Archive for the ‘VStar’ Category

TCP J18102829-2729590’s undulations

October 29, 2016

My visual estimate of nova TCP J18102829-2729590 last night was magnitude 8.0 using my trusty Meade LX-90 at 82x magnification. In my light-polluted corner of suburban Adelaide, 7×50 binoculars just aren’t good enough for this.

The third observation from right, three days ago, showed an apparent rapid increase in brightness. For me, one of the attractions of novae is their less than predictable nature.

Looking at the light curve today, my observations look a bit like (purple) buoys bobbing up and down on the surface of an undulating ocean.

tcp-j18102829-2729590-lc-oct-29

Maybe I’m spending too much time looking at novae at the moment. My wife would probably agree with you, even though she’s very understanding. 🙂

ASASSN-16ma = PNV J18205200-282210

October 29, 2016

ASASSN-16ma, the nova candidate in Sagittarius, has been designated PNV J18205200-282210 by IAU CBAT as per today’s AAVSO alert notice.

I made another visual estimate of the nova again last night at magnitude 10.3.

asassn-16ktlcsep29

Two novae in Sagittarius!

October 28, 2016

Since my last post I’ve made two more observations of TCP J18102829-2729590, on Oct 26 and 27. Mine are the larger purple data points. Fraser Farrell pointed out a nice recent Sky & Telescope News article about this nova.

tcp-j18102829-2729590-lc-oct-28

Another nova was discovered in Sagittarius on Oct 26: ASASSN-16ma. There are only a few observations of this one so far. Mine is at top right under the cross hairs.

asassn-16ktlcsep28

ASASSN-16ma is currently three magnitudes fainter than TCP J18102829-2729590, but the latter arrived on the scene first, after all.

The weather looks good for tonight and tomorrow so I hope to get some more observations in over the weekend.

Nova TCP J18102829-2729590 still on the rise

October 24, 2016

tcp-j18102829-2729590-lc-oct-25

Nova TCP J18102829-2729590 in Sagittarius is still on the rise although not at the same rate as a day or so ago. Early days though: these things are unpredictable.

The official AAVSO alert notice was posted overnight: https://www.aavso.org/aavso-alert-notice-560

I have ongoing alignment problems with my LX-90 8″ scope (16 years old) and they caused me enough grief last night that I couldn’t make a visual estimate before the nova was below my fence line. I’ll try again in the next day or two.

Nova in Sagittarius

October 23, 2016

Not far from one of my favourite Cepheid variables (W Sagittarii), a nova in Sagittarius was discovered 3 days ago (TCP J18102829-2729590) by Koichi Itagaki of Japan. It has risen from magnitude 11 to 8 in that time.

The plot below shows the 10 visual and Johnson V observations submitted so far to the AAVSO International Database:

tcp-j18102829-2729590-oct-23-lc

Two thirds of the visual observations are from Andrew Pearce in Western Australia. My single observation so far, made tonight, is under the cross hairs at upper right, with Andrew close on my heels. It’s always reassuring when two observations made close in time (less than an hour in this case) by different observers agree, within the limits of precision of the chosen method (visual estimation: approximately one tenth of a magnitude).

Many of my visual estimates of variable stars are made with 7×50 binoculars. Tonight I used my Meade LX-90 8″ telescope (magnification of 82x) because the nova is still too faint for my binoculars. There’s a beautiful asterism near the nova that makes the field hard to miss and makes for an enjoyable observation.

x16826ks

Last night I took images of the nova with the intention of carrying out wide field DSLR photometry, however there’s a star quite close to the nova. When combined with the amount of defocus normally used for DSLR photometry, separating the light from the two stars becomes impractical. So, I haven’t submitted an observation (untransformed) from that imaging run.

I’ll follow this object visually with interest for as long as the weather and my equipment allow.

Nova Lupi 2016 update

October 5, 2016

The nova in Lupus (ASASSN-16kt) continues to decline, having peaked at a visual magnitude of 5.6, declining to 6.5 in less than a day.

The plot shows my two binocular observations before the weather in Adelaide went loopy (as opposed to Lupi), the last under cross-hairs at magnitude of 7.2. It’s now down to around magnitude 9.0.

asassn-16ktlcoct05

The sky is clear tonight, and may be okay for a couple more days, so I might attempt some tri-colour DSLR observations. Tonight’s out due to an ASSA meeting. Typical! 🙂

ASASSN-16kt update

September 28, 2016

I made a second observation of the nova in Lupus last night (Sep 27). It had faded from a visual magnitude of 6.7 on Monday to 7.2 (both in purple below). Observations since then show a further brightness decline.

asassn-16ktlcsep28

I was pleased to see my first observation counted among those submitted by Elizabeth Waagen (AAVSO) for inclusion in “telegram 4322” from the the Central Bureau for Astronomical Telegrams in Harvard (my first). See the AAVSO alert from Elizabeth for more details.

There was no chance of another observation tonight after the storm here in Adelaide today; no power so no light pollution but no clear sky either. I’d say another day or two will go by before I can observe it again.

DSLR photometry of BL Tel

August 28, 2015

 

 

Today I submitted an August 22 DSLR observation of the long period eclipsing variable BL Tel to the AAVSO international database.

My observation (9.124  (0.031) V), is shown under the cross-hairs in the images: Visual and Johnson V together and V alone.

BLTel-2015-08-22-BDJB-V-Vis

BLTel-2015-08-22-BDJB-V

Minimum should be happening around about now (~Aug 27).

I have images from Aug 25 that I’ll process this weekend. The conditions were less than ideal, but I managed to get some data before the clouds became a persistent problem.

I hope to take some more images this weekend.

Thanks to Peter Williams for prompting me to consider making observations of BL Tel which is nicely positioned high in the evening night sky now.

Another Nova Sgr 2015 No. 2 update

March 30, 2015

I’ve made 10 observations of the nova since March 19, mostly visual, 3 DSLR, one of which has yet to be processed.

The (rather noisy) light curve is starting to show the kind of early oscillations that seem to be common in novae and certainly the last two bright novae I’ve seen. The red fit “line” helps to make this more obvious.

LC-and-20-degree-polyfit-2015-03-31

The cross-hairs are over my most recent observation early this morning.

Nova Sgr 2015 No. 2 update

March 25, 2015

I made visual and DSLR photometric observations of the nova on March 21 and 22. The image below shows the nova before sunrise on March 22.

NovaSgr2015_2_Mar22-arrowed

The light curve shows my most recent submission under the cross hairs.

LC-2015-03-25

 

It appears that the nova has peaked but these objects are unpredictable so we may see some fluctuations yet. The local weather has made observations difficult for the last 3 days.