1. Employment of AGIS for Nano-Jasmine
- Scope of study
Mission details
Disparity to Gaia
Investigation using AgisLab software package
Preliminary examination – Transits Projection
Revision of AgisLab for Nano-Jasmine
Standard Errors for Astrometric Parameters
Potential Convergence of Agis Solution for NJ

2. Mission Specifications – Nano-Jasmine
Pre-cursor to JASMINE (2020) and Small JASMINE (2015)
Japanese Astrometry Satellite Mission for Infrared Exploration
Respective accuracies: - Nano-Jasmine : 1mas, 5cm diam
- Small Jasmine : 10 u-arsec, 30cm diam
- JASMINE : 10 u-arcsec, > 80cm diam
Due for launch in July of 2010 (Gaia:2011)
JAXA, ISSL, University of Tokyo, University of Kyoto

3. Nano-Jasmine Satellite
Cubic in shape: 50 x 50 x 50 cm
Being launched on Cyclone-4 rocket
in Brazil (Alcantera)
Adopts the Ritchey-Chretien
optical system.
Telescope has a diameter of
5cm with a beam combiner
placed in front of the primary
mirror.
Observing in visible spectrum

4. Hipparcos vs Nano-Jasmine
Similar objectives to Hipparcos ( 1-2 mas)
- Nano-Jasmine : 1 mas
Measure annual parallaxes of bright stars (7
mag) with an accuracy >1mas after two years
of operation.

5. Disparity to Gaia
Orbit – Sun-synchronous (unlike Lissajous Orbit of Gaia)
Shorter mission length: 2 years
Basic angle of 99.5 degrees
One single telescope with two fields of view separated by basic angle created using a mirror system ; Ritchey-Chretien optics system
Hence, different geometry

6. Sun-synchronous Orbit
Orbital plane of the satellite rotates in inertial space with the angular velocity of the earth’s orbit around the sun.
Approx deg/day eastward to keep in sync with this orbit
Object allowed to be in a “fixed" position in space rather than an orbit in which its relative position changes continuously.

7. Ritchey-Chretien Optical System

8. Ritchey-Chretien Optical System
Telescope has a diameter of 5 cm with a beam combiner placed in front of the primary mirror. Focal length of 167cm
Reflecting optics and three flat mirrors (the light path after the 2nd mirror is folded by the plane mirrors).
The telescope also has a beam combiner for global field astrometry whose basic angle is 99.5º, so that the apparent relative distribution of stars can be resolved into a satellite's motion and an actual distribution of stars.
Deformation of optical components - Structure and optics = same material.
All mirrors and their structural supports: aluminum alloys using ultra-precise machinery and tools.

9. Flexibility of AgisLab
Creation of a GPDB equivalent for Nano-Jasmine
Extraction of Gaia-specific elements
Implementations for both missions for Orbit, Geometry and Attitude
Ability to preferentially select mission properties-files

10. Number of transits image for N-J and Gaia
Nano-Jasmine: One single CCD
Average value output :
Gaia : 106-CCD array with SMs and Photometers
Average value: 88 (*9 = 792)

11. Desired Accuracies
Levels of accuracies as outlined in the mission specification document:
Position: Alpha: <= 10 milli-arcsecond
Delta: <= 10 milli-arcseconds
Proper Motion: Alpha_Star: <= 4 milli-arcseconds per year
Delta_Star: <= 4 milli-arcseconds per year
Parallax: <= 10 milli-arseconds

12. Error Plots for Astrometric Parameters}
Position: Alpha (α0) and Delta(δ0)
Parallax (π0)
Units:
Position and Parallax: μ-arcsec
Proper Motion: μ-arcsec/day
Proper Motion: Mu_alpha (μα) and Mu_delta (μδ)

13. Values calculated from the graphs:
Position : alpha m-arcsec
: delta m-arcsec
Parallax : m-arcsec
Proper Motion : mu_Alpha u-arcsec/day
: mu_Delta u-arcsec/day
Latter results for proper motion are given in unit of u-arcsec/day.
Simple conversion calculation gives an average value of ~ m-arcsec per year - in accordance with the desired value of <= 4 m-arcsec per year.

14. Source-Attitude Update Results
Convergence Plot
- Update settings:
100 iterations
100,000 sources generated – full mission solution
True observations (no noise)

16. Source-Attitude Update Results
Convergence Plot
Update settings:
100 iterations
100,000 sources generated – full mission solution
Noisy observations

18. Agis for JASMINE itself (Small-Jasmine too?)
Same mission duration
CCD-array similar (14 x 7) , Gaia (13x7 roughly)
Parallaxes, positions with accuracy of 10 u-arcsec
Proper motions with the accuracy of 10 u-arcsec/year
For stars brighter than z » 14 mag
JASMINE: Infrared, GAIA: Visible
Focal length 50m (Gaia:35m)
Observe about one hundred million stars belonging to the disc and bulge component of our Galaxy, which are hidden by the interstellar dust extinction in optical bands (Perhaps in Gaia)
Both in Lissajous Orbit

19. Error Comparison Maps Median values for the ICRS in AGIS plots
Comparisons between different stages of the Iterative Solution
Based on noisy solutions – both AL and AC directions

20. Comparison of Standard Error plots estimates with Final Converged Solution plot
The orange regions of the estimate plot (error 3.2E3) – match the green regions in final iteration map (4.0E3)
Green regions of the estimate plot (1E3 – 1.7E3) – consistent with corresponding values of 5E2 to 2E3 exhibited in the iteration map.
Highly satisfactory result. Can also be performed for other astrometric parameters

21. Next Stages
Establish an equivalent to the IDT and First-Look as part of the wider tessellation scheme adopted for the JAXA mission

22. Thank you
Questions?