I have just made my first estimate of V1010 oph of 6.1 magnitude i voided it very slightlty fainter than th 6 mag comp star.
This star has a very low perod of .6 days when should i make the next obs.It was 7-06 pm aest when i made the estimate,i still have the scope outside when should i make the next estimate.
With a star of such a short period, you should make an observation every hour over the time you're out doing observations. You want to get as many points of data as you can because what you're trying to do is catch the beginning, middle and end phases of the eclipse. Having all those points will also help to produce a nice curve as well. You will then be able to accurately determine the length of the eclipse and other characteristics of the system.
Can you do a measurement at 11 pm?
If so, what was it?
Regards, Rob
Might be able to catch some change (and what direction) with that, but it's not ideal. It will be interesting to see what the result is if he can take the measurement.
Might be able to catch some change (and what direction) with that, but it's not ideal. It will be interesting to see what the result is if he can take the measurement.
Hi Carl,
Your idea of hourly measurements was a good one. I was hoping Orestis could get the measure at 11pm as well. If not, he can "catch up" in the next few days. I will suggest times.
The best way of keeping tabs on stars like this is to plan a few days before, an observing run over at least two nights. That'll give you a good spread so far as the time is concerned plus a little leeway if you miss a measurement or two for various reasons. If he can repeat the run a few days later, then he can compare and contrast the results and get a good handle on the variability of the system.
Ideally, he should plan his run around the given ephemeris for the system. That way he can compare his results with the known characteristics of the system.
This would be an ideal system to generate a photometric based set of observations for a project. You could really tie down the period of the system, the length of the eclipse, the orbital elements etc. Pity he doesn't have a CCD camera. Even a mono DSI would be OK for the job.
I only took 2 obs one at 7-06 of 6.1 mag and one at 8-06 at 6.1 mag,i thought hourly obs would be ideal.I did not notice any change.I packed up early because i had school the next day,but maybe i can stay up longer somehow.
But determining .1 differences is very difficult using just my eye,I will try again soon.It is well placed for comparison and i voided it very much the same as the mag 6 star.
From my interpretation of the table on the 26/27 of this month at 13 hours Ut or 23 hours AEST the star will be in mid eclipse,the duration of primary eclipse is 4 hours.So i should observe 2 hours before and 2 hours after 11 pm to get a light curve.It doesn't say anything about secondary eclipse.
This is made for northern latitudes will it make a difference down under?
It only shows mid eclipse for three days of the month why is that?
Thanks in advance and i will try my best to observe this star.
cheers Orestis
They don't list mid-eclipses for Americas daytime hours. You'll notice all the UT times are 0 to 12.
For the 11-12th Jun, the time for mid-eclipse is 3 UT.
If you were in New York, approx. longititude -74 degrees or 5 hours west of Greenwich (15 degrees = 1hour), the time would be about 3-5=-2 or 10pm 11th Jun.
In Sydney, 10 hours east of Greenwich, 3 UT=3+10=13 or 1pm 12th Jun i.e. during daytime.
Now for V1010, the period is about 16 hours (closer to 15.87 hours).
From 11-12th Jun, add 16 gives 19 UT. Or 19-5=14 or 2pm 12th Jun NY time. Daytime for them.
This is however 19+10=29 or 5am 13th Jun Sydney time.
Now add another 16 hours.
19 UT+16=35 or 11 UT, given as 10.5 or 10:30 UT in the table for 12-13th Jun.
In other words, daytime mid-eclipses for America are left out. These are the ones we need for Australia. You can estimate them by adding approx. 16 hours to the UT times.
I am finding this very difficult to test.I was out yeterday with the 50mm finderscope trying to estimate in sub zero temps at 1 am and had noticed little change if none at all.
I estimated it at 6.4 mag though i don't know if that was wishfull thinking.
I need to find a star with a higher period to determine change.
I am finding this very difficult to test.I was out yeterday with the 50mm finderscope trying to estimate in sub zero temps at 1 am and had noticed little change if none at all.
I estimated it at 6.4 mag though i don't know if that was wishfull thinking.
I need to find a star with a higher period to determine change.
I don't understand the ephemeris.
Thanks anyways
cheers Orestis
Hi Orestis,
You don't need to do an all night vigil. You just need to sample sections around A, B, C, D (see diagram) of highest and lowest magnitudes at selected times over a number of days to confirm the cycle.
