Mike's Astro Photos
Dec.02 2009

Pre-Discovery Photos of NOVA ERIDANI 2009

by , under Stars

My first amateur attempt at nova detection

My first amateur attempt at nova detection

I posted last Friday about a Nova that was discovered by Japanese astronomer Koichi Itagaki on November 25th, 2009. Mr Itagaki has discovered 50 super novas and is the 8th most successful super nova hunter in the world. I researched Mr Itagaki’s astronomy career a little and learned he has a day job that has nothing to do with astronomy! Here’s a picture of Mr Itagaki’s observatory — that is so money!

This is the original email from Russian Astronomer Dennis Denisenko posted on the Global Meteor Observing Forum

Subject: Important! Check your Leonids images of Nov. 15-18

Dear meteor observers!

Possible Nova in Eridanus was discovered by famous Japanese astronomer
Koichi Itagaki on Nov. 25.536 UT (CBET 2050) at magnitude 8.1.  It was
then retrospectively found on ASAS images dated by as early as Nov.
19.241 UT being yet brighter at 7.3 mag (AAVSO Special Notice #181).
The star has 15th magnitude at quiescence.

No images of possible Nova Eridani are available between Nov. 10.236 UT
when it was fainter than 14.0 and Nov. 19.241 UT.  Looks like the real
maximum has been missed!  Since the spectrum of the star in outburst
shows bright Balmer emission lines with expansion velocity of 3400-3600
km/s, this object is likely a classical Nova rather than a cataclysmic
variable of WZ Sge type.  This means that the real outburst amplitude
should have been 13-14 magnitudes rather than the observed 7.5, and some
time between Nov. 10th and 19th it *could* have been as bright as mag
1-2!!!  But nobody knows it for sure.  Not yet!

Here is where your help is needed.  Please check your photos (and
probably even videos) from the nights of 2009 Leonid shower activity
containing Orion and its surrounding constellations.  The Nova is
located near the Orion-Eridanus border, about 7 deg West and 2 deg South
of Regulus.  Precise coordinates of the star are:

R.A. = 04h47m54.2s, Decl. = -10d10’43” (J2000.0)

The position of star is shown with blue dashes on the following chart
(stars to 6.5m are shown):


If you find the images taken any time between Nov. 10 and Nov. 19
covering the area of interest, please check them for the presence of the
Nova Eridani 2009, or send them directly to me for the analysis and
photometry via E-mail address below in my signature.  Also, feel free to
send this message to other mailing list and circulate it among your
fellow astronomers.  This is really a rare coincidence that many images
of the sky were taken just in time during the Nova outburst because of
the Leonid meteors activity, and reconstructing the light curve of this
variable star would be very important.

Best regards,


Denis V. Denisenko
Space Research Institute
Profsoyuznaya st., 84/32
117997, Moscow, Russia

After reading the email I found 4 pictures of Orion and posted one to the Forum. While I waited for a reply I plotted the pictures in Stellarium (awesome planetarium app — download it, its free). I looked in the general area Denis had specified and realized after a bit of hunting that at a specific location in the picture a star was present, but in the star chart it was just empty space. This was the first time I ever tried to identify a Nova in an astro photo and it was very exciting when I made my conclusion as to which star in the photo was in fact the Nova (granted I had a good bit of help from Denis and Koichi on where to look, but it was still challenging and exciting to make this discovery on my own.)

A little later that day J.Bortell wrote to the Meteor Obs List and confirmed the existence of the Nova in my picture. J wrote:


Indeed, the nova is clearly indicated on your image, appearing to be
magnitude 6.9-7.0 . Definitely worth passing it along to the proper
agency/individual for further examination.

J.Bortle (AAVSO member)

The interesting thing about J’s magnitude rating is it shows the Nova was brighter on the 17th than it was on the 19th or 25th. Here are the magnitude readings: Nov 25 = 8.1 ; Nov 19 7.3 ; Nov 17 6.9 — (stellar magnitude is a counter intuitive scale where the lower the number the brighter the object, the moon being a -12 and the sun -26.) Denis mentioned the expected peak magnitude would have been between 1-3, so I think the peak probably would still have been a few days earlier than the 17th.

Denis wrote me back on Monday and also confirmed the Nova existed inside my pictures at the point I identified. He asked me to report the picture to the Central Bureau of Astronomical Telegrams ( an email address at harvard.edu). Denis said there was a chance the image would be mentioned in the next Electronic Telegram (CBET) about this Nova — wouldn’t that be cool! He also said Nova Eridani 2009 is just a temporary name and the official name will be determined later by the people from the General Catalogue of Variable Stars (GCVS) team in Moscow. How awesome would it be to discover a Nova on your own and then have it named after you! Hmm, this Nova hunting might be a fun thing to explore.

Here’s the pre-discovery picture of Orion that shows Nova Eridani:

Pre Discovery Photo of Nova Eridani - November 17th, 2009

If you want to see higher res images or the RAW camera files email me at mike.hankey@gmail.com


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