Continuing V issues

Hi Alan,

I hope that you feel better soon!

TT Mon's light curve looks fine, except for one CCD observer.  That person should be contacted.

Likewise for S Tuc, one observer seems to be measuring the wrong star.  Otherwise, I don't have a clue as to why their observations are so discrepant.

These are obvious candidates for marking as discrepant and letting AAVSO staff follow up.  It is really hard for software to pick out these kinds of problems, which is why HQ relies so heavily on volunteers (especially observers familiar with a star) to identify measures to examine.

Both stars are too faint to be on the normal Bright Star Monitor program; if they were there, they could act as deciding votes as to which observations are likely to be correct (if anyone wanted something more than your excellent visual observations!).

Arne

Hi Alan:

I think most observers would state that V observations may be 10x more precise but not 10x more accurate than visual observations (excluding you, Sebastian and Mike L, of course). If either a visual observer or a ccd observer selected the wrong star, they would both arrive at an inaccurate target magnitude.

I looked at the TT Mon observations on the LCG2 because I took one measuremnt recently. Whew, I was pretty close to your mags!

I noticed that one CCD observer's set shows a divergence from your visual estimates at magnitudes fainter than 11.5 or so, but not when brighter . My guess is that as TT Mon fades below that mag, the ccd photometry software target centroid jumps to an adjacent star that is brigther than the correct TT Mon target?

The truth is that your eyes and brain are much better at avoiding misidentification and the resulting inaccurate measurement than a photometric "black box". We ALL need to look at / check the image or visual field to get the magnitude of the correct target! That truth is unfortunately sometimes forgotten.

Ken (MZK)

PS: I'll talk to Sara or Elizabeth to see if they can help with TT Mon.