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Old photometric sequence data

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bskiff
Old photometric sequence data

This is mainly for the chart-seqeunce team.  About 25 years ago, by way of teaching myself to do single-channel 'all-sky' photometry, I observed a substantial number of chart sequence stars at the request of Chaz Scovil.  This was all done using the venerable Lowell 21-inch/53cm telescope, which had a permanently-mounted single-channel photometer with intermediate-band Stromgren filters.  It was straightforward to get Johnson V magnitudes from the Stromgren y filter measurements.  Some of these were published in a series of IBVS flyers, but a large number were not.  All the data were delivered to Scovil, but I do not know whatever happened to them.  I wonder now whether the data are still useful.  Most are for well-observed red variables, though some other types of stars are included.

I attach an example (simply the first of the stack in RA order), which is for T Cas.  I have just now compared my numbers with the current chart.  In general the data match well, though my accuracy is often 10x higher than what's shown in the chart photometry table.

Perhaps an obvious thing to do is to prepare a list of the fields covered to see if the chart team have any interest in these.  The data include some hundreds of stars in some dozens of fields.

\Brian

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HQA
HQA's picture
old photometric data

Hi Brian,

I think that data would be useful, in its entirety.  The main plotting program that the sequence team uses, SEQPLOT, uses a database that includes multiple small datasets such as yours.  When a sequence is needed, any small dataset in the area can be included.  We'd just have to find someone who was willing to reformat your file into a version that can be easily imported.

I don't remember any sequence stars coming directly from Chaz.  The Chart Team, back in the mid 2000's, documented all AAVSO sequence stars along with identifications and accurate coordinates.  Any original reference information may have been left out of that accounting.  My memory is not good enough to remember.  Perhaps Vance Petriew, who headed the Team, would know more.

Arne

bskiff
old photometric data

OK, I will go through the various lists, revisit the source data, and build a simple file with names, RA/Dec, and data.  Since my first note, I went through my files for a quick look, and found that there were about 40 fields with typically 8 or 10 stars per chart.  Some will not go faint enough for visual observers, but be entirely suitable for digital imaging.

\Brian

arx
arx's picture
A Bit of AAVSO History: Comparison Star Database Working Group

Arne wrote:

"The Chart Team, back in the mid 2000's, documented all AAVSO sequence stars along with identifications and accurate coordinates."

I'd like to digress from the main topic into a bit of AAVSO history. There were actually three teams involved in this project, I believe. I made the following note at the time:

"AAVSO Teams. Published AAVSO Web Site 3 Nov 2004

Chart Team: Arne Henden, Charles Scovil, Bruce Sumner, Marc Beismans, Robert Stine, Hazel McGee, Dan Taylor, Richard Huziak, Christopher Watson, Tom Steckner

Photometry Sequency team: Ron Zissell, Doug West, Michael Koppelman, Bruce Gary 

Comp Star Database Working Group: Vance Petriew, Rick L. Merriman, Keith Graham, Tim Hager, Carlo Gualdoni, Roy Axelsen, Brian Skiff, Dan Taylor, Joe Maffei, Curt Schneider, Christopher Watson, Arno van Werven, Mark Munkacsy, Jim Bedient, Radu Corlan, Steven Fanutti, Doug Hodgson, Dolores Sharples, Pedro Pastor."

The reason for this note is that I have seen one other descirption of this part of the history of the development of what eventually became the VSP, and it also referred to the Chart Group (a very important and hard working team), but made no mention of the Comparison Star Database Working Group. It was the responsibility of the latter group to examine every printed chart, as they then existed, check every comparison star, identify each one in existing catalogues, and document the 'best' position then available.

I was proud to be a member, along with Brian and the others, of the Comparison Star Database Working Group, under the able leadership of Vance Petriew. I thus have a personal (perhaps egotistical) interest in keeping the memory of it alive in the AAVSO's history.

Roy

bskiff
More on comp stars

As Roy notes, I did do some work on the comp star IDs, but surely only a tiny fraction of the total done by other folks.

I have been somewhat casually building an all-sky file UBVRIc data along the lines of my large spectral-types database.  The current photometry file has ~100,000 entries, with much material not in the Mermilliod collections, not at VizieR etc.  Very much a work in progress.  Every entry has the bibcode and coordinates associated with it.  This is copied to the Lowell ftp area:

ftp://ftp.lowell.edu/pub/bas/starcats/ubvri.dat

...about 11Mb of flat text.  I have been slowly rejiggering the old 'LONEOS' database (which is at VizieR) with improvements to add the source bibcode, missing colors (color-indices), complete lists etc.

\Brian

arx
arx's picture
More on comp stars

Brian is modest. I remember at the time how he worked through many more charts than I seemed to manage.

It also just ccurs to me that Mike Simonsen's name does not appear in the list of Chart Team members posted above. I can clearly recall email discussions with him at the time about comp star database entries. My recollection was that he led rhe chart team, but others can correct me if that is wrong.

Roy

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