What have I done?!

[Andreas]

Hi stargazer friends,

I was recently out with my scope for the first time since before summer.

My goal was to shoot M31, but when I was done with all calibration and such, the dew was already all over the secondary, making the image blurry.

So I thought like "what the heck", and grabbed my microfibre cloth and rubbed all over the secondary until it felt dry.

And now afterwards, I realised how stupid I was, as from what I've heard, you shouldn't touch the mirror even though it's dirty.

So now I wonder if I could have damaged the mirror in some way, and/or if I have to clean it or something?

Andreas

[Jim Steele]

Relax its probably ok, each clean does degrade the mirror so i would tend to avoid unless its really bad

[Macavity]

People become a little paranoid about optics? A microfibre cleaning cloth

will not have done any measurable damage?!?

Increasingly I feel that telescopes are made to be working devices? A bit of 100^o VODKA on a kleenex has been pressed into emergency service here! But I concede that *my* scopes are hardly "expensive" ones... If I owned a high performance APO etc., I might worry...

"Germany's finest" (Telekop service) carry a stock of commensurate optics,

if you do any real damage? http://www.teleskop-...----Optics.html

[emadmoussa]

It's always the rule that the best way of cleaning a mirror is ''don't clean a mirror'', but if it's dewed up, just point the telescope downwards and leave it to dry. Then if you have to, use a specially made solution to clean. I use Baader magic kit for my C11 -- the corrector plate tends to get very dusty quite quickly after few nights out.

Before you use the cloth, try to blow off all the remnants of dust or pollen or what have you.

[Gomtuu]

I can recommend using a dew shield, but as stated above, one clean with a microfibre cloth is probably not going to have made much difference to the secondary.

[Andreas]

Thanks for all soothing answers!

However, as I couldn't see the mirror when I "cleaned" it (or after), I was still afraid that some dust particles could be left over from the microfibre cloth, so I took a picture.

It does not look too good in my opinion, and I wouldn't be surprised if most of the particles where left over from the cloth.

So what do you think?

Should I leave it as it is, or dismount it for a proper cleaning?

I'm specially worried about the two big particles in the upper left corner after that I had noticed them when I looked trough the focuser.

No big deal maybe.. but still..

Andreas

[emadmoussa]

They look like sticky specks of dust, you probably need a cleaning solution. But prbably you'll still get good image despite this.

[Andreas]

They look like sticky specks of dust, you probably need a cleaning solution. But prbably you'll still get good image despite this.

Alright, but would you clean it our leave it as it is?

And if you would clean it, what sort of cleaning solution would you use?

Andreas

[emadmoussa]

I suggest that you go out and give it a test run. If the image is OK, then leave it. some dust shouldn't affect the telescope performance.

If it's blurry, the best cleaning solution out there is the Baader Optical Wonder Fluid http://www.firstlightoptics.com/misc/baader-optical-wonder-fluid.html

[RT65CB-SWL]

Quote: "...A bit of 100º VODKA...", hi Macvity, what brand 'hic!' Balkan Vodka is 80+º. I'll drink to that, (after reading the warning label)!

[Peter Drew]

I'd leave well alone for now, give it a good wash with mildly soapy distilled water in the future when it really needs cleaning.

[Gomtuu]

I'd leave well alone. A few marks/specks of dust are not going to make any difference.

I've known people to panic over condensation streaks on the primary. It generally makes very little difference.

[LukeSkywatcher]

I'd tend to leave it as it is. It really shouldnt make any difference to the views.

[Mark at Beaufort]

the best cleaning solution out there is the Baader Optical Wonder Fluid http://www.firstligh...nder-fluid.html

I understand that it is not recommended to use this Optical Fluid on mirrors. However, It is fantastic on optical lenses - EPs and Front Objectives.

I would leave your secondary alone for the time being so that you can test it out and study the results. If it is really bad then clean as you would the main mirror as Peter Drew recommends above.

Mark

[Naemeth]

Mirrors have to be absolutely covered in filth before it will start to show any difference. You might lose 7% reflectivity from a mirror caked in dust, but remember that a 7% loss in light is roughly what you get when using Ultra-Wide designs / complex designs with 7 or so elements. I haven't heard anyone complain about noticing a drop in light .

Oh, and lenses are fine to clean with microfibre cloth and baader wonder fluid, just not mirrors.