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Request to observe the eclipsing variable V610 Cyg

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Request to observe the eclipsing variable V610 Cyg

According to Lichtenknecker-database of BAV in Germany, there is no minimum observation of V610 Cyg since 1948 untill this year.
I have investigated this variable, have improved its period and have made observations to verify new elements. 
I have also asked Japanease variable star observers to catch minima and Mr. Maeda in Nagasaki has observed minimum twice on 6th and 9th this month.

GCVS and VSX give 1.497998 d. as the period of V610 Cyg.
Judging the shape of its phase plot, it seems the period of this variable must be doubled, about 3 days.
To verify this hypothesis, it is necessary to observe min II, especially its minimum magnitude in V-band.
Unfortunately it is impossible to observe min II from Japan or Europe in next months, because the period is almost 3 days (2.99604 d.) (see ephemeris below).

So I would like to request for observing min II of V610 Cyg in USA!
I will be very grateful for your collaboration!

For photometry please use UCAC4 654-101596, 21 29 19.988 +40 40 57.45, 11.785V(APASS) as comparison star.

The improved ephemeris of minima of V610 Cyg for August 2015:
date    UT    n
2    6.07    -2.5
3    18.02    -2
5    5.98    -1.5
6    17.93    -1      observed
8    5.88    -0.5
9    17.83    0       observed
11    5.79    0.5
12    17.74    1
14    5.69    1.5
15    17.64    2
17    5.6    2.5
18    17.55    3
20    5.5    3.5
21    17.45    4
23    5.41    4.5
24    17.36    5
26    5.31    5.5
27    17.26    6
29    5.22    6.5
30    17.17    7

for September
date    UT    n
1    5.12    7.5
2    17.07    8
4    5.03    8.5
5    16.98    9
7    4.93    9.5
8    16.88    10
10    4.84    10.5
11    16.79    11
13    4.74    11.5
14    16.69    12
16    4.65    12.5
17    16.6    13
19    4.55    13.5
20    16.5    14
22    4.46    14.5
23    16.41    15
25    4.36    15.5
26    16.31    16
28    4.27    16.5
29    16.22    17


New AAVSO Sequence for V610 Cyg

There is new AAVSO sequence available for V610 Cyg  at .

Jim Jones, Sequence Team


thank you, jji for new sequence for V610 Cyg!

Thank you, jji for new sequene for V610 Cyg.

The star 118 with AUID 000-BLR-728, is the same star, which I have quoted as comparison star.

And here is a preliminary phase plot of this variable with improved elements.

Duration of observation per night

What is the total duration you are looking for each night either side of the minimum time?

Just asking for planing purposes so if possible I can give you enough data either side for your needs.

John R

Observations of last night

Today WGR has submitted his observations of last night. 
The descending part of the eclipse is observed.

Gary, thank you for your observations!

I have read in details of submission, that the magnitude of the comparison 
star 118 is set as 11.3179V.
The darkest (and last) data of the observations is 13.8266.
If we use APASS magnitude, 11.785 for comparison star 118
the last data would be 14.2937.
This is much darker than the minimum magnitude, 13.86 observed on
August 9th. in Japan.
So the min II could be much darker than min I and this means
there are two minima and the period must be about 3 days.

WGR's picture
More V610 Cyg

I just put last night's result (JD 7252) on the AID/LCG.  Mostly flat.



Phase plot with data from observations

Thank you Gary for your new observations!

I have made phase plot with data from two nights(16/17 and 17/18 August 2015) and old observations.

The eclipse of V610 Cyg will occur in coming night!

In the coming night, 19/20 Aug.(JD7254), the eclipse of V610 Cyg will occur. 
The duration of the eclipse is over 7 hours and 
the mid of eclipse, the minimum will be about at 5:30 UT(JD7254.72917).
It would be very nice, if so much as possible both descending 
and ascending sides of eclipse are observed.
I hope, someone can observe this eclipse including the minimum.

clear sky!

WBY's picture
V610 Cyg Tonight

V 610 Cug Tonight

Well, I will give it a try. Unfortunately tonight we are expecting our first rain in central Texas since the unusual spring floods ended at the beginning of June. Chances here do not look great but the clear sky clock is showing a break in clouds around the time of minimum. 

We'll see what happens. 

Brad Walter, WBY

WGR's picture
Observe V610 Cyg

Hello KKI

Thanks for the headsup on V610 Cyg.  I was just about to do the math and see what was up with it tonight.  Its clear now on Nantucket, and predicted clear until 2am local time.  I will jump on it as soon as our Public Lecture, which should end in twilight tonight.  