Attached are the phases for the next few days based on the table Rob K referred you to. I've adapted it for Australian EST time. The reason you've not detected much change so far is that you've been reading the higher magnitudes around the centre of each cycle.
If I've interpreted everything correctly, there should be a primary eclipse (minimum magnitude) at 9:30 tonight. Check it out (weather permitting).
That looks alright, Rob. If he takes 5 or 6 readings around each of A-D, he should get a good idea of the curve and be able to construct one for himself. He could also sample for E at some times and that should allow him to fill in the gaps.
I don't know how useful it'll be to him...he might need CCD input...but if he goes here:
I managed to do some readings of my own between 6:30pm and 11:30pm last night and confirmed the minimum magnitude around 9:30pm. It was actually quite dramatic to see the change over so short a period of time.
Did you observe the main eclipse on the 9/6/11 Or the same one I observed on the 10th ?
On the 10/6 and 11/6 I observed V1010 OPH and saw a very nice change in brightness but for the secondary eclipsing the primary,it was awesome,I couldn't believe how quickly this star changes.I tried to get obs around B C D and E.Though it was cloudy during E and at 6am when i went out it was too bright to see.
Heres my data from the obs session all in AEST(sorry i will change it later to UT)-
6.20 pm- 6.2 m(about one hour off B too bright during 5.30)
9.06 pm- 6.4 m(Half hour off C)
2.45 am- 6.2 m( about one hour off D because of clouds)
3.30 am-6.5 m(Half way between D and E)
At the beginning(6.20)I think that the primary star had already started to be eclipsed by the secondary component and at 9.06 was pretty much in mid eclipse then it rose back up again at 2.45 though at 6.2 I think it had already started to be eclipsed by the primary component and then at 3.30 it was at 6.5 which is lower than the 6.4 dip but then i didn't get a measurement after that becuase of clouds unfortunately.
And I am lucky I got the measurements I got because I stayed up all night checking the sky for gaps of which I found some luckily.
All these observations were made from my balcony using a 8X50 Finderscope.Apart from all the clouds the conditions were great and the moon had set at the 2.45 am obs.
Again thanks guys for all the tremendous help and I will try shortly to observe the primary minimum.
Cheers Orestis
Ps-Rob If you made that chart with the light curves which I think you did ,I think your awesome and i couldn't of done this without you thanks Rob .
Last edited by orestis; 11-06-2011 at 07:00 AM.
Reason: spelling
Did you observe the main eclipse on the 9/6/11 Or the same one I observed on the 10th ?
On the 10/6 and 11/6 I observed V1010 OPH and saw a very nice change in brightness but for the secondary eclipsing the primary,it was awesome,I couldn't believe how quickly this star changes.I tried to get obs around B C D and E.Though it was cloudy during E and at 6am when i went out it was too bright to see.
Heres my data from the obs session all in AEST(sorry i will change it later to UT)-
6.20 pm- 6.2 m(about one hour off B too bright during 5.30)
9.06 pm- 6.4 m(Half hour off C)
2.45 am- 6.2 m( about one hour off D because of clouds)
3.30 am-6.5 m(Half way between D and E)
At the beginning(6.20)I think that the primary star had already started to be eclipsed by the secondary component and at 9.06 was pretty much in mid eclipse then it rose back up again at 2.45 though at 6.2 I think it had already started to be eclipsed by the primary component and then at 3.30 it was at 6.5 which is lower than the 6.4 dip but then i didn't get a measurement after that becuase of clouds unfortunately.
And I am lucky I got the measurements I got because I stayed up all night checking the sky for gaps of which I found some luckily.
All these observations were made from my balcony using a 8X50 Finderscope.Apart from all the clouds the conditions were great and the moon had set at the 2.45 am obs.
Again thanks guys for all the tremendous help and I will try shortly to observe the primary minimum.
Cheers Orestis
Ps-Rob If you made that chart with the light curves which I think you did ,I think your awesome and i couldn't of done this without you thanks Rob .
Orestis,
Great work in getting those readings under cloudy conditions. Hopefully, a break in the clouds will let you catch the primary eclipse sometime soon.
My observations were around the time of the primary eclipse on Thurs 9th June. It was fortunately clear that evening.
Wait until you observe this event. It is quite dramatic.
