[AAVSO-DIS] The Nature of 2MASS J18381408-0531148

[Sebastian Otero]

> I agree.  Why does NSVS have it at V= 10.35 - 12.72.  Is that not actually 
> V?

No. It's unfiltered that's why red stuff looks brighter. Actually the ROTSE1 
passband is very broad covering from mid-B to mid-I and peaking near R. But 
the magnitudes are calibrated to Tycho-V using a formula that is supposed to 
give an equivalent to a V scale (for more info, check out the NSVS data 
release paper). But as you have noted, red stars are completely off.
This mira has a J-K of 1.8, this is really red.. The B-V is probably redder 
than 3.
So NSVS magnitudes are just ROTSE1 magnitudes.

Cheers,
Sebastian.