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Questions tagged [data-analysis]

Analysis of data is a process of inspecting, cleaning, transforming, and modeling data with the goal of discovering useful information, suggesting conclusions, and supporting decision making.

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cross-matched SDSS-WISE catalog

Please where can I find cross-matched SDSS and WISE dataset for a machine learning project? (Galaxy-star-qso classification task)
Fanoela Rabemanotrona's user avatar
2 votes
2 answers
55 views

Computing error bar for vertex of parabola-fit lightcurve

I have a long-term lightcurve for my source, to which I have used orthogonal distance regression to fit a quadratic model [expected flux]=a[year]²+b[year]+c. Part of our data analysis includes finding ...
HobbitJack's user avatar
2 votes
3 answers
141 views

Parameters erroneously measured to be negative

I am interested in physical quantities which are strictly non-negative, but which, due to errors, may realistically be estimated as negative. The only examples I can think of are interstellar ...
J. Webb's user avatar
  • 53
3 votes
0 answers
102 views

Astronomers need Data Analytics or Data Science?

I am aiming to do my masters in Astronomy, and I would prefer it to be on the data side of it. I am looking to skill-up and am confused if I should take up Data Analytics courses or Data Science ...
Akriti Rajput's user avatar
1 vote
0 answers
42 views

plotting light curve for x ray data

how can I plot the light curve for Chandra X-ray data? I want to extract the counts within the specified energy range from the light curve. e.g., I have to extract the counts within the energy range ...
Walker's user avatar
  • 61
1 vote
0 answers
40 views

Tiling the sky with astropy-healpix

I have a bunch of files containing sources with galactic l and b values. What I want is to redistribute the sources such that each new file contain sources that fall within 15 degrees of a central l,b ...
Debajyoti Sengupta's user avatar
8 votes
1 answer
194 views

Basics of Tracklet-less Heliocentric Orbit Recovery (THOR) - simple breakdown of how it works?

The New York Times's April 30, 2024 Killer Asteroid Hunters Spot 27,500 Overlooked Space Rocks begins: With the help of Google Cloud, scientists churned through hundreds of thousands of images of the ...
uhoh's user avatar
  • 30.6k
1 vote
0 answers
25 views

How can I use SDSS archive to find the radial velocities of binary stars?

I need to plot a radial velocity curve of a given binary star system, and I think that the SDSS apogee survey has what I need, but I havent had any luck finding anything on it. It this the right tool ...
Zandini3's user avatar
3 votes
0 answers
29 views

Which distortion polynomial does the astrometry.net platesolver use?

I am investigating whether it is feasible to predict the distortion of a widefield image platesolved by Astrometry.net and. its documentation says it uses the Simple Image Polynomial to estimate ...
requiemman's user avatar
6 votes
3 answers
178 views

How could a Dyson Swarm be detected?

My understanding is that a completed Dyson Sphere would be detectable because we would see a star that seemed to produce only infra-red light, and much less than would be expected from an object of ...
Ryan_L's user avatar
  • 643
1 vote
1 answer
95 views

How can I join as contributor to open source code on GitHub? [closed]

I want to join as a contributor, e.g., making pull or merge requests on GitHub, in an existent open source astronomy project. How do I start? What's the typical scenario? Writing directly to the ...
nuwe's user avatar
  • 771
1 vote
0 answers
21 views

How to determine semiamplitude from Julian Date data?

How could I determine semiamplitude from these data for NGC300 X-1 without fitting, only with data of phase and JD? This is a common problem for exoplanets, X-ray binaries and other general binary ...
riemannium's user avatar
1 vote
0 answers
46 views

On building a compatible pipeline for astrometry using both Gaia or Vera-Rubin's data

As the title states, I'm considering building a pipeline for astrometry to analyze Gaia and Vera Rubin's data. As, being honest, I have little experience with astrometry, I'm not sure if this is (or ...
nuwe's user avatar
  • 771
3 votes
1 answer
153 views

What are These Strange Data Spikes in my Catalog Data?

This question has been completely rewritten as I have found a bit more information and been helped enough to hopefully ask this question better. Hi everyone. I am an undergraduate pursuing an honors ...
Ataaamic's user avatar
  • 161
6 votes
1 answer
188 views

How to Determine Absolute Magnitude of a Galaxy using HST FITS Image

I'm attempting my first serious research project but due to... various circumstances, I am going to mostly be solving problems like this on my own with minimal outside help. As for the actual problem, ...
Ataaamic's user avatar
  • 161
6 votes
1 answer
808 views

Could an hypothetical hidden black hole companion to the sun be revealed by proper motion data?

