Forum Replies Created
-
Posts
-
The spectrum of the central coma is now on my BAA observer’s page here
Had another go at this one. Here it is in the BAA database overlaid on Pickles G0v)
https://britastro.org/specdb/data_graph.php?obs_id=9503&std_spectra_id=p_g0v
(One of the most frustrating observations I have tried to make. It literally skimmed along the roof line just arcminutes below it for over an hour before it finally popped up just as the sky was starting to brighten.) It was still at air mass 3.5 and there was thin cloud so the SNR is poor but consistent with the type reported previously (late F /early G)
https://www.astronomerstelegram.org/?read=14593
Cheers
RobinHi Derek,
What date was this ? Objective grating setups showed a nice little sodium coma and tail.
My early example on 7th July
https://britastro.org/comment/8806#comment-8806
and a better one a few days later by Mike Harlow
https://britastro.org/comment/8832#comment-8832
but the sodium dropped in intensity after that and was lost in low resolution spectra around 22nd July
Cheers
Robin
A spectrum has now confirmed it an “ordinary star” so the source of the variability is unclear.
https://www.astronomerstelegram.org/?read=14593
A series of spectra covering a period of variability could be interesting. (The clouds rolled less than a minute after I finally got the star on the slit of the ALPY600 when it finally cleared the rooftop at 16 deg altitude). Although extremely noisy, the spectrum is also consistent with the “normal star” description)
Cheers
Robin
One of these perhaps ?
https://www.semrock.com/FilterDetails.aspx?id=FF01-387/11-25
seen in action here
https://wirtanen.astro.umd.edu/46P/CN_filter_test.shtml#Jorma_update
Here is the approximate extent of the spectrograph slit superimposed on Denis’s image.
The CN emission is actually much more intense than the raw spectrum image suggests as the spectrograph sensitivity is low in the UV. The comet would look pretty spectacular in a narrow band CN filter !
I took a low resolution spectrum across the coma last night. Here is the raw image including sky lines
Hi Mike,
The database contains over 8000 spectra currently and is accessible to anyone. It is fully searchable by object name, type of object, observer, resolution, date and as with the variable star database, storing spectra here gives long term security of the data and it will likely still be available to researchers long after we have all passed on.
There is a link to all the BAA spectroscopy resources including the database as a sticky at the top of the section of the forum dedicated to spectroscopy.
https://britastro.org/forum/143
(These resources are all brought together on one page in the Equipment and Techniques section)
Cheers
Robin
I believe this is commonly because potentiometers on the motor control have become unbalanced and need adjusting. For example as here
https://www.b82maidbronn.de/lx200.htm
There was someone in the UK (Alan Sickling) who used to know all about these. His email was alan (at) sickling(dot)co(dot)uk but this was from over 10 years ago now
Cheers
Robin
Hi David,
All is not lost. There is a field star showing a nice telluric absorption band at ~7620A which you can use to get an approximate wavelength calibration. (~25A/pixel off the posted image but that may have been reduced down from the original)
Robin
This one also looks to be at maximum
https://alerce.online/object/ZTF21aaqwjlz
Assuming the z = 0.035 in TNS estimated from the classification spectrum equates to 150Mpc distance, this puts the absolute V magnitude at -19.7, about right for a typical type Ia with no extinction
It looks like it is now close to maximum.
https://alerce.online/object/ZTF21aarqkes
At a distance of 40Mpc (from NED) an apparent magnitude of 14.6 gives an absolute mag of -18.4 not allowing for any extinction
An ALPY200 spectrum from last night continues to give a good match to a type Ia at the host redshift
Cheers
Robin
A couple more spectra of QSO at higher redshifts (4.41, 4.564) from the PS-ELQS catalogue here
I see Ivan Walton caught SN2021hpr on the night of 2nd April 14 hours after discovery in this member’s image
crop below
I’ve just realised this is the second supernova in this galaxy this year. SN 2021do (type Ic) reached mag 16.5 mid January but is now down to mag 20
https://alerce.online/object/ZTF21aaaubig
Cheers
Robin
It was bright enough for a slitless spectrum using the Star Analyser last night
https://britastro.org/observations/observation.php?id=20210406_144443_9e1c6a4cf219d14d
Cheers
Robin
