Jeesh, just use a manual lens.
Here are some of my star trail notes:
Battery independent Nikon F2
(I would not hesitate using a Nikon FM series camera if I had one)
Normal to wide (50mm to fisheye)
Locking cable release
Stiff black felt square (5 ½ x 5 ½ inch) to block unwanted light on lens from motor vehicles and air craft.
ISO 100; f/8; 30 minutes plus film reciprocity
I have friends who have autofocus lenses and have a difficult time achieving good focus because it's difficult/impossible for the AF mechanism to focus on stars and because many autofocus lenses typically focus past infinity, making it very hard to focus manually on screens that weren't made for that.
I've found with manual focus SLR and rangefinder lenses that the infinity stop works very well for tracked stars and star trails.
A plastic cup that fits over the lens and is either black or lined with black material is a great aid for blocking plane and satellite trails.
Also be sure that you don't have any leaks from an electronic viewfinder display onto the film with long exposures. I have one SLR that does that, but it has a mechanical B setting, so I can use it, but have to pull the batteries first. Many electronic shutters run the batteries down very quickly with time exposures. My DSLR using friends have to bring an outboard power supply for their cameras.
Some lenses are best stopped down 1/2 to a full stop for best image quality, especially at the corners. Test.
I'm not a real Nikon user, so I can't speak to specific appropriate bodies.
Well considering all of that, forget the n6006 and use a Nikon F or F2. Or a Nikkormat, I have the Nikkormat and it is absolutely fantastic, all the heavy metal kerchung of the F without the pricetag. You can find them for next to nothing, I have seen flawless copies trade for as little as 25 dollars. I got mine free in a lens deal, I purchased a set of lenses from a seller on Craigslist and he threw it in for free.
I also purchased a Nikkormat FT2 for 40 bucks with a 50mm f1.4 pre-AI, which is a regular Nikkormat with a flash hotshoe and the ability to meter AI and AI-S lenses. I ended up selling it for 100 bucks with a 28 f3.5 attached to it.
The only caveat is you must use a shutter cord with a locking mechanism, I made the mistake of buying one that doesn't, unless you want to hold a cord for 5 hours.
Do not use the Nikkormat EL, it has an electronic shutter and thus uses batteries. All other Nikkormats (I have the first-generation FTN) use a battery for the metering system.
Also, this may or may not be myself bragging about the low-light AF of my EOS Canon 5D digital, but I can AF it at night using radio towers in the distance with their indicators on. I set the focus to center focus, set the metering to spot metering on AF point (not necessary but I find it helps) trip the AF and I'm golden. I have used it to AF a lens that went onto a 35mm EOS with poor low-light AF with success. I'll AF it on my 5D, mark it with something in case it moves, set the focus to manual and turn off the stabilizer, throw it on my EOS 650 and get tack sharp exposures.
Should have thought to mention:
You can use a diffraction mask in front of the lens to create diffraction spikes, making it easier to see when you're in focus on a star with an autofocus lens and SLR body. You can purchase them online or make them yourself. Here are links to two different styles most commonly in use these days:
But I'm not sure how well these would work on a wide angle lens.