Thank you for observing the minimum II

Thank you, AHM, ATE, WGR very much for your submissions of observations last night!
The minimum II is now observed. I have not yet analyzed data exactly, 
it seems that the minimum occured a little earlier than my prediction.
Here is the light curve of observations. (Data points with error larger than 0.11 
are omitted.)

pva's picture
ToM for V610 CYG

 I was able to get a good run last night on V610 CYG with no clouds.  Data has been submitted to the AID.  Attached is my plot, Minima calcuations (Fourier Fit) and the data as viewed in Bob Nelson's spreadsheets using my HJD corrected date.

ToM JD = 2457254.72920 +/- 0.0005
HELIOCOR = 0.00346024
HJD = 2457254.73266

So the prediction for 5.5 hrs UT last night was right on.  I will eventually publish this ToM when I get caught up with my other data reduction I have in the queue.

Clear Skies,
Vance Petriew (PVA)
Regina, Canada


WBY's picture
V610 Cyg LC from 20150820UT

Attached please find The light curve PDF from my observations on 20150820 UT. I had clouds moving through at the beginning and I had a software hang that required a reboot to clear but fortunately I got the minimum and it seems to agree very well with the Others. unfortunately, I had to stop at about 06:30 UT. Ground fog was starting to move up the hill toward the observatory. 

I took an initial vbbv series at the beginning but I had interference from clouds and the data is not good. Therefore I hesitate to use it for transformations. Is the untransformed data OK or do you want me to transform anyway? The best estimate from my suspect data gave me a B-V of about 0.872. How does that compare with data you may have?

Brad Walter, WBY

Transformation would add about 0.016 to the V mag slightly shifting the eclipse curve. 


The minimum was observed.

I am very grateful to those who submitted observations of this variable star,
which is "lost" and forgotten! It is great, that so many people contribute to revive the star!

AAVSO community is fantastic! 
I think, TOM is now so precisely observed that we can find minima in future without problem.
Thank you, PVA for the data reduction, TOM and P! It is very nice!
I have made light curve with data from observations.(SGEO, you may have observed a nearby star?)

WBY, data, which I have, are without transformation. 

Your B-V is pretty good!
For B-V, there are 17 measurements in APASS data. 
I have attached a file B-V vs Vmag from APASS here.



WBY's picture
B-V Values

Thanks for posting the B-V values. I tried to use SeqPlot to get one from APASS, but the new .jnlp file keeps giving me an "Unable to Launch Application" message. I had no trouble before the website changed to https  protocol. The new .jnlp file is supposed to work with the secure protocol, but isn't working, at least for me. 

By the way My V mag at 0.872 looks high relative to the average of the 17, and it was taken with V at about 13.5 where there are lots of data points. I picked what looked like the most reliable B-V single measurement and it looks like I should have picke the average at 0.825 The resulting difference in the shift of the V light curve is a whopping 0.001 magnitude. I will submit transformed data since that is what AAVSO the shift in the values between untransformed and transformed is +0.0149 magnitudes for the transformed values. . You can back out the transformation from my data if you want.  I will have my data uploaded to AAVSO within the hour. 

Transformed LC  and Excel Spreadsheet attached. I updated the spreadsheet to include corrected error calculations.

Brad Walter, WBY 

Oh Doc, . . .  some IT magic is needed here. I already sent an e-mail to Sara. 


Thank you WBY

Thank you for submission of your observations! Very nice!

I have attached 17 observations of APASS as text file here. Are they useful for you?

The first data in B and V band were  obtained in 2010 while other data in 2011, and seem to be not consistent with others, so B-V also. B-V doesn't vary significantly in eclipse even in minimum.


WBY's picture
APASS Data for V610 Cyg

Yes it was helpful to confirm that even with the clouds passing through, my quick B-V series was close enough to use for transformation calculation.  


Brad Walter,WBY

a tiny problem with APASS data(Photometry sequence)

As I mentioned yesterday, in APASS there are 17 photometry entries of V610 Cyg, and also of comparison star, labeled 118. In both cases the first data obtained in 2010 are clearly too bright (about 0.1mag) versus other 16 data obtained in 2011.
So I think, the V magnitude of 118 must be in stead of 11.785 a little darker(+0.008), 11.793.
With the star labeled 127 there is no problem, because there are only data obtained in 2011, which are consistent.

I have attached APASS data of the star labeled 118 here.

We have now enough good data from last minimum.  It would be also very nice, if we get data out of eclipse. Now three days are gone. The next minimum is coming tonight already!

observations light curve 19/20 Aug.2015 updated

I have added data of observations by WBY to light curve.  Without magnitude offset. JD not HJD

observations light curve 22/23 Aug.2015

GFRB, thank you for your observations!

