[Aavso-photometry] CCD 'fainter-than' question

Tue May 27 18:03:44 EDT 2008

For CCD observing, what constitutes a 'fainter-than' observation?  If I 
can see the variable on the image but only 10:1 S/N (50 minimum needed 
for observation, below), is that a 'fainter-than'?

Thanks,
Bob Crumrine (CRR)
near Rochester, NY

aavso at aavso.org wrote:
> AAVSO Alert Notice 379
>
> Support for Spitzer observations of tremendous outburst amplitude dwarf novae (TOADs)
> May 16, 2008
>
> Dr. Steve Howell (NOAO) requests monitoring of a subset of the known and 
> suspected tremendous outburst amplitude dwarf novae (TOADs) in support of
> Spitzer Space Telescope observations of these objects. Observers are asked
> to increase their monitoring of the objects in the table below in support
> of this campaign.  We note that several of these objects -- notably the 
> WZ Sge stars WZ Sge, GW Lib, and V455 And -- are not expected to 
> superoutburst during the next year, but observations are still encouraged
> in case they exhibit unexpected behavior.  
>
> The following table lists the observed magnitude range and an outburst 
> threshold for each star. Any observation above the threshold should be 
> considered in outburst, and any observation at or near the maximum is 
> likely a superoutburst.  If the object is in outburst or near maximum,
> please contact the AAVSO immediately.  Spitzer observations will not
> be triggered immediately, however, an Alert Notice will be issued 
> requesting concentrated coverage of the star.
>
> Name      RA(J2000)   Dec(J2000) thrshld. maximum minimum  type  period(m)
> ------------------------------------------------------------------------------
> WX Cet   01:17:04.20  -17:56:23.0  13.5     9.5    18.5    ugwz   83.9
> UV Per   02:10:08.00  +57:11:20.0  15.0    11.0    17.5    ugsu   93.3
> UW Per   02:12:29.59  +57:05:19.7  15.5    13.5    18.0    ug    unknown
> PQ And   02:29:29.54  +40:02:40.2  15.0    10.1    19.0    ugwz  unknown
> SW UMa   08:36:42.70  +53:28:38.0  15.0     9.7    16.5    su/dq  81.8
> EG Cnc   08:43:04.00  +27:51:50.0  15.0    11.9    17.0    ugwz   84.6
> BZ UMa   08:53:44.20  +57:48:41.0  14.5    10.2    15.9    ugsu   97.9
> RZ Leo   11:37:22.2   +01:48:58.0  14.5    11.5    19.2    ugwz  109.5
> QZ Vir   11:38:26.80  +03:22:07.0  13.5    10.0    15.7    ugsu   86.4
> BC UMa   11:52:15.90  +49:14:42.0  15.0    10.9    18.3    ugsu   91.2
> HV Vir   13:21:03.10  +01:53:30.0  15.0    11.5    19.0    ugwz   83.5
> UZ Boo   14:44:01.21  +22:00:54.8  15.0    11.5    20.4    ugwz  unknown
> EK TrA   15:14:00.40  -65:05:36.0  14.0    10.4    16.6    ugsu   90.5
> GW Lib   15:19:55.40  -25:00:25.0  14.0     9.0    18.5    ugwz   76.8
> V544 Her 16:38:05.40  +08:37:59.0  16.0    14.5    20.0    ug    unknown
> DH Aql   19:26:10.8   -10:15:29.0  15.0    12.5    18.3    ugsu  unknown
> KX Aql   19:33:53.70  +14:17:48.0  15.5    12.5    18.4    ug     86.9
> WZ Sge   20:07:36.50  +17:42:15.0  14.0     7.0    15.5    ugwz   81.6
> VY Aqr   21:12:09.2   -08:49:37.0  15.0     8.4    17.5    ugwz   91
> V455 And 23:34:01.45  +39:21:41.0  14.0     8.5    16.5    ugwz   81.1
>
> Both visual and CCD observations are useful, and multicolor photometry 
> would be greatly appreciated.  Visual observers are asked to observe these
> objects as normal; if they are already in your list of objects, please 
> continue, and if not, please add them to your nightly observing program.  
> CCD observers are asked to use exposure times such that you can obtain a
> signal-to-noise of 50 per observation.  CCD observers are asked to 
> obtain filtered photometry, in at least two filters if you are capable of
> doing so; single-filtered or unfiltered observations are also appreciated.
> Time-series observations are not required except for cases where superhumps
> have not yet been observed or the orbital period is unknown, and then are
> only requested when the star is in outburst.  For both visual and CCD 
> observations, "fainter-than" observations are also important, particularly 
> for objects with faint minima, so please report them as promptly as 
> positive detections.
>
> This campaign begins now (May 16, 2008) and continues through May 2009. 
> Once an object has been verified in superoutburst, Spitzer observations 
> will be scheduled within 2-4 weeks of maximum, and will be repeated twice
> -- 4-6 weeks and 6-10 weeks later. Observers are asked to provide nightly
> monitoring of these stars, and to begin intensive observations if and when
> any of them go into outburst to determine whether the star is in
> superoutburst.
>
> For more detailed information on this campaign, visit the following URL:
>
> http://www.aavso.org/news/toads_campaign.shtml
>
>
> This campaign is being organized for Dr. Howell at AAVSO Headquarters by
> Dr. Matthew Templeton.
>
> -------------------------------------------
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