We are having a string of clear nights, so I am happy to have observed it for a third night in a row. Visual Observation from suburban Brisbane:
Dec 9th 0319 hrs EST Local Time (Dec 8th 1719 hrs UT)
7x50 binoculars - easy to see
Unaided Eye - not seen due to twilight and city light pollution
Based on nearby stars it still looked to be at Mag 4.5
No colour was observed as twilight was underway
Quote:
Originally Posted by Jon
Photometry yesterday morning Dec 7 17:40 UT: V = 4.276, B = 4.85. B-V increasing; the nova's getting pinker as the hydrogen emissions make more of a contribution to its total flux.
Where can I find some info to help decode the definitions of V and B / B-V ?
Quote:
Originally Posted by UK1
We have just started to get some clear skies in the morning is the nova still visable, ?
and where shoulfd I be looking ? please
many thanks
I saw it clearly naked eye on 8th Dec @ 2:30am. Lined up the scope and intended to take a pic + spectrum, then naturally the clouds rolled in just as I had focused...
I'm hoping to have another go this weekend.
Where can I find some info to help decode the definitions of V and B / B-V ?
I'm certainly no expert but I'll explain it as I understand. B and V refers to different types of photometric filters, Blue and Visual (green) respectively. Others are available, for example U (ultraviolet) and R (red). See http://en.wikipedia.org/wiki/Photometric_system
Photometric magnitudes are generally measured through these filters, so the filter type will be listed with the magnitude reading.
B-V is simply the magnitude from the B filter minus the magnitude from the V filter. The B-V colour index gives a crude measure of the colour of the star, the higher the number the redder the star. So when Jon says 'B-V increasing' he is effectively saying the star is getting redder.
I got up after 3:00 am Qld time and looked at the nova with binoculars from my front driveway. I think I could just see it unaided, but it was on the limits for my eyes and the conditions.
After looking around for a while with the binoculars, I decided to grab the Canon 60D and the iOptron Skytracker. By the time I got set up, waited for some cars to go by, and tweaked the focussing, twilight was starting. Anyway, finally got a short exposure (maybe around 30 seconds - using a manual trigger and counting). Maybe tomorrow I will try again.
I'm certainly no expert but I'll explain it as I understand. B and V refers to different types of photometric filters, Blue and Visual (green) respectively. Others are available, for example U (ultraviolet) and R (red). See http://en.wikipedia.org/wiki/Photometric_system
Photometric magnitudes are generally measured through these filters, so the filter type will be listed with the magnitude reading.
B-V is simply the magnitude from the B filter minus the magnitude from the V filter. The B-V colour index gives a crude measure of the colour of the star, the higher the number the redder the star. So when Jon says 'B-V increasing' he is effectively saying the star is getting redder.
Thanks for the info Malc. Am I correct in saying calibrated photometry can be used to provide an accurate apparent magnitude of the nova when all of the filter (passband) readouts are combined?
I have just been outside to check in on this nova. From my location it is hard to see with the unaided eye but easy in bino's. Observing visually through 7x50's it still appears to be around Mag 4.5 with no obvious colour. Nearby stars HIP64425 apparent Mag 4.56, HIP65271 apparen Mag 4.50 and TYC8661-2282-1 apparent Mag 4.90 were used to compare apparent magnitudes.
Last edited by Shark Bait; 10-12-2013 at 03:43 AM.
Thanks for the info Malc. Am I correct in saying calibrated photometry can be used to provide an accurate apparent magnitude of the nova when all of the filter (passband) readouts are comined?
I have just been outside to check in on this nova. From my location it is hard to see with the unaided eye but easy in bino's. Observing visually through 7x50's it still appears to be around Mag 4.5 with no obvious colour. Nearby stars HIP64425 apparent Mag 4.56, HIP65271 apparen Mag 4.50 and TYC8661-2282-1 apparent Mag 4.90 were used to compare apparent magnitudes.
The V filter is so called because its passband is centred on that of the human eye, mire or less. So V on its own will give you the best approximation to visual magnitude.
Adding the magnitudes from the whole UBVRI set of photometric filters will actually give a result they varies from the visual mag as you are including light that the eye can't see. For instance, the I (infrared) filter actually appears opaque - the eye can't see these wavelengths. But novae are actually extremely bright in I (this one no exception). The star is surrounded by an expanding shell of dust and gas that blocks a lot of light , but heats up and thus radiates in infrared.
Got a better view last night, clouds were less intrusive. Still very low on the horizon at 22:00 but good in binos and the 80mm although still a lot of 'soup' affecting the seeing. Unable to discern any dominant colour.
Tick THAT one off !
The V filter is so called because its passband is centred on that of the human eye, mire or less. So V on its own will give you the best approximation to visual magnitude.
Adding the magnitudes from the whole UBVRI set of photometric filters will actually give a result they varies from the visual mag as you are including light that the eye can't see. For instance, the I (infrared) filter actually appears opaque - the eye can't see these wavelengths. But novae are actually extremely bright in I (this one no exception). The star is surrounded by an expanding shell of dust and gas that blocks a lot of light , but heats up and thus radiates in infrared.
Thanks Jon. The information you and Malc provided have helped me to gain an understanding of what you do.
It looks like SE QLD's run of clear nights is over for the time being. I hope you get clear skies to continue gathering data on this nova.
V1369 Cen (Nova Centauri 2013) tonight, in moonlight. Canon 650D, 55mm lens, 5 x 5 sec, ISO 6400, F/5.6. Flick between the two pics for identification. Have posted another spectrum in the Spectroscopy section.
Set the alarm for 3:30 to have a look at it. Rather bright, could not see any color in it. Was observing until 6:00. Got the Argo fixed on it and was seeing it clearer as the sun come up. Well worth getting out of bed early for.
Clouds cleared about 11 pm last night but from my preferred location ( back steps ) the dang thing was behind a big Macrocarpa Tree.
Took a few shots through the office window with the 300mm on the SONY at ISO 2500 and 10 secs. It certainly appears but still in the soup, no detail and a bit of trailing. A wider feild might do better but would also pick up all the street lights just below, it's bad enough with all the LP at that dec. By the time it clears the tree and gets some altitude on it it's already dawn.
At least I can say I saw and I shot it
Have been waiting patiently this past week for a break in the clouds and at last we had our first cloud free patch to the South just after midnight last night. The nova was an easy naked eye sight under our dark skies. I enjoyed the 7X50 binocular view the best with a nice sprinkling of stars in the field of view.
So success at at last - I was getting worried that I would miss out altogether on logging this one.
Set the alarm for 3am and got a nice view from the southern Sydney suburbs this morning. Hello thermonuclear explosion! It was pretty easy with the naked eye, and comparison with stars in Musca and near Acrux put it at very approximately 3.9 or 4.0 to my fairly untrained eye. It appeared to me slightly brighter than the stars just south of Acrux (4.0 & 4.1), but definitely fainter than Gamma and Delta Muscae (3.6 & 3.8). It was tricky to estimate because the stars I used were higher than the nova, so my estimate may be quite well off. I didn't note any obvious colour. Also interesting for me is that it's not so far from the position of the first nova I ever saw - it's about 2 deg from the location of a much fainter Centaurus nova in 2012.
Nice binocular views of Jupiter just 1/4 deg from Delta Gem, and my first view of Mars for a while.
Got up at 3.30am and even though the sky was hazy I could still see the nova naked eye. I thought it would have faded a lot more by now. Look forward to following it over the next few days.
Also, observed the nova on Saturday at Crago through the 16-inch scope. I thought it had a distinct reddish-pink colour.
Got up at 3.30am and even though the sky was hazy I could still see the nova naked eye. I thought it would have faded a lot more by now. Look forward to following it over the next few days.
Also, observed the nova on Saturday at Crago through the 16-inch scope. I thought it had a distinct reddish-pink colour.
RichardJ
It's re brightened significantly. I took some photometry which I'll process later today, but my quick and dirty visual estimate was 3.8.
Visual Observation from suburban Brisbane: 
