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Couldn’t see it without my 15×70 binoculars, at 22:30ut last night I estimated it was around 7.5, typo error not 5.5 as I previously wrote. Observed it in 31st through haze and it seemed about the same as the previous night. But not the best conditions to observe
I had a quick look last night at around 21:45ut and it seemed around mag7 but sky conditions weren’t that good due to haze. I wonder if that’s it for the second peak and it will fade or even if we will see more peaks, very interesting article in the latest vas circular about it being miss- classified ages ago. Thinking about it how accurate was the position as it’s a crowded star field
Reasonably clear a few high altitude clouds, hindered by my neighbours washing setting off her security light in a the gentle breeze. So wait 5 minutes until it goes out.
Seems to be fading when compared to the weekend, last night I estimated it at mag7.9
I’ve had 9 continuous nights of clear skies but last night the transparency was awful, doesn’t look a lot better tonight so far. I hope to follow this one for some time in Binoculars and a 10 inch Newt. Skies around here suffer from a lot of LED street lights.
This morning the BBC Weather reporter was blaming our very poor sky conditions on high altitude smoke from the USA wild fires. For the last two nights ie 21/22 July and 22/23 July the moon has looked as if it was in Eclipse and very few stars dimmer than second Magnitude were visible naked eye. Thunder Storms in Forecast for the next 48 hours .. So not much chance of getting an upto date image of this long lasting Nova.
I wondered if there might be evidence of any asymmetry in the nova due to shocks or clumping of fast/slow ejecta and if it might show up in linear polarisation and wavelength dependence. Measurements from 21-22/07/2021 [file attached] don’t seem to show much other than interstellar polarisation characteristic.
I thought I would give this bright nova a try with iTEL 18 (300 mm) in Spain. Even with only a 5 sec exposure the images were saturating. Then all iTEL images are charged as if they were 60 sec exposures – not economical.
So I will stick to fainter objects unless someone can point out a workaround.
Stewart
Stewart, Yes, it’s back up to 5.6 unfiltered tonight (July 26) which is not far short of its brightest at the previous peak. I’m doing 1s exposures and it is not far off saturating my camera. It is very hazy here but I think I’ll get the binoculars out again.
The good news is that iTEL are forgiving of my mistakes in setting up runs. They have refunded my account which I think is very good of them.
seems to be fading quickly, easily visible in my 20×70 binoculars on Wednesday 28th but last night the 1st August I couldn’t see it. Was going to get my telescope out but clouds rolled in just as I set up.
Here is a spectrum of Nova Cas 2021 taken on 6th August with a LISA (R~1065) and calibrated in absolute flux using a concurrently measured V magnitude of 7.70. There are broad emission lines of H I Balmer and He I, all with P-Cygni absorption dips, and weak Fe II emission lines with double peaks. The H-alpha line is so strong that exposures had to be kept to 40 sec to avoid saturating. Further information about the spectrum and more plots can be found on the ARAS Forum at
http://www.spectro-aras.com/forum/viewtopic.php?f=36&t=2744&p=15888#p15888
David
Never ceases to amaze me each night I observe it. I hope it continues for a long time. I hope there will be a paper on what is going on with iy.
This paper on ArXiv today on the light curve of the nova includes spectroscopy from BAA members: https://arxiv.org/abs/2111.02463
Interesting paper and it’s good to see the BAA acknowledged, looks like it will keep the professionals busy for a while.
It is slightly strange that they decided to use a subset of all the available spectra (There are currently 104 in the BAA, 392 in the ARAS and 113 in the AAVSO databases, most of which would meet the resolution criterion though many are likely duplicates) I wonder what the selection criterion was.
Seems V1405 Cas has been detected in X-rays according to the link below.
ATel #15111: V1405 Cas is now a faint Super-Soft Source (astronomerstelegram.org)
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