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AAVSO Target Tool

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HQA's picture
AAVSO Target Tool

First, kudos for the developers.  The tool looks great and should be useful to many observers!

I'd personally like to see three additional links/columns, of course all difficult to program.  First, it would be nice to have a link to the current light curve for selected targets, so that you can see the typical behavior of the star, or the current phase (you might not be able to observe as faint as the Mira is right now, for example).  Second, a link to a finding chart would make it easier for the observer (you've done it for the VSX entry, so maybe this would be fairly simple).  Finally, Ron Kaitchuck came up with a graphical program to show the altitudes of the stars he wanted to observe as a function of time through the night.  In this way, he found it easier to choose targets - the one that stayed up all night, or switching as they cross the meridian, or whatever).  He wrote that in ~1980, so it oughta be much easier today!  A link to such a dynamic chart would be valuable in planning your night.

A very good start - thanks!



stellakafka's picture
New tool for our community - ATAT :)



I was planning to announce this tool to our community first thing today, but Arne beat me to it :)


For the last year, we have been working with a group of very talented developers to create a new online tool that would give information of targets that need observing, to those observers who want recommendations on what to observe each night. After multiple integrations, discussions, improvements, tests, more tests and more improvements, I am delighted to introduce our AAVSO Target Tool. It provides lists of stars that are in need of observing, and that are visible from the location of your observatory. The recommended lists of objects were selected by our observing section leaders; a star’s recommended cadence of observations was determined based on individual star characteristics and completeness in our database. You can select targets based on their specific types (CVs, LPVs, eclipsing etc) and/or simply what can be observed from your observing site. Targets that are part of our alerts are marked as “high priority”.


You can find this tool at:


For more information on how you can use the tool’s functionalities, please go to the relevant help page at:


Many thanks to Prof. Keivan Stassun, Dan Burger and their team members,

Chandler Barnes, and Kenneth Li, from Vanderbilt University who worked hard to build this tool for the AAVSO. It was a pleasure to work with our observing section leaders, John Percy, Gary Billings, Dennis Conti, Andrew Pearce, Michael Poxon Gerry Samolyk and Frank Schorr, on target selection, discussing the idiosyncrasies of various targets. Credit also goes to our past president Jeno Sokoloski who secured funding for this tool through the Research Corporation for Science Advancement foundation, and Sara Beck from HQ who helped coordinate all this process.


We hope you enjoy it. Comments are welcome, as we try to improve the tool’s functionality. Happy target selection!

Best wishes – clear skies,


JBD's picture
New tool for our community

I looked at the new tool and I think it's simple and great!
I will play with it for better know it
Thank you!


mishnik's picture
AAVSO Target Tool

I want to ask a question about the AAVSO Target Tool . What does "Observing
Cadence (d)" ? This is how many observations should be per day? If indicated 0.2 or 2.9, then how much?


stellakafka's picture
Hello Nikolay,

Hello Nikolay,


The cadence (in days) represents how frequently a star should be observed to ensure at least a long-term light curve. A cadence of 2.9 means that this star should have at least one observation every 2.9 days; a cadence of 0.2d requests data essentially every ~5 hours. Each target has one unique cadence depending on the nature of its variability.

I hope this helps. Please let me know if you have more questions.

Best wishes – clear skies,


PYG's picture

I still don't understand why the observing frequency for DNe remains at 5d.  I posted this question before and it didn't get answered.   DNe should be observed every night, even if an outburst has just ended. Might someone please correct this!


stellakafka's picture
CV cadences

Hello Gary,


The cadence for CVs was set up to ensure that there will be long-term light curves of all objects. It is following the RoboScope model – one point/week – which successfully has built up solid light curves of all objects in that program. It also reflects the LSST observing cadence, which is one data point/4-5 days for each star.


As you are a seasoned CV observer, you know well that each object in the CV list (be it DNe, NL, N, AM Her etc) has its peculiarities due to outbursting behavior, orbital variability (including eclipses), accretion rate variations, or eruptions (novae). The timescales for those are very short and ideally we would like each star to have continuous time series every night in all filters to capture all behaviors. This is not practically possible, and could result to having decent coverage only for certain stars in the group. If the cadence is too short (e.g. 1 day) the flag will never turn green for neglected CVs that have sparse observations. A longer cadence enables different targets with red flags to be brought to the attention of observers who need guidance on what to observe each night, with the hopes of building uniform long-term light curves for all targets in the list.


Please note that the tool is meant to provide feedback on targets of interest, so that no star will be left behind. If someone wishes to take data on their favorite object every night, they should do so! Furthermore, if you think that there is a handful of objects that require more frequent observing, please let us know. The cadence can be revised as needed, based on star peculiarities. At the same time, looking at the CV targets, half of CV flags are red or are approaching the cadence limit (orange). This tells me that observers haven’t observed those stars, even with the cadence of 1 point/5 days. Before adjusting any cadences, I would like to see most of those flags turning green, to ensure that data are being submitted for all stars, not only a few favorites.


Best wishes – clear skies,


mishnik's picture
Data update

Why do not the observational data update? I today uploaded data on "AM Cas" and "HT Cas", but it is indicated that the last observations were a week ago.

BSJ's picture
Data update - fixed!

Hi Nikolay,

Thank you for reporting that. Apparently, there was a bug in the program when "All" is selected but it has been fixed now.

In the future when you submit observations, the "Last Observed" flag should turn green within about an hour of your data upload.

Best regards,


Need a definition of need?

What specifically do you mean by "targets that need observing"?

I'm interested in possibly setting up some type of variable star observing curriculum for high school and community college students along the lines of Russ Genet's efforts for double star observing. A quick search and I noticed about 10 years ago GNAT published their Variable Star Catalog that

..contains data for 26,042 variable star candidates, including 5,271 which are periodic at the 99% confidence level... The data primarily represent newly discovered variable star candidates as only 59 of them appear in the General Catalog of Variable Stars.

So I guess my question is whether there've been updates to this catalog and whether these candidates might meet the definition of "need". Thanks - Jesse


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