If the Sun were in a binary star system with a black hole companion, the Sun would be orbiting the black hole, and this should be reflected in a change in the observed proper motion of nearby stars. ...
tutizeri's user avatar
  • 357
1 vote
1 answer
63 views

Moon's libration from Mathematica data

Wolfram Mathematica provides "TransitTime" option (for the Moon in particular). Knowing this time moment, you can get the position of the moon at upper culmination (for example, for each day ...
lesobrod's user avatar
  • 123
1 vote
0 answers
42 views

CMB maps analysis (Planck, ESA, FITS)

I wanted to analyze Planck mission FITS files and was wondering about the parameters. So the map uses color coding for temperature-based anisotropies right? So the maximum angular resolution is ...
user2820052's user avatar
4 votes
2 answers
243 views

Formation of spacecraft instrumentation [closed]

List of spacecraft instruments are selected to meet a mission's science goals. Let's take New Horizons as an example and study the composition of Pluto's atmosphere, the shape and geological ...
ayr's user avatar
  • 795
2 votes
1 answer
66 views

Calculating intensity of moonlight per unit area

I have a photodiode that can measure intensity in picowatt to milliwatt range. I have a telescope of 5 inch diameter. I want to calculate the intensity of moonlight received by this area? This will ...
Tumpa's user avatar
  • 31
4 votes
2 answers
76 views

Radio Astronomy Data Handling (Filtering What One Needs)

Suppose we have some radio astronomy data for some specific moment (not a time series). Can we, using some computer program, filter out and get, say, only the data (EM radiation), whose sources are at ...
avpol's user avatar
  • 41
0 votes
0 answers
40 views

How can I better align stamps from Hubble images?

I am trying to do difference imaging with Hubble ACS/WFC images and have been using TweakReg to align images and cutout stamps. The problem is that residuals haven't been great and I'm looking for ...
cassandra's user avatar
2 votes
0 answers
32 views

Sloan Digital Sky Survey - Obtaining Spectral and Photometric Datasets

I am working on a soft computing (fuzzy logic), genetic algorithm, explainable AI (XAI) classification system for astronomical objects from the Sloan Digital Sky Survey. The dataset I am currently ...
todd45040's user avatar
2 votes
0 answers
82 views

How can I compute reasonable errors on my Gaussian fits to the observed strong optical lines of interest?

I'm fitting Gaussians to optical lines spanning from H-beta to Sulfur using Astropy's Gaussian (https://docs.astropy.org/en/latest/api/astropy.modeling.functional_models.Gaussian1D.html) model with a ...
Astroturf's user avatar
  • 1,111
1 vote
0 answers
34 views

Bad syntax for region SIMPLE -- dmextract CIAO 4.15

I am trying to perform a radial profile analysis using Chandra's CIAO 4.15 dmextract function but keep getting the following error: "bad syntax for region SIMPLE". I cannot find any relevant ...
adastra2001's user avatar
1 vote
1 answer
174 views

How to get star position from the Gaia data set?

I’m trying to recreate the Milky Way as a particle system inside Houdini, and I wanted to explore using the Gaia data as a starting point. I’ve downloaded an example source file from the data set but ...
kinkersnick's user avatar
2 votes
1 answer
88 views

Unusual amount of white dwarfs in star clusters in my analysis

I'm trying to plot H-R Diagrams of open clusters using data from Gaia DR3. My workflow is something like this: Plot apparent magnitude vs log(distance) in pc. An overdensity would indicate the ...
Ambica Govind's user avatar
2 votes
0 answers
49 views

ds9 configuration issue

I'm trying to use DS9 for X-ray image analysis. Before that I have to configure it for use, I need to click on option using web proxy. Beside use internal web browser checkbox there should be another ...
ALIEN X's user avatar
  • 21
0 votes
0 answers
29 views

What are examples of spatio-temporal data sets such that subjects are observed only once and are, thus, indexed in time only once?

What are examples of spatio-temporal data sets such that subjects are observed only once and are, thus, indexed in time only once? Here's a hypothetical example in the ecology realm: consider a tree's ...
Ron Snow's user avatar
  • 101
3 votes
2 answers
103 views

How to construct optimal Wiener Filter?

I am trying to construct a Wiener Filter, to filter the ratio of the peak from the cross-correlation function, between a galaxy spectra and a template spectra, with the peak of the auto-correlation ...
trynerror's user avatar
  • 849
0 votes
1 answer
268 views

What am I doing wrong in this ppxf application?

I am trying to derive the kinematics of a galaxy spectra. To test my results I want to implement the Penalized Pixel Fitting method. For the galaxy spectrum I use a central line with sufficient S/N. I ...
trynerror's user avatar
  • 849
2 votes
1 answer
272 views

How can someone take narrowband data from an OSC narrowband filter

To those who aren’t aware, an OSC narrowband filter is a filter with multiple band passes, for different emission lines. These can include a combination of Hα, Hβ, OIII, SII, and other emission lines. ...
Topcode's user avatar
  • 166
4 votes
1 answer
187 views

Where can I get raw photos of planets clicked by HST, Voyager 1 and 2, Cassini for Saturn and Galileo for Jupiter?

I intend to process RAW images of planets clicked by HST,Voyager 1 and 2, Cassini and Gallileo spacecrafts using a few softwares. I am in search of where I can get these raw images from.
Dhruv Nayak's user avatar
3 votes
1 answer
143 views

Convert image from Jy/sr to Jy/pix

I want to convert the units of an image from Jy/sr (Janskys per steradian) to Jy/pix and I know the pixel scale in arcsec. The way I do this, in python, is the following: ...
Sketos's user avatar
  • 31
3 votes
1 answer
77 views

Solar-winds: public NOAA data

I was searching for interesting data from space recently, and stumbled onto https://www.swpc.noaa.gov/. The long and short is that they offer some interesting solar wind data Of particular interest to ...
Kai Harris's user avatar
2 votes
0 answers
61 views

Finding the uncertainty in period for String-Length Minimization calculation

I wrote a Python script that calculates the period of an unevenly sampled data set using the String-Length Minimization method. You can read about that method here: A period-finding method for sparse ...
Zachary Kennedy's user avatar
9 votes
2 answers
148 views

What's a good example of published astronomy pipeline coding libraries

I am a software engineer and I am preparing a presentation to aspiring astronomy PhDs on how to use best-practice software engineering when publishing code (such as include documentation, modular ...
nsimplex's user avatar
  • 191
1 vote
1 answer
80 views

Do astronomical datasets exist that receive duplicates or are there multiple datasets that contain the same entities (stars)?

I am currently doing my PhD in computer science, and I have almost no astronomical knowledge. I am currently researching on duplicate detection in databases (so detection of multiple entries referring ...
Lasklu's user avatar
  • 21
0 votes
1 answer
116 views

2D Galaxy Spectrum taken by long-slit-spectrograph

I have the 2D data (shape(1125,2058) taken by a long slit spectrograph, which looks as follows: The y-axis corresponds to the distance from the center, where the center is at the most bright green ...
trynerror's user avatar
  • 849
13 votes
2 answers
3k views

How did asteroid (7482) 1994 PC1 get its "face"? Is it reconstructed from optical or radar imaging, or something else?

(Image sources linked below) NPR's March 10, 2023 Newly found asteroid has a 'very small chance' of hitting Earth, NASA says includes an image of what looks like a computer reconstructed 3D surface of ...
uhoh's user avatar
  • 30.6k
12 votes
2 answers
758 views

How has the resolution of astronomical spectrographs improved over time?

Is there something like a Moore's law for spectral resolution? Maybe a chart from which one could extrapolate?
2080's user avatar
  • 1,890
1 vote
0 answers
44 views

Best resource for exoplanet statistics?

While the number of detected exoplanets is still low, is there a model that, considering the number and duration of made observations, and the fact that (non)detections depend on orbital plane ...
2080's user avatar
  • 1,890
2 votes
1 answer
356 views

How does one actually fold a light curve?

I'm studying the variable stars (periodic variables with brightness changes repeating over time), and to examine the shape of the light curve it is useful to fold the data points at this period and ...
Saturn.'s user avatar
  • 49
2 votes
2 answers
348 views

Reduced chi square value

I am currently plotting a continuum of observed data. I need to check the effectiveness of the fitted continuum with the reduced chi-square method. Ideally, should the reduced chi-square value ...
summer's user avatar
  • 31
11 votes
3 answers
2k views

What is the most common activity of astronomers in the JWST? [closed]

I am no astronomer. I am a computer scientist. I recently read this article: JWST has changed the speed of discovery, for better or for worse - Astronomers are working at a furious pace to analyze and ...
Demis's user avatar
  • 883
3 votes
1 answer
93 views

How can we make sure that it is physically the same source when we do cross matching?

When we go through multiple astronomy catalogs, we often do Cross-matching. We compare the position parameters $(\alpha, \delta)$ of different sources (galaxies, quasars, etc.) in the equatorial ...
Chang's user avatar
  • 31
2 votes
2 answers
90 views

What determines how accurate a particular method is at finding the period between Lomb-Scargle and String Length Minimization?

I've been using the Lomb-Scargle and String Length Minimization methods to find the periods of various astronomical objects with unevenly spaced data. I wanted to see if I could find any patterns ...
Zachary Kennedy's user avatar
1 vote
1 answer
116 views

Database for distant stars

I'm looking for a database of stars that lists as many of the known stars as possible. Ideally, I'd like it to have information on the radius of the stars, the distance from the earth and the ...
EmeraldThunder-'s user avatar
4 votes
1 answer
2k views

How does one convert between Modified Julian Date (MJD) and a standard (mm/dd/yr, hr:mm:ss)

I looked online and couldn't see an actual formula or anything, so I figured I'd ask here. If I had an MJD like the following: 59145.6678 How would I convert that to a month, day, and year with the ...
Zachary Kennedy's user avatar
2 votes
0 answers
106 views

Where to get MOST data?

Where to get MOST data (light curves), please? Does a database or a list of objects that were exist? I mean MOST spacecraft.
Anna-Kat's user avatar
  • 505

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