[Aavso-photometry] 3C 66A And - Monitoring of Blazars - Alert Notice 353

[arne]

Tim Crawford wrote:
> Regarding the "3C 66A And" Target and FOV:
> 
> The Sumner Sequence link only provides B & V data.
> 
> In as much as:
> 
> 
>>Dr. Boettcher has requested the following hierarchy
> 
> of observations:
> 
>>Cousins R nightly or multiple times per night; add B
> 
> if possible; one
> 
>>UBVRI set per night if possible; signal-to-noise
> 
> ratio of 50 or better.
> 
> A possbile better source of an actual chart with BVRI
> sequence data for 3C 66A And would be from the GTN
> Progarm Object Catalog:
> 
> http://gtn.sonoma.edu/participants/catalog/index.php
> 
> 3C 66A is the first object listed.  Simple select the
> View Details "button" and the chart with sequece data
> will appear.
> 
The Alert Notice also said that if Rc filters were not available
that V-band measurements were acceptable, and gave thresholds
for V in the table.  For V-band users, the Sumner sequence
works fine.

I checked the Heidelberg chart that Tim gave above, and the
four comparison stars they list have quite good V measures.
However, using the "I" column plus "V", and creating (V-I),
gives colors that seem too blue in comparison with my (B-V).
Since this link does not give any reference for their photometry,
I would be a bit suspicious of the R/I values, and in fact don't
even know if they are Rj/Ij or Rc/Ic.  Use the values listed,
but be sure in your "comments" field to include the standard
star magnitudes used so that these measures can be corrected
later if found in error.
Arne