Q: What are ITAR restrictions on export & transport of night vision devices out of the US?
Q: What is the difference between tube manufacturers?
A: There is a whole lot of discussion about this on various tactical/military sites like AR15.com, but with regards to astronomy applications of night vision, this is a good post about the differences between ITT and L3 for White Phosphor tubes.
Q: It seems that Night Vision is really effective for cutting out light pollution from urban areas. Does this mean that I don't need to go out to dark sites any more? Alternatively, if I live under dark conditions, is NV basically useless for me?
A: The answer to both questions is a resounding "NO!" Night Vision devices amplify the light that is already there. If you have a lot of light pollution, it will also amplify the light pollution. Of course, this can easily be solved by using filters to cut out the unwanted light, and then the NV device can make up for the loss of brightness via artificial amplification. So in a sense, you're getting "free contrast", at the cost of potentially distracting scintillation "sparkling" in your field of view. However, if you are under truly dark skies, with great transparency and naturally great contrast, Night Vision will simply make your experience much more magical. It can amplify just the "good photons" with no decrease in contrast, and no need to block out light-polluted bands of the spectrum. The sky will be "filthy with stars".
Q: Can I use night vision devices to look through a traditional eyepiece?
A: Yes! However, there are optical considerations and depending on the particulars of your telescope, eyepiece, and night vision device, you may experience coma, vignetting, or other optical limitations. See the "Digiscoping" section of the Optical Considerations of Night Vision page for more information.
Q: Isn't Night Vision awfully expensive for such a small, simple device? Is it really worth it?
A: Emphatic yes, followed by a paragraph of eloquent advocacy for NV+astro; coming soon Posts to reference: