In the most recent update I made some small changes, most importantly about when I prefer to use the website.
The present post is a complement to this post of mine:
Easy astronomy for total amateurs
I have been using the website:
https://stellarium-web.org
for a long time, but I have also installed the free program Stellarium from this site:
https://stellarium.org/
The program is not perfect but it's still very good:
1) the program has much more options and is much more configurable,
2) the program is much less burdening for the computer.
Please notice that I still regularly use the website, especially when I want quick results, better visuals or deeper star field.
When I am using the website on an old laptop I can hear the CPU fan working very hard, but I don't have this problem with the program on the same laptop. The program is even less burdening for the computer when you change the frames per seconds (fps) in the config file (more on that at the end of the post).
There are tons of options in the program, but the most important thing is the fact that I can simulate light pollution for the exact time of my planned observations (to simulate light pollution on the website I had to set the time for twilight hours – for much earlier time).
Please notice that while simulating light pollution EVERYTHING that I can actually see in reality looks better than in the program! More shiny and more impressive! The program is good at simulating WHAT you can see, NOT how you can see it!
To achieve a satisfying effect in the program I have to use these four options together (they are all under the “Sky” tab):
1) Sky – Light pollution,
2) Stars – Absolute scale (influences also planets and moons),
3) Stars – Relative scale (influences also planets and moons),
4) Stars – Limit magnitude.
To explain why I use a particular configuration of the settings above I have to show you some examples that introduce changes step by step.
Please open all pictures in separate tabs and switch back and forth between the tabs to see the differences better.
Light pollution 1 (smallest), Absolute scale 1 (default), Relative scale 1 (default) and Limit magnitude turned off (default):
As you can see the brightest stars are unnaturally big! This is the way classic (paper) sky-charts show magnitude of stars – by their size. This is also the way the Stellarium website shows the night-sky. Fortunately in the Stallarium program we can make the view more natural.
Light pollution 1, Absolute scale 1, Relative scale 0.5 and Limit magnitude turned off (“my default” setup):
Now the brightest stars look much more natural AND there are actually MORE stars visible overall! I saved this combination as “my default” setup.
Light pollution 4, Absolute scale 1, Relative scale 0.5 and Limit magnitude turned off:
The Milky Way is still visible, but from my balcony I can't see it at all, so I have to turn it off.
Light pollution 4, Absolute scale 1, Relative scale 0.5, Milky Way turned off and Limit magnitude turned off:
This view is already quite depressing, but there are still too many stars visible! From my balcony I can't see “so many” stars, even though light pollution in my home city is “only” Bortle class 6, probably because there are many street lamps near my balcony that are blinding me directly.
Light pollution 4, Absolute scale 0.25, Relative scale 0.5, Milky Way turned off and Limit magnitude turned off:
This combination of settings almost perfectly simulates what stars I can see from my balcony with the naked eye (when the field of view is extremely big) and with 8x42 binoculars (when the field of view is still bigger than in any telescope).
Please notice also that the stars that I can actually see in reality look better than in the program! More shiny and more impressive! The program is good at simulating WHAT stars you can see, NOT how you can see them!
Please notice that there are hardly any stars visible in the naked eye, but when I zoom in more and more stars appear, just like in real life – even the weakest binoculars allow you to see much more stars even in big light pollution!
However when I zoom in to a field of view typical for a small telescope, for example 1.9 degrees there are some “extra” stars in the program that I can't see in my telescope.
If you are interested, the value of 1.9 degrees was calculated this way: 700 mm telescope / 25 mm eyepiece = magnification 28x; typical apparent field of view of eyepieces is 52 degrees, so the field of view is equal to 52 degrees / magnification 28x = 1.9 degrees.
Light pollution 4, Absolute scale 0.25, Relative scale 0.5, Milky Way turned off and Limit magnitude turned off (the same combination as previously, but the field of view is now very small and the view centers at a different place):
From my balcony I can't see “so many” stars in my telescope, so I have to trim the “extra” stars further down. On several occasions I verified that from my balcony in my telescope the limit magnitude is around 9.0 (this value would be different for another telescope and/or for another observatory point).
Light pollution 4, Absolute scale 0.25, Relative scale 0.5, Milky Way turned off and Limit magnitude 9.0.
This combination of settings almost perfectly simulates what stars I can see from my balcony in my telescope in big magnifications. Please notice also that the stars that I can actually see in reality look better than in the program! More shiny and more impressive! The program is good at simulating WHAT stars you can see, NOT how you can see them!
The problems, as always, are with globular clusters, galaxies and nebulas. They are very sensitive to light pollution and it's impossible to predict what can be seen from a particular observatory point in a particular telescope. In the program there are photos of such objects incorporated into the view, but they always appear better than in my binoculars or in my telescope (in a given field of view). There's no combination of settings that simulates what I can see when I look at such objects.
In the program Stellarium there are additional problems with globular clusters and with galaxies that are non-existent on the website.
In the program there are photos of globular clusters instead of actual stars, while on the website there are hundreds of separate stars that on their own build proper pictures of globular clusters (without any photos). When you set the time to an early hour in the program the photos fade and stop being visible, while on the website you can see all the stars as tiny points.
What's worse in the program within globular clusters there are some stars visible that are NOT actually THERE!!! This is ridiculous! Here's the globular cluster M13 in big magnification (around 65x):
Do you see the 2 stars inside the cluster? Here's the same place after I turned off the option “Deep-sky objects background images”:
In the program these “stars” have no name and they are of magnitude 8.05 and 8.40, but in reality there are NO such stars! On the net I found this info: “M13 is composed of several hundred thousand stars, the brightest of which is a red giant, the variable star V11, also known as V1554 Herculis,[12] with an apparent visual magnitude of 11.95”.
I think that the same problem concerns galaxies – in the program in the heart of the Andromeda galaxy I found two “stars” that I think are not actually there, but I'm not completely sure. Let's focus on the M13.
When I turned the Limit magnitude off more stars appeared, but NOT in the center of the cluster!
So, in the program the cluster looks like a donut! This is probably why the button for the option “Deep-sky objects background images” isn't visible by default.
If you are interested, this button can be activated in the file config.ini that can be usually found in the folder …\AppData\Roaming\Stellarium. You have to set the value “true” in the line “flag_show_nebulae_background_button”.
In the same file you can also make one crucial change – you can set a constant value for frames per second. When the maximum value for FPS is low enough then the program is even less burdening for the computer processor. When the minimum value for FPS is high enough then there is no “stuttering” while using the program. Personally in the lines “maximum_fps” and “minimum_fps” I set the same value 7.
Even thought the program has some flaws it's VERY good and on some levels it's better than the website! What a treasure!
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