Nova Cas 2021

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Viewing 20 posts - 61 through 80 (of 87 total)
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  • #584280
    Daryl Dobbs
    Participant

    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 

    #584285
    Daryl Dobbs
    Participant

    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 

    #584297
    Jeremy Shears
    Participant

    Gradual brightening continue. Now brighter than 7.0

    #584408
    Daryl Dobbs
    Participant

    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

    #584498
    Jeremy Shears
    Participant

    Recent brightening trend continues

    #584499
    Daryl Dobbs
    Participant

    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. 

    #584502
    Neil Morrison
    Participant

    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. 

    #584503
    john simpson
    Participant

    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.

    #584517
    Stewart John Bean
    Participant

    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

    #584519
    Nick James
    Member

    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.

    #584521
    Stewart John Bean
    Participant

    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.

    #584560
    Daryl Dobbs
    Participant

    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. 

    #584574
    David Boyd
    Participant

    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

    #584645
    Jeremy Shears
    Participant

    This nova is still showing lots of interesting activity. And it’s still 8th mag

    #584730
    Jeremy Shears
    Participant

    The nova that keeps on giving!

    #584731
    Daryl Dobbs
    Participant

    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.

    #584891
    Jeremy Shears
    Participant

    This paper on ArXiv today on the light curve of the nova includes spectroscopy from BAA members: https://arxiv.org/abs/2111.02463

    #584892
    Daryl Dobbs
    Participant

    Interesting paper and it’s good to see the BAA acknowledged, looks like it will keep the professionals busy for a while.

    #584893
    Robin Leadbeater
    Participant

    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.

    #585017
    Daryl Dobbs
    Participant

    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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