]

You may have a future in helping plan the HS2 project then. 😁

[Paul M]

11 minutes ago, Stardaze said:

My back is in tatters, I’ve a sore finger and a blurred eye.. all through trying to align a mirror 🙄

Collimation is a skill you develop as you go along. 

If you are visual only then collimation is less critical. I only ever collimate my 6in Fullerscope by Newt rack-of-the-eye. Not gadgets or gizmos and it's great.

I've used a laser collimator on my 250 PDS then fine tunes it rack-of-the-eye!   But now that I'm poking a camera down the tube I know it's not good enough so I've just ordered in my first ever Cheshire eyepiece but I won't knock myself out over collimation. I'll be done in 15 minutes for better or for worse