What's next?
James Roe
recognizing ways to clarify other variables such as ASAS variables,
etc. I still need a philosophical foundation to put meaning into it.
Here are my immediate thoughts, please comment/expand.
1. AAVSO maintains the International data base for actual
observations. Is it the intent/desire that this data base
(eventually) contain all known measurements of star variability? I
have no trouble uploading my own measurements but I take pause at
uploading others (eg, ASAS). What are the guidelines?
2. AAVSO maintains the Variable Star Index (VSX) which I understand
to be a listing of all known variable stars with various attributes.
Again, I have no qualms about submitting evidence of variability on my
own data but could use some guidelines. EG, what if I can't identify
the star class? What if my data have no photometric comparisons,
taken with clear filter, etc? With respect to other's data, what is
the protocol. For example, I have looked at several ASAS variables
which are listed in VSX but there is no supporting light curve or
other. In a couple of cases (that I have looked at), I suspect the
period data is wrong (due to the wide cadence) and am looking at some
new measurements of my own to, hopefully, refine the period. One can
also "mine" the actual data from the ASAS site, determine a nice phase
curve, etc. Again, what is the protocol for reporting this data?
3. Just another example. MY Lyr is recognized in VSX and there are
some data for it in the IDB (from Martin Nicholson) but ASAS shows
some independent data that would appear to complement Martin's data.
Is this a worthwhile chore (to upload the ASAS data to IDB)? It seems
to me this would make a nice student project (when combined with lots
of other examples)? Martin has been urging folks to look at various
candidates lately.
I recognize that a lot of this type work (maybe most?) is "grunt" work
but, what the hey, what else would I enjoy doing on a cloudy night?
Jim Roe [ROE]
Patrick Wils
> I have no trouble uploading my own measurements but I take pause at
> uploading others (eg, ASAS). What are the guidelines?
I think there are several issues with uploading ASAS data to the AID, so I personally would not recommend doing it.
> Again, I have no qualms about submitting evidence of variability on my
> own data but could use some guidelines. EG, what if I can't identify
> the star class?
Assuming that you exhausted all available options (other datasets, second opinions, ...), there are always the GCVS types L, S, I for resp. slow, fast and irregular variability and which actually just say there is not enough data to determine the type.
> What if my data have no photometric comparisons, taken with clear
> filter, etc?
There should in most cases not be a problem to determine whether the star is really variable, or to detremine type and period, etc.
> With respect to other's data, what is the protocol.
Mention the source of the data.
> For example, I have looked at several ASAS variables
> which are listed in VSX but there is no supporting light
> curve or other.
When variables have been uploaded in bulk, the supporting evidence can often be found in the publication from which these variables originated. In the particular case of ASAS variables, a light curve can always be obtained through the ASAS link-out in the detail sheet.
> In a couple of cases (that I have looked at), I suspect the
> period data is wrong (due to the wide cadence) and am looking at some
> new measurements of my own to, hopefully, refine the
> period. One can also "mine" the actual data from the ASAS site,
> determine a nice phase curve, etc. Again, what is the protocol for
> reporting this data?
You are invited to submit a revision of the VSX entry (click on the "Revise" link in the VSX Detail Sheet) in that case. Always make a reference to the origin of the data.
Patrick
Arne Henden
You ask several questions, and each requires a fairly lengthy reply. I'll start
by answering the first one.
I'm have some success at finding new variables in my own images and in
recognizing ways to clarify other variables such as ASAS variables,
etc. I still need a philosophical foundation to put meaning into it.
Here are my immediate thoughts, please comment/expand.
1. AAVSO maintains the International data base for actual
observations. Is it the intent/desire that this data base
(eventually) contain all known measurements of star variability? I
have no trouble uploading my own measurements but I take pause at
uploading others (eg, ASAS). What are the guidelines?
from thousands of observers over more than 100 years. ASAS probably has that many
variable-star observations from one site over about 10 years. The two datasets are
complementary, yet different.
What we would like is "one stop shopping." Researchers come to the AAVSO to obtain
every possible observation for any variable. This saves enormous time, not only in
locating observations, but also in placing the observations into a common format.
We also provide a significant value-added component: light curve generator, data
download, period-determination software, observing tools for new observations of
research targets, etc.
The ideal solution is for the AAVSO to continue collecting observations from individuals,
along with ferreting out every last published observation. We would then include information
from other on-line catalogs whenever queries are made for a particular variable, presenting
the researcher the entire available dataset for that star, even if it comes from multiple
sources. We shouldn't be in the business of duplicating the database of ASAS or
SDSS or whatever; just providing a convenient access to those datasets. (The exception
is if the external database is slow or off-line significant fractions of time so that the
researcher doesn't get the whole picture in a timely fashion. Then, we might consider
uploading observations daily, or suggesting that we host a copy of the database here.)
That was the defined role of the Virtual Observatory, assuming that each holder of
a database would provide a VO interface to their data. We hope that we can use
such standardized access methods for most of the external datasets, but we may
have to provide customized accesses to others. I think this is a better approach than
trying to load all ASAS observations of a variable star into the AID in a timely manner.
We are working on such "metatables" of data, but with limited manpower. In the
meantime, volunteers like Shawn Dvorak have uploaded some ASAS measurements
into the AID so that they can at least be used.
Another aspect of the AID, though, is long-term archival. We have multiple backups
and intend to stick around for a long time to come, so any observation submitted to
us is likely to be available to researchers for the indefinite future. It is unclear how
some of the current surveys, especially those run by small groups, will provide
access to their databases when their survey ceases. There are data storehouses
like VizieR available that provide a good method of storing reasonably-sized
datasets, and I hope that research teams make use of them. We can provide
off-site storage of databases on our internal servers, and possibly act as mirror
sites as well, as another level of protection. I don't want those important survey
results to be lost!
So the short answer to your question is that we're probably a year away from
providing access to other databases. It is a political question as well as an
implementation question. Uploading their observations is a short-term
solution, necessary in some cases for research projects, but probably less
useful in the long term. I think a better use of volunteer time would be in uploading the
older observations from Harvard Annals, the RASNZ, photoelectic observations
published in AJ in the 1960's, etc. - the datasets that will continue to be neglected
without human intervention. Brian Skiff has been doing many of these, and
Matt is preparing a more formal project with those goals. I'd contact him directly
if you want to start getting involved now.
Arne