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Nova Cas 2021

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Jeremy's picture
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Nova Cas 2021

Yuji Nakamura (Kameyama, Mie, Japan) has reported the discovery of a possible nova, PNV J23244760+6111140, on March 18.4236 

Tonny Vanmunster confirmed the transient later that day at V = 8.95 +/- 0.03 (CBA Extremadura Observatory using a 0.40-m f/5.1 telescope and SX-46 CCD camera) 

ATel #14471 reports spectroscopic classification of the object as a classical nova (Hiroyuki Maehara (National Astronomical Observatory of Japan), Kenta Taguchi (Kyoto University), Yusuke Tampo (Kyoto University), Naoto Kojiguchi (Kyoto University), Keisuke Isogai (Kyoto University). 

Nova Cas 2021 is at RA 23 24 47.73 Dec +61 11 14.8 (J2000.0) 

This is a bright nova and further observations are encouraged. The field is circumpolar from UK and it should be a binocular object. Charts and sequences are available from the AAVSO Variable Star Plotter.

 

 

 

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missed chance

Argh !   

It was clear last night here too and I was looking round for interesting targets for spectroscopy. This would have shot to the top of the list but nothing on vsnet-alert. Where better should I be monitoring ?

EDIT: I see it is on vsnet-alert.  My brain did not register the alerts for some reason  I think I must have thought Cze was some obscure southern constellation and moved on. :-(

Cheers
Robin

Cheers

Robin 

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BAAVSS Alert

Robin makes an important point here about alert systems. There are many such available.

One that might be of interest to BAA Members is the BAA VSS Alert Group. You can find out how to sign up here.

The aims of the group are to distribute information on variable vtar activity currently observed by BAA VSS members. The Nova discovery was announced there.

Hope you get some more clear sky, Robin!

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Around 7.6 unfiltered

Attached stack of 11x1s shows it around 7.6 unfiltered (Gaia G reference) just now (Mar 19.80).

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The astrometry I get using

The astrometry I get using Gaia DR2 is 23:24:47.70 +61:11:14.8 with a very high SNR and 1.29 arcsec/pix sampling. There are four stars within 5" in Gaia DR3. The closest to that position is 15.36G offset by 0".47 in RA, 0".04 in Dec.

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Did you get the binoculars

Did you get the binoculars out, Nick?

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Yes, and I can see it just

Yes, and I can see it just below M52. I'm not sure about making a magnitude estimate though!

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Nova Cas 2021

Here is a single-shot image from tonight with Canon 77d through a 14" SCT  exp. 15 sec. iso 3200.

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Nova Cas 2021: Low resolution spectrum

Quick look low resolution spectrum.  Reveals a bright continuum with strong hydrogen emission lines and some other as yet unidentified emission lines. Field is 12 x 6 arc minutes and conveniently includes an 'ordinary' A-type star spectrum for comparison(!) with hydrogen absorption lines. Taken with a 26cm, 3 degree objective prism on a 12inch F/3.6 astrograph.  24 x 20 seconds. 19th March 2021 at ~21:00GMT.

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Nova Cas 2021

This spectrum of Nova Cas 2021 was recorded with a LISA spectrograph on a C11 during a short break in generally overcast skies tonight. It shows strong emission lines of the hydrogen Balmer series and He I. There are P Cygni profiles extending to around -2500 km/s relative to the rest wavelength on all emission lines. The spectrum was calibrated in absolute flux using currently recorded B and V photometry which gave V = 7.77+-0.04 and B-V = 0.50.

David

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V1405 Cas

CBET 4945 designates this nova as V1405 Cas. My image of it and M52 which is a degree to the north is here.

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NovaCas2021

On Tuesday 16th March I was imaging Caroline's Rose in Cassiopeia with a 50mm lens, so I had a wide enough field of view that the area around Nova Cas was in shot. In my stacked image I can just see a tiny star in the right place according to the finder chart circulated by the SPA, just above HIP 115566. It would have been much fainter back on 16th, I really hope to get another shot to compare it in the next few days.  The attached photo was taken with a Canon 1100D with 50mm fixed lens. It's a stack of 280 x 8 seconds. I've included an inverted version as well.

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Waiting fir the clouds to clear!

Well I’ve printed off the comparison chart, and I have the RA and Dec ready to go- just need a clear sky tonight!

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Nova Cas 2021

I took some pre-dawn images via T11 at New Mexico (0.51m CDK) a couple of hours ago. The 'pretty pic' unfiltered 120 sec image is here.

http://martinmobberley.co.uk/images/v1405cas_20210320_1143_mpm.jpg

I also took some much shorter V filtered images. The brightest pixels in the nova disc were 30% of the way to saturation in a 5 second V shot.

Using the AAVSO chart's somewhat dimmer mag 9.0 and 9.1 stars gives a V mag of 7.70 at 11:45 UT this morning (Mar 20). JD = 2459293.98958.

Regards,
Martin

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Nova Cas 2021

I imaged the field last night March 20 at 1939UT.  Not having access to the sequence I used the manitudes of field stars on Stellarium giving an estimate for the Nova of Magntude +7.7 .  Image attached.  Details on Image.

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Nova in field

Wow, it's bright - and so nicely placed in Cas next to M52 and the Bubble Nebula! I carried out a 41 x 5s stack this eve: not scientifically useful, but a pretty pic, I think.

Attachments: 
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449's anniversary

In Cassiopeia!  Would that it could have waited a year until the 450's anniversary of Tyco's Nova of 1572.  

