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supernova SN 2022hrs is currently near maximum at mag 13 in NGC4647
https://www.rochesterastronomy.org/snimages/
It was formally classified as a type Ia (an exploding white dwarf in a binary system) by amateur Claudio Balcon using a slit grism spectrograph based around a Star Analyser just 50 minutes after its discovery was announced on TNS
https://www.wis-tns.org/object/2022hrs

Here is is with the ALPY600 (spectrum fits file in BAA spectroscopy database)
and with the Star Analyser 100

Hi all, Hi Robin,

Thanks for this informations, i take a spectrum of this sn last night with my alpy on C8. Here is the spectrum
I have a strange line at 4531A. I think it's a artefact, but it's present on each spectra (5 x 600s). Have you any idea ?
Matthieu

Matthieu Le Lain wrote:
I have a strange line at 4531A. I think it's a artefact, but it's present on each spectra (5 x 600s). Have you any idea ?

Nice spectrum ! You sometimes see sharp emission lines from contamination from the galaxy spectrum but this does not look like that. I suspect it is an artefact. (A cold pixel or a hot pixel that has been made black by the dark subtraction perhaps ?) Can you see it in the images? Does it look like a single pixel? (A real absorption line would appear across the full thickness of the spectrum)

Cheers
Robin

Yes, it is !

Thx for your help Robin

Here is the spectrum, without it
Matthieu

hello,

here is also the spectrum of SN 2022hrs last night:
vincent

Supernovae within the reach of amateurs have magnitudes usually between +12 and +18. So far, using the Alpy600 with Atik 314L+ (for spectrum) and Atik Titan (for observation and guidance) I have reached magnitude +14. The telescope is a SC8" at f/6.3. The problem to go lower is that I have to see the object, to keep it in the slit of the spectroscope, and guide it if possible. Is there a way to improve in that regard? How to get a better view of faint objects?
Cheers Juan José Pueyo

Bonjour à tous,

Un peu de retour après une reprise du sport !!! Ou il y a aussi le triptyque : repos-hydratation-alimentation qui ne permet pas trop de faire des nuits blanches !! je profite d'une pause pour refaire chauffer l'Alpy et j'espere bientot le Lhires.

Ma contribution pour cette SN : Alpy600 sur C11 - Atik414

Hello,

Bertrand tu sembles confondre décalage Doppler et vitesse d'expension, respectivement ici de 248 A (-11699 kms) et 0.5fwhm=~100 A (4830 kms)

Benji

Juan Jose Pueyo wrote:Supernovae within the reach of amateurs have magnitudes usually between +12 and +18. So far, using the Alpy600 with Atik 314L+ (for spectrum) and Atik Titan (for observation and guidance) I have reached magnitude +14. The telescope is a SC8" at f/6.3. The problem to go lower is that I have to see the object, to keep it in the slit of the spectroscope, and guide it if possible. Is there a way to improve in that regard? How to get a better view of faint objects?
Cheers Juan José Pueyo

Hi Juan José,

To guide on faint targets I offset guide using another star in the field. (I use PHD2 for guiding but it should be possible to do this with other guider programs.)

First I take a deep image of the field from the guider camera (typically 20x20 sec, aligned and stacked) and measure the difference in pixels X and Y between the star I want to guide on and the target. I also note the X Y coordinates of the centre of the slit.

I then add the XY offset to this, place the guide star at this position and start guiding. I usually then take a long guider exposure, say 15 sec to check everything is ok before starting a long exposure on the spectrum camera (typically 1-2 hours in 600 or 1200 seconds exposures)

Here is an example from last night of a 15 second exposure from the guide camera. (SN2022fuc at mag 16.5) The guide star was bright enough to use shorter exposures for guiding.
I use the same technique for extended objects like galaxies and nebula and for comets and asteroids where PHD2 can be programmed to automatically change the offset to keep the target on the slit

Cheers
Robin

Robin Leadbeater wrote:
First I take a deep image of the field from the guider camera (typically 20x20 sec, aligned and stacked) and measure the difference in pixels X and Y between the star I want to guide on and the target. I also note the X Y coordinates of the centre of the slit.

This is the image I used to measure the offset (4x20sec)