The Official Site for the AAVSO Charts and Sequences Team
Since it seems every time we get a new member many of the same questions come up, I thought I'd make a website we can use as our policies and procedures manual. So here it is. Bookmark this site, we will be referring to it a lot.
The initial plan is to include the guidelines for creating and revising sequences, documenting sources and preferences for photometry and discussing the tools and projects the sequence team is working on.
Priorities (last updated October 21, 2013)
Right now the priorities are to:
2) Complete the evaluation and entering of the remaining comp stars from Project Snapshot for southern sky sequences. This is a big project containing about 800 comp stars and I need help!
6) Fix anything else that can be fixed now, without new photometry. This includes bugs to VSP and DB issues. (ONGOING)
7) Create new and revised sequences as photometry becomes available from BSM and APASS. (ONGOING)
18) Fill requests for specific sequences made to the website form (ONGOING)
22) Address all errors reported to CHET as soon as possible. (ONGOING)
23) Create and upload sequences for DSLR program stars.
Tens of thousands of hours of labor were invested in creating the charts, first by hand, then on blueprints, then paper copies, then eventually plotted by planetarium software and labeled by hand, distributed as image files available online or on disk.
This has eliminated the need for teams of workers creating multiple charts of various sizes, magnitude limits and field rotation. But it has not completely automated the process. People using a specific set of criteria still select the comparison star sequences used on all VSP charts. Until such time as there is an all sky photometric catalog of sufficient magnitude range and accuracy, this task will remain the job of the AAVSO Sequence Team.
This is still a manual process, and the end result is what we call a sequence file. This is information in a specific format that contains the data VSP needs to label the chart properly and create a table with the magnitudes and colors of the comparison stars. A sequence file looks like this.
Observers are encouraged to report errors appearing on charts, such as duplicate magnitudes, gaps in the sequence, mislabeled stars or missing labels. These are entered into the Chart Error Tracking Tool, CHET. Part of the job in front of the sequence team is to fix the existing inconsistencies on charts utilizing the new photometry available now. As more fields are calibrated, more and more old problems are being addressed.