aka AAVSO   |   CAMBRIDGE, MA   |
GuideStar Charity Check


EIN: 04-2164402


The mission of AAVSO is to enable anyone, anywhere, to participate in scientific discovery through variable star astronomy.
We accomplish our mission by carrying out the following activities:
· observation and analysis of variable stars
· collecting and archiving observations for worldwide access
· forging strong collaborations between amateur and professional astronomers
· promoting scientific research, education, and public outreach using variable star data

Ruling year info



Dr. Brian Kloppenborg

Main address

185 Alewife Brook Parkway, Suite 410


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Subject area info


Population served info


Retired people


NTEE code info

Astronomy (includes Observatories) (U31)

What we aim to solve

SOURCE: Self-reported by organization

AAVSO’s future and impact. Over the past two years, we listened to our members, studied the astronomy community’s needs, identified the ways our data supports research, and developed new ways to assist members with observing technology. We focused on three objectives: membership satisfaction, organizational impact, and long-term financial stability. Our challenge is to attract the interest of a diverse group of individuals worldwide in the observation of variable stars. These individuals will work to increase the size and quality of our current database that is used by professional astronomers in their research and they are critical to maintaining the AAVSO's 110 year legacy of data collection by citizen astronomers.

Our programs

SOURCE: Self-reported by organization

What are the organization's current programs, how do they measure success, and who do the programs serve?


The Caroline Hurless Online Institute for Continuing Education (CHOICE) is a collection of informal, online short courses on topics chosen to help members of the AAVSO and other adult populations contribute more to science. It has two main goals towards this end. First, we hope to train our participants to be better observers, analysts, researchers, writers and advocates. Second, by improving the quality of our data products and making them easier to use, it will help astronomers and researchers best utilize AAVSO data.

Population(s) Served
Young adults

AAVSO’s Exoplanet Observing Program is established to provide amateur astronomers with best practice techniques for conducting exoplanet observations, as well as to act as a central coordination point for professional/amateur exoplanet collaboration efforts. For example, upcoming space missions, such as TESS (Transiting Exoplanet Survey Satellite), will be requiring extensive involvement by the amateur astronomer community in conducting followup exoplanet observations.

Population(s) Served

The AAVSO International Database has over 34 million variable star observations going back over one hundred years. It is the largest and most comprehensive digital variable star database in the world. Over 1,000,000 new variable star brightness measurements are added to the database every year by over 700 observers from all over the world.The AAVSO International Database is not only the largest but also the highest quality variable star database available to researchers. The AAVSO and its technical staff spend more time and resources on database maintenance and quality control than any other organization of its kind.

Population(s) Served

The 10-Star Training Tutorials are designed for novices who have no prior experience observing variable stars. It is a walk through of how to find the star, how to make an estimate and how to submit the estimate to the AAVSO. If you are new to the AAVSO then these are great tutorials to get you started.

The tutorial begins with stars that are easy to find and observe. Slowly the stars become more challenging as you go down the list. By the time you reach Epsilon Aurigae at the bottom of the list, you’ll be an expert variable star observer contributing real data to professional scientists!

Population(s) Served
Young adults

The AAVSO has a long tradition of mentoring its new observers. Since the earliest days of the AAVSO, experienced observers have helped new observers by corresponding, answering questions, and even providing personal guidance at the telescope.

The Mentor Program is primarily designed to pair new observers with experienced partners who can teach them about observing techniques, tools, methods, etc., as well as give them advice on target selection and interesting projects they might pursue.

We teach visual, CCD and DSLR observers how to do everything from printing comparison star charts, to finding the variables in the sky to reporting uncertainty in their CCD/DSLR observation reports.

Population(s) Served
Young adults

Spectroscopic monitoring of variable stars is a relatively unexplored domain within astronomy, with the potential to produce a wealth of new information. While individual objects, such as some cataclysmic variables (CVs), have been studied with high time resolution spectroscopic observations spanning days or weeks, long-term spectroscopic monitoring data for variables does not yet exist. Many interesting variable phenomena occur on time scales of months or years, meaning we lack the information that could prove critical in advancing our understanding, and in solving long-standing problems (such as the perplexing behavior of Semi-Regular variables or the still-not-fully-understood RV Tauri variables). Even for shorter period variables, there is surely much to be learned from high time resolution spectroscopic observation. There are many bright variables with little spectroscopic data available, meaning observers with spectroscopes on smaller telescopes have an opportunity to make an impact!

