Algol variables

[IB20]

Can any SGLers recommend a good resource for a list of observable Algol variables or eclipsing binaries?

[JeremyS]

Go to the BAA VSS website: https://britastro.org/vss/

Click the link “Eclipsing binaries” under Observational Progammes.

There is an handbook on observing EBs here: https://britastro.org/vss/Handbook15b.pdf

[IB20]

55 minutes ago, JeremyS said:

Go to the BAA VSS website: https://britastro.org/vss/

Click the link “Eclipsing binaries” under Observational Progammes.

There is an handbook on observing EBs here: https://britastro.org/vss/Handbook15b.pdf

Blimey, this is perfect. Thanks Jeremy!

[StarryEyed]

The British Astronomical Association have merged their variable data with the American Association Variable Star Observers. 

Lots of great info there but most useful is their variable predictions page. It will give predictions for the current day visible from your location (if you create an account) Which you absolutely should for many reasons other than just this. 

https://filtergraph.com/aavso/default/index?ev=on&settype=true

 

[robin_astro]

20 minutes ago, StarryEyed said:

The British Astronomical Association have merged their variable data with the American Association Variable Star Observers

The variable star brightness data submitted to the BAA is still held independently in their database but that data is then also periodically uploaded to the AAVSO database. 

Robin

[IB20]

As a first, easy go I’ve been plotting a mag course of Sheliak as I don’t have to spend any time finding it and can judge it naked eye. Pretty amazing how much it’s changed in 3 consecutive nights. Going to try and do it the whole of June if conditions permit. 

[IB20]

Still doing this, it is super easy but sometimes it’s just remembering. Lots of CLOUD entries so far though 😭

I’m doing naked eye and may try binocs for July. 👍🏻
I’ll stick it through R at the end of the month and see how it’s gone. 😊

[IB20]

With the clouds rolled in for the foreseeable I’ve decided to wrap my Sheliak observing and plot the data. Certainly have learned lots during this, particularly the things that can affect apparent magnitude. Poor transparency, referencing against other variables and expected bias all play a huge part when trying to stay objective and record an accurate reading. It’s been fun though, yet frustrating at the start when the cloud seemed to coincide with the dimmest magnitude.

Need a new target now…

 

[robin_astro]

Have you tried folding your data? (Shuffling the points back by multiples of 12.944 days so the the values all fall in the same orbit?) You should be able to pick up the shape of the light curve during the period. Alternatively there are programs which can analyse the data to find any periodicity  but I am not sure if there is  enough data to do that successfully.

Cheers

Robin

[robin_astro]

1 hour ago, robin_astro said:

Have you tried folding your data? (Shuffling the points back by multiples of 12.944 days so the the values all fall in the same orbit?)

This is easy to do for example in Excel by converting the date-time to decimal days, dividing by the published period and getting the decimal part by subtracting the TRUNC function to produce the phase. Look out for  the primary and secondary eclipses. I just tried this roughly with your data.  I suspect  you might be quite pleased with the result 

Edited August 18, 2022 by robin_astro
correction to excel function

[IB20]

So I just had a go with your recommendation but used an AAVSO equation to convert to phase and got the following. Probably like you say, not enough data and too many cloud breaks but I think you can see the binary nature of the curve. It shows up the outlier that I observed too, i remember thinking it was a strange one at the time as it was bright but was around minimum!

 

Edited August 18, 2022 by IB20

[robin_astro]

Yep both primary and secondary eclipses are clear. With data over a long enough time you can generate this sort of chart  without knowing the period in advance eg using software like Tonny Vanmunster's Peranso

https://www.cbabelgium.com/peranso/

Cheers

Robin

[IB20]

14 minutes ago, robin_astro said:

Yep both primary and secondary eclipses are clear. With data over a long enough time you can generate this sort of chart  without knowing the period in advance eg using software like Tonny Vanmunster's Peranso

https://www.cbabelgium.com/peranso/

Cheers

Robin

Great stuff, thanks for your help Robin. 

[robin_astro]

Sheliak (Beta Lyrae) is not your run of the mill eclipsing binary though. There is an interesting page on it on the AAVSO site

https://www.aavso.org/vsots_betalyr

and the spectrum is monitored by amateurs as part of the Pro-Am Be star survey program.

http://arasbeam.free.fr/?lang=en

A company originally set up by amateurs to make spectrographs is even named after it

https://www.shelyak.com/beta-lyrae-shelyak-2/?lang=en

[robin_astro]

3 hours ago, robin_astro said:

With data over a long enough time you can generate this sort of chart  without knowing the period in advance eg using software like Tonny Vanmunster's Peranso

For fun I ran your data through Peranso without knowing the period in advance and it came up with this.

 

Pretty close to the published period and light curve shape on the AAVSO page

 

Cheers

Robin

[Ratlet]

That is phenomenal.  Cracking read through from beginning to end

[Malpi12]

On 17/06/2022 at 17:34, IB20 said:

’m doing naked eye and may try binocs for July.

Need a new target now…

Very nicely done @IB20 , very interesting. Have you found a new one yet?

 From @JeremyS's link this one (sort of a bit below and left of Lyra) in Sagitta looks interesting for bino (or in my case dslr on tripod because my eyes are very old !)
U_Sge,  Max, m6.5   Min2 m6.7   Min1 m9.3   Period, 3.38d  Dur, 14h
a swift sharp fall to min1, and a rapid interval should give us a chance between storms !

[IB20]

On 24/08/2022 at 19:36, Malpi12 said:

Very nicely done @IB20 , very interesting. Have you found a new one yet?

 From @JeremyS's link this one (sort of a bit below and left of Lyra) in Sagitta looks interesting for bino (or in my case dslr on tripod because my eyes are very old !)
U_Sge,  Max, m6.5   Min2 m6.7   Min1 m9.3   Period, 3.38d  Dur, 14h
a swift sharp fall to min1, and a rapid interval should give us a chance between storms !

Looks a good target. I’m thinking of trying a longer period variable, maybe around 6-12 months. Just need to find a suitable target in a constellation that I can access throughout that period. It would reduce the need for daily observations, maybe 3-4 a month, which even with our iffy weather should be doable.