[Robin Leadbeater]

Perfect ! Thanks David.  (I had tried underlining but that did not work so did not explore further.) I have changed my recent post. I think Bold, Italic looks quite good 🙂

Cheers

Robin

[Robin Leadbeater]

An R~5500 LHIRES spectrum of Halpha/He I 6678 last night. 

Lots of evolution over a day in spectra in BAA database

The interstellar line at 6613 is strong too. (I did a bit of Googling on that last night and it seems although it is thought to be molecular in origin, the species does not seem to be known. Does anyone know more about this )

[Robin Leadbeater]

Long exposure astro cameras with higher dynamic range are certainly better for photometry but I played around with  8 bit camera photometry a few years back and found it was possible to do high(ish) precision photometry with 8 bit cameras (even exoplanets, just)  provided you sum many frames to get the counts. eg

http://www.threehillsobservatory.co.uk/astro/Photometry_GO_Com.htm

http://www.threehillsobservatory.co.uk/astro/TrES_1.htm

One thing to watch though with these cameras is that the gamma is set to 1 so the response is linear.

Cheers

Robin

[Robin Leadbeater]

http://www.astronomerstelegram.org/?read=14224

The confirming spectrum was taken with an ALPY600 and 10 inch telescope

(Here it was clear earlier last night but the arrival of the alert in my in box coincided with that of the clouds)

Robin

[Robin Leadbeater]

Another spectrum at ~12 days past maximum. Still bright at ~mag 14.5 but interfering moonlight reduced the SNR.  Significant evolution since the pre maximum spectrum 

https://britastro.org/specdb/data_graph.php?obs_id=8176%2C8020&multi=yes&legend_pos=ne

but still a good match to a typical type Ia 

[Robin Leadbeater]

Yes this one is against a bright background. This can be subtracted out using regions above and below the target in the slit but it does depend on this being uniform (both in brightness and spectroscopically) so you have to watch for galactic features. 

The last time I checked the ATels  this group were suggesting the spectrum resembles that of an F star. This rather rang alarm bells with me though as that is that is what might be expected from the integrated light from the galaxy. I see now here though it has been classified as an Fe II nova. What brightness would you estimate?  (Not that I am going to be observing any time soon from the forecast. As I am writing this the hailstones are hammering on the window)  

[Robin Leadbeater]

These are some I have managed to tease out in the past (full scale in the attachment)

[Robin Leadbeater]

Hi Nick,

Has 2020vak been positively identified as an M31 nova?  I am not saying it isn’t but it wasn’t clear from  the amateur spectrum posted on TNS

https://wis-tns.weizmann.ac.il/object/2020vak

Cheers

Robin

[Robin Leadbeater]

“Today I noticed the graphs had gone from my posts . I have put the latest back into the 26th Oct post. Any thoughts on the reasons? Are some formats preferred?”

file size perhaps?  jpg of graphical images tend to be larger and poorer quality than png for example

Robin

[Robin Leadbeater]

Interestingly there was another transient AT2020ftc discovered the same date 10 hours earlier at almost (but not quite) the same coordinates I wonder if it is the same object, one with incorrect coordinates or perhaps an asteroid? 

[Robin Leadbeater]

Forget it. I have just noticed although it has just been put on TNS the discovery date is 2020-04-02. A bit late for them to be announcing it !

[Robin Leadbeater]

https://www.bbc.co.uk/iplayer/episode/m000nysp

at 22min 43sec

Advisory –  not suitable for astronomers of a nervous disposition or those with high blood pressure  

[Robin Leadbeater]

Another spectrum on a better night (2hr 20min exposure at mag ~15.5 The limit at this resolution).   Not much happening compared with a week ago

https://britastro.org/specdb/data_graph.php?obs_id=8021%2C8002&multi=yes

Robin

[Robin Leadbeater]

Interesting. The spectrum seems consistent with a dwarf nova outburst. I managed to salvage a couple of short exposure spectra from aborted runs on the 10th and 12th. They are very noisy though so the only significant feature is the hot continuum shape.

Robin

 

[Robin Leadbeater]

A short clear spell tonight. Not long enough to get a spectrum but off the spectrograph guider it looked about a magnitude fainter than on 8th  

[Robin Leadbeater]

ALPY 600 ~12A resolution. A blue continuum with weak Balmer absorption

[Robin Leadbeater]

Sorry Andrew, I missed this

Impressive.  I have just updated my copy of Visual Spec and I see Valerie has added a wavelets feature

[Robin Leadbeater]

“It’s amazing how people go on finding creative ways to waste their time and resources”

I have to say I’ve done my fair share of that in astronomy too 🙂

[Robin Leadbeater]

I like that the residuals follow the expected shape, noisy at the ends of the spectrum where the sensitivity is lower. It gives confidence that you are removing noise, not signal

[Robin Leadbeater]

Now classified as a type Ia supernova by Italian amateur Claudio Balcon using a home built spectrograph designed around the Star Analyser. Congratulations to Claudio and the XOSS team for their discovery !

 

Robin

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