We provide here brief overviews of: the information that we can derive from a star’s spectrum; how to work with spectroscopic data; what to consider when selecting equipment for spectroscopy; the specific types of variables we recommend for spectroscopic observation; and, how to submit your spectra to the AAVSO. Much more detail is provided in the accompanying manuals and guides.

Population(s) Served
Young adults

Free online webinars on a variety of astronomy topics and research areas presented by AAVSO members and observers.

Population(s) Served

One hour programs on a variety of topics to teach and inform the general public about variable star

Population(s) Served

An introductory program in astronomy presented by recognized, Spanish speaking astronomy professionals

Population(s) Served

The purpose of the JAAVSO is to promote the AAVSO's overall mission by serving as the preeminent publication venue not only for AAVSO Members, but for the entire community of variable star scientists and researchers.The JAAVSO has been published since 1972. It is a research publication dedicated to variable star astronomy and related topics. The JAAVSO is a refereed publication, open to any and all amateur and professional members of the variable star research and observation community, as well as related scholarly groups such as computer and information scientists, historians, and educators. Manuscripts originating from students are encouraged.

Population(s) Served

Where we work

Our results

SOURCE: Self-reported by organization

How does this organization measure their results? It's a hard question but an important one.

Total dollars received in contributions

This metric is no longer tracked.
Totals By Year
Type of Metric

Input - describing resources we use

Direction of Success


Context Notes

AAVSO is committed to reducing the draw on our endowment by raising funds through an Annual Campaign and educating our members on legacy gifts. We are making steady progress in this area.

Number of Publications that used AAVSO data

This metric is no longer tracked.
Totals By Year
Type of Metric

Context - describing the issue we work on

Direction of Success

Holding steady

Observations Submitted by AAVSO Members

This metric is no longer tracked.
Totals By Year
Related Program

AAVSO International Database of Variable Star Observations

Type of Metric

Output - describing our activities and reach

Direction of Success


Context Notes

The cumulative number of observations submitted by members since 1911 is 54,394,485

Our Sustainable Development Goals

SOURCE: Self-reported by organization

Learn more about Sustainable Development Goals.

Goals & Strategy

SOURCE: Self-reported by organization

Learn about the organization's key goals, strategies, capabilities, and progress.

Charting impact

Four powerful questions that require reflection about what really matters - results.

The AAVSO will be leading a citizen astronomy movement by encouraging its international community to
collaborate with professional astronomers, enabling novel science.
Our observers contribute to long-term and short-term scientific projects. The AAVSO is committed to
supporting their work by providing the resources and opportunities needed to maximize their impact.

The AAVSO’s superpower is its active, enthusiastic, and diverse international community of stakeholders

The AAVSO website is the hub of our international community. It is the platform that supports our programs
and initiatives and celebrates our accomplishments.

The AAVSO accomplishes its mission through the combined efforts
of its staff, volunteers, observers, and members — 2,000 people
sharing a common passion and joy of observing variable stars and
contributing to scientific research. Over two hundred active volunteers
augment the six-person staff.
During the strategic planning process, we identified ways to improve
how we organize and guide our work efforts.
We established new operating committees to improve our effectiveness
that include staff, board members, and volunteers from our
Programs Committee
IT Committee
Marketing Committee
Membership Committee
Observing Section Leadership Team

The AAVSO’s long-term financial stability
depends on balancing income and expense
while not overdrawing from our endowment.
During the strategic planning process, we
scrutinized all of our expenses. This included a
detailed analysis of the work done by our staff,
contractors, and volunteers.
Next, we analyzed our income,


fostering key partnerships with high-profile
international groups
• promoting the Journal of the AAVSO (JAAVSO) as
a recognized publication of variable star research
• encouraging professional-amateur collaborations
and mentorships
• maintaining and enhancing relevant tools for data
submission, retrieval, and analysis
• leveraging our observers’ expertise to educate
other citizen scientists
• educating our members and observers
• creating introductory learning materials to
encourage and support aspiring observers
• providing access to reliable data found in the
AAVSO databases
• creating engagement opportunities for individuals
with limited resources
• maintaining a help desk managed by our professional staff

