Corrosion of lightbridge 12" secondary

[winterlight]

I had my LB 12" for 2.5 years now (not sure how long the previous owner had it for). Recently I notice multiple 'corrosion' spots measuring 2-5mm on the secondary. Is there a 'cure' or is it time to get it recoated?

[NGC 1502]

You could try a careful clean, it might not be corrosion. But if that doesn't sort it, I wouldn't panic,

it would have to be very bad to affect the view.

Maybe a recoat sometime though.

Regards, Ed.

[WWPierre]

Oh, oh. I live right beside the sea, although with many rivers emptying into the head of the fjord, the water is not that salty, but I do keep my scopes on a covered deck, open to the air on one side. I guess this is something I will have to keep an eye on.

[fatwoul]

Maybe try one of these? Dunno if they're any good, but £25 to protect a grand's worth of telescope seems worth a try. I mean, it's got to be better than nothing, right?

[Mark at Beaufort]

I would recommend cleaning the secondary mirror following the same procedure that is undertaken for the primary. My secondary had small spots but once I cleaned it the mirror was perfect again.

Mark

[TheThing]

Oh, oh. I live right beside the sea, although with many rivers emptying into the head of the fjord...

That sounds awful! Fancy a swap of homes?

[albedo0.39]

The LB's are known for having coatings that were not designed for our humid atmosphere. As a result, they often go cloudy well ahead of expected time.

Not to worry. A trip to Galvoptics or Orion optics will sort it out (a recoat) and don't forget to keep an eye on the primary... from my experience, it's only a matter of time until that starts to show signs

Good luck !

Steve

[LukeSkywatcher]

Any pictures of the corrosion so we can better diagnose?

[GuillermoBarrancos]

Maybe try one of these? Dunno if they're any good, but £25 to protect a grand's worth of telescope seems worth a try. I mean, it's got to be better than nothing, right?

I am also thinking about buying one of those. They seem really good.

Especially with the strong winters we have here.

[fatwoul]

I am also thinking about buying one of those. They seem really good.

Especially with the strong winters we have here.

Ugh and the yucky Augusts we have here. I haven't seen the sun in about three weeks! I like the rain, but this is ridiculous.

I've been thinking about those covers since I posted that, and I reckon one of those covers would be really useful for extended imaging sessions - where you want to set your scope up for 2 or three days undisturbed, but don't want to risk the scope being caught in a change of weather. I don't think I'd want to use the cover for extended periods.

[dogfish]

I have one of those covers, very good value, but I wouldn't leave it outside permanently. Great for star parties though.

Cheers, Martin

[WWPierre]

That sounds awful! Fancy a swap of homes?

A temporary swap would not be out of the question. Find me in Google Earth at REMOVED, Squamish, B.C. Canada. There is a street view as well. Every morning I thank Fate, or Kismet, or the Gods, or Whoever is responsible that I ended up where I am. You can see some documentation of my good life at Album1 pictures by WWPierre - Photobucket

[fatwoul]

...You can see some documentation of my good life at Album1 pictures by WWPierre - Photobucket

That's a lot of firewood.

[winterlight]

Will try some cleaning first. Hopefully will be able to post some before and after pictures

[winterlight]

Some photos before I start cleaning

[peeceeTal2M]

From the look of the photo's i'd say all it needs is careful cleaning

[winterlight]

Will distilled water with cotton do? Not sure if I should use any detergent or alcohol

[NGC 1502]

Hi, I just know I'm gonna be shot down for this, but here goes anyway !!

I clean my secondary in situ with a microfibre cloth & isopropyl alcohol (from chemist)

Go carefully, blow away any obvious grit first, fold the cloth in a pad, put some

alcohol on the cloth & wipe, looking through the focuser so you can see whats

going on. Don't rub or press hard.

To finish off, you can "huff" the secondary with your breath & wipe very carefully.

Don't try for perfection. Mirrors show every smidgeon of grot. If you see an

improvement, quit while your ahead, a few smears won't affect the view one jot.

I have cleaned newtonian secondaries like this for years & never had a problem.

This procedure is easier with larger scopes when there is more room to work,

with a 12" truss tube, you've got loads of room.

I think the hyper caution in books & online may stem from the worry about any

comebacks if it goes pear shaped.

The cleaning may or may not sort it, but if it were me, thats what I'd try.

My radar is on for incoming missiles !!

Cheers, Ed.