Possible Nova in Sagittarius (Nova Sagittarii 2012 No. 3)

[starfinder]

I just saw this article on the Sky & Telescope website about a discovery made 2 days ago:

'' A flaring star discovered
independently by two
Japanese observers has
brightened to near 9th
magnitude — putting it
within easy range of most
backyard telescopes. ...''
http://www.skyandtelescope.com/observin ... 51575.html

[starfinder]

I think I have managed to image the star tonight from here in Singapore.

Here is an image with annotations added. The star is between the two yellow crosshair lines, and the rectangular side box shows the star (bottom left) at 100%.

The data on the other two identified stars is taken from The Sky6 planetarium program.

The suspected object is one of the reddest stars I've imaged. I estimate it at around mag 9.9 based on a comparison of the other stars.

http://i.picoodle.com/4ccj668d

[Clifford60]

Great job, Sg Deep Sky special object (DSSO) hunter, haha

[Gary]

Congrats! Well done. Another successful attempt with a 8" SCT under Singapore skies.

[starfinder]

Thanks!

Yup, this shows again that meaningful imaging of relatively faint celestial phenomena can be done from our light-polluted Singapore skies, using just amateur-class and consumer equipment.

I've this morning done a close comparison of the suspect star in my image identified by the two yellow cross-hairs against a large scale mag14 chart generated using the AAVSO's Variable Star Plotter webpage. I can confirm with 100% certainty that the suspect star in the image corresponds with the star identified in the AAVSO's chart as the (possible) nova.

[starfinder]

Jiahao and I went to Labrador Park this evening to attempt to observe the suspected nova visually. I brought my LX-90 8" SCT and set it up by the seaside promenade next to Carpark B. Labrador Park is off Pasir Panjang Rd and at the end of Alexandra Rd.

We managed to view the suspected nova in Sagittarius at 143x (with a Pentax 14mm XL eyepiece) and at 286x (with a 2x barlow added). The star was just barely visible with direct vision at 143x but was clear and distinct at 286x.

It seemed to be no different in brightness to the adjacent star with the ID no. GSC 6262:329 which is stated to be mag 11.3 in The Sky6 planetarium software. So perhaps the suspected nova is around mag 11.3 or maybe its reddish colour makes it appear dimmer than it really is.
However, we could not really see any colour in the suspected nova even though in the images it has a strong red hue.

Generally, the skies at Labrador Park are darker than at my home. We also viewed several globular clusters such as M13 (Her), M92 (Her), M62 (Oph), M22 (Sgr), and NGC6441 (Sco) which Jiahao showed to me. The globulars were surprisingly bright and some of the component stars could be seen. From my memory, the view of these DSOs was much better at Labrador Park than from my home nearer the city centre. I think it would be quite a good place to hold observation gatherings.

Here is an image of the suspected nova in Sagittarius taken with the same settings as yesterday, i.e. ISO 1600 and 15s. The darker sky at Labrador Park is evident in the blacker background and fainter stars captured as compared with yesterday's image. Again, the suspected nova star and another star adjacent to it (GSC 6262:329) are also shown at 100% in the rectangular yellow box at right. The star seems to have at most dimmed slightly in today's image as compared with yesterday's, i.e. by comparing it with the surrounding stars.

http://i.picoodle.com/5bej67mg

[Gary]

Good job Gavin and JiaHao! Thanks for checking out the place. A pity I couldn't join you guys last night. Will check out this park in the near future.

[jiahao1986]

Man it looks even redder on my PC screen!

[Airconvent]

Great job Gavin and Jiahao. I guess Gavin is not called "Starfinder" for nothing! If this keeps up, I have to change his nick to "novafinder".

[starfinder]

The object has been confirmed as a nova, and has been given the designation Nova Sagittarii 2012 No. 3, see:
http://www.aavso.org/aavso-alert-notice-463
http://www.cbat.eps.harvard.edu/iau/cbe ... 003156.txt

Some extracts:
"Spectra by ...confirm the object as a nova. The spectra... indicate Nova Sgr 2012 No. 3 is of the He/N type."
"a spectrogram... reveals that the nova-like nature of PNV J17522579-2126215 is confirmed; the
spectrum is dominated by intense hydrogen emission."
"The object appears to be heavily reddened, with strong interstellar Na I lines visible in absorption."
"...no progenitor star could be identified on a Palomar Sky Survey plate from Sept. 1950."


Its latest brightness estimate as at 3 July 2012 puts it at mag 12.4. So it has dimmed quite quickly from the peak of around mag 9 on around 28 June. That makes it a very fast nova I think.

Interestingly, this nova was discovered independently by two Japanese astronomers in images using quite simple equipment: one using a 8" reflector and the other using a 180mm lens.

I hope to be able to image again soon.

About novae generally, see:
http://en.wikipedia.org/wiki/Nova
"A nova (plural novae) is a cataclysmic nuclear explosion in a white dwarf star. It is caused by the accretion of hydrogen on to the surface of the star, which ignites and starts nuclear fusion in a runaway manner. Novae are not to be confused with supernovae or luminous red novae. ..."