• empower individuals to grow and learn in
variable star astronomy through AAVSO
meetings, webinars, and new observing section
• ensure that our virtual and in-person events
provide welcoming opportunities for exchanging
ideas and information to maximize engagement
• connect professional and amateur astronomers
• promote inclusionary practices to guarantee the
fulfillment of our mission to fully involve anyone,
anywhere in scientific research.
• communicate the value of our observers’ data
to professional astronomers

we are building a content-development strategy for our website that will provide:
• a solid and secure technical infrastructure
• curated databases
• best practices in software and content management
• enhanced cybersecurity
• updated software tools to facilitate observation submissions, data download and analysis

We established new operating committees to improve our effectiveness
that include staff, board members, and volunteers from our
Programs Committee
IT Committee
Marketing Committee
Membership Committee
Observing Section Leadership Team

We are putting the following plan in place to
balance our finances, increase member support
and enable the AAVSO to grow and thrive.
• Reducing this year’s annual endowment
withdrawal to below five percent.
• Increasing non-endowment income by
working with professionals to develop a
comprehensive fundraising campaign.
Focus areas include:
o identify grant opportunities supporting
our mission
o identifying and contacting foundations
that support science research
o developing marketing materials to increase
our visibility
• Increasing volunteer involvement.
• Initiating a $200,000 Strategic Plan
Fundraising Campaign in 2020.

The AAVSO will be able to achieve its goals with the following resources:

Qualified staffing
Active Board of Directors
Supportive members
Staff, member and Board Committees to share the work
Endowment fund
110 years of experience

Established Committees are actively working together- Marketing,IT, Diversity, Membership, Observing Sections
Annual Campaign has been completed
Decreased the draw from our endowment
planned for the sale of our building to increase the endowment and available draw to support operations
website has been updated both technically and content presentation
survey of professional astronomers has been completed plan for increase participation in the AAVSO

How we listen

SOURCE: Self-reported by organization

Seeking feedback from people served makes programs more responsive and effective. Here’s how this organization is listening.

done We shared information about our current feedback practices.
  • Who are the people you serve with your mission?

    Anyone from anywhere who is interested in contributing to real science through variable star observing and data recording. We currently engage over 5000 people from around the world.

  • How is your organization using feedback from the people you serve?

    To identify and remedy poor client service experiences, To identify bright spots and enhance positive service experiences, To make fundamental changes to our programs and/or operations, To inform the development of new programs/projects, To identify where we are less inclusive or equitable across demographic groups, To strengthen relationships with the people we serve, To understand people's needs and how we can help them achieve their goals

  • What significant change resulted from feedback?

    Staff and Board underwent customer satisfaction training and training on how to work with people from all ethnicities and genders. Board and staff participated in a strategic planning process as part of the Harvard Community Action Program (CAP) The process included AAVSO members, staff, Board and friends of the AAVSO. Programming was reviewed and changed in response to member suggestions and the current interests in the world of astronomy. A long term plan was put into place that addresses all areas of our community.

  • Which of the following feedback practices does your organization routinely carry out?

    We collect feedback from the people we serve at least annually, We aim to collect feedback from as many people we serve as possible, We take steps to ensure people feel comfortable being honest with us, We engage the people who provide feedback in looking for ways we can improve in response, We act on the feedback we receive, We tell the people who gave us feedback how we acted on their feedback

  • What challenges does the organization face when collecting feedback?

    It is difficult to get the people we serve to respond to requests for feedback, We don’t have the right technology to collect and aggregate feedback efficiently, The people we serve tell us they find data collection burdensome

Revenue vs. expenses:  breakdown

SOURCE: IRS Form 990 info
Note: When component data are not available, the graph displays the total Revenue and/or Expense values.

Liquidity in 2021 info

SOURCE: IRS Form 990


Average of 211.42 over 10 years

Months of cash in 2021 info

SOURCE: IRS Form 990


Average of 5.4 over 10 years

Fringe rate in 2021 info

SOURCE: IRS Form 990


Average of 27% over 10 years

Funding sources info

Source: IRS Form 990

Assets & liabilities info

Source: IRS Form 990

Financial data

Source: IRS Form 990 info


Revenue & expenses

Fiscal Year: Oct 01 - Sep 30

SOURCE: IRS Form 990

Fiscal year ending: cloud_download Download Data


Balance sheet

Fiscal Year: Oct 01 - Sep 30

SOURCE: IRS Form 990

The balance sheet gives a snapshot of the financial health of an organization at a particular point in time. An organization's total assets should generally exceed its total liabilities, or it cannot survive long, but the types of assets and liabilities must also be considered. For instance, an organization's current assets (cash, receivables, securities, etc.) should be sufficient to cover its current liabilities (payables, deferred revenue, current year loan, and note payments). Otherwise, the organization may face solvency problems. On the other hand, an organization whose cash and equivalents greatly exceed its current liabilities might not be putting its money to best use.

