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Questions - astronomy

Different values of a_lm coefficients for different values of Nside in HealPix

I am using HealPix to calculate the outflow rate of particles through a sphere with some radius and I am trying to determine coefficients of spherical harmonics (basically fit some data with spherical...
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Jack

python

astronomy

healpy

Votes: 0

Answers: 1

Latest Answer

In order to get the same values of a_lm coefficients it is necessary to normalize values of individual pixels with the pixel surface - dividing with 4*pi/npix. Another thing, in case it might be helpf...
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Jack

Faster alternative to SkyCoord.separation?

I am using SkyCoord.separation to find the pixels around a given coordinate from an array. I have noticed the separation function takes too long. I have to repeat the calculation on a huge data set an...
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Akshaya Subbanna

python

coordinates

astropy

astronomy

Votes: 0

Answers: 1

Latest Answer

Here is a pretty fast implementation that uses numexpr for extra speed. You can also do this with plain numpy but it isn't as fast. import numexpr def sphere_dist(ra1, dec1, ra2, dec2): "&qu...
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Tom Aldcroft

how to solve 2nd order coupled equation by using python?

I am trying to solve 2nd order coupled equation by odeint. I don't know how to pass two constant list z0 and w0 but I tried here is my code. import numpy as np from scipy.integrate import odeint impor...
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zircon

python

numpy

differential-equations

astronomy

odeint

Votes: 0

Answers: 1

Latest Answer

Start with def cpld(u,r): v0 , v0div , R0 , R0div = u and finish with return [*dzdr, *dwdr] You will have to unpack the result of the numerical integration, which is a list of 4-dimensional ...
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Lutz Lehmann

How to set limits around (on both sides of) 0, in a polar Matplotlib plot (wedge diagram)

I am making a wedge diagram (plotting quasars in space, with RA as theta and Dec as r). I need to set the limits of a polar plot on both sides of 0. My limits should go from 45 degrees to 315 degrees ...
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Laura

python

numpy

matplotlib

astronomy

Votes: 0

Answers: 1

Latest Answer

It appears that matplotlib will only make the theta limits span across theta=0 if you have a positive and negative value for thetamin and thetamax. From the docstring for set_thetalim(): Values are w...
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tmdavison

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