Visualize a given RA/DEC equatorial coordinate

[gerben-b]

Hi Don,

Some time ago I created moon_cam using your Astronomy engine (javascript). Currently I am creating an advanced version with a built-in planetarium. Most of it is working now and i will publish that soon on github, but one thing is missing: I would like to plot a given equatorial coordinate on my screen and for that I need to transform given RA/DEC (equatorial) coordinates into ALT/AZ (horizontal) coordinates. This means that the coordinates for this purpose cannot be related to a celestial body.

Can you give me some pointer on how to do this with your engine?

Thanks,
Gerben

[cosinekitty]

Hi @gerben-b! I'm glad to hear you are making good progress on your project. Yes, what you want to use is the Horizon function. It does exactly what you describe. It optionally corrects for atmospheric refraction, which I suspect you will want.

[gerben-b]

Thanks, that is indeed exactly what I need. The first thing that I want to do is display a cross hair on my planetarium. That will help me to better understand where I am in relation to e.g. the moon.

Also I noticed you have the Gallilean moons of Jupiter now in your engine, very nice indeed :-) Thanks for everything.

[cosinekitty]

When you get your project up on GitHub, please let me know. I would love to take a look at it!