Multicoated vs Fully Multicoated

[aiesh_kaul]

Hi Everybody,

I am new to astronomy and panning to start with a pair binoculars. While browsing through various products, I have come across the "Coating" specification. I can see some binoculars specified as Multicoated and some as Fully Multicoated. When I called one of the retailers, he told me that Multicoated and Fully Multicoated means the same thing. There is no difference between the two.

Could anyone please suggest me what is the truth behind this. It would be great if anybody can explain the definitions of these two terms.

Thanks,
Jimmy

[dannat]

the truth is a multi-coated binocular has only one or more glass surfaces with multiple coatings, some surfaces may be single coated -fully multicoated means all glass surfaces have multiple coatings

[barx1963]

There are retailers and then there are retailers!! Having recently heard of a retailer assuring a customer that the Horsehead Nebula would be visible in a 4" scope, there are maybe some whose knowledge is less than perfect.

Malcolm

[ausastronomer]

Hi Jimmy,

You should read this.

http://binocularsky.com/binoc_minefield.php

Now, having directed you to that article which is 100% correct, you can generally take it as given with binoculars costing less than $300; that those having fully multicoated optics and BAK 4 prisms will be a better quality than those that are only "multi coated" and don't specify BAK 4 prisms. You should also look for binoculars having 10mm , or more, of eye relief. In 99% of cases binoculars costing > $300 will have fully multicoated optics and BAK 4 prisms and generous eye relief.

Another golden rule. Don't listen to what the assistant in the store tells you about astronomical telescopes, or binoculars, unless it is a store that specialises in these types of products like the Binocular and Telescope Shop, or similar. The staff working in stores like Camera Stores and Australian Geographic haven't got the first clue about astronomy related products and they will generally tell you what they think you want to hear.

Cheers,
John B