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AAVSO Alert Notice 440

PEP Observing Campaign on P Cygni

May 17, 2011:  Ernst Pollmann, an active spectroscopist in Germany and leader of Active Spectroscopy in Astronomy, has requested the assistance of AAVSO photoelectric photometry (PEP) observers in a campaign to observe the S Doradus variable P Cygni through the 2011 observing season.

PEP data are needed for correlation with spectra of P Cyg obtained by Ernst and other spectroscopists as they study this very interesting star.

CCD and DSLR observers can also observe P Cyg, if special care is taken to ensure the star is not overexposed. We strongly encourage CCD and DSLR observers to use standard V filters and perform a full system calibration and transformation of your data onto the Johnson V system. This will enable researchers to easily combine your observations with those of PEP observers. All observers should work to obtain photometry accurate to better than 0.05 magnitude.

V observations are requested. Please use the following comparison and check stars:

Comp: SAO 69101 (NSV 24943) V=4.936, B-V= -0.086
Coordinates: RA = 19 55 51.80  Dec = +38 29 12.0  (J2000.0)

Check: SAO 69803 (36 Cyg) V=5.573  
Coordinates: RA = 20 18 28.66  Dec = +36 59 59.290  (J2000.0)

P Cyg coordinates: RA = 20 17 47.20  Dec = +38 01 58.6 (J2000.0)

PEP observers should email their formatted, unreduced reports to AAVSO Headquarters, or use the comparison and check stars identified above and do their own reductions. The WebObs utility for PEP observations is not yet available, but it should be later in the year. In the meantime, observers may submit transformed data via the standard WebObs utility. Observations should be submitted to the AAVSO International Database as P CYG.

Finder charts for P Cyg (do not use the comparison stars given in these charts; use only the comparison and check stars id entified above) may be generated using the Variable Star Plotter (VSP):

This campaign is included on the AAVSO Observing Campaigns page:

Thank you very much for your participation in this campaign - your observations will be crucial to its success!

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

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