I have also observed in Switzerland. There came clouds and the light curve is not so good. I have attached the light curve of both observations.(HJD)


fguenther's picture

I hope they are usefull.  My mount decided to flip just before minimum, thus the interruption.

Frank (GFRB)

RZD, thank you for your observations!

You have observed V610 Cyg in the phase out of eclipse. Data show constant light curve. Such observations are also very useful to get the whole phase plot of this variable. Especially constant light curve at phase 0.25 and 0.75 could imply that the period must be about 3 day and not 1.5 days.

I will make phase plot with all data and post it here tomorrow.

ATE, thank you for your observations

Observations cover before the beginning of eclipse untill just before the minimum.
Very nice light curve.

I wanted to post a phase plot of this variable using all data sets of observations untill now, but could not.Excuse me. Perhaps it takes me several days to make it.

Phase plot with data from observations in August 2015

I have made preliminary phase plot with all raw data from observations in August 2015.

epoch: 2457244.2431, P: 2.996038302 d. There is no mag. offset. No data is omitted.

Thank you for observations on 28/29 Aug. 2015

I have made light curve with data from observations by ATE, FJQ and GFRB.

FJQ's picture
Thank you for observations on 28/29 Aug. 2015

To:  Kasai,

RE:"I have made light curve with data from observations by ATE, FJQ and GFRB."

Hope the quality of my data helps nail down V0610 Cyg's eclipse period!  I tried to do 01Sep15's sub-minima, but coastal fog cut short my run; I uploaded the transformed 93 observations just now.  I'll try to shoot one or two more long time series of this when I get to my dark-sky/high-elevation site starting 05Sep15.

FJQ -James, Los Angeles, CA

Thank you for observations on 31 Aug/1 Sep 2015

Hi ATE, thank you for your observation. I have made the light curve of your observation.

We have now enough good observations of minimum. I think, it would be very useful, if we get data out of eclipse. This variable must have almost constant magnitude out of eclipse and we can calibrate data with APASS data. Observation can be short run. 

V610 CYG toma de datos fuera de eclioses


Procuraré hacer  el seguimiento de V610 CYG fuera de mínimos para que puedas calibrar los datos con APASS.

Gracias por incluir mis datos en tus curvas de luz.

Atentamente,  Teófilo.


WBY's picture
OOE Observations at Last


I finally got a set of OOE observations as you requested, 33 V observation spanning a little more than 1.5 hours on 20150914. The XLS files are attached. This time I got six solid VBBV sets to establish transformed values and the correction was essentially identical to the one I derived from just a couple of B observations during the eclipse on 20150820 UT. The OOE observations seem consistent with the observations I obtained during ingress through minimum. The three spreadsheets are, V photometry and LC, B photometry and transformation  term calculation. 

I trust this gives you what you needed from me. Have fun with it

Brad Walter, WBY


WBY, thank you for your observation OOE

Brad, thank you very much for your observing V0610 Cyg OOE. Your data are very helpful! Excuse me for my slow reply.I have checked "recent observations" for V0610 Cyg every day but have'nt seen this forum for several days. 

I am working on whole data. The result will be very good! I will anounce it here, when it is done. 

WBY's picture
V610 Cy OOT BSW Observations 20150914

I haven't posted these observations to AAVSO yet but will shortly. 

NorseStars's picture
V610 Cyg lightcurve for 9-19-15 UTC

60 images from 2457284.650208 to 2457284.739838 capturing the minimum.


WBY's picture
Data corrections

Ooops, (I used a somewhat different expression when I discovered the gross error) I don't know if it is creeping senility or simply that I have gotten out of practice doing transformation calculations manually since TA arrived on the scene for multicolor time series, but when looking over my spreadsheet for the 9/14 data to prepare a submission to WebObs I realized that I applied transfomrations incorrectly to the 8/20 data during eclipse as well as the 9/14 OOT Data. That's what I get for writing the formulas into a spreadsheet from memory without either thinking through the process or at least verifying the formulas and then re applying the incorrect spreadsheet to another set of data. 

The mistake made a significant but not huge difference. The result is to make all of the V observations about 0.011 brighter. New Spreadsheets are attached. I will resubmit corrected 8/20 data to AAVSO


WBY's picture
All Uploaded

OK corrections to 8/20/2015 observations and the new observations on 9/14/2015 are all uploaded to AAVSO. 

Report about this campaign in the AAVSO Newsletter No.66

Dear all, I have reported about this campaign in the AAVSO Newsletter No.66. You can read this newsletter now online,  My article is on pages 16 and 17.

Thank you, who has contributed to this project and has sustained me. It was a great work!


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