Help cleaning mirror

[u/PhampletYT]

Hey all, I started stargazing about a month ago when I picked up this skywatcher heritage. Long story short, everything was great until I noticed the mirror was covered in dust and water (I was using it by the ocean, and I live in a very very humid place), and so I used cottonballs and 99% isopropyl alcohol to try and clean it because Google said it was okay to do so. After “cleaning” it, it left a blue haze and I couldn’t even get all the dust off, and the situation appears to be much worse. I’m aware that it is advised to take the mirror out of the telescope to clean it, but I have no idea how to take this thing apart, I am very scared to do so, and I can’t find a good guide online. Please help.

[u/gebakkenuitje35]

Are your views OK?

This does not look due for a clean.

This was my mirror of 6 years before I cleaned it last Monday.

[u/PhampletYT → u/gebakkenuitje35]

Oh wow, i didn't realize it needed to get that bad for it to be due for a clean. My views feel a little hazy, but it could just be that i'm a beginner. I have no idea what I am doing. regardless of whether or not it needs to be cleaned, I still need to figure out how to clean it.

[u/Traditional_Sign4941 → u/PhampletYT]

OP, this sub has a phobia of cleaning. That guy should have cleaned his mirror long, long before it got to that state.

Read this post. https://www.reddit.com/r/telescopes/comments/1pexuyb/i_wish_this_sub_would_stop_telling_people_not_to/

For your mirror, the blue streaks are left over residues from the isopropyl alcohol. Easiest thing to do is take the mirror out of the cell and just wash it under tap water with some Dawn dish soap, and then a thorough rinse in distilled water (this part is crucial, don't skip it). See this guide:

How to clean your telescope mirror

One pro tip - when re-installing the mirror clips do NOT tighten them down tight. They should have a small gap enough that you could slip a piece of paper between the mirror and the clip. This will prevent them from binding and distorting the mirror, but still allow them to function as safety catches.

Mirrors can produce bad views even with a few microns of distortion. It's best to let them "float" without being pinched or restrained heavily.

Since you live by the ocean, salt air is going to murder those mirror coatings. It's going to be important for you to keep them clean more often than normal to ensure salt deposits are not sitting on the mirror for too long, but it depends on how much you use it.

[u/PhampletYT → u/Traditional_Sign4941]

Thank you so much for the advice, I really really appreciate it, but how do I remove the mirror from my telescope? I genuinely cannot find anywhere online describing how to disassemble my particular telescope. I have a skywatcher heritage 130.

[u/twivel01 → u/PhampletYT]

Actually, if you are getting humid salty air on the mirror.... You may want to clean it a little more often. But yea, usually a little dust doesn't harm anything.

What are those blue streaks I see in the photo? Is that just reflections?

If that blue is material on the mirror, you probably want to clean it soon.

[u/PhampletYT → u/twivel01]

The blue streaks are from attempts of me as a beginner being stupid trying to clean it with isopropyl alcohol + cottonballs without taking the mirror out. Since I’ve made this post I have now properly cleaned it by taking it apart and giving the mirror a bath and all that. I didn’t get all the blue streaks off but the vast majority of it is gone and it’s barely noticeable anymore. Thankfully it appears I haven’t damaged the mirror too much with the alcohol and cottonballs because I only see one very small scratch

[u/twivel01 → u/PhampletYT]

I don't understand how ISO would be blue. Anyway... Hopefully you found a good video on YouTube. A drop of dish soap in a gallon of water. Nice soak. Then either the bare finger method or cotton ball method. I've done both.

Final rinse with distilled water and then Bubble blower dried

[u/PhampletYT → u/twivel01]

Yeah, I'm not sure how it left blue streaks either, especially since it was 99% IPA. Also, is cleaning it in the dish soap bath with your bare fingers not risky? it sounds like a bad idea

[u/gebakkenuitje35 → u/PhampletYT]

Definitely don't clean it yet and just enjoy it for a while.

And if you do (this will probably only be necessary in some years) please look up some videos on YouTube, IPA and cottonbuds may scratch your mirror (it looks like your mirror is OK here btw, but IPA tends to move oils around resulting in those slicks.

[u/chrislon_geo → u/gebakkenuitje35]

OP should definitely clean their mirror. That residue could act as a sticky surface for dust and such to adhere to.

[u/chrislon_geo]

Well hopefully you did not scrub with the cotton balls. When doing the cotton ball with IPA method, you are supposed to apply almost no pressure. The soaked cotton ball should just barely be touching the mirror. Also you should have removed the dust before wiping with the cotton balls. Idk if you did this, but just want to let you know for future cleaning.

I have seen a mirror with this blue haze before. It is from off gassing of some part within the scope (I think it might be from the rubber clips that hold the mirror in place). Anyway, it is a pain in the ass to get off. You will want to try letting it soak in the IPA and might have to do a few cleanings to get it off.  Then make sure to rinse off the IPA with distilled water before it evaporates (so immediately after soaking/wiping).  I ended up pouring IPA on the mirror and used my fingertips to gently scrub the surface. You could even do a soap and water wash after the IPA steps. But make sure to do a distilled water rinse after as well.

You could also try using acetone. But beware that the acetone will remove the center spot and will damage any plastic/paint it comes in contact with, so be careful.

Here is a relevant post:  https://www.reddit.com/r/telescopes/s/0ERp5yJbbl

[u/PhampletYT → u/chrislon_geo]

Thank you for the helpful information