KIC 8462852 Hereford Arizona Observatory Photometry Observations #7
Bruce Gary, Last updated: 2018.10.18 17 UT

  Observing break

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.

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

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

List of Observations (for all earlier observations, before 2018 Feb 25, go to link)


Daily Observing Session Information (most recent at top)


r'-mag = 11.7859(21), i'-mag = 11.5863(20)


r'-mag =  11.7849(18), i'-mag = 11.5866(20)



r'-mag = 11.7838(17), i'-mag = 11.5836(19)


r'-mag = 11.7842(16), i'-mag = 11.5844(18)


r'-mag = 11.7819(17), i'-mag = 11.5837(20)


r'-mag = 11.7830(20), i'-mag = 11.5838(22)


r'-mag = 11.7831(19), i'-mag = 11.5846(21)


r'-mag = 11.7867(18), i'-mag = 11.5837(18)


r'-mag = 11.7892(18), i'-mag = 11.5867(18)


r'-mag = 11.7866(18), i'-mag = 11.5863(18)







2018.08.27  Dome failed to synchronize after ~ 07 UT

2018.08.26  Cloudiness a problem


Clouds came starting at 9.0 UT.


Computer glitch led to dome not tracking telescope, so data is less precise than usual.


Finally, a 1-hour "partial hole" in the monsoon cirrus clouds!

My Collaboration Policy

At my age of 79 I'm entitled to have fun and avoid work. Photometric observing and figuring things out is fun. Writing papers is work. Besides, most people really don't care about what others have done. So, if anyone wants to use any of my observations for a publication, you're welcome to do so. But please don't invite me for co-authorship!

My light curve observations are "in the public domain." This means anyone can and may download my LC observations, and use (or misuse) any of that data for whatever purpose. If my data is essential to any publication just mention this in the acknowledgement section.


    Wright, Jason T., "A Reassessment of Families of Solutions to the Puzzle of Boyajian's Star," arXiv  (a 1.1-page paper)
    Schaefer, Bradely E., Rory O. Bentley, Tabetha S. Boyajian and 19 others, 2018, "The KIC 8462852 Light Curve From 2015.75 to 2018.18 Shows a Variable Secular Decline," submitted to MNRAS, arXiv 
    Bodman, Eva, Jason Wright, Tabetha Boyajian, Tyler Ellis, 2018, "The Variable Wavelength Dependence of the Dipping event of KIC 8462852," submitted to AJ, arXiv.
    Bodman, Eva, 2018, "The Transiting Dust of Boyajian's Star," AAS presentation, link 
    Yin, Yao and Alejandro Wilcox, 2018, "Multiband Lightcurve of Tabby's Star: Observations & Modeling," AAS presentation, link (navigate down, etc)
    Sacco, Gary, Linh D. Ngo and Julien Modolo, 2018, "A 1574-Day Periodicity of Transits Orbiting KIC 8462552," JAAVSO, #3327, link
    Boyajian, Tabetha S. and 198 others, 2018, "The First Post-Kepler Brightness Dips of KIC 8462852," arXiv 
    Deeg, H. J., R. Alonso, D. Nespral & Tabetha Boyajian, 2018, "Non-grey dimming events of KIC 8462852 from GTC spectrophotometry" arXiv 
    Bourne, R., B. L. Gary and A. Plakhov, 2017, "Recent Photometric Monitoring of KIC 8462852, the Detection of a Potential Repeat of the Kepler Day 1540 Dip and a Plausible Model," arXiv:1711.10612     
    Bourne, Rafik and Bruce Gary, 2017, "KIC 8462852: Potential repeat of the Kepler day 1540 dip in August 2017," submitted to AAS Research Notes, preprint: arXiv:1711.07472
    Xu, S., S. Rappaport, R. van Lieshout & 35 others, 2017, "A dearth of small particles in the transiting material around the white dwarf WD 1145+017," approved for publication by MNRAS link, preprint arXiv: 1711.06960 
    Gary, Bruce and Rafik Bourne, 2017, "KIC 8462852 Brightness Pattern Repeating Every 1600 Days," published by Research Notes of the AAS at link; preprint at arXiv:1711.04205
    Gary, B. L., S. Rappaport, T. G. Kaye, R. Alonso, J.-F. Hambsch, 2017, "WD 1145+017 Photometric Observations During Eight Months of High Activity", MNRAS, 2017, 465, 3267-3280; arXiv
    Neslusan, L. and J. & Budaj, 2016, "Mysterious Eclipses in the Light Curve of KIC8462852: a Possible Explanation, arXiv: 1612.06121v2  (a "tour de force"; I highly recommend this publication)
    Neslusan & Budaj web site with animation of their way of explaining Kepler D1540 dip:
    Wyatt, W. C., R. van Lieshout, G. M. Kennedy, T. S. Boyajian, 2017, "Modeling the KIC8462852 light curves: compatibility of the dips and secular dimming with an exocomet interpretation," submitted to MNRAS, arXiv  
    Grindlay interview about Schaefer's assertion that KIC846 exhibited a century long fade using DASCH data: link
    Hippke, Michael and Daniel Angerhausen, 2017, "The year-long flux variations in Boyajian's star are asymmetric or aperiodic," submitted to ApJL, arXiv 
    Sacco, G., L. Ngo and J. Modolo, 2017, "A 1574-day Periodicity of Transits Orbiting KIC 8462852," arXiv
    Rappaport, S., B. L. Gary, A. Vanerdurg, S. Xu, D. Pooley and K. Mukai, 2017, "WD 1145+017: Optical Activity During 2016-2017 and Limits on the X-Ray Flux," arXiv, Mon. Not. Royal Astron. Soc.
    Steele, I. A. & 4 others, 2017, "Optical Polarimetry of KIC 8462852 in May-August 2017,"MNRAS (accepted), arXiv.
    Simon, Joshua D., Benjamen J. Shappee and 6 others, "Where is the Flux Going? The Long-Term Photometric Variability of Boyajian's Star," arXiv:1708.07822 
    Meng, Huan Y. A., G. Rieke and 12 others (including Boyajian), "Extinction and the Dimming of KIC 8462852," arXiv: 1708.07556  
    Sucerquita, M., Alvarado-Montes, J.A. and two others, "Anomalous Lightcurves of Young Tilted Exorings," arXiv: 1708.04600   Also: New Scientist link and Universe Today link.
    Rappaport, S., A. Vanderburg and 9 others, "Likely Transiting Exocomets Detected by Kepler," arXiv: 1708.06069 
    Montet, Benjamin T. and Joshua D. Simon, 2016, arXiv 
    Boyajian et al, 2015, MNRAS, "Planet Hunters X. KIC 8462852 - Where's the flux?" link
    Ballesteros, F. J., P. Arnalte-Mur, A. Fernandez-Soto and V. J. Martinez, 2017, "KIC8462852: Will the Trojans Return in 2011?", arXiv
    Washington Post article, 2015.10.15: link
    AAVSO Campaign Notice requesting KIC646 observations
    AAVSO LC Generator (enter KIC 8462852)
    Web page tutorial: Tips for amateurs observating faint asteroids (useful for any photometry observing)
    Book: Exoplanet Observing for Amateurs, Gary (2014): link (useful for any photometry observing) 
    wikipedia description of Tabby's Star  
    My web pages master list, resume

    B L G a r y at u m i c h dot e d u    Hereford Arizona Observatory    resume 
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Nothing on this web page is copyrighted.