Questions tagged [skyfield]

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2 votes
1 answer
90 views

What is the mathematics needed for understanding DE440 and translating it into xyz coordinates?

I would like to write my own code to process NASA's DE440/DE441 ephemerides, but I do not know the mathematics needed to do this. I understand packages such as pyephem have implemented variations of ...
Ana's user avatar
  • 181
2 votes
0 answers
53 views

Moon position differences on JPL Horizons, GMAT, Skyfield (using DE421)

I found a relevant difference in the positions for the Moon when calculating its Geocentric position with GMAT and Skyfield (https://rhodesmill.org/skyfield/), in both cases with JPL DE421. ...
Thibault's user avatar
1 vote
1 answer
50 views

Transforming radio sources in a T-RECS catalogue from one field to another

I have sources that I extracted from The Tiered Radio Extragalactic Continuum Simulation (T-RECS) catalogue for a deep field. I use these sources to generate a sky model at different fields within a ...
Supremum's user avatar
1 vote
3 answers
139 views

Are there such circumbinary planet configurations that two suns move towards each other by the sky?

Is it possible that suns move towards each other (not necessarily in opposite directions)? Such a configuration would cause interesting dusk and midday light cycles, in my opinion. Basically the ...
ivan866's user avatar
  • 109
3 votes
1 answer
114 views

How to plot the precession of the equinoxes using Skyfield?

I'm trying to create a map of the northern sky showing Earth's axial precession, like this wikipedia illustration by Tauʻolunga: I have figured out how to plot the stars using Skyfield but I'm ...
Sten L's user avatar
  • 133
6 votes
2 answers
274 views

Light or neutrinos graze or pass through the Sun and arrive at Earth - need an expression for Sun's gravitational effect on observation direction/time

Skyfield's Github has discussion Jupiter hiccup #815 which then links back to to Non-physical gravitational deflection corrections for Solar System bodies #734. The script and plot from #815 are shown ...
uhoh's user avatar
  • 31.6k
1 vote
1 answer
112 views

python skyfield hipparcos sun mean longitude (L)

I calculate the ra and decl or the stars as below. Can I add the sun's mean longitude L (=M+w) to: ...
sybe's user avatar
  • 63
2 votes
0 answers
64 views

How to get high-quality sky image for specific location & date

I'm working on an ink drawing album cover inspired by this Frank Hurley photo from the First World War, and want to put an accurate starry sky behind it in my album artwork.: The tower in the image ...
S. Imp's user avatar
  • 385
2 votes
1 answer
623 views

How to calculate the Earth's axial tilt (obliquity)

How can I calculate the Earth's axial tilt in degrees. I tried Skyfield, Poliastro and PyEphem. I know it's changing -0.47"/year, and it was ...
Unix's user avatar
  • 155
2 votes
0 answers
199 views

Make a guide map to comet comet Leonard C/2021 A1 using Skyfield

Sky and Telescope's How Bright will Comet Leonard Get? includes the skymap and projected (possible) light curve for comet Leonard C/2021 A1 that will potentially reach +4 magnitude this month. It has ...
uhoh's user avatar
  • 31.6k
3 votes
1 answer
105 views

why are my Sha and Declination calculations not the same as the answers from the Nautical Almanac?

...
sybe's user avatar
  • 63
4 votes
1 answer
140 views

Skyfield missing some rise and set dates

To compute the Andromeda Galaxy Risings and Settings I essentially use this code (in a more colplex code, but this serves the purpose): ...
Luca Berti's user avatar
1 vote
1 answer
168 views

How to compute rising / setting times for stars and deep sky objects with Skyfield?

I'm trying to compute rising and settings times for various objects with the Skyfield library. While the task is quite easy and well documented for planets (using the ...
Luca Berti's user avatar
2 votes
1 answer
102 views

predicting angular seperation between planetary objects and earth satellites

I am struggling to calculate the angular separation between a satellite in earth orbit and a planetary object using the Skyfield library. It's equivalent to calculating the angular separation between ...
elliot e's user avatar
3 votes
3 answers
2k views

Calculating the position of stars at a given point in time

Is there any particular methods that help us calculate the position of a star at a certain point in time? This question is what I am trying to achieve, but for me, I do not want to use the data ...
Prashanth Kumar B's user avatar
1 vote
1 answer
283 views

RA expressed in degrees

Using the Python package Skyfield I thought that I could get the RA expressed in degrees simply by doing ra.degrees, but I get the following message this angle is usually expressed in hours, not ...
Cirédérf Eniomel's user avatar
3 votes
1 answer
176 views

How to find the local azimuth of the highest point of the ecliptic

I would like to use pyephem or skyfield1 to find the degree of the local horizon (starting from South = 0°) at which is located the highest point of the ecliptic. Note that I am not trying to find the ...
Cirédérf Eniomel's user avatar
4 votes
2 answers
207 views

Discrepancy between my results of Great Conjunction 2020 and Wikipedia

Using python-skyfield to calculate the upcoming conjunction of Jupiter and Saturn. I'm off a few minutes with the times on Wikipedia. Wikipedia Great conjunction times (1800 to 2100) Using Right ...
Gary Ilijevich's user avatar
2 votes
1 answer
398 views

How can I calculate the right ascension of an observer on Earth's surface in the TEME frame with python.skyfield?

I would like to calculate the right ascension of a point on earth as specified above with the Skyfield Python library, and I can not figure out how to do this. I know that calculating the geocentric ...
fl0ta'''s user avatar
  • 43
1 vote
1 answer
138 views

Can I calculate the apparent position of comet NEOWISE C/2020 F3 from a topographic position with Skyfield?

I'd like to get .altaz(next_several_weeks) of this comet from Skyfield and .separation_from() other planets. It reads the JPL ...
uhoh's user avatar
  • 31.6k