Auto levels and long distance readings, accurate?

I'm able to read the rod at 500' and still see down to 0.01' when the heat waves aren't too bad

Is that with or without a rod target?

I don't have the manual and I can't find one online either.

https://www.wild-heerbrugg.shop/index.php?cPath=1_3_19_73

There is a reason 250' is recommended as a distance limit for levels, well two reasons. Curvature and refraction. You say it yourself; "when the heat waves aren't too bad". Draw a circle on a sheet of paper, then draw a radius in it, label the radius with 20,906,000' (radius of the earth), then solve the triangle at 500'. How much curvature did you get? 

Then look up with Google the formula for refraction corrections. You should find them somewhere and apply those to 500'. 

I would do these calculations endlessly by hand and developed some distances ranges for each .01' of corrections to apply to my elevations. 

At 490' I would apply .01' (I know it isn't 0.0100000' at 490', I was looking for a range) and so forth up to 2000m. It's not a linear change. 

But the refraction calculation is a guess, it's environmental and changes with heat, clouds, time of day.

Those calculations you should learn, but the better practice is to limit your distance to 250', balance your turns and close everything into bench mark control. 

Do you know how to peg the level?

That needs to be done daily. 

It's not the level, it's the environment. 

Balancing backsight and foresight distances at least approximately is important. This doesn't have to be precise if you do the refraction and curvature calculations.

Also, you need to avoid having different conditions in each path that would change temperature of the air, such as grass one way and asphalt the other.

Reliable elevations at 500'? To the foot, maybe even the 10th but not the hundreth. Not with any optical device. You are looking through a medium that distorts the visible light waves. You can mitigate the curvature and refraction but your mitigation might not be enough to compensate for any given condition.

The temperature gradient is what will get you.

Curvature, balanced sights, sighting/reading errors, all of those things are systematic and may be accounted for with good procedures.

But it is very difficult, if not impossible, to adjust for refraction due to temperature at that range. (Also, as a general rule if you have to sight over that distance, there's something keeping you from moving closer, and that something often affects temperature in ways that you cannot reliably model, especially from day to day.)

It's still possible to get good results, depending on the goal/aim of the work. But I would make every effort to restrict those long shots to early morning or late evenings when the temperature gradient is lowest.

Bluntly, I'm calling BS on being able to read the rod to the hundredth at 500 feet. Not on the clearest frosty day of winter. Half that is stretching it. In any case, the attempt would cost more time than reading a couple of turning points. 

@norman-oklahoma 

I thought I had an NA1, but it's actually an NA2 which has a 32x magnification. I can definitely read to the hundredth on the rod at 500' if the heat waves aren't too bad, whether or not the accuracy is to the hundredth is another question. If I tried reading the rod at 500' with my Sprinter level, I'd never be able to read to the hundredth with it's 24x magnification. I think the optics are just better/clearer on the Wild, regardless of the magnification.

Balancing backsight and foresight distances at least approximately is important. This doesn't have to be precise if you do the refraction and curvature calculations.

IF you balanced the foresight and backsight, wouldn't the curvature equal out? 

and...there is THE RIGHT WAY...(limit distances to under 150 meters under the best conditions)

https://geodesy.noaa.gov/library/pdfs/Special_Publication_No_140.pdf

@dmyhill 

Sure, if they are closely enough matched the curvature cancels. And the refraction sort of cancels, but probably not as well.

Curvature and refraction almost cancel each other out at about 300 ft depends. So i like the 250 ft range. Now the temperature is another issue. When doing NGS levels you can attend a class very good. You will see they have temperature readings at level and rods. A very good reason for this. 500 ft is pushing it no matter what the specs or magnification is. Yes you can read something at that distance. Especially on a good overcast day. But take a stick and stab it into a pond or even bathtub the stick appears to bend. So you appear to read a hundredth of a foot. Sometimes you will sometimes you will not. Balancing the BS and FS help but that keeps those two readings close. Another reason why on levels run the NGS old book on standards is such a good read. Bs and fs of any set up cannot exceed a certain amount. Also the total of BS and FS cannot exceed. So every turn can be within specs and you still exceed the overall run. Especially if all fs for example are always longer than bs. Umbrellas were a valuable tool on a level crew. Especially in the days of Dumpy and Y levels. They were sensitive to sun heat etc. I would be guessing you are going to have some compensating errors that might make your loop appear to close or not. Cut it in half if you are allowed on the distance. Now if you must take a bit of time and read what is done with levels for 2nd order and why distance are mandated between the different classes. Another one on the longer range levels is rivers and valley crossings. If memory serves me correctly you will have the corrections formulas in that rivers and valleys crossings at least some explanations on much longer site distances with a level.  

@bill93 , et al…

Balance the turns and stay at 300' or less and you should be alright.

@geeoddmike thats the Depends in my statement.