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Eruption of the Recurrent Nova RS Oph!


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The Recurrent Nova RS Oph is in eruption. It was reported at mag 5 last evening (Aug 8th) by Alexandre Amorim and Eddy Muyllaert:

Aug. 7.969 11.2v Alexandre Amorim
Aug. 8.913  5.0v  Alexandre Amorim 
Aug. 8.920  5.1v  Eddy Muyllaert 
Aug. 8.931  5.1v  Keith Geary

RS Oph last erupted in Feb 2006.  BAAVSS charts can be downloaded here.

At mag 5, it is borderline naked eye visibility, although binoculars will be the most appropriate instrumentation in the initial stages. Do try to witness this important piece of history! The unfolding story will be covered on the BAA Forum here.

In quiescence, RS Oph is normally about mag 12.5. It has been observed to erupt in 1898, 1933, 1958, 1967, 1985, and 2006. It reached about mag 5 on average. A further two eruptions, in 1907 and 1945, have been inferred from archival data.

RS Oph is located at RA 17 50 13.17 Dec -06 42 28.6 (J2000.0)

Edited by JeremyS
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Thank you, Jeremy, I will check it out in the next clear evening (Tueday hopefully). It seems best viewed around 10:30pm from the UK, but only rises to about 30 degrees altitude. I was looking in this area just last week, trying to split Tau Oph and there was no sign of RS Oph in my 9x50 finder when star hopping. Looking forward to observing this fast brightening event.

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24 minutes ago, Nik271 said:

Thank you, Jeremy, I will check it out in the next clear evening (Tueday hopefully). It seems best viewed around 10:30pm from the UK, but only rises to about 30 degrees altitude. I was looking in this area just last week, trying to split Tau Oph and there was no sign of RS Oph in my 9x50 finder when star hopping. Looking forward to observing this fast brightening event.

Good luck Nik! Yes it’s fairly low but given how bright and historic I hope others will have a look.

We certainly have been blessed with nova these past 12 months!

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Posted (edited)

There is chart showing where RS lies in the constellation of Oph here: https://en.wikipedia.org/wiki/RS_Ophiuchi#/media/File:RSOphLocation.png

 RSOphLocation.png

it is NW of nu Oph, which is also shown on the BAA VSS chart I linked to in the first post. This star is mag 3.3 (also called comparison star A on the BAA chart). 
 

Edited by JeremyS
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Thanks for the heads-up chaps...

Looking at the forecast here it's going to be a one-off chance tonight, and that's if I'm lucky. 

Checked the spectroscope collimation. Checked th emount and its cables..Renewed the dessicant tablet in the ancient Atik 314......now what else can Mr Murphy possibly bring to the party?

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Looking at the AAVSO chart. There are some visual observations (bino and naked eye) estimating 4.5 - 5.0 from the past 12 hours or so.

image.thumb.png.bc31a14a790a48befe15b0c5bfd75f46.png

We've had cloud, mist and torrential rain  all day, but it's startong to clear up. Some forecasts are saying clear spells for an hour around midnight! Fingers crossed.

Thanks (again) to @JeremyS for the heads-up!

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We're at our Cumbrian getaway but it's clouded out completely.

If it clears up later I'll try with the bins. 

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2 hours ago, PeterW said:

I though naked eye novae were fairly rare, we’ve had a handful in a few months… what’s going by on????!!!!

Peter

I know! Amazing isn’t it? Can’t remember a time quite like this!
 

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I got this at 11:30 with 120 mm achro. Would say it was a tad dimmer then Zeta Serpentis which is 4.69. But brighter then 5.6 stars. So 5 seems right. I'm only 30 mins from where this was discovered which is mad!

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Well, that was fun, thank you Jeremy, , , and for his next trick he is going to magic-up a supernova for us  :) :)

2869s.jpg.c01f5f2ac4295c590cd48cb21847a251.jpg

Yes I agree with @Muc 👍 🙂
I couldnt decide between it, zeta Ser, and mu Oph by my aged eyes. So I had a look at my pics with an unmod Canon, stack of 9x 2sec @6400iso (ancient fslr50mm f2.5 lens)
and got this via DSS, Gimp>grey-scaled (yes, it is very yellow/orange)  & Fiji
mags are  from Stellarium.

21:50utc Aug2021.  My Fiji peak values are 204.9, 235.9, 231.4, 234.4 if anyone is good at log mag scales ;)

mags.thumb.jpg.39423249d3e01a6c93a8c8667ecf6cd9.jpg

Edited by Malpi12
added date & time
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10 hours ago, Muc said:

Also distinct orangey yellow colour

That tallies with my notes from the 2006 outburst accompanying my Star Analyser spectra which described it as straw coloured a few days after outburst. If it follows the same trend as then it should change to a deep red over the next week or so as the H alpha emission comes to completely dominate the spectrum.  Over on CN Keith Geary describes it as blue  when he discovered it in outburst, now pale yellow last night and George Wallerstein describes it as purple initially at the outburst in 1958 in this interesting S&T article from 2005 published just before the 2006 outburst

https://skyandtelescope.org/observing/celestial-objects-to-watch/when-will-rs-ophiuchi-next-blow-its-stack/

 

Edited by robin_astro
clarification
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2 hours ago, robin_astro said:

That tallies with my notes from the 2006 outburst accompanying my Star Analyser spectra which described it as straw coloured a few days after outburst. If it follows the same trend as then it should change to a deep red over the next week or so as the H alpha emission comes to completely dominate the spectrum. 

 

That's great info, will try and keep a regular eye on to see these changes but I'm sure clouds will have a strong say in that!

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A couple of raw data shots taken last night..

First one had Hydrogen wavelengths in green, the second has Silicon in orange.

image.thumb.png.be0371da7223f1b65a51393ad242d347.png

image.thumb.png.40422d1c1c4b59a413d5de804d872715.png
 

Looks like there is far more emission at the Hydrogen Beta wavelength (4861 angstrom) compared to the alpha (6563). When I've found out how to flatten the continuum in Vspec there should be some nice P Cygni features visible. The (possibly) Silicon lines roundabout 5000 ang look fairly prominent. The very narrow line peaks are probably not real. 

Eyeballing the H-beta peak comes up with a radial expansion of about 2000 km/sec.

 

Edited by rl
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@JeremyS...Interesting...

I could'nt get Iron to fit those peaks just to the right of Hbeta. . I stepped through the periodic table option. I'm sure the Japanese experts are right...probably something wrong with my calibration. Their H-alpha is much stronger as well. 

Edited by rl
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I didnt see this thread Jeremy, so i posted a "heads up" an hour ago. Looking good for a view tonight from the dark skies of the North Norfolk coast, i will try and get a quick image with the nifty fifty as well. Looking forward to seeing this and some Persids.

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