New Orion Short Tube 80-A w/multi-coatings

I would like to get some opinions on Orion's new Short Tube 80-A with improved fully multi-coated optics.

I have one of the of the first 80 short tubes so, I was wondering if the new coatings will actually improve the image brightness in astronomical applications. Will there be a noticeable difference? What's your guesstimation?

Thanks in advance.....Roger in Tampa

No.

Dmitri

Uncoated lenses lose 4% on each air-to-glass surface. Single MgF2 coats usually loose 1.5%. Multicoatings lose around 0.5%.

So given that this 80mm used to not be multiciated on "all" surfaces, let's assume that meant one surface multicoated, the other 3 with standard MgF2 coat.

Results for the 4 surfaces:

Fully Multicoated = 2% total loss of light
1 Multi, rest single = 5% total loss.

Once you apply these losses to the actual objective, the 80mm with full multicoating acts like a 79.2mm objective with zero loss, and the older one with only one surface multicoated and the rest single coated would perform like a 78mm objective with zero loss.

I doubt anyone could see that difference. So in short, as already stated, answer is no, but now you can understand why ;->

-Bill

ps - 134 words 8)