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The RS Oph datapoint that Mike refers to was made on
030529. The actual, differential measures are:
HJD V B-V V-R R-I
2452788.9493 10.746 1.135 0.886 0.922
with errors under 0.01mag in all magnitudes/colors.
This field is quite reddened, so you can probably
include some reddish stars in the sequence.
The AAVSO 113 is probably a bit too red, though.
Mike Simonsen wrote:
> I have been working on the same field for a couple days now. There is new
> photometry from Henden covering several of the brighter stars included on
> both AAVSO and Otero's charts.
>
> The existing AAVSO sequence for RS Oph has few real problems. Webbink's
> values match quite well with Henden's from 9.3-13.3 where a direct
> comparison can be made. The brighter mags seem to match well with Tycho.
>
> The one significant outlier, as Linnolt has mentioned, AAVSO 113 SE of the
> variable, is quite red (B-V
> 1.6) and actually 11.1V.
> I prefer not to use red stars in sequences, but in some areas near the
> galactic equator there is little choice in the matter.
> There are several red stars in both sequences, but as long as observers
> report the comparison stars used and chart information to AAVSO with their
> reports this should not be a significant problem.
>
>
> The recent reported brightening of RS Oph does seem to be real. Henden's
> most recent observation (of unknown specific date UT, sorry) is 10.759V, B-V
> 1.108 with errors expected to be +/-0.003.
>
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