Reply To: Magnitude precision on BAA-VSS charts.

[Andy Wilson]

Hi Paul,
Sorry this is causing you hassle. The point is these ‘warning’ messages are very useful to a large number of our observers. A ‘warning’ simply means ‘can you take a quick look at this to make sure it is expected’. It allows you to proceed with adding the data as only the observer has the knowledge of whether to expect a recognised chart or the other warning messages that are generated. When the upload generates an ‘error’ message then that means something is wrong and it won’t let the upload proceed.
We do have some AAVSO charts in the database. These tend to be older charts before they implemented their latest chart system, or charts created at a specific point in time. When I created the database I had discussions with the AAVSO about getting a copy of their chart data to add to our database. The problem is their charts are not static. A chart ID is not guaranteed to generate the same chart when entered at a later date, as any changes to the AAVSO chart database will result in the same ID giving a slightly different chart.
The chart is particularly important to the visual observers as the BAA database can recalculate magnitudes to the latest sequence. It can actually do that for digital as well as visual observations where sufficient information is provided, though we currently only have it turned on for visual observations.
As a final note, I would point out the AAVSO charts are fantastic and used by many BAA observers. It is just the BAA database cannot use them for more detailed processing as their chart IDs do not uniquely identify the comparison stars and their magnitudes.
Best wishes,
Andy