J/AJ/161/237 Positions of Triton with Sheshan Station telescope (Zhang+, 2021)
New positions of Triton based on Gaia DR2 and new image-processing methods.
Zhang H.Y., Qiao R.C., Yu Y., Yan D., Tang K.
<Astron. J., 161, 237 (2021)>
=2021AJ....161..237Z 2021AJ....161..237Z
ADC_Keywords: Minor planets; Solar system; Positional data; Optical; Infrared
Keywords: Natural satellites (Solar system) ; Neptunian satellites
Abstract:
The large time span and precise observational data of natural
satellites is of great significance for updating their ephemerides and
studying their dynamic characteristics. With the help of the new
image-processing methods and the Gaia DR2 catalog, all CCD images of
Triton taken with the 1.56m telescope of Shanghai Astronomical
Observatory during 2005-2009 were reanalyzed. The median filtering
algorithm is used for image preprocessing to remove the influence of
the halo of Neptune, and an upgraded modified moment, called the
intensity-square-weighted centroiding method, is applied to determine
the centroids of the stars and Triton. A total of 2299 positions of
Triton were obtained, including 263 new observed positions and 2036
updated observed positions. Such five-year time span data with high
precision will be very helpful to improve the orbit parameters of
Triton.
Description:
During 2005-2009, mainly in August and September, when the opposition
of Neptune happened, the 1.56m telescope located in Sheshan Station of
Shanghai Astronomical Observatory (N31.096°, E121.184°, H97m,
IAU code:337; diameter=156cm, CCD=2112x2048pix, resolution=0.32",
bandpass 300-1100nm) was used to continuously observe Triton and
Neptune. Since our purpose is to get precise positions of Triton, to
obtain a good signal-to-noise ratio (S/N) of Triton, the exposure time
was set from 10 to 100s, while the images of Neptune are overexposed,
so we did not calculate the positions of Neptune. During the
observation, no filter was used. For all observations, a binning of 2
lowast 2 was used to increase the S/N of Triton and decrease the
readout time, so the spatial resolution of the single pixel of the
image is 0.64".
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 49 2299 Observed positions of Triton
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See also:
J/A+AS/120/107 : 1989-1994 CCD observations of Triton (Veiga+ 1996)
J/A+AS/131/291 : 1995-1997 CCD positions of Triton (Veiga+ 1998)
J/AJ/119/936 : Triton stellar occultation candidates (McDonald+, 2000)
J/A+A/425/1107 : Observations of Triton and Proteus (Vieira Martins+, 2004)
J/MNRAS/376/1707 : 1996-2006 observations of Triton (Qiao+, 2007)
J/A+A/617/L5 : Water delivery in Pluto & Triton atmospheres (Poppe+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 yr Obs.Y [2005/2009] Observation date, Year, UTC
6- 7 I2 "month" Obs.M Observation date, Month, UTC
9- 17 F9.6 d Obs.D Observation date, Day in Month, UTC
19- 20 I2 h RAh [21] Hour of Right Ascension (ICRS)
22- 23 I2 min RAm [11/49] Minute of Right Ascension (ICRS)
25- 31 F7.4 s RAs Second of Right Ascension (ICRS)
33- 33 A1 --- DE- [-] Sign of the Declination (ICRS)
34- 35 I2 deg DEd [13/16] Degree of Declination (ICRS)
37- 38 I2 arcmin DEm Arcminute of Declination (ICRS)
40- 45 F6.3 arcsec DEs Arcsecond of Declination (ICRS)
47- 49 I3 --- Site [337] IAU observatory code (1)
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Note (1): 1.56m telescope Sheshan Station of Shanghai Astronomical Observatory
North 31.096deg, East 121.184deg, Elevation 97m, IAU code:337.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 09-Aug-2021