01315+1521 BU  506 (Eta Psc)

Coord 2000	01315+1521		Discov num	BU  506		Comp			Coord arcsec 2000	01 31 28.99 +15 20 45.0
Date first	1878		Date last	2008		Obs	28
Pa first	13		Pa last	62		P.A. Now (θ)	72.8°
Sep first	1.0		Sep last	0.6		Sep. Now (ρ)	0.47"
Mag pri	3.83		Mag sec	7.51		delta mag (ΔM)	3.68		Spectral class	G8III (yellow)
Pri motion ra	+028		Sec motion ra
Pri motion dec	-006		Sec motion dec
Notes	N O (See Notes, Orbital solution)

This double is physical.

Precise pa	61.8		Precise sep	0.61		Name	Eta Psc		Constellation	Pisces
SAO	92484		HIP	7097		Tycho2	1198-01597-1		HD	9270
HR	437		GC	1839		ADS	1199		BD	BD+14 231
Bayer	Eta Piscium		Bayer name	Eta Psc		Flamsteed	99 Piscium		Flamsteed name	99 Psc
Distance	107.18		Distance ly	349.62		last precise pa	61.8		last precise sep	0.61

Period (P)	850.5y	± 66.5	Periastron (T)	2040.3y	± 66.9	Semi-major axis (a)	1.228a	± 0.144
Eccentricity (e)	0.469	± 0.053	Inclination (i)	58.5°	± 2.5	Longitude of periastron (ω)	86.9°	± 4
Node (Ω)	32.8°	± 2	Note			Grade	5	(1=Definitive, 9=Indet.)
Equinox	2000		Last observation	2000

label rho theta 2000 0.626 54.7 2001 0.618 55.5 2002 0.609 56.3 2003 0.600 57.1 2004 0.591 57.9 2005 0.582 58.8 2006 0.574 59.7 2007 0.565 60.6 2008 0.556 61.5 2009 0.547 62.5 2010 0.538 63.5 2011 0.529 64.5 2012 0.520 65.6 2013 0.512 66.7 2014 0.503 67.8 2015 0.494 69.0 2016 0.485 70.2 2017 0.477 71.5 2018 0.468 72.8 2019 0.460 74.2 2020 0.452 75.6 2021 0.443 77.1 2022 0.435 78.6 2023 0.428 80.2 2024 0.420 81.8 2025 0.413 83.5 2026 0.405 85.3 2027 0.399 87.1 2028 0.392 89.0 2029 0.386 91.0 2030 0.380 93.0 Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st.
		Measures: green=micrometric, blue=interferometric, purple=photographic

coord_2000	discov_num	comp	epoch	obs	pa	sep	mag_pri	mag_sec	spectr	notes	coord_arcsec_2000
01315+1521	BU 506		2000	26	54	0.6	3.83	7.51	G8III	NOD	013128.99+152045.0
01315+1521	BU 506		2008	27	62	0.6	3.83	7.51	G8III	NOD	013128.99+152045.0

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