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Dave Smith    1,381
Variable star OV Boo is getting brighter again. My last three nights out I haven't published as the trend in the brightness had seemed fairly predictable but on Friday night the overall trend seemed ok but the amplitude of the oscillations seemed to have increased. Last night the brightness has gone up. This increase has been confirmed by Roger Pickard of the BAA variable star section (Director) so it is getting quite exciting. Tonight could be clear and it will be interesting to see what happens next.
 
Here is the chart covering all my observations. The rapid oscillations have continued as before.
 
Dave

OV Boo 20170326chart.jpg

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laudropb    5,832

Had a look last night and made a visual estimate. Looks like it will be clear tonight, so looking forward to seeing if there is any change.

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Dave Smith    1,381

Here is an update. Last night's results now included. I've also put last night's readings on their own chart and the pattern seems to be changing, There were secondary peaks between the main peaks which seem to be disappearing. Hopefully one day there will be an explanation of the pattern.

By the way, this is NOT a complaint, but I have now had 9 out of 13 consecutive nights clear and the next two nights are forecast to be clear - this must be some sort of record. Certainly very useful for studying this star.

Dave

OV Boo 20170327achart.jpg

OV Boo 20170327chart.jpg

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Dave Smith    1,381
1 hour ago, andrew s said:

Hi Dave, nice work you seem to show the basic period well. I assume you have seen this https://arxiv.org/pdf/0708.0097.pdf .

Regards Andrew

Thank you Andrew. No, I hadn't seen that so have downloaded  it. Is their star actually OV Boo or very similar?

Dave

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andrew s    641

According to SIMBAD it is the same star (unless I made a mistake) .

Regards Andrew

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Dave Smith    1,381
55 minutes ago, andrew s said:

According to SIMBAD it is the same star (unless I made a mistake) .

Regards Andrew

Thanks again Andrew. I eventually got the link between the two, so no mistake.

Dave

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Dave Smith    1,381

Thanks Andrew, I have been adding my results to the BAA website regularly. There are offsets due to the filter (or no filter) used. Most of the results on the database are fro Roger Pickard and myself.

Last night was unfortunately foggy here in Essex.

Dave

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Dave Smith    1,381

It is interesting that Denis hasn't submitted his results to the BAA database (He did submit a load of obs last October)?

Dave

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JeremyS    467
On 28/03/2017 at 17:22, Dave Smith said:

I have been adding my results to the BAA website regularly.

Hello Dave,

recent results on OV Boo, including your photometric measurements were shown at today's BAA meeting at the Royal Astronomical Society in London. This was during the Sky Notes talk by Dr David Arditti.

Well done!

Jeremy

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Dave Smith    1,381
11 hours ago, JeremyS said:

Hello Dave,

recent results on OV Boo, including your photometric measurements were shown at today's BAA meeting at the Royal Astronomical Society in London. This was during the Sky Notes talk by Dr David Arditti.

Well done!

Jeremy

Thank you Jeremy, that has made my day. :icon_biggrin:

By the way I am planning on coming to the VSS meeting in Winchester, I hope there will be an opportunity to say hello. Unfortunately I was too late to come for the whole weekend meeting.

Dave

 

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JeremyS    467
4 hours ago, Dave Smith said:

By the way I am planning on coming to the VSS meeting in Winchester, I hope there will be an opportunity to say hello. Unfortunately I was too late to come for the whole weekend meeting.

Hello Dave,

excellent - I will be there. Be sure to say hello. Pity the BAA Winchester weekend was sold out so quickly. It's a fantastic event and next year will be 2018 Apr 6 to 8

All the best,

Jeremy

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dokeeffe    58

Thanks for posting about this interesting star. I'm currently attempting to collect some data on it right now. Will post here (if successful)

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Dave Smith    1,381
2 hours ago, dokeeffe said:

Thanks for posting about this interesting star. I'm currently attempting to collect some data on it right now. Will post here (if successful)

Excellent. It's getting quite faint now but still doable. I'm taking more readings right now.

Dave

 

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dokeeffe    58

Yes it was quite faint. Just reduced the data and created a quick plot. Its a crazy star!

I think I got one full eclipse cycle but did not have very dense coverage around the big drops in magnitude

OVBoo.png

The x axis is date-time formatted as dd hh:mm (so 01 21:10 = 2017/04/01 21:10)

Edited by dokeeffe
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Dave Smith    1,381

That is excellent. The fine detail has changed quite a lot since the start. Apparently, from the paper quoted by Andrew above, this star is a brown dwarf orbiting a white dwarf and the brown dwarf and accretion disc are not contributing to the light curve. My results for last night were a bit random probably due to high haze that did turn into fog. I'm doing some more tonight until cloud stops play. The forecast for the rest of the week looks dire!!

Do you belong to the BAA? I am sure they would like your data added to the database.

Dave

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dokeeffe    58

Dave,

I dont belong to BAA but I submit data to AAVSO. I'm only getting started really. I've only submitted a few points so far. I'd be interested in submitting data to the BAA too. 

Yes I read the abstract and intro of the paper. What a strange view it would be if we could get closer... Although not too close :icon_biggrin:

Cloudy here tonight so nothing for me to do. According to my forecast it might be clear for me tomorrow so I might have another look.

Derek

 

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Dave Smith    1,381

It's great that you submit data to aavso. I do also. Jeremy may be able to advise on submitting to the BAA. I don't know if you have to be a member to do so.

I'm also really just starting. It was pure chance that I saw and acted on the alert of this star going into outburst. I'm now hooked. It is also great to have observers widely spread geographically as it is then more likely that someone has clear skies.

What software are you using to analyse your data. I am using Muniwin which is free and can output data suitable for upload to both the BAA and to aavso.

Dave

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dokeeffe    58

I'm using astropy and 2 affiliated astropy packages. CCDProc to do calibration. Then photutils to do photometry combined with the AAVSO's comparison stars. 

Basically I have a bunch of python scripts that automate the calibration, some other ad-hok scripts to download comparison stars and do photometry. 

I'll check Muniwin out. I've also used astroimagej but Its really tricky to use. 

Derek

 

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JeremyS    467
On 03/04/2017 at 23:43, Dave Smith said:

Jeremy may be able to advise on submitting to the BAA. I don't know if you have to be a member to do so.

Indeed I can. You don't have to be a member of the BAA to submit data to the Variable Star Section database. In fact you would be most welcome to do so, Derek. Our data go back to 1840.

You'll need to register and you will then be given an observer code. The database is at: http://www.britastro.org/vssdb/ 

On the other hand, if you are keen on variable stars, why not consider joining the BAA? Our membership is international.

Best regards,

Jeremy

BAA President

 

 

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JeremyS    467
On 03/04/2017 at 22:42, dokeeffe said:

I think I got one full eclipse cycle but did not have very dense coverage around the big drops in magnitude

OVBoo.png

Very nice data, Derek! You are doing a splendid job with your photometry

All the best

Jeremy

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Scosmico    150

 Hi Jeremy, 

I had a look at the BAA website at the variables section and I found it to be a bit overwhelming for someone who has been absent for a while or new to Astronomy.

Would have a list of variables for beginners, occasional or just a prodigal astronomer returning to the hobby?

Many thanks

Saulo

Edited by Scosmico
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JeremyS    467
8 minutes ago, Scosmico said:

Would have a list of variables for beginners, occasional or just a prodigal astronomer returning to the hobby?

Hello Saulo,

Yes, we do have quite a bit of info available in our beginners area: https://www.britastro.org/node/9542

Scroll down to Variable Stars and you'll see several articles that might be of help. For some stars to start with, have a look at the Variable Star Section's Absolute Beginners page at: http://www.britastro.org/vss/absolute_beginners.htm

All the best,

Jeremy

Edited by JeremyS
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JeremyS    467

So it appears OV Boo is well into its fade at the moment. But re-brightenings, perhaps to the original outburst brightness, might well occur. It's definitely worth keeping an eye open for these. They don't last long, perhaps a day or two. Kudos to those that detect any re-brightening.

Good luck!

Jeremy

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