by **Asterix** » 16 Jun 2019, 00:00

"I'm not aware of anybody is using sidereal time. Maybe in 1867. Now it is UTC or Julian" Sorry, Han, but that is how these historical observations are documented.

Before closing down here also the other one.

Thanks and regards,

Marcel

Can you notice why the following case seems to produce a less accurate result?

Reference: #316

Loc."E" Lat N: 59.77263889

Loc."E" Lon E: 30.33027778

Star catalogue:

HIP: 72105

RA(J2000): 221.2467394

Dec(J2000): 27.07422497

PM_RA [mas/yr] -50.95

PM_Dec [mas/yr] -21.07

Observation Date/Time:

Date: 1868.02.05

LAST Hr: 05:38:48.7 (observed time)

Calculation with corresponding UT1

Time UT1: 18.611627558

dCyJ2000: -1.3190068305 centuries from J2000

after applying proper motion:

RA(date): 221.24883589

Dec(date): 27.073452985

Precession Matrix T0->T:

T0: 0

T: -1.3190068305 centuries from J2000

A[1,1]: 0.99948322253

A[1,2]: 0.029478403824

A[1,3]: 0.01281840786

A[2,1]: -0.029478404373

A[2,2]: 0.99956539955

A[2,3]: 0.00018893908104

A[3,1]: -0.012818406597

A[3,2]: -0.00018902476874

A[3,3]: 0.99991782298

after Nutation:

A[1,1]: 0.99948234635

A[1,2]: 0.029503395975

A[1,3]: 0.012829252162

A[2,1]: -0.029503927087

A[2,2]: 0.99956465462

A[2,3]: -0.00014787204991

A[3,1]: -0.012828030768

A[3,2]: -0.00023071757616

A[3,3]: 0.99991769173

RA, Dec -> Cartesian:

X: -0.66946797007

Y: -0.58708358979

Z: 0.45513239354

multiplying with Precession/Nutation-Matrix and

adding Aberration:

VX: -7.0032342811e-05

VY: -6.4720410462e-05

VZ: -2.8031318128e-05

results in Cartesian:

X: -0.68067340125

Y: -0.56720809325

Z: 0.46379030728

and converting back to

Polar:

RA: 219.8045904

Dec: 27.629820296

and converting further to

Horizon:

Htrue: 4.8620883086

"I'm not aware of anybody is using sidereal time. Maybe in 1867. Now it is UTC or Julian" Sorry, Han, but that is how these historical observations are documented.

Before closing down here also the other one.

Thanks and regards,

Marcel

Can you notice why the following case seems to produce a less accurate result?

Reference: #316

Loc."E" Lat N: 59.77263889

Loc."E" Lon E: 30.33027778

Star catalogue:

HIP: 72105

RA(J2000): 221.2467394

Dec(J2000): 27.07422497

PM_RA [mas/yr] -50.95

PM_Dec [mas/yr] -21.07

Observation Date/Time:

Date: 1868.02.05

LAST Hr: 05:38:48.7 (observed time)

Calculation with corresponding UT1

Time UT1: 18.611627558

dCyJ2000: -1.3190068305 centuries from J2000

after applying proper motion:

RA(date): 221.24883589

Dec(date): 27.073452985

Precession Matrix T0->T:

T0: 0

T: -1.3190068305 centuries from J2000

A[1,1]: 0.99948322253

A[1,2]: 0.029478403824

A[1,3]: 0.01281840786

A[2,1]: -0.029478404373

A[2,2]: 0.99956539955

A[2,3]: 0.00018893908104

A[3,1]: -0.012818406597

A[3,2]: -0.00018902476874

A[3,3]: 0.99991782298

after Nutation:

A[1,1]: 0.99948234635

A[1,2]: 0.029503395975

A[1,3]: 0.012829252162

A[2,1]: -0.029503927087

A[2,2]: 0.99956465462

A[2,3]: -0.00014787204991

A[3,1]: -0.012828030768

A[3,2]: -0.00023071757616

A[3,3]: 0.99991769173

RA, Dec -> Cartesian:

X: -0.66946797007

Y: -0.58708358979

Z: 0.45513239354

multiplying with Precession/Nutation-Matrix and

adding Aberration:

VX: -7.0032342811e-05

VY: -6.4720410462e-05

VZ: -2.8031318128e-05

results in Cartesian:

X: -0.68067340125

Y: -0.56720809325

Z: 0.46379030728

and converting back to

Polar:

RA: 219.8045904

Dec: 27.629820296

and converting further to

Horizon:

Htrue: 4.8620883086