Champlane Observation: CTIO 4m/MosaicII June 22-23, 2009

ChaMPlane Observation with CTIO 1m (YALO) Y4KCam

June 9-12, 2011

I. Target

The target is a new candidate qLMXB found in the J1655 field of the ChaMPlane survey. It resembles the black-hole X-ray binary GRO J1655-40, with a subgiant secondary and orbital period of 2.62 days
Object     Type     RA (J2000)   Dec (J2000) nH/10^22  Dist    Mv     R     log(F_X/F_R) log(L_X)
New qLMXB  G4-6IV   16:54:08.14  -39:56:36.1  0.4(1)  2.2kpc  ~3.0  16.19(2)  -2.7(5)    31.0(7) 
J1655-40   F5IV     16:54:00.14  -39:50:44.9  0.6(1)  2.8kpc  ~1.2  16.14(1)  -2.9(4)    30.9(7) 
Teleascope Pointing 16:54:04.14  -39:53:40.6
The Y4KCam is a 4Kx4K CCD camera with 20'x20' field of view. The CCD has excellent blue sensitivity, especially at U-band. The resolution is 0.289"/pixel.

The New qLMXB candidate and J1655-40 are only 6' apart. Use the above telescope pointing to cover both objects.

Here are the founding charts: New qLMXB. 2.5'x2.5' N-up. E-left.

New qLMXB and J1655-40. 9'x9' N-up. E-left.

II. Exposure Sequence

Use SDSS u,g,r,i,z to take light curves continuously. 3-5min exposures. Take a few B, V, Rc, Ic images for reference. No need to take photometric standard, as J1655-40 are well calibrated.

CTIO Yale 1-m Telescope Y4KCam Filter Transmissions

III. Observation Plan

The astronomical twilight on June 9-12, 2011 ends at 19:16 and begin at 6:10 local time. There are 10h56m from evening to morning twilight. Try to start 10-15 min before and to end 10-15 after the astronomical twilight zone to get a little more observing time.

Here is an observing elevation chart.

postscript CTIO 2011 june Ephemeris Back to Top

IV. Biases, Flats etc.

1. Biases and Domeflats

Use command "zero" to take 15 biases, and use command "doobs" to take 7 domeflats each (V R I & Ha) in sequence, in each afternoon before observing. Dark is not necessary.

2. Skyflats

Take some skyflats in the evening or morning twilight if possible. I filter skyflats are probably the most needed in order to correct the fringes. Ideally, dark skyflats made from object fields (or blank skys) are the best. But there are too many stars in the Galactic plane which makes this impossible (and we don't have time to spend on taking blank skys). So we need to take some twilight skyflats. Timing is very crucial for this. Here are some simple steps for doing evening twilight skyflats:

3. Pointing and Focus:

V. References

The quiescent light curve and the evolutionary state of GRO J1655-40

The quiescence optical light curve of Nova Scorpii 1994 (=GRO J1655-40)

The black hole transient Nova Scorpii 1994 (=GRO J1655-40): orbital ephemeris and optical light curve

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Ping Zhao: