The Apache Point Observatory Lunar Laser-ranging Operation: Instrument Description and First Detections

Murphy, T. W.; Adelberger, E. G.; Battat, J. B. R.; Carey, LN; Hoyle, C. D.; LeBlanc, Philip N.; Michelsen, Eric L.; Nordtvedt, Kenneth; Orin, A. E.; Strasburg, Jana D.; Stubbs, C. W.; Swanson, H. E.; Williams, Earl L.

doi:10.1086/526428

Cited by 110 publications

(103 citation statements)

References 23 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…. However, thermal regulatory measures may be necessary (this will be done through a microprocessor controlled venting system) to ensure these variations are equalized and kept to a minimum as much as possible i.e., \1°C (Murphy et al 2008) to allow excellent telescope pointing, thereby increasing the chance of being on-target with the retroreflectors located on the lunar surface.…”

Section: Analysis Of Thermal Variationsmentioning

confidence: 99%

“…The ultimate objective, which is beyond the scope of this paper, is to develop a dynamic thermal model that can mitigate the thermal variations on the entire telescope to B1°C and subsequently, feed these corrections into a telescope pointing model (currently under development in HartRAO) to counteract resulting pointing offsets. With regards to optimal thermal modelling of a telescope, it is worth mentioning that a major challenge is to develop solution strategies that can mitigate and stringently regulate the thermal variations to *1°C (Murphy et al 2008). …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal analysis of the LLR optical telescope tube assembly based in Hartebeesthoek Radio Astronomy Observatory

et al. 2015

View full text Add to dashboard Cite

The Hartebeesthoek Radio Astronomy Observatory of South Africa is currently developing a lunar laser ranger (LLR) system based on a one metre aperture telescope in collaboration with National Aeronautics and Space Administration and the Observatoire de la Côte d'Azur. This LLR will be an addition to a limited list of operating LLR stations globally and it is expected to achieve sub-centimetre range precision to the Moon. Key to this expectation including the overall telescope operational performance is thermal analysis of the telescope structure, based on the thermal properties of component materials and their interaction with the environment through conventional heat transfer mechanisms. This paper presents transient thermal simulation results of the telescope's optical tube and one metre primary mirror in terms of thermal variations and consequent structural deformations. The results indicate that on a non-windy, cloud-free and winter day, the temperature gradients on the structure could be within 1°C with respect to the temporal ambient air temperatures at the site when these are between 9 and 23°C. Furthermore, these gradients were coupled with thermally-induced total deformations that vary between 2.9 and 40.7 lm of the assembled telescope components. In overall, these findings suggest that both the tube and especially the mirror may respond very slowly to ambient temperatures; however, correcting for structural thermal variations is imperative in maximizing the pointing accuracy of the telescope thereby increasing the chance being on-target with the retroreflectors located on the Moon surface.

show abstract

Section: Analysis Of Thermal Variationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal analysis of the LLR optical telescope tube assembly based in Hartebeesthoek Radio Astronomy Observatory

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The ARC 3.5-m telescope is used for APOLLO, the APO Lunar Laser-ranging Operation (Murphy et al 2008), so it routinely tracks specific locations on the Moon. We specified our target locations in selenographic coordinates and slewed to a recognizable crater near the LCROSS target area using additional tracking velocities so that the telescope would track at the lunar (non-sidereal) rate, then used offsets to optimize the pointing.…”

Section: Pointing and Trackingmentioning

confidence: 99%

LCROSS (Lunar Crater Observation and Sensing Satellite) Observation Campaign: Strategies, Implementation, and Lessons Learned

et al. 2011

View full text Add to dashboard Cite

a permanently shadowed region of the lunar surface to create an ejecta plume. The resultant impact crater and plume were then observed by the LCROSS Shepherding Spacecraft as well as a cadre of telescopes on the Earth and in space to determine the nature of the materials contained within the permanently shadowed region. The Shepherding Spacecraft then became a second impactor which was also observed by multiple assets.The LCROSS Observation Campaign was a key component of the LCROSS mission. The goal of the Observation Campaign was to realize the scientific benefits of extending the LCROSS observations to multiple ground and space-based assets.This paper describes the LCROSS Observation Campaign and provides an overview of the Campaign coordination and logistics as well as a summary of the observation techniques utilized at a multitude of observatories. Lessons learned from the LCROSS Observation Campaign are also discussed to assist with the planning of future unique observing events.

show abstract

“…The findings were consistent with general relativity to 1 in 10 4 as well as determining the recession of the Moon from Earth by 3.8 cm yr -1 (Gefter, 2005). An improvement to 1 mm accuracy between the Earth and the Moon has been achieved by the 3.5 m arrangement at Apache Point Observatory in New Mexico (Murphy et al, 2008). This requires a 3.3 x 10 -12 s exactitude in the one way trip or 6.7x 10 -12 s both ways.…”

mentioning

confidence: 99%

Recent astronomical tests of general relativity

Treschman¹

2015

Int. J. Phys. Sci.

View full text Add to dashboard Cite

The Apache Point Observatory Lunar Laser-ranging Operation: Instrument Description and First Detections

Cited by 110 publications

References 23 publications

Thermal analysis of the LLR optical telescope tube assembly based in Hartebeesthoek Radio Astronomy