Sloan Digital Sky Survey - Obtaining Sprectal and Photmetric Datasets
Todd Simpson
Greetings,
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 using includes the photometric images values for the five filter bands, u, g, r, i, z.
https://skyserver.sdss.org/dr9/en/tools/quicklook/quickobj.asp
My original intent was to try to classify irregular galaxy objects based on spectral emission spikes as certain wavelengths. I have discovered in this journey the dataset I have been using is of photometric values for the object images, not detailed spectral data across the entire observable spectrum for the object.
https://www.kaggle.com/datasets/muhakabartay/sloan-digital-sky-survey-dr16
The SDSS Sky Server query that produced this dataset is:
Data server
Data can be obtained using SkyServer SQL Search with the command below:
-- This query does a table JOIN between the imaging (PhotoObj) and spectra
-- (SpecObj) tables and includes the necessary columns in the SELECT to upload
-- the results to the SAS (Science Archive Server) for FITS file retrieval.
SELECT TOP 100000
p.objid,p.ra,p.dec,p.u,p.g,p.r,p.i,p.z,
p.run, p.rerun, p.camcol, p.field,
s.specobjid, s.class, s.z as redshift,
s.plate, s.mjd, s.fiberid
FROM PhotoObj AS p
JOIN SpecObj AS s ON s.bestobjid = p.objid
WHERE
p.u BETWEEN 0 AND 19.6
AND g BETWEEN 0 AND 20
My Question: How can I download a matching dataset of object spectral values that will match the photometric data values for the objects I’m currently using? Could I write a different query that would use the same parameters of selection except retrieve the spectral data for the same 100000 objectIds from the first dataset? I can visually retrieve a particular object’s detailed spectra using the fetch_sdss_spectrum(plate, mjd, fiber) command in Python.
Final Question: Can someone tell me any method of retrieving spectral details for the Sloan Objects that I can use to evaluate and design an fuzzy architecture for classification of objects?
Thank you in advance,
-Todd