Fiscal year ending: cloud_download Download Data


Financial trends analysis Glossary & formula definitions

Fiscal Year: Oct 01 - Sep 30

SOURCE: IRS Form 990

This snapshot of AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS (AAVSO)’s financial trends applies Nonprofit Finance Fund® analysis to data hosted by GuideStar. While it highlights the data that matter most, remember that context is key – numbers only tell part of any story.

Created in partnership with

Business model indicators

Profitability info 2017 2018 2019 2020 2021
Unrestricted surplus (deficit) before depreciation $1,049,796 $30,331 -$240,354 -$911,566 $2,419,897
As % of expenses 119.2% 3.0% -25.5% -96.2% 262.3%
Unrestricted surplus (deficit) after depreciation $987,362 -$22,542 -$291,154 -$962,093 $2,373,192
As % of expenses 104.7% -2.1% -29.3% -96.4% 244.8%
Revenue composition info
Total revenue (unrestricted & restricted) $665,724 $1,949,464 $110,788 $212,157 $1,024,120
Total revenue, % change over prior year -15.9% 192.8% -94.3% 91.5% 382.7%
Program services revenue 5.3% 1.6% 33.7% 18.7% 2.6%
Membership dues 12.0% 3.9% 88.2% 41.7% 11.6%
Investment income 26.5% 63.5% 246.3% 177.7% 24.2%
Government grants 0.0% 0.0% 0.0% 0.0% 0.0%
All other grants and contributions 27.8% 10.7% 168.9% 50.2% 43.4%
Other revenue 28.4% 20.2% -437.1% -188.2% 18.1%
Expense composition info
Total expenses before depreciation $880,559 $1,004,271 $942,519 $947,090 $922,730
Total expenses, % change over prior year -10.4% 14.0% -6.1% 0.5% -2.6%
Personnel 54.2% 51.1% 59.4% 61.1% 62.1%
Professional fees 11.3% 17.5% 10.1% 3.6% 3.8%
Occupancy 0.0% 0.0% 0.0% 0.0% 0.0%
Interest 0.0% 0.0% 0.0% 0.0% 0.0%
Pass-through 0.0% 0.0% 0.0% 0.0% 0.0%
All other expenses 34.5% 31.4% 30.5% 35.3% 139.2%
Full cost components (estimated) info 2017 2018 2019 2020 2021
Total expenses (after depreciation) $942,993 $1,057,144 $993,319 $997,617 $969,435
One month of savings $73,380 $83,689 $78,543 $78,924 $76,894
Debt principal payment $0 $0 $0 $0 $0
Fixed asset additions $0 $0 $0 $0 $0
Total full costs (estimated) $1,016,373 $1,140,833 $1,071,862 $1,076,541 $1,046,329

Capital structure indicators

Liquidity info 2017 2018 2019 2020 2021
Months of cash 7.7 9.5 6.2 6.9 7.3
Months of cash and investments 185.8 163.7 170.5 158.5 192.2
Months of estimated liquid unrestricted net assets 136.3 119.9 124.5 112.4 146.8
Balance sheet composition info 2017 2018 2019 2020 2021
Cash $564,624 $798,883 $486,964 $548,290 $558,090
Investments $13,066,896 $12,903,911 $12,903,636 $11,962,011 $14,221,800
Receivables $0 $0 $0 $0 $0
Gross land, buildings, equipment (LBE) $2,029,140 $1,907,498 $1,916,248 $1,837,128 $1,827,926
Accumulated depreciation (as a % of LBE) 34.9% 33.7% 36.2% 36.1% 38.3%
Liabilities (as a % of assets) 0.4% 0.7% 0.5% 0.9% 0.7%
Unrestricted net assets $11,319,002 $11,296,460 $11,005,306 $10,043,213 $12,416,405
Temporarily restricted net assets $212,159 $201,382 $173,184 N/A N/A
Permanently restricted net assets $3,366,044 $3,367,794 $3,367,794 N/A N/A
Total restricted net assets $3,578,203 $3,569,176 $3,540,978 $3,545,270 $3,587,907
Total net assets $14,897,205 $14,865,636 $14,546,284 $13,588,483 $16,004,312

Key data checks

Key data checks info 2017 2018 2019 2020 2021
Material data errors No No No No Yes


The people, governance practices, and partners that make the organization tick.

