Nova Cas 2021

[Terry McKnight]

Yes it is the Bubble Daryl. I was using an Ha filter as there was some local light pollution and it did indeed pick up some nebulosity from the Bubble.

[Mike Harlow]

Taking a closer look at my image from 19th March I just got the Bubble nebula at the edge of the field. Image on my members page: V1405 Cas and the Bubble nebula.

Mike.

[John Coffin]

This is Monday night’s spectrum with bright helium emission lines.

There are P Cygni profiles in the hydrogen Balmer series and the helium lines With a velocity of about 1400 km/ sec.

[Hugh Allen]

At last a slightly murky break in the clouds here in The Mendips, to allow me to record the evolving spectrum of this beautiful nova. There are many neutral helium emission lines as well as the hydrogen Balmer series, all with very striking P Cygni profiles due to Doppler shift in the expansion along our line of sight. It is always a thrill to capture the spectrum of a unique object like this

Hugh

[Mr Ian David Sharp]

Hi all,

Clear last night. Managed to get a few exposures early on. Average mag. over 8 x 20 second exposures was 8.133 +/- 0.030. This was with no filter.

Equipment: C9.25 @ f/. SX TRIUS 694 Pro CCD, Calibrated with Bias, Flats and Darks. Photometry processing in AstroArt 7.

Cheers

Ian.

[Robin Leadbeater]

Finally got my spectrum a couple of days later. A nice full set of H Balmer and HeI  P Cygni profiles 

Cheers

Robin

[Harri Kiiskinen]

My RGB-vesion, 3x5x15s with FSQ-85ED and QHY163M. 

-Harri 

[Hugh Allen]

This evening’s spectrum compared to Monday night’s. An increase in Balmer emission and very slight decrease in HeI emission (assuming that the magnitude is similar between the two nights)

Hugh

[Hugh Allen]

In my Alpy 600 spectroscope, the evolution of the spectrum of Nova Cas 2021 is really quite gentle over the last couple of weeks. According to Vmag data from the AAVSO databse, the visual magnitude has also changed only slightly over this time so I’ve made my comparisons in relative flux. The P Cygni profiles on the emission lines remain very strong. Apart from the forest of strong neutral Helium emission lines (HeI) and the hydrogen Balmer lines, I’m also suggesting the presence of two strong pairs of silicon emission lines and even some weaker nitrogen NII lines.

Cheers

Hugh

[Jeremy Shears]

News in from Kato-san at vsnet overnight that V1405 Cas might be brightening.  Several observers in Japan reported vis or V=7.4 on Apr. 26. He notes “The nova before this brightening was apparently in “premaximum halt” “.

Time will tell – further observations encouraged!

[Daryl Dobbs]

Pity it’s cloud, when I looked at it last Thursday it appeared to be mag 8.3 but trees are beginning to interfere. Interesting nova I’ll have to start submitting my observations one day

[David Boyd]

Hi Jeremy,

The BAA light curve shows it has been rising steadily for the past 2 weeks. 

David

[Gary Poyner]

Hi David,

It seems the BAAVSS database has not combined the alias ‘Nova Cas 2021’ with the correct designation V1405 Cas.   The latter shows visual and other photmetric data – which also shows the rise in brightness.

Gary

[Mike Harlow]

A recent Astronomer’s telegram, ATel 14577, details changes in the spectrum with the emergence of iron lines.  Lots of spectra on the ARAS web site show these lines developing with He I lines fading.

The He I lines labelled in my low res spectrum from 23rd April may actually be Fe II instead… More spectra planned when the skies clear again…

[Hugh Allen]

Confirmation of the emergence of FeII lines after 2021 Apr 3. All spectra are in the BAA database:

[Andy Wilson]

I’ve now merged V1405 Cas and Nova Cas 2021 into a single object. Either id can be used to upload data, and they will both show in the V1405 Cas light curve.

Cheers,

Andy (BAA Photometry Database Manager)

[Mike Harlow]

Hi Hugh,

A link to the BAA database would be useful for those of us who haven’t used it.  That’s what I like about ARAS, all the spectra are easily visible to anyone…plus they are stored in a database for scientific research by the specialists.

And that’s a very nice spectrum…a full sized version on your members page would be good.

Thanks,

Mike.

[Robin Leadbeater]

Hi Mike,

https://britastro.org/specdb/

The database contains over 8000 spectra currently and  is accessible to anyone. It is fully searchable by object name, type of object, observer, resolution, date and as with the variable star database,  storing spectra here gives long term security of the data and  it will likely still be available to researchers long after we have all passed on.

There is a link to all  the BAA spectroscopy resources including the database as a sticky at the top of the section of the forum dedicated to spectroscopy.

https://britastro.org/forum/143

(These resources are all brought together on one page  in the Equipment and Techniques section)

Cheers

Robin

[Mike Harlow]

Hi Robin,

Thanks for the information, that’s very useful,

Mike.

[Hugh Allen]

Hi Mike

The link to the Spectroscopy Database is in the tool bar to the right of this forum thread, back up towards the top of the page under the ‘Observations’ heading. Once inside, click on the ‘Review Spectra’ tab and all of the search fields are right there. The spectra can be plotted on the screen or dowloaded as fits files for analysis at your leisure. It’s a fabulous resource.

I put up an animation on my Member page, from the blue-green end of the spectrum. Actually I might add another one for the yellow-red end

Nice to see your prism spectra!

Cheers

Hugh

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