All Questions
Tagged with astronomy computational-physics
16
questions
1
vote
1
answer
36
views
Determining star position and velocity to deduce closest approach?
I am trying to replicate the results found for Gliese 710's closest approach of ~0.05 parsecs in 1.3 million years approximately. I thought that by plotting the sun at (0,0) and using the stars ra,dec,...
- 39
3
votes
1
answer
67
views
Modelling a fully relativistic White Dwarf Star
I am trying to model a fully relativistic white dwarf using different central densities. Using the below equations:
$\frac{dP}{dm} = -\frac{Gm}{4\pi r^4}$
$\frac{dr}{dm} = -\frac{1}{4\pi\rho r^2}$
and ...
- 31
0
votes
0
answers
101
views
Galaxy S4G database: convert pixel to kpc
I am referring to S4G database (https://irsa.ipac.caltech.edu/data/SPITZER/S4G/overview.html ).
The information on the length of galaxies, and various length parameters are given in terms of pixels.
...
- 1,023
1
vote
0
answers
64
views
What are astrocentric co-ordinates?
A program I am using requires the ecliptic astrocentric cartesian coordinates of the Earth and the Sun in AU however I have never come across these co-ordinates before and the internet doesn't provide ...
- 11
4
votes
1
answer
205
views
Drawing night sky of planets other than Earth (invariable plane ambiguity)
I'm writing an application that draws maps of night sky that can be visible from other planets (ultimately they are to be exoplanets). Mostly I do it out of curiosity :).
I's thinking a lot where I ...
- 137
0
votes
1
answer
695
views
How do I convert a .FITS into a numpy array (or a file that can be used in Python)? [closed]
I'm trying to train an AI algorithm to determine photometric redshifts of galaxies, and to do so I have a .FITS file which contains the training data. I need to convert this .FITS file into a format ...
- 11
0
votes
2
answers
329
views
How to represent orbital velocity of a planet on an elliptical path in terms of time?
Before reading this long message, please know that this is question is posted to know whether there is a method to find the relation between between the orbital velocity of a planet on an elliptical ...
- 115
0
votes
0
answers
104
views
How can we calculate solar and lunar longitude in java?
I want to develop panchangam logically. So, I want to find solar longitude and lunar longitude.
Could you please help me to find the solar and lunar longitudes in java or any mathematical formula for ...
0
votes
0
answers
30
views
Lane-Emden. Quasi-linearization method
ow to prove this theorem? I have a doubt.
Theroem: Suppose that $w(x,\alpha)$ solved
$\ddot{w}+\frac{2}{x}\dot{w}+\alpha^{2}w=0$ with $w(0)=1$,
$\dot{w}(0)=0$, $w(1)=0$.
Then $v(x,\alpha) := \omega w(...
- 1
0
votes
1
answer
170
views
Are the orbits in my simulation correct? [closed]
I'm creating a simulation of our solar system.
I used data from https://nssdc.gsfc.nasa.gov/planetary/factsheet/ and I supplied the planets with perihelion and aphelion values. But I'm afraid the ...
2
votes
1
answer
314
views
Sidereal time calculation from orbital elements and mean anomaly
I'm following the instructions given here for calculating the apparent position of the planets in the sky and I've come to calculating the sidereal time in section 1.8.
The formula for calculating ...
- 121
1
vote
0
answers
54
views
Cosmological parameters from a certain data set
Specifically, I need to find the cosmological parameters $Ω_i$ from a certain data set (with error bars) of redshift $z$ and luminosity distance $d_L$ using a Fisher Information matrix. I know that my ...
1
vote
0
answers
63
views
Numerical error in implementation of universal variables [closed]
I am trying to implement (in Python for now) low thrust orbit propagation for spacecraft using universal variables. For a given central body with the gravitational parameter $\mu$ and an orbit with ...
- 39
1
vote
1
answer
847
views
SDSS spectra FITS format: what do the rows mean?
This might be in the FITS Header, but I couldn't find it.
I am looking at the FITS files for SDSS 1D spectro images from DR7 using the SDSS Data Archive Server at das.sdss.org (there might be an ...
- 907
2
votes
1
answer
2k
views
Precession of Mercury (Python simulation)
I was trying to simulate the precession of Mercury based on the perturbed solution, and my questions about its implementation in python can be seen here: https://scicomp.stackexchange.com/questions/...
- 129