Form 1023/1024 is not available for this organization


Dr. Brian Kloppenborg

Dr. Brian Kloppenborg (Ph.D. Physics - Astrophysics Specialization) is an astrophysicist and entrepreneur. He earned a Ph.D. in Physics from the University of Denver, and a B.A. in Physics from Hastings College. Prior to joining the AAVSO, Brian worked as a Research Scientist at Georgia Tech Research Institute, where he served as a subject matter expert, lead engineer, product owner, and project director on a variety of government programs. He also ran a small business that provided data science, machine learning, and GPU accelerated computing services. Brian's research interests include photometry, spectroscopy, astrometry, and long-baseline optical interferometry of eclipsing binaries, novae, and young stellar objects. His work is published in Nature, ApJ, JAAVSO, and similar scholarly journals.

Number of employees

Source: IRS Form 990


Officers, directors, trustees, and key employees

SOURCE: IRS Form 990

Show data for fiscal year
Compensation data
Download up to 5 most recent years of officer and director compensation data for this organization


Highest paid employees

SOURCE: IRS Form 990

Show data for fiscal year
Compensation data
Download up to 5 most recent years of highest paid employee data for this organization


Board of directors
as of 06/07/2023
SOURCE: Self-reported by organization
Board of directors data
Download the most recent year of board of directors data for this organization
Board co-chair

David E Cowall MD

Retired physician

Term: 2021 - 2023

Board co-chair

!st Vice President RIchard Berry

Kristine Larsen


David Cowall

Robert Buchheim

Ken Hudson

Richard Berry

Robert Stephens

Thomas Maccarone

Texas Tech

Peter Bealo

Antonella Nota

International Space Science institute

Patrick Boyce

Boyce Education Foundation

Arne Henden

Sarah Austrin Willis

Financial Health Network

Martina Arndt

Bridgewater State University

Dennis Conti

Board leadership practices

SOURCE: Self-reported by organization

GuideStar worked with BoardSource, the national leader in nonprofit board leadership and governance, to create this section.

  • Board orientation and education
    Does the board conduct a formal orientation for new board members and require all board members to sign a written agreement regarding their roles, responsibilities, and expectations? Yes
  • CEO oversight
    Has the board conducted a formal, written assessment of the chief executive within the past year ? Yes
  • Ethics and transparency
    Have the board and senior staff reviewed the conflict-of-interest policy and completed and signed disclosure statements in the past year? Yes
  • Board composition
    Does the board ensure an inclusive board member recruitment process that results in diversity of thought and leadership? Yes
  • Board performance
    Has the board conducted a formal, written self-assessment of its performance within the past three years? Yes

Organizational demographics

SOURCE: Self-reported; last updated 3/27/2023

Who works and leads organizations that serve our diverse communities? Candid partnered with CHANGE Philanthropy on this demographic section.


The organization's leader identifies as:

Race & ethnicity
Gender identity

Race & ethnicity

Gender identity


Sexual orientation

No data


We do not display disability information for organizations with fewer than 15 staff.

Equity strategies

Last updated: 12/14/2022

GuideStar partnered with Equity in the Center - an organization that works to shift mindsets, practices, and systems to increase racial equity - to create this section. Learn more

  • We have long-term strategic plans and measurable goals for creating a culture such that one’s race identity has no influence on how they fare within the organization.
Policies and processes
  • We seek individuals from various race backgrounds for board and executive director/CEO positions within our organization.
  • We help senior leadership understand how to be inclusive leaders with learning approaches that emphasize reflection, iteration, and adaptability.
  • We engage everyone, from the board to staff levels of the organization, in race equity work and ensure that individuals understand their roles in creating culture such that one’s race identity has no influence on how they fare within the organization.


Fiscal year ending
There are no fundraisers recorded for this organization.