Dighappy,
is this nest actually on your property ??
i have read that a dose of Diazinon dust applied with a
bulb duster directly into the nest will take care of
the hornets which depending on the number of workers in the nest could range from a 100 to 700 .
other than the dust and or some anhyrdous ammonia ( which will "freeze" the hornets ) and will also cause a "cold" burn when it comes in contact with skin as it is rather dangerous to use as it is considered a gas and it will literally choke a person that inhales it to say nothing of how it will burn !!!!!!
here's a link that may be helpful in getting rid of the hornets and their nest.

Like you say, you have passed within 5 feet of them and they never bothered you. That is about standard for these. Although large and scary looking, I often lay near them and watch their comings and goings. Vibrations set them off, especially if the nest is shook. Otherwise thay are remarkably peaceable. If you want the nest, you'll have to beat the birds to it. The queen abandons the nest before the first frost, usually burying herself in the leaf litter nearby. The remaining workers dwindle in number, victims of old age, other insects and birds. Eventually there will only be a couple of lethargic old biddies left. At this point, going out in the early morning (the cooler the better) with a pair of snips will get you the branch. Then hang it in a protected area until regular frosts occur. At this point (or any time temps are in the 40'sF or lower), a gently shaking will dislodge any remaining adults.

I used to collect them, had about 5 at one time. There are some drawbacks to having them in the home. Not what you would think though, I never had a single live wasp emerge from the nest. However, these nests are constructed of mud, saliva and whatever. When introduced into the dry air of the average home, some of the mud will fall out of the layers. A fine dust/grit will constantly fall. If you hang it over fine furniture or some such things, you will rue the day it caught your eye. Also, if there are any unhatched larvae/pupae, they will be killed from the cold, but their corpses will draw critters that eat such things. After a few weeks of dry temps, the dried tissues of the juveniles seem not to interest anything, and even spiders don't hang around, nor do flies go near. These tasty tidbits of larvae/pupae are what draw birds to tear the nest open at the first sign of abandonment.

Handling the nest the first time will give you the willies, but with the recent cold, I would feel confident in advising the plan above. No need to run for nasty chemicals or dangerous methods. Nature provides a safe easy way to pluck these masterpieces from the tree. They are annual events, and are not reused by anything next spring.

Thanks Pennsylvania Pete.

Great info. What the web is all about.

And good photos, too.

Just passing through looking for advice, but I have to say WOW what a beautiful nest!

There's a nest exactly like that in a tree on a neighbor's property across the road. Being a beekeeper, I'm the local expert, and I surmised it was bald-faced hornets. They won't survive the winter, I don't think, and I advised them to take down the nest after a few subfreezing days. Then pop it in a deep freezer for a week, then defrost and keep as a trophy.