Questions tagged [algorithm]
Questions about a stepwise procedure to solve logical and/ or mathematical problems.
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Flowchart of the pipeline of key processes for modeling wavefront distortion of astronomical objects: ground-based observation case
Associated with: Mathematical modeling of the influence of components of the interstellar medium on the distortion of the wavefront of the observed object
Being inspired by this article, as well as ...
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calculate declination and right ascension with limited information
I'm trying to make a game with high accuracy moon position so I followed some equations on geoastro.de Basics of Positional Astronomy and Ephemerides and with some help from the questions answers, I ...
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Wrong results of calculating moon's altitude and azimuth
I'm trying to calculate moon's altitude and azimuth and I followed this formula by geoastro.de Basics of Positional Astronomy and Ephemerides
There is an example to test the formula at the end of the ...
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Is the "light-time" correction for the Moon's position in Meeus "Astronomical Algorithms" putting the Moon in inertial position or apparent position?
Originally posted on Space Exploration SE, I was encouraged to post it here.
I'm looking at the second edition of Meeus's "Astronomical Algorithms," chapter 47, "Position of the Moon.&...
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Current sources for astronomical equation coefficients
For a project I needed to implement some of the code to calculate the position of the sun and moon. To do this I'm using Meeus. Everything is working but in doing so I've started to wonder about the ...
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Modern equivalent of Astronomical Algorithms by Jean Meeus?
I understand that the Meeus book is a classic in astronomical calculations. I've read through many chapters of it now and while the content is great, it'd be nice to have discussion based on more ...
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How can I replicate AstroImageJ's pixel to RA/Dec algorithm in my own code?
EDIT: solved, thanks to Eric Jensen's suggestion (in a comment on his answer) that I include the correction to my right ascension value as a function of my declination. All other comments were helpful ...
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Calculation of Julian day is off for negative dates
I bought the book Astronomical Algorithms by Jean Meuss and I am reading it in order to build a small library I will use for another project.
I made a program in Rust to calculate the JD given a date ...
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How the heck does JPL actually do the numerical integration for their development ephemerides? (general questions)
After writing this answer to JPL Horizons - "highly accurate measurements of planetary positions" - how do they do it? which draws from Park, Folkner, Williams & Boggs 2021 The JPL ...
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How to find the first Julian day with the same Earth-Sun constellation
There are quite some sources for astronomical calculation formulas, e.g. Astronomy Answers: Position of the Sun, which is e.g. used by KDE's Night Color plugin to calculate the time of a sunset or ...
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Calculate the general appearance of the night sky over +/-15,000 years
I want to see what the stars looked like up to 15,000 years into the past and future.
I've chosen 15,000 years in order to see a full precession cycle.
To make things easier, I would be satisfied with ...
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Sunset and sunrise formulas adopted by IAU
I'm developing a C++ computer library with the formulas in the book "Practical Astronomy with your Calculator or Spreadsheet 4th Edition" but I have a problem with the formula 49, "...
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What image analysis approaches/algorithms are used to detect near-Earth objects?
Disclaimer: I am not an astronomer or astrophysicist. I'm a computer scientist.
Astronomers collect vast amounts of image data through astronmical surveys.
The data is then analysed for signs of ...
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What is the application of pseudorandomness in astrophysics?
What are the advantages of using pseudorandom numbers in Monte Carlo simulation instead of random numbers? What are other applications of pseudorandomness in astrophysics? Many thanks.
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How does one use SPICE to calculate sunrise and sunset?
I've seen it mentioned here that SPICE can be used to calculate sunrise and sunset. How?
According to the official documentation, SPICE is used to calculate:
Time system conversions
Positions of ...
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Can automatic algorithms completely eliminate the impact of Starlink and other satellites?
According to a comment by user @J:
With that said, other than aesthetics, machine vision algorithms are wildly more advanced today than in the past - strategies to remove passing satellites don't ...
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Algorithm to fit galaxies
Do you know of any other data analysis algorithm that fits 2-D analytic functions to galaxies and point sources directly to digital images, other than GALFIT? Especially to subtract lens light from ...
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Converting equatorial coordinates to Cartesian coordinates for extragalactic distances
I'm trying to search for galaxy clusters with the friends-of-friends (FoF) algorithm. I have the equatorial coordinates ($\alpha, \delta$) and redshifts ($0.5<z<2.5$) of galaxies that I wish to ...
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Why is the boundary of friends-of-friends (FOF) halo corresponding to iso-density contour?
The friends-of-friends algorithm (hereafter FOF) is commonly used to find halos in cosmological simulations. (For more information, please refer to here and here)
I found that some literature argues ...
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Why do people choose 0.2 as the value of linking length in the friends-of-friends algorithm?
The friends-of-friends algorithm (hereafter FOF) is commonly used to find halos in cosmological simulations. And FOF depends on only one parameter, linking length, $l_\mathrm{link}=b \left(\frac{V_u}{...
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Constellation a celestial body is in
Given its right ascension and declination, find out the constellation a celestial body is in.
Does anyone know of an algorithm (C#, js) for that?
It would read the constellation boundaries (e.g. ...
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How to algorithmically distinguish between different types of nebulae?
I remember that there are five types of nebulae:
Planetary nebulae have not much to do with planets, but are emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red ...
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Mapping illumination to moon phase (font) icon
I use algorithms that give me the moon phase, age and illumination (and more) for a given timestamp and location. I am struggling to map that information to a (font) icon of the Moon Phases font. Each ...
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How to calculate the moon's illuminated fraction tilt?
I use "Astronomical algorithms" book by Jean Meeus for programming algorithms for the moon data calculations. I've already created a lot of methods but stuck on the calculation of the moon's ...
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problems finding rise set and transit times at high latitudes using Meeus' algorithms
I am implementing Jean Meeus' algorithm from his book "Astronomical Algorithms", 2nd ed. for rise, set and transit times in Swift. It seems to provide very good results (no more than 1 ...
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How to tell which of the ecliptic cross horizon angles is to the east?
Jean Meeus' Astronomical Algorithms, 2nd ed. p. 99 gives a formula for finding the two longitudes where the ecliptic crosses the horizon:
$$\tan\lambda = \frac{-\cos\theta}{\sin\epsilon \tan\phi + \...
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Deducing the hour based on RA
I'm making a technological project. The goal is to write a program that gets an image of the nightsky and predicts the hour in which the photo was taken.
I implemented a well-known method using the ...
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How do they know the non-uniformities seen on the disk of π¹ Gru are real and not artifacts?
@RobJeffries' answer to What is this web on the surface of the Sun? explains why convection cells on some other stars can be far larger than they are on our Sun and includes a near-infrared VLT ...
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Jean Meeus - calculating moon rise, transit and set times - help isolating error in logic
I've been working my way through the Jean Meeus Astronomical Algorithms book for a few weeks, to implement some of the key algorithms for a personal project. This task has been a little more complex ...
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How (the heck) does Astrometry.net work?
What magic is this?
This answer to my question Astronomy detective question: what part of the sky are these photos of? What are a few of the stars? nails it, and the output (linked there) contains ...
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How to apply Fast Folding algorithm?
I have High Time Resolution Universe dataset. I have applied de-dispersion on this HTRU dataset, and thereafter I applied the folding function to fold the dataset.
How I can find that the periodicity ...
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How actively is Deep Learning being used in exoplanet identification?
Papers, like this one from Google, show that Deep Learning and Machine Learning are effective in detecting exoplanets from luminosity data provided by telescopes like TESS or Kepler.
These models ...
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How to improve efficiency in periodicity detection?
Our data set has $10^4$ data points, but has a long baseline and many gaps.
If we bin the data, there would be $10^8$ data points ($[t,\rm {value}]$), but only about 1% are non-zero values.
How to ...
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Astronomy/Astrophysics Project With C++/C/Python [closed]
I am a Computer Science Engineering student, in the 1st year of college. I'm insanely interested in making a project regarding astronomy/astrophysics but I don't know where to begin from. I know C, C++...
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Computing orbit positions of Jovian Satellites / Moons using JPL data
I've been trying to build a model of the solar system in a game. Thus far I've succeeded in placing each of the planets in position using Keplerian elements and formulae from https://ssd.jpl.nasa.gov/...
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Finding Asteroid Geocentric Longitude and Latitude
I started using the software that comes with Jean Meeus book Astronomical Algorithms. I am now using the updated code from naughter(dot)com/aa.html.
I am able to calculate the heliocentric longitude ...
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How to convert VSOP's xyz coordinates to heliocentric spherical lbr coordinates?
I ran VSOP2013 in Fortran, and I now have the following position $x, y, z$ as well as velocity $v_x, v_y, v_z$ data.
How do I convert the position to heliocentric ecliptic spherical coordinates $l, b,...
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Algorithm to stack astronomical images
I'm looking for a simple algorithm to compare astronomical images (of the same sky region) against each other, compute their movement and rotation, to finally stack them.
At the moment I'm already ...
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What are the reasons for referring to equinox J2000 or the equinox of the date?
(Background: Trying to learn something about the mathematical and computational part of astronomy I have acquired a copy of Meeus' "Astronomical Algorithms" and implemented the material up to Chapter ...
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Does an algorithm exist that takes an image of the night sky and tell you where in the milky way that perspective likely originates? [duplicate]
In Stargate they talk about using the stars on other planets to figure out their location. I know that's fiction, but it made me wonder if such an algorithm (with arguably little usefulness right now) ...
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What is exactly the "longitude of the perigee"
Some moon phase calculation algorithms (apparently derived from Duffet-Smith's book, example here) seem to use a parameter called "longitude of perigee at epoch". What exactly is this?
Can I assume ...
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Hubble HST scheduling algorithm
NASA developed SPIKE: Intelligent Scheduling of Hubble Space Telescope Observations (HST) and this.
My question is simple, is there a programming library, preferably in python or C#, to implement the ...
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Are there standard algorithms and procedures for creating unique sky maps based on latitude/longitude/date/time?
I am trying to build an astronomy app that will use the user's latitude and longitude, along with the current date and time, to create a 3D view of the celestial sphere as seen based on that data. ...
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What method is used to calculate the 'quality' of a solar/planetary image?
What sort of algorithm is used to calculate the relative quality of an image, such as is performed by PIPP, Registax, or Avistack?
Such applications take planetary or solar images and prior to ...
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