potentially bright supernova in NGC3254

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  • #574232
    Robin Leadbeater
    Participant
    A supernova has been reported in NGC3254
    It is currently too faint for most amateurs at mag 18 (right at my limit with the ALPY200) but according to the published spectrum it is a type Ia, possibly caught a remarkable 2 weeks before maximum so based on the distance to NGC3254 and that from the spectrum there does not seem to be much redenning, it could reach ~mag 13.   
    One to watch!
     

    Robin
    #580565
    David Swan
    Participant

    K Itagaki’s latest image on David Bishop’s site puts the SN brightness at around 13.6 (clear filter, presumably V mag zeropoint).

    Unfortunately there’s been quite poor weather in NE England recently – with just snatches of clear sky – so I haven’t been able to get at this object.

    #580566
    Paul Leyland
    Participant

    It’s happened 4 weeks too early for me.  Not back in La Palma until mid-February, where I can reach mag 20 or better with around an hour’s exposure.  Can’t even reach mag 8 from here.

    Oh well.

    #580567
    Robin Leadbeater
    Participant

    Hi Paul,

    It has not maxed out yet so if it follows the normal Ia light curve will likely be around  mag 16 in a month’s time so still an easy imaging target. 

    Note my original comment on mag 18 being out of range for amateurs referred specifically to spectroscopy, not imaging. With my ALPY 200 the target has to be about 6.5 mags brighter for spectroscopy than for a conventional photometry image. The big advantage with slit spectroscopy though is most of the sky background is kept out by the slit so you can get away with much higher levels of light pollution. My limiting spectroscopic magnitude is ~17.5 which corresponds to mag 24 for photometry. I would need much darker skies to do photometry  that deep in a conventional image though.

    Cheers

    Robin

    #580570
    Robin Leadbeater
    Participant

    Peter Somogyi has now posted an amateur spectrum on the ARAS forum using an ALPY 600

    http://www.spectro-aras.com/forum/viewtopic.php?f=38&t=2205#p12098

    He has also posted a spectrum of sn2018hna which I classified as a type II when discovered back in October 2018 at mag 16 but strangely has been rising steadily since it was discovered and is currently mag 13.7

    http://www.spectro-aras.com/forum/viewtopic.php?f=38&t=2214

    The differences in the spectrum between the two (Ia  and IIP) are very obvious

    Cheers

    Robin

    #580607
    Robin Leadbeater
    Participant

    A spectrum from last night with the ALPY 600 compared with a best match type Ia near maximum from GELATO

    #580608
    Andrew Robertson
    Participant

    I did get a visual sighting last night in my 12″ Mewlon but skies not the best, a bit claggy, NELM mag 5 to mag 5.5. Comparing to field stars I estimated it to be about mag 13.3. Comparison stars:

    Brighter than GSC 01976-0429 mag 14.1

    Fainter than GSC 01976-0815 mag 12.2

    About the same as GSC 01976-0125 mag 13.3

    Andrew

    #580651
    David Swan
    Participant

    For those who are interested and haven’t visually observed or imaged this yet, this transient is still quite bright and nicely placed in Leo Minor for evening obs.

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