If you like costume drama historical documentaries, this one about Johannes Kepler, including his time with Tycho Brahe, is quite excellent:

https://curiositystream.com/video/4108

(in case it's cloudy when you go outside to look for the new nova of 2021)

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Sunday 21st March 2021 Nova Cas 2021

I was struggling to find it with binos but was imaging the coordinates in a brief cloudless window of opportunity and managed 7 six minute subs which I still have to process. Here is a rough image straight out of EKOS.

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Cleaned up version

Here is my cleaned up version. I had to shoot it in Ha with my ASI183MM with the WO ZS103. Processed with PixInsight and Photoshop.

7 x 360 second subs and then it clouded over!

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Nova

Nice picture, is that the nebulosity around the Bubble Nebula coming into view at the bottom. I managed to spot it during a brief break in the clouds through binoculars

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Nova

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.

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V1405 Cas and the Bubble nebula

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.

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Spectrum from 22nd March

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.

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Nova Cas 2021 Alpy spectrum
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

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Nova Cas 2021 Photometric magnitude

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.

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Finally got my spectrum

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

Cheers

Robin

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N Cas 2021, RGB

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

-Harri 

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Nova Cas 2021 Mar 22 v Mar 24

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

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Nova Cas 2021 spectrum evolution to Apr 3

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

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News in from Kato-san at

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!

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V1405 cas

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

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V1405 Cas

Hi Jeremy,

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

David

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Re: V1405 Cas

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

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V1405 Cas and Nova Cas 2021 now merged

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)

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Spectral changes

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...

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Confirmation of emergence of singly ionosed iron emission lines

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

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"BAA Database"

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.

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BAA database

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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Database etc.

Hi Hugh,

Thanks for the info, that's very useful.

And I must say your animations of the changing spectrum are fascinating to watch.  Really excellent work and thanks for sharing them on your members page.

Mike.

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BAA spectroscopy resources

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

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BAA spectroscopy resources

Hi Robin,

Thanks for the information, that's very useful,

Mike.

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V1405

Clouds interfered last night but first glimpse I’ve had of it for a week through my opticron 15x70’s, difficult to estimate the magnitude due to clouds but I estimate around 7.8. Seems to have brightened quite a bit since a week ago 

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Now mag 6 !

 The steady rise has turned into a rapid  brightening to mag 6 currently

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Nova Cas 2021 spectrum

Luckily I was out last night (7th) taking another spectrum of the nova but with slightly better resolution.  As soon as I found the field in the finderscope it was obvious the nova had brightened significantly. The spectrum now shows very well defined P-Cygni features on most of the emission lines.

Astronomer's telegram ATel14614 gives a nice update on the nova's evolution. 

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Mike's 12deg prism spectrum processed in BASS

Hi Mike,

i hope you don't mind. I had a go at processing your spectrum image in BASS:

I calibrated it using the emission line wavelengths from one of my own Alpy spectra. And I made a response correction using the reference star BD +60 2540 that you highlighted in your image. I used the Pickles reference for an A5III star because there is no reference for an A5II. I think the calibration and response correction came out pretty well:

Anyway, it was a bit of fun and I think it shows the quality of your spectrum down in the green-blue end. I think the red end was maybe saturated in your image which could explain the fat, squat appearance of the Halpha emission

Cheers

Hugh

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Processed spectrum

Hi Hugh,

Wow...that's a really nice spectrum!  I'm impressed that you got such a nice result from the .jpg without even seeing the .fts file. Anyway, it does show one thing...I need to get to grips with some spectroscopy software to produce some more useful results.

You're right that the red end is saturated as it's difficult to get the exposure right to show both ends correctly exposed, especially for red objects. 

Some background on the prism.  It was instrument no. 179 in the BAA instrument collection and I took it out on loan in 2012.  Thanks to Bob Marriott for organising the loan and even delivering it in person!  I purchased it from the BAA a few years back when the instrument collection was finally sold off.  Apparently it has been used by some famous names in the past including Mike Hendrie and David Sinden.  But most notably it was used in the 1980s and 1990s by Maurice Gavin for much of his pioneering work on spectroscopy with film and CCDs.  This work was published in the BAA Journal in 1996:  'Stellar spectroscopy with CCDs-some preliminary results'.  J. Br. Astron. Assoc. 106(1) 1996, p11-15.

It may be old technology but as you've shown it can still produce useful spectra. And given it's history I feel I should keep using it as long as I can.

Thanks for taking the time to analyse my spectrum...I must make more effort!

Mike.

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Bright nova

I last viewed the nova in mid-April so I'm keen to get out to see it after the increase in brightness. Hopefully tonight will stay clear! This shot is from 12 April.

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Second capture

I managed to get to the same site on the moors and get a shot of the brighter nova. Unfortunately, it was very windy so my capture was not as good as the previous one. You can see how much brighter it is though! 

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Visual estimate

I made a visual estimate this morning at 00:25 hrs UT using 7x50 bins and put it at mag 5.4

Andrew

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Naked-eye

I've seen a naked eye observation of the nova, reported on the VSnet list. Filipp Romanov observing from Nakhodka, Russia (nr Vladivostok, 42degN) had it at 5.1 vis last night (2021 05 10.75). "It was easily seen next to the star 4 Cas against the background of the Milky Way", Romanov notes.

This is the first NE obs report I've seen. It will be interesting to hear if a BAA member gets to see it with their NE, although its position is quite challenge, along with bright skies.

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Nova Cas at maximum?

An image from 23:30UT last night (10th)...nova at centre of 25 x 25 arc minute frame, north up. It may seem like overkill to image a mag 5.3 nova with a 30cm telescope (!) but I'll be able to follow it as it fades back to mag 18,19 or less with the same set-up.  Should make a nice sequence...maybe even an animation...!?

I did look but couldn't see it naked-eye. But it was very nice through binoculars and the 4 inch F/5 finderscope on the main telescope. 

Mike.

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