I have changed my interpretation of OOT during the past 6 months. Instead of fade rates that differ at g'-, r- and i-bands I now favor a constant OOT at all bands with a 4-month fade feature with different depths at each band. The late September feature that I called a "brightening" would then be re-interpreted as a return to normal OOT (i.e., the same OOT level as existed in 2018 May). This is illustrated in Fig. 1a.
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Links on this web page

    g', r' & i' Magnitude vs. date  
    V-mag and g'-mag vs. date   
    AAVSO light curve   
    List of observing sessions 
    My collaboration policy
    References    

Links on another web page
 
    Comparison with AAVSO observations   
    Finder image showing new set of reference stars
    HAO precision explained (580 ppm) 
    DASCH comment  

  Go back to 6th of six web pages  (for dates 2018.02.25 to 2018.08.01)
  Go back to 5th of six web pages  (for dates 2017.11.13 to 2018.01.03)
  Go back to 4th of six web pages  (for dates 2017.09.21 to 2017.11.13)
  Go back to 3rd of six web pages  (for dates 2017.08.29 to 2017.09.18)
  Go back to 2nd of six web pages  (for dates 2017.06.18 to 2017.08.28)
  Go back to 1st of six web pages  (for dates 2014.05.02 to 2017.06.17)
    Reference Star Quality Assessment  (the 10 best stars out of 25 evaluated)  

This is the 7th web pages devoted to my observations of Tabby's Star. When a web page has so many images that download times are long, a "split" is made and this is the latest one.

g', r' and i' Mag's vs. Date


Figure 1a. HAO g', r' and i'-magnitudes for the past 7 months. The "OOT only" trace since 2018 May is chosen to be "flat" in order to illustrate one interpretation, namely, that since May there has been a shallow (~ 0.5 %) fade at g'-band lasting ~ 4 months, which ended in late September. The fade amount was greater at r'-band than g'-band, and there was no fade at i'-band. If true, this would be puzzling.


Figure 1b. This is an alternate interpretation. It involves different fade rates for each band starting in 2018 May, with a recovery in late September. 

V and g'-Mag vs. Date


Figure 2a. HAO magnitudes at g'-band for the past year. The "OOT only" trace is the second "U-Shaped" component needed to account for the upper-boundary of measurements (presumably the out-of-transit, or OOT, level). The OOT level since 2018 May was chosen to be constant.


Figure 2b. Alternative OOT interpretation. 


3a. This shows the last 2.5 years of C-, V- and g'-band HAO measurements (C- and V-mag's adjusted to match g'-mag's).

Figure 3b. This shows the last 2.5 years of C-, V- and g'-band HAO measurements (C- and V-mag's adjusted to match g'-mag's).


Figure 4. Normalized flux light curve for the past 1/2 year, based on the g'-band measurements and the associated OOT model that does NOT include a fade since 2018 May. 


Figure 5. A 1.4-year plot of "normalized flux" based on the previously displayed g'-band measurements and associated OOT model (with two U-shaped features). The HAO data for April are too sparse for showing dip structure well; the graphs in the next section do a better job of that sine they include AAVSO measurements. (The OOT model does NOT include a fade since 2018 May.) 

AAVSO Light Curve

Rafik Bourne has kindly provided the following light curve based on (mostly) AAVSO data. They provide day-timescale temporal resolution.


Figure 6. AAVSO daily data (plus occasional HAO data, with arbitrary offsets for each observer and band) for the last 2.6 months. Posting date: 2018.10.06 02 UT