AAVSO: American Association of Variable Star Observers

Help and FAQ AVSpec Logo

New to AVSpec?

Welcome! The AAVSO invites any and all interested in advancing science and astronomy through the observation and study of variable stars. This particular database is devoted to the submission, collection, and retrieval of the different colors of light emitted by variable stars in the form of spectra.

Given that these stars vary in brightness over time, the variation in different colors of its light changes over time as well. We can measure this variation by observing a spectrum, which is produced by separating the light into its component colors. Done carefully and correctly, spectroscopy is one of the best methods by which we can understand our universe and the plethora of stars within it.


How to use AVSpec to find spectra

Finding observations of variable star spectra is easy with AVSpec. One can use the search page to access the entire database, with searches based on not only star names and aliases, but also by on-sky positions, observation times, resolution, and even observer name. Every observation has a record page where all the details of the observation can be reviewed, and the spectrum can be manipulated live.

The observations can be downloaded as FITS files, which contain a key-indexed header with useful information regarding the observation parameters. In addition, AVSpec automatically appends to the header information from the Variable Star Index (VSX) with all of the relevant information about the star, as well as information about the observing equipment and location for heliocentric corrections.


How to contribute to AVSpec

It is relatively easy to acquire the ability to conduct spectroscopy. A piece of material known as a grating can be inserted in place of a filter, and an existing imaging camera can then be used to record the now split colors of light. Or you may choose to invest in standalone spectrographs, for which there are many options available. Several software packages exist to reduce the data. For more detailed information on the techniques of spectroscopy, please visit our observing manual in the documentation section below.

If you are already able to perform spectroscopic measurements, then the next step is to get started with your first submission to AVSpec. Once you have registered your equipment and observing site on your Observer Profile, the steps are simple:

    1. Observe the spectrum of a non-variable star from our list

    2. Reduce the observation into a 1-dimensional spectrum

    3. Submit the observation to AVSpec in the form of a FITS file

    4. The test observation will be automatically checked for consistency within moments

    5. A member of our validation team will perform a final quality check

    6. If all is good, then submit observations of spectra of variable stars of your choosing!

Currently, variable star observations will be published following a secondary validation round. This precautionary measure is to ensure good data quality and is planned to be removed at some point in the future so that observations can be immediately published. For more information, please consult our quick guide in the documentation section below.



1. I can't find my equipment listed on the submit page.

There are multiple types of equipment packages that you can submit. AVSpec will only list those which have the Observing Type "Spec". Please make sure your package has this label.

2. I want to submit Star X, but it's not in the list. What do I do?

If you are seeing a list of stars, that means it is your first submission. This submission must be a standard star (see below). Once this spectrum has been validated, you will be able to submit data any star as long as it is in VSX.

3. I tried to submit a spectrum, but it says I was unsuccessful. How do I determine what's wrong?

When the submission fails a log file is created. At the bottom of this file it will tell you what issue it found. If this doesn't provide enough information or you need more assistance, please email avspec@aavso.org and include the log file.


Standard Stars

AVSpec requires all observers to submit an observation of a non-variable "standard" star. The reason for this is to catch any issues arising from improper technique and/or reduction. Our team of expert validators has access to extremely high-resolution spectra of these standard stars and will use it to compare one-to-one with the observations submitted by first-time users. 

Please find a page containing the names positions of the standard stars here.



If you wish to know more about spectroscopy, observation files, or the technical details of the database:

Quick guide: Get started submitting spectra

AAVSO Guide To Getting Started in Spectroscopy: An in-depth guide to spectroscopic observations

Technical manual: Header requirements, processing structure, code documentation

Your First Echelle Submission: Instructions for uploading an echelle spectrum


Still have questions?

Please send an email to avspec@aavso.org and we will reply to you as soon as we can.


AVSpec development was developed by John R. Weaver (Mayall Fellow; University of Copenhagen), and is now maintained by Bert Pablo (AAVSO) and Lauren Herrington (AAVSO). Substancial contributions were also made by George Silvis (AAVSO) and Sara Beck (AAVSO)