The document summarizes the scientific results from the Lunar Ultraviolet Telescope (LUT) onboard the Chang'e-3 lunar lander. It discusses the LUT instrument specifications and performance on the Moon, including its ability to point accurately and achieve magnitudes of 13.5-15.5. Scientific results included a bright source catalog from lunar sky surveys, monitoring of variable stars that are difficult from Earth, and placing the lowest upper limit on OH concentration in the lunar exosphere. The LUT was able to identify a rapidly mass-transferring binary star system and observe an Algol-type eclipsing binary.

1. Lunar Astronomy with the LUT on Chang’e-3
lander
National Astronomical Observatories, CAS/
Guangxi University
J. Wang on behalf of LUT group
Beijing
2018/12/07

2. Contents
 Lunar-based Ultraviolet Telescope
 Performance on the Moon
 Scientific results

3. The dreams to observe the Universe on the Moon
Far UV camera
with Appolo 16

4.  Lunar-based Ultraviolet Telescope (LUT, Cao+11)
 A small, but automatic, telescope aboard CE-3 working in NUV.
The FIRST automatic telescope landed on the extraterrestrial body in
mankind history.
 Scientific Objectives
– Monitoring variable stars
 Pulsating or binary stars, e.g., RR Lyr variables
 Variable stars in clusters
 Activities of solar-like stars
– Survey the sky
 Especially survey the low galactic latitude region;
 Violent flare stars
Lunar-based Ultraviolet Telescope I

5.  Milestones
– July 2004: Proposal Conception
– Feb. 2009: Project Approval
– Sep. 2009: Engineering Model
– Dec. 2011: Flight Model
– Dec. 02. 2013: Launch
– Dec. 16. 2013: First Light
– Jan. 2014 -- : Observations
– The FIRST automatic telescope on the
Moon for mankind.
LUT
First image
RA. 16:45:00
Dec 50:26:00
(Draco)
Lunar-based Ultraviolet Telescope II

6. Lunar Enterprise Daily,2015/01/01

7. A supporting system for LUT scientific obs
Exp vs S/N
Ins. setup
Finding chart & catalog
Obs sequence head
Obs sequence：
Time slot
Position of Gimbal
Rotation step
Target & comp coordinate

8.  Instrument Specifications
 Comp: Telescope+Pointing Reflector
Item Value
Diameter 150mm
Focal Length 562.5mm
Wavelength 245—340 nm
Field of view 1.36  1.36 Square Degrees
CCD camera E2V 47-20 UV enhanced
Working time lunar day time
Life time > one year
Weight 13.6 kg
Lunar-based Ultraviolet Telescope III

9. Performance on the Moon I
Sky Coverage: inside the red
circle Pointing calibration
Allow the telescope to point to any target &
trace smoothly
 Flux calibration
– ~13.5 mag in lunar day time
– ~15.5 mag with dark sky
4 images combined (dark
sky)

10. Data Processing
 Almost following the standard processing of
astronomical CCD photometry;
 Bias & dark corrections;
 Scattering light subtraction;
 Aperture photometry;
 Astrometry calibrations
 Flux calibrations with standard photometry stars;
 Pipelines have been developed with using the popular
astronomy software package, IRAF & Python.
Performance on the Moon V

11. Scattering light subtraction
 Dedicated pipelines were developed to subtract
the scattering light.
The scattering light imageCCD image
Subtracted image

12. Scientific results I
 Sky Survey in NUV
– Bright sources catalog (Meng+2016)
– 86 467 stars down to 16mag

13. Scientific results II
 Monitor of various variable stars hard to be done on ground
Identification of rapidly mass-transferring binary stars in a 6-
stars system!
AI Dra: Algol-type eclipsing binary
with P=1.1988 days.

14. Scientific results III
 The lowest upper limit on OH concentration in lunar
exosphere
Method Surface
concentration（cm-3)
HST spectroscopy <106(5σ)
Apollo12/14/15 CCGEs <107
Chandrayaan/CHACE <2 ×109
LUT background emission <4 ×104
Chandrayann-I M3 3μm OH absorption distrib

15. The End
Thanks