In this article, I would like to talk about the fact that the most important thing to watch and shoot starry sky is location hunting, with my real experience.
A picture is worth a thousand words. Lets see two examples below. Both pictures are Milky Way photo.
The first is Mt. Fuji and the Milky Way taken from Lake Shoji, one of the Fuji Five Lakes. This is a beautiful picture, but the original light and color of the starry sky are lost due to the influence of artificial light. Although Lake Shoji is quite out of the way, the sky is still brightly illuminated by the city lights. It is so hard to correct them even in Lightroom.
Next is the second photo. This is a picture of the Milky Way taken at New Zealand's Tekapo, a world-famous place for starry sky observation. The original colors and shades of the Milky Way have been faithfully reproduced.
In fact, I spent overwhelmingly more time to edit the first photo in Lightroom than the second photo. It took me a long time to extracted the light of starry sky by applying multiple filters due to the strong light pollution around.
Please refer to the video that shows the development of the second photo from RAW. I didn't do much, and the editing was done in less than 10 minutes.
By the way, you may have noticed that the direction of the Milky Way is opposite in the two photos because New Zealand is in the southern hemisphere.
Of course, no-moon-light and good weather are very important things to see starry sky. In this article, we will focus on difference between places. Other things are summarized in the other article, so please take a look at it.
Answer:the amount of light pollution
As I said at the beginning, the amount of light pollution is overwhelmingly different. Let's take a look at a comparison between Japan and New Zealand in Light Pollution Map. Tekapo, especially famous for its starry sky, is located around the center of the southern island, there is almost no light pollution. (The colored part is light pollution. Blue < yellow < red)
Meanwhile, let's take a look at Japan. Not only Kanto but also remote islands in Okinawa and Hokkaido are colored. Yes, there is no place in Japan where you can observe and shoot starry sky as beautiful as New Zealand.
I experienced this myself. Before I went to New Zealand, I was taking photo of the starry sky in various parts of Japan. But when I shoot starry sky for the first time in Tekapo, I was so surprised to capture so many stars in my own camera.
High altitude and clear air are also important, but there is no significant difference in elevation and clarity of air between Lake Shoji (900m) and Tekapo (710m). I am convinced that light pollution has the greatest impact.
In this article, we introduced the fact that location hunting is the most important for watching and shooting starry sky. Unfortunately, in Japan, there seems to be no better place to see the starry sky than New Zealand.
Since you only live once, I strongly recommend that you visit New Zealand. That's almost space.(I've never been to space though LOL)
I know it is expensive for tours, and there are many people who are worried about traveling abroad, so I'm writing an article how to enjoy sightseeing in New Zealand as much as possible at low cost. (I have summarized Iceland in the past too)
I'm so glad if you are interested in that.