Letter to Users of 2018 Bulletin
The major changes made to the AAVSO Bulletin in 2011 in content, format, and methods of access are preserved in this year's Bulletin. This latest version of the AAVSO Bulletin provides a flexible resource that you can customize to serve your observing and research needs. In my 2012 Letter to Observers I gave the history of the AAVSO Bulletin, showing how it is has evolved over the decades.
In Bulletin 81, only those stars with an AAVSO mean curve have been included; the stars in earlier Bulletins indicated with an asterisk (*) as having no mean curve have not been included. The number of stars was reduced partly in order to help focus your observing energies on those long period variables we feel very strongly must continue to be observed on a regular basis. Some of the removed stars will be added back to the Bulletin as mean curves are determined for them.
The semiregular variable V Boo demonstrated double-maxima behavior, similar to R Cen and R Nor, for several years. However, in 2016, the double-maxima behavior became much less pronounced and V Boo was returned to the regular list of Bulletin stars.
I know there are many astronomical objects competing for your observing time, especially for users of moderate- to large-sized telescopes and CCDs. However, I urge you not to neglect the AAVSO Bulletin stars! There are still numerous stars in need of better coverage, particularly around minimum - even stars whose behavior at minimum no-one has ever seen. If we are to determine dates of minimum accurately, we need to know how these light curves look around minimum. When you browse through the light curves (use the Light Curve Generator link in the Bulletin table), look for ones with sparse or no coverage and choose one or two of these to follow through minimum for at least a few cycles if you can. You will be going where no-one has gone before! You can also determine which Bulletin stars are most in need of observations by clicking on the "Bulletin 81 in order of need" link on the Bulletin 81 webpage - this file lists the Bulletin stars in order of the number of observations received last year and gives that number (from 0 to 1,573). Also, essentially all of the far-southern stars need more observations.
The Bulletin stars have decades - some, well over a century - of ongoing data provided by you and your colleagues, and continued continuity is essential to the researchers who will be analyzing these stars in the decades to come. Take a look at the table of AAVSO maxima and minima dates from 1900 through 2017 (click on the "T" link in the Bulletin table) and see the unique history you can be part of. Many thanks to each of you for your valuable astronomical contributions. We look forward to continuing to receive your observations!
Elizabeth O. Waagen
Senior Technical Assistant (Science Operations)