Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Bright nova in Perseus - N Per 2020

  • Please log in to reply
68 replies to this topic

#51 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 30 December 2020 - 08:25 PM

Hey Robin, to get lower noise was that a longer exposure to boost SNR or was the previous curve simple smoothed a bit?

This is a new observation the next night under better conditions compared with previous observation. The total exposure time was a bit longer (2hrs 40min) but that would have made only a marginal improvement on the SNR. (sqrt(160/120) = +15%)  The main difference was less thin cloud around so more signal for more of time.

 

Cheers

Robin



#52 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 30 December 2020 - 08:43 PM

 

The peaks in the profile are clearly brighter in the red than the blue

There may some blending with other lines causing the asymmetry. eg Ca II 8498. I had a look at some of the other lines in this part of the spectrum at high resolution tonight. I will reduce them and publish tomorrow, though the thin cloud was back again unfortunately.

 

Cheers

Robin



#53 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 04 January 2021 - 03:34 PM

 I had a look at some of the other lines in this part of the spectrum at high resolution tonight. I will reduce them and publish tomorrow, though the thin cloud was back again unfortunately.

 

 

Finally got these reduced. (The C II line was heavily contaminated with strong H2O telluric lines which I have removed using a template generated from a measurement of Castor with the same instrument)

 

Cheers

Robin

 

Nova_Cas_2020_LHIRES1200_20201230.png


  • RobboK and mwr like this

#54 mwr

mwr

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 12 May 2018

Posted 05 January 2021 - 02:21 AM

Finally got these reduced. (The C II line was heavily contaminated with strong H2O telluric lines which I have removed using a template generated from a measurement of Castor with the same instrument)

 

Cheers

Robin

 

attachicon.gifNova_Cas_2020_LHIRES1200_20201230.png

Francois Teyssier will talk about this nova during a workshop organized by Shelyak (https://www.shelyak....r-2020-4-VF.pdf) and I have seen that the ARAS, AAVSO and BAA spectroscopy databases are full of excellent spectra of this nova. Are you involved in a joint ProAm-working group that analyses the spectral data? 



#55 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 05 January 2021 - 08:32 AM

Yes I will be attending the workshop and have submitted many spectra of various novae to databases (The BAA database is the definitive depository  for all my spectra) though it is not my main area of interest. See here for a recent example of a paper using my data (and others submitted to ARAS)

 

https://arxiv.org/abs/2007.13337

 

I am not aware of an official Pro-Am working group on novae, though Francois and Prof Steve Shore do coordinate the collection and analysis of nova spectra through ARAS. There is an ARAS eruptive newsletter published by Francois et al which covers novae but the main long term focus is on symbiotic systems

 

http://www.astrosurf...tionLetter.html

 

Cheers

Robin


Edited by robin_astro, 05 January 2021 - 08:37 AM.


#56 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 05 January 2021 - 08:45 AM

 See here for a recent example of a paper using my data (and others submitted to ARAS)

 

https://arxiv.org/abs/2007.13337

 

 

One problem here is that some professionals use amateur data without full acknowledgement or contacting them. (Nobody amateurs were consulted in this case) Other professionals however would have included the main contributors as co-authors)  Prof Steve Shore comments on how amateurs should become more involved in the use of their data in the latest eruptive variables newsletter. 

https://groups.io/g/...020_q3/79310591

 

Cheers

Robin



#57 mwr

mwr

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 12 May 2018

Posted 05 January 2021 - 10:03 AM

One problem here is that some professionals use amateur data without full acknowledgement or contacting them. (Nobody amateurs were consulted in this case) Other professionals however would have included the main contributors as co-authors)  Prof Steve Shore comments on how amateurs should become more involved in the use of their data in the latest eruptive variables newsletter. 

https://groups.io/g/...020_q3/79310591

 

Cheers

Robin

This is indeed a problem. Once your data is available in public databases, the control over your data is lost. In the worst case your data is interpreted or analyzed improperly. Thus, I fully agree with Steve Shore's comment. One solution would be to sensitise the editors of astronomical journals for this issue.

 

Anyway, I hope to get a free place in the nova-workshop and can listen to properly analyzed excellent ProAm data analysis and interpretation...


Edited by mwr, 05 January 2021 - 10:06 AM.


#58 mwr

mwr

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 12 May 2018

Posted 17 January 2021 - 05:27 AM

 

 

Anyway, I hope to get a free place in the nova-workshop and can listen to properly analyzed excellent ProAm data analysis and interpretation...

The nova-workshop is now available in French on Youtube (http://www.spectro-a...php?f=33&t=2703) and, as announced yesterday by Olivier Garde, also in English:

 

- Part #1 :
https://www.youtube....h?v=Peo8w6j0jhc

- Part #2 :
https://www.youtube....h?v=CUHJBnh8QnA

 

The analysis of the spectra has revealed some puzzling phenomena and an in-depth analysis of the ARAS/BAA data by an professional astronomer (Steve Shore) will be published soon in an ARAS letter. 


Edited by mwr, 17 January 2021 - 08:02 AM.


#59 smithrrlyr

smithrrlyr

    Vostok 1

  • -----
  • Posts: 174
  • Joined: 05 Feb 2017
  • Loc: Michigan

Posted 19 January 2021 - 05:51 PM

One problem here is that some professionals use amateur data without full acknowledgement or contacting them. (Nobody amateurs were consulted in this case) Other professionals however would have included the main contributors as co-authors)  Prof Steve Shore comments on how amateurs should become more involved in the use of their data in the latest eruptive variables newsletter. 

https://groups.io/g/...020_q3/79310591

 

Cheers

Robin

I guess I would say that the degree of acknowledgement depends on how the data are made available.  If I contribute nova photometry to, say, the AAVSO database, and someone writes a paper using photometry from the database, then I would expect the database to be acknowledged, but not me individually. On the other hand, if I carried out a long series of observations at the behest of a particular astronomer, then I would expect individual acknowledgement and involvement in any resultant paper. Whether I might deserve authorship would have to be decided on a case by case basis.  If my expertise was called upon to interpret my data, then I might deserve more credit.



#60 ssmith

ssmith

    Viking 1

  • *****
  • Posts: 933
  • Joined: 28 Jun 2012
  • Loc: Colorado

Posted 20 January 2021 - 06:21 PM

Its been  over a week since I last observed N Per 2020 and in that time - as the nova has faded - it has turned noticeably red.  As explained (by Robin_Astro) in the thread on Nova Cas where I noticed the same change in color, this is typical in the latter stages of the Nova as the spectral continuum falls away.  It is particularly striking in my latest photo of N Per 2020.

 

N Per 2020 C9 1-19-21 1600 30s 3fr.jpg


Edited by ssmith, 20 January 2021 - 06:29 PM.

  • robin_astro, flt158, RobboK and 3 others like this

#61 PeterAB

PeterAB

    Sputnik

  • *****
  • Posts: 39
  • Joined: 20 Nov 2019
  • Loc: Southern Wisconsin, USA

Posted 26 January 2021 - 11:23 AM

Steve,

 

Thanks for the update on N Per 2020.   I lost it visually between my 1-5-21 (~m11.5) and 1-11-21 observations.    It looks  at least a couple of magnitudes  below my visual limit now.

 

What did you use for a telescope, camera and exposure for this picture?

 

Peter


Edited by PeterAB, 26 January 2021 - 11:32 AM.

  • flt158 likes this

#62 ssmith

ssmith

    Viking 1

  • *****
  • Posts: 933
  • Joined: 28 Jun 2012
  • Loc: Colorado

Posted 26 January 2021 - 06:27 PM

Hi Peter -

 

Photo details: C9.25 @ f6.3 - Olympus M10 mkii - 30sec, ISO 1600.

 

As of Jan 25 the reported magnitude for N Per 2020 has dropped to 15.5.  The faintest stars on my photo are ~17.0 so I still have a bit of room to take some more photos before it fades away if the weather cooperates.


Edited by ssmith, 26 January 2021 - 06:28 PM.


#63 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 26 January 2021 - 06:41 PM

Another measurement of The OI 8446 Angstrom  line at R~7000 resolution. The continuum is almost undetectable for me now at this resolution (signal/noise ~2) but  the emission line is still pretty strong

 

novaper2020_20210124_872_Leadbeater_inc_image.png

 

The line profile has changed a lot from 28th December

https://www.cloudyni...020/?p=10762902

 

 


  • RobboK likes this

#64 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 26 January 2021 - 06:59 PM

 

 

As of Jan 25 the reported magnitude for N Per 2020 has dropped to 15.5.  The faintest stars on my photo are ~17.0 so I still have a bit of room to take some more photos before it fades away if the weather cooperates.

The light in the visible spectrum is extremely concentrated in the H alpha now, for example  

 

http://www.spectro-a...&p=15371#p15368

 

If you have an H alpha filter the other faint stars would disappear but the nova  would  still be almost as bright lol.gif

 

Cheers

Robin


Edited by robin_astro, 26 January 2021 - 07:01 PM.


#65 Rich (RLTYS)

Rich (RLTYS)

    Fly Me to the Moon

  • *****
  • Posts: 7,248
  • Joined: 18 Dec 2004
  • Loc: Glen Burnie (Maryland)

Posted 29 January 2021 - 04:40 PM

I have a pile of observations of N Per 2020 I've yet to catch up on. crazy.gif



#66 mwr

mwr

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 12 May 2018

Posted 04 February 2021 - 11:52 AM

With the continuing expansion of this nova the emitting gas becomes less dense and the line at 8446 A, which is generated by the hydrogen Lyman/OI photoexcitation is becoming more intense with respect to the O I line at 7773 A. 

 

Beyond 9000 A there are more lines detectable but it would be daring to give assignments for these lines without a high resolution reference. Is somebody aware of NIR data of this nova beyond 9000 A ?

ProAms are still able to record excellent spectra of this fading Nova (magnitude is now around 16 according to AAVSO data). James Foster has recently posted a nice LISA-IR spectrum in the ARAS forum showing a very intense O I line at 8446 A indicative of a considerably lower density of the emitting gas in the expanding shell:

 

http://www.spectro-a...tart=120#p15391



#67 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 04 February 2021 - 06:16 PM

That was taken a month ago though when it was much brighter, three weeks earlier than the O I 8446 profile here

https://www.cloudyni...020/?p=10835880

 

 

The H alpha and O I 8446 lines are still intense relative to the continuum though. This was a quick look a few days ago at low resolution with my ALPY 200 faint object setup

 

novaper2020_20210130_988_Leadbeater.png

 

Cheers

Robin


  • RobboK likes this

#68 robin_astro

robin_astro

    Apollo

  • -----
  • Posts: 1,224
  • Joined: 18 Dec 2005

Posted 04 February 2021 - 06:59 PM

The evolution of the O I8446 line profile shape at high resolution during January is remarkable.

 

novaper2020_O8446.png

 

Note that they are plotted relative to the local continuum so do not represent the true difference in intensity. The flux in the V band dropped by a factor of 100 between the two dates from mag 10.5 to 15.5  (And in the I band from mag 8.8 to 12.5, though the I results would have been strongly influenced by the flux in the 8446 line which dominates that part of the spectrum)

 

 

Cheers

Robin

 

 


  • RobboK likes this

#69 mwr

mwr

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 12 May 2018

Posted 05 February 2021 - 04:22 AM

That was taken a month ago though when it was much brighter, three weeks earlier than the O I 8446 profile here

https://www.cloudyni...020/?p=10835880

 

 

 

Hi Robin,

 

great high resolution spectra of the O I 8446 line! Please note that I was actually referring to the O I 8446 line intensity with respect to the the O I line at 7773 Angström as quoted above. James Foster's spectrum was the last spectrum that I could find that allows to estimate the relative intensities of these diagnostically important O I line ratios. Robert Williams discusses the importance of the O I 8446 & 7773 relative intensities here: https://arxiv.org/ft...8/1208.0380.pdf

 

The evolution of the O I 8446 line profile shape is really puzzling. Is there an explanation? 




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics