Lens/Mirror coatings

[Ogri]

Am I right in thinking that refractor lenses have more useful coatings (useful to me, that is), such as anti-glare, than reflector mirrors (I'm guessing the mirror coatings are more about protecting the mirror)?

To try and get into this hobby, given my eye problems, I'm thinking about trying a refractor with 'multicoatings' along with a Variable Polarizing Moon Filter (e.g. Moon & Neutral Density Filters - Variable Polarizing Moon Filter ) which also reduces glare.

Rather than spending too much to find out (I was intrigued by a comment I read here somewhere that an ED80 I think it was, required a much longer exposure for photography, which suggested to me - admittedly a maybe wrong impression - that the ED coatings may indeed cut down dramatically on the type of light that really hurts my eyes), I'm tempted to go for something like a Startravel 80 with its Multi-Coated Objective Lens, or something like it that is short tube and Rich Field so I can have some fun well away from the moon, if possible cheap and secondhand (the experiment may be futile, after all, but if successful, I could then aim for getting one of those ED type 'scopes, and eventually perhaps do a bit of webcam observing to help reduce the time spent putting my eyes next to EP's).

The best daylight glasses I have ever owned, had green polarizing (green is great for contrast during the day) along with blue mirroring and anti-UV coatings. They were so effective, I could feel my eyeballs immediately cooling down as soon as I put them on (somebody thought they were sunglasses and stole them, and I didn't realise the significance of the blue mirroring, and inadvertently had silver mirroring on the replacements - and now have no cooling effect).

As you can imagine, it would be great to find out just what these Multi-Coated Objective Lenses are coated with and what they might help protect against, if anything.

Anybody know?

[pvaz]

About the coatings I honestly don't know but I seriously doubt thats their function. I think they work pretty much as the EP ones.

However that web cam idea may actually be the best option. I sow a thread around here that talked about a specific type of web cam that stacking on the fly and showed colour on objects such as M27, M42 in real time. Besides potentially solving your problem it will actually allow you to see more! As I remember it wasn't cheap but I think it was cheaper then an 80mm ed scope.

[pvaz]

Found a link with a few cameras:

Astro video cameras - Watec 120n - Mintron @ Modern Astronomy

I never used one so you should do some research to see if it's what you want or not.

[Ogri]

Thanks Paulo, yes, I guess the lens coatings are more about transmission than protection, but kinda hoped they may inadvertently have a 'serendipitous' benefit for me.

Thanks for the link too.

[Capricorn]

Caotings are present to stop reflections from the air/galss surfaces. They reduce the reflected light from 4% at each surface down to say 1%. So more light gets to the eye.

Basically if it isn't reflected off then it is transmitted through.

They are not there to reflect or cut out wavelengths. In fact the opposite.

Unsure about the description of your best glasses.

Polarising is not colour dependant, so green polarisation is strange.

Blue mirroring, sounds like a poor anti-reflection coating that was put on for red and green transmission and ended up reflecting the blue spectrum. Possible as you mention UV coating, UV being up from blue. Guessing that it reflected the UV and carried over in to the blue spectrum.

[LukeSkywatcher]

As you can imagine, it would be great to find out just what these Multi-Coated Objective Lenses are coated with and what they might help protect against, if anything.

Anybody know?

I honestly cant comment on multicoated lens on telescopes as i am so new to telescopes (but Steve from FLO only today assured me that they are a GOOD thing and the coating is pretty ROBUST with regards to cleaning). However... on the flip side of that (and i am still a novice) i have been observing with bins for nearly 30 yrs and only in the last yr i have become the owner of bins (20x90) that are fully-multicoated. I dont know what they are coated with but i can tell you that even under a full moon my bins allow me to observe faint fuzzies and galaxies with no problem. The full multi-coating must be doing something right.

[Ogri]

Caotings are present to stop reflections from the air/galss surfaces. They reduce the reflected light from 4% at each surface down to say 1%. So more light gets to the eye.

Basically if it isn't reflected off then it is transmitted through.

They are not there to reflect or cut out wavelengths. In fact the opposite.

Unsure about the description of your best glasses.

Polarising is not colour dependant, so green polarisation is strange.

Blue mirroring, sounds like a poor anti-reflection coating that was put on for red and green transmission and ended up reflecting the blue spectrum. Possible as you mention UV coating, UV being up from blue. Guessing that it reflected the UV and carried over in to the blue spectrum.

Well I had a choice of tints with the polarising, and remembered from clay shooting that the best for contrast in bright conditions, is green, and the best for contrast in poor light conditions, is amber (so I have 66% amber coatings for my night/poor light glasses, along with silver mirroring, and they work well at the heavier tint level than say normal night driving glasses that would be around 33%, due to my locked open pupils).

As far as I am aware, there are only two types of mirroring available for spectacles, one is blue and the other is silver. A friend took a photo of me when wearing them, and the blue showed up really clearly, better than the mirroring even (which was how I clicked that I'd got the replacements wrong).

The mirroring helps as a pretty good anti-reflective coating as well (for the eye side of the lens), as I understand it.

"The full multi-coating must be doing something right. "

Thanks for that Paul, it might be quite encouraging.