# Questions tagged [spherical-astronomy]

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### Correct longitude from longitude over 180°

Last week, one of my exercise tasks was about determining the an observer's position on Earth, when in their zenith is a certain star with known right ascension and declination. We were supposed to ...
63 views

### Demonstration- formula for angle between horizon and ecliptic

The most precise and quite intuitive formula I could find online is here: https://www.celestialprogramming.com/snippets/angleBetweenEclipticAndHorizon.html \cos I = \cos ϵ \sin ϕ − \sin ϵ \cos ϕ \...
1 vote
56 views

### Transformation matrices and their derivation (if possible) for ICRS frame for reference to other frames

I am finishing up my thesis write up and one of the chapters in my thesis is on astronomical coordinate systems since in my analysis of data I have converted the available astrometry from the ICRS ...
136 views

### Angular distance calculation in Equatorial and Galactic coordinates

I calculated the angular distance between the Galactic Center and Andromeda in Equatorial and Galactic coordinates and observed that the distance is calculated differently depending on the coordinate ...
121 views

### Discrepancies in the equations for converting Horizontal coordinates to Equatorial coordinates

Hello I am trying to convert my Horizontal coordinate system dataset into Equatorial coordinate system. However, it seems that all the information from the internet is different. I will use symbols as ...
1 vote
185 views

### how to calculate ecliptic coordinate of moon's ascending node?

Assume we have the ecliptic coordinate of moon; how can we calculate the ecliptic coordinate of its ascending node? I think one approximate way is to use the moon's coordinate for two subsequent days ...