Mars Seasonal Polar Cap

[ImmersiveTheatres]

I am carrying this issue over from #3535.

I've just discovered the latest versions of Stellarium includes a simulation of the Mars polar cap.

As an astronomy teacher using Stellarium in mobile planetariums for over 10 years (immersive-theatres.com), I think the simulated ice cap is currently very unrealistic and a major distraction for the audience. I can just hear the children asking: 'is Mars bald?'; 'does Mars have a plate on its head?', etc

Remember when I zoom in on Mars in the planetarium with a 4K projector, the planet looks HUGE - and the unrealistic ice cap is very noticeable, and distracts from what I wish to teach about the planet ie. its colour, surface features, etc.

I therefore request that either the polar ice cap:

• is made optional in the config.ini file

or

• instructions are made available on how a user can modify the appearance of the ice cap ie. change the colour, the texture, make it non-circular, etc.

Thank you for being responsive to user requests like mine.

Tens of thousands of children view Stellarium in my domes every year, so the improvements / changes you include for the specific needs of planetariums (eg. the option for stars to twinkle with the atmosphere off to allow the sky to look as dark as possible, etc) are appreciated and enjoyed by many, many people in my domes alone.

I also always share these improvements with the international mobile planetarium community; so around the world, hundreds of thousands of people annually get to benefit from such improvements. Therefore thank you again.

[github-actions]

Hello @ImmersiveTheatres!

Thank you for suggesting this enhancement.

[gzotti]

Please provide a series of dated photos that shows the true extent of shrinking and growing ice caps, off-white color or other features that you like to see instead. #2040 was developed based on current scientific models. Twinkling stars with atmosphere off is a weird error I would never agree on showing.

[ImmersiveTheatres]

The Mars northern ice cap varies considerably throughout the year (and not all years are the same of course). Below is a series of images from: https://www.sciencedirect.com/science/article/pii/S0019103514004424

I assume the Stellarium polar ice cap is currently static, fixed at maximum size?

Can we please have the option to at least reduce the size as required?

In Stellarium we have SO many options over SO many parameters regarding the Universe (one reason it is such a wonderful application). It would be good to also have some control - or the option to remove altogether - something as nuanced and ephemeral as the Mars polar ice cap.

[gzotti]

Oh wow, look, I never knew Mars looks like a 13-petal flower centered on the pole!

Please invest half a minute to play with the date settings to verify or falsify your assumptions. Then use your newly-found powers to introduce children and grown-ups to the dynamic growing and shrinking of Martian polar caps as the seasons go. Tell them it's a simulation, and the real ice caps may show some details around the edges not covered yet in the simulation. Think about methods to improve the modelling, quick fixes or true improvements. And please show series of earth-bound images, not artificial polar views from spacecraft around Mars, so we could compare views.

[Atque]

You could simply use the survey texture of Mars to hide the polar caps, and you get a much more hires texture as a bonus.

[ImmersiveTheatres]

You could simply use the survey texture of Mars to hide the polar caps, and you get a much more hires texture as a bonus.

Amazing! Thank you @Atque. This is all I was asking for, an alternative option for Mars.

Yet I can't see how to save this setting. Every time I restart Stellarium, it reverts back to the non-survey texture of Mars.

I see there is a section in the config file:

[hips]
show = false

Yet even if I change this to:
show = true

..it makes no difference and on restart Mars reverts back to the non-survey texture.

Searching online, I have also tried the following:

[hips]
planet_surveys/Mars = "CDS/P/Mars/HRSC/Colour"

[astro]
flag_use_hips_planets = true

But it doesn't help.

Is there a way to preserve the Mars survey texture as default?