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Alert Notice 339: Far Ultraviolet Spectroscopic Explorer Cataclysmic Variable Survey AND Preliminary NGC 6811 Deep and Wide Field Campaign Announcement

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July 6, 2006

1. FAR ULTRAVIOLET SPECTROSCOPIC EXPLORER (FUSE) CATACLYSMIC VARIABLE SURVEY

Dr. Patrick Godon (Villanova University) has requested help for a campaign to observe cataclysmic variables with the orbiting FUSE observatory. The goals of these observations are to help schedule the FUSE observing time and to obtain time series optical data simultaneously with the FUSE observations for correlation of the optical and ultraviolet data.

We request that visual observers add these stars to your program and observe them every clear night as part of your regular observing routine. This will build a baseline of activity and also inform us of any abnormal behavior in these stars (outbursts, standstills, etc.). Some of these objects are quite faint in quiescence, so visual fainter-than observations are acceptable.

We request that CCD observers make an estimate of the systems with a V filter once a week. Then, during the FUSE observing periods, take time series data for as long as possible, also in V. Set your exposure length to whatever is neccessary to achieve 0.01 precision.

The FUSE observing schedule is not yet known. When possible, Dr. Godon will notify us about a week prior to the FUSE scheduled observing period and we will issue an AAVSO Special Notice.

Below is a list of the stars in the FUSE survey (2000.0 coordinates). It is estimated that about half of them will be observed by FUSE, but we do not know which ones yet.

	Desig.   Name      RA          Decl.        Range          Type
   0515-79  AQ MEN    05 07 53.76 -79 51 23.2  15.1 - ? B     UG:
   0606-71  AD MEN    06 04 30.91 -71 25 22.7  15.0 - 16.6p   UGSS
   1102-55  V342 CEN  11 07 14.64 -55 57 44.2  14.1 - 18.0p   UG
   1150-56  V1040 CEN 11 55 26.72 -56 41 52.0  12.5 - 14.6V   UGSU
   1612-54  HP NOR    16 20 49.58 -54 53 23.0  12.8- 16.41V   UGZ
   1617-55  IK NOR    16 25 29.00 -55 20 01.0  12.9 - 16.3p   UG
   1651-57  V433 ARA  17 00 06.06 -57 51 52.1  17 - ? V       NL/UGZ
   1815-83  NSV 10934 18 40 35.30 -83 43 13.0  11.3 - 15.0p   ?
   0206+57A TZ PER    02 13 50.91 +58 22 51.9  12.00 - 15.60V UGZ
   0217+70  AM CAS    02 26 23.45 +71 18 31.4  12.30 - 15.20p UGZ
   0401+50  FO PER    04 08 34.99 +51 14 48.3  11.80 - 16.00V UG
   1523+62  ES DRA    15 25 31.79 +62 01 00.2  13.90 - 16.30p UGSU

   The following stars have already been observing by FUSE,
   so just monitoring observations are needed:
   1638-55  V663 ARA  16 46 57.71 -55 41 21.2  15.90 - <16.30p UGSU
   1709-75  DT APS    17 22 47.98 -75 09 55.9  14.40 - <15.80p UGSS
   0015-74  VW TUC    00 20 19.10 -73 52 08.0  15.40 - <16.50p UG:

AAVSO charts exist for the northern hemisphere objects. Mati Morel (RASNZ) has developed sequences for the southern hemisphere objects, some of which are based on RASNZ charts. Charts for all stars can be plotted with the new AAVSO Automated Chart Plotter at the following URL:

http://www.aavso.org/observing/charts/acp/  [obsolete link; charts may be created using VSP at http://www.aavso.org/vsp]

Note: The Automated Chart Plotter is currently in beta testing and can only be used for fields included in this Alert Notice. Please report bugs through the AAVSO Bugzilla system at http://www.aavso.org/bugzilla/ . [obsolete link]

Of the campaign, Dr. Godon writes: "I am amazed to see the observing potential of small (and not so small) telescopes and I optimistically look forward to this collaboration. Many of these faint southern objects are not well known and some of the data collected might be more important than the FUSE data itself!

"For example we might be able to determine the period of the binary, the sometimes unknown period of the outburst/quiescence cycle, and from magnitude estimates we could even assess the distance of some of these objects (depending of course on the brightness, visibility and inclination of each object).

"Each FUSE observations will last about 20,000 sec of good exposure time, which means maybe up to about 40,000 sec of raw exposure time, or about half a day. FUSE will provide an FUV spectrum between 910 A and 1180 A in 'time tag' mode (similar to your time series). So, in addition to the FUV spectrum, we can also extract a light curve from the FUSE observation. These FUV light curves can then be compared to the time series obtained in the optical. So I definitely think that a time series concurent with FUSE is important. Sometimes the FUSE observations have a very low Signal to Noise (S/N; due to low quiescence, off target, jitter, etc..) and in that case the AAVSO observations will be the only source of data for our survey. For these objects, and any which FUSE does not observe, the AAVSO data will be used instead."

This campaign will be coordinated by A. Price.

2. PRELIMINARY NGC 6811 DEEP AND WIDE FIELD CAMPAIGN ANNOUNCEMENT

In September 2006 the AAVSO will be coordinating a month-long observing campaign based on a field near NGC 6811. This campaign is in support of an observing run with the Case-Western Schmidt Telescope (CWST) at Kitt Peak being coordinated by Dr. Steve Howell (NOAO). The goal is to look for new variable stars and possible exoplanet transits in this field which will ultimately be observed by the NASA Kepler Discovery Space Mission (http://kepler.nasa.gov/), currently scheduled for an October 2008 launch.

The 0.9m CWST telescope will be observing a field of approximately 1.25 sq. degree every night for around a month beginning around September 1, at the end of the Arizona monsoon season. They will be observing primarily in an R-type filter (Cousins or Sloan), with a few B and V images sprinkled in between. The observing each night will consist of consecutive 2-3 minute integrations and will last as long as darkness and weather allow. Their estimated magnitude range for good photometry is R=13-19.

AAVSO observers will be asked to:

  • + Observe all stars brighter than mag 13 in the entire field with an Rc filter, for as long as possible while the CWST telescope is operating.
  • + Observe all stars in the field, as faint and for as long as possible, in Rc when the CWST telescope is not operating (due to poor weather or daylight).
  • + As a secondary goal, if we obtain good coverage of these core goals, observe all stars in bands other than Rc.

Due to the large field of view and length of the campaign, this will require detailed coordination and cooperation of observers to be organized via the AAVSO-Photometry Discussion Group. You do not need to sign up for the discussion group to participate. Public archives of the discussion group are available here:

http://www.aavso.org/pipermail/aavso-photometry/  [obsolete link]

Monitor the discussion group for further updates and details in the coming weeks.

The web page will be updated with new photometry, light curves and other visual information to supplement the conversation on the discussion group. The URL will be:

http://www.aavso.org/ngc6811

The precise location of the field to be observed has not been determined by the CWST team yet, but it will be centered approximately on the open cluster NGC 6811. We would like to begin obtaining baseline data now for training purposes and to establish the behavior of brighter stars in the field. The 2000.0 coordinates for NGC 6811 and known or suspected variable stars within 60' are below:

	1934+46  NGC 6811   19 37 10     +46 22 30      open cluster
  Variables:
  1932+46  NSV 12196  19 35 17.80  +46 25 08.0    ?
  1937+46  BR CYG     19 40 54.70  +46 47 06.0    EA/SD
  1938+46  NSV 12304  19 40 58.50  +46 50 32.0    ?
  1937+46B NSV 12298  19 40 39.60  +46 45 09.0    ?

Charts for the field, along with a sequence from B. Skiff's LONEOS database, Glushkova et al. 1999 (1999AstL...25...86G), and the existing AAVSO sequence for BR Cyg, can be plotted with the Automated Chart Plotter via the following URL. (Thanks to Wolfgang Renz and Brian Skiff for help in collecting the photometry.) Further field photometry is being acquired by the CWST team and more comp star measurements and bandpasses will be added as they become available.

http://www.aavso.org/observing/charts/acp/   [obsolete link; charts may be created using VSP at http://www.aavso.org/vsp ]

Note: The Automated Chart Plotter is currently in beta testing and can only be used for fields included in this Alert Notice. Please report bugs through the AAVSO Bugzilla system at http://www.aavso.org/bugzilla/ .

Please observe any field that includes NGC 6811. Begin taking observations every night in BVRc filters and do weekly time series runs in Rc (V if Rc is unavailable). Go ahead and reduce your V frames using the available comparison stars. Hang on to any Rc frames for reduction after we have published some R band comp stars. When ready, upload observations of the known variables/suspects listed above to the AAVSO, but save your other data for now. We will develop a system to send us observations of all the stars in the field in the coming weeks. Stay tuned the AAVSO-Photometry Discussion Group for details.

In summary, we would like observers to begin practicing taking data on stars in a field which includes NGC 6811. We will use the next two months to refine our observing strategy, establish a coordination protocol, and develop a system for submitting observations of all field stars to the AAVSO. Keep your FITS files handy as we may want them uploaded as well. Start practicing and stay tuned to the AAVSO Photometry Discussion Group for updates and discussion in the next few weeks!

Additional background on this campaign was presented at the recent 95th AAVSO Spring Meeting. A PDF of the presentation is available here:

http://www.aavso.org/aavso/meetings/spring06abstracts.shtml  [obsolete link; use http://www.aavso.org/95th-spring-meeting-aavso-scientific-paper-session-abstracts ]

Stay tuned!

This campaign will be coordinated by A. Price.


This Alert Notice was prepared by A. Price.

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