The first clue lies in the details in the image combined with knowing a little about photography, any photographer who knows about exposure will tell you that you will not be able to capture the bright sun and the details in the shadows at the same time in one image, the same rings true for the image above.
Having that knowledge when looking at the image will tell you that the image is one of 2 or more captures combined into one.
Knowing that the image is captured at night also tells you that it must have been rather dark outside, but the image appears quite bright, that with some photography knowledge will tell you that a longer exposure has been used and highly likely in combination with a high iso, the clouds which looks a little blurry is also a good tell tell sign.
I can continue along this path even further, but my point is that the mystery of night photography is all in the images you see, what you need to know is the info that will allow you to break down those images, demystify them and easily be able to do simular captures.
Fyi, the image above is 3 captures, one for the sky and aurora, another image at + 1 stop for the reflection and a third at +2 stops for the details of the mountains.
I know that on the tripod ballhead I have to turn a small screw 3 full circles counter clockwise to be able to attatch the camera on top, I know that if I unlock the mode dial and turn it clockwise until it stops I am in Mirror-up mode, if I go one back I am in timer mode and I have already set the menu at virtual horizon so I can level the camera at any time I want.
As long as you know the layout of the camera and can do basic adjustments without looking you will have a bit advantage when it comes to night photography, it is so simple but incredible effective.
Much the same goes for your other gear, tripod, lenses and so forth, the important thing is that you know enough to have control when the situation you want to photograph arises.
Night photography isn´t as hard as you might think but some essential gear is required in order to take images that are usable.
A camera - I highly recommend a DSLR camera or mirrorless that can perform at higher iso levels (800+).
Lens - For general night sky photography I would recommend a wide angle lens 35mm or lower for full frame cameras, 24 or lower for aps-c cameras, for such imagery of the moon a very long telephoto lens is really good, 400mm+ (300mm can work, but it gets a little small).
Tripod - A tripod is crucial, personally I recommend a tripod with a ballhead and if you can afford it a carbon fibre tripod.
Not essential but I would absolutely recommend getting a cable release for your camera so you can trigger the shutter without touching the camera to get sharper images as you have to rely on longer exposures and besides it is quite cheap.
Getting correct focus is vital,good ways to achieve that is to use light sources like a bright star, the moon or distant artificial lights to get the lens to focus at infinity (which is what you want to get those stars to be points of light), get where you want to shoot when there is still some daylight and pre-focus before it gets dark or to set the focus at infinity (middle of the infinity symbol on most lenses) take a test shot, zoom in to check and adjust if you have to.
If you are pressed for time to capture an image, set the focus a little under the infinity symbol and close the lens down by one stop (f/2.8 -> f/4 for example) so you are sure it will be sharp, better that it is a little darker and sharp.
Most lens manufacturers has a slight tolerance for where infinity focus is actually spot on, generally around 5%, so despite having it dead center it might not be 100% correct, testing that beforehand can make a big difference.
The image above falls within acceptable levels in my book, if I use a little bit of noise reduction and edge sharpening the image will look just fine even on larger prints.
Choosing the right iso depends a lot on what you want to capture, for instance the milky way you want to push the iso to higher levels to captures those faint stars, 3200 and 6400 iso is very common to use for such.
Aurora on the other hand you want to keep the iso a bit lower to retain a higher colour quality but not too low or the aurora just looks like a cloud of green/red, I generally stay at 1600 or 800 depending on the strenght of the aurora, a combination of both 1600-2500 is a good bet.
It all depends on what camera you have, for instance the Sony A7S is a high iso monster, all bets are off with this camera, Ive seen crazy high iso images from it look super clean, downside is that it is only 12mp and it is quite expensive, the Canon 100D on the other hand does not fare as well on higher iso, it has just over 800 iso sensitivity so iso 1600 is almost pushing it, you can go that high but you need some agressive noise reduction in post.
Test out a series of shots at night starting at 200-400 and work your way up as high as it goes, import the images to your computer to look at the full size and decide how high iso you can live with, pay special attention to the shadows and edges of the image.
There is something called "The rule of 600/RO600" where you divide 600 by the true focal lenght of your lens determined by the crop factor of the camera, a full frame cameras like the Canon 5D Mark II, Sony A7r and Nikon D800 has a crop factor of 0, so a 50mm lens on a full frame camera is 50mm, an APS-C camera has a crop factor you multiply the focal lenght with to give you the true value, Canon APS-C cameras has a crop factor of 1.6 and Nikon APS-C cameras has a crop factor of 1.5, so a 50mm lens on a Nikon APS-C camera has a true focal lenght of 75mm.
Ex: RO600 with a 16mm lens on Canon APS-C= 600 / (16x1.6= 25,6) = 23,4 Seconds exposure time before star trails occur.
It is not an absolute dividing 600 by true focal lenght, especially around the edges of the image where star trails show up much faster than the center, to be safe I suggest dividing 500 instead of 600.
There is an app for iphone and android called "The photographers ephemeris" it tracks by gps your position in relation to moonrise/set and sunrise/set, it is really great for the times you want to capture the moon or sun on very spesific locations in the sky, it will also tell you when it is new moon.
For milky way photography it is the best time to be out, up here where I live in northern Norway we generally get auroras all the time so getting actual clean captures of the milky way is a lot harder than you would think, I know, it is a luxury problem. :)
And if there is something you just can´t figure out you can always search for it on google/youtube and other sources, odds are you will find a good guide on the subject very fast.
Try yourself out by looking at the image right above, try to figure the settings that was used to capture it and under what conditions.
But if you spend your money right you can get really high quality gear for a lot less than pro level equipment, buying used cameras and lenses might also be a good option, I would recommend you to buy from someone you know if possible, or if a seller has lot of good feeback that is also a good option, spend the time doing some research on the right camera and lens for you that meets your budget and try to get the best deals possible.
Some resources to get you started:
http://www.dxomark.com/ - Lab testing of lenses and camera, also rates based on sharpness, low-light performance and more.
http://www.lenstip.com/lenses_reviews.html - Real world testing of lenses, pay special attention to coma and flare performance.
Use both in tandem to find the perfect lens and camera for your needs, and don´t forget to look up reviews of any tripod you want to buy as well.
For example a used Canon 5D Mark II with a Samyang/Rokinon 14mm F2.8 is a very cheap and killer combo, especially considering that the 5D Mark II is a full frame camera, and also now that the Nikon has released the D810 the price for a used D800 has plummeted.
If I had a 1000$ budget to start out doing night photography it would not be much of an issue finding the best possible gear for that price range, looking at the used section I found Nikon D3300 going for 350$, a Sigma 10-20mm F3.5 EX going for 450$ and the last 200$ I would buy a Velbon Sherpa 4430D w/QHD-43D ballhead , all saving me roughly 5-600$ by buying some of it used.
* Weather - Check the weather report.
* Camera, lens, tripod - Batteries charged (spare battery for long nights), memory card(s) empty, lens cleaned, tripod in full working order.
* Settings ready - Check iso, whitebalance, aperture, timer mode or mirror up if you have cable release.
* Bag packed - Photo gear, coffee/cocoa, some food/snacks, warm clothes, wood for fire if needed.
* Steady - make sure the tripod stands firm on the ground.
* Focus - Get the focus correct as soon as you get to the location.
* Test shots - Both to check your composition, if the image is sharp and that everything is looking as it should.
* Fire away. :)
Even though it is tempting to look at every image you shoot, if your settings and everything else is right you know that the images will be fine, use that time instead to enjoy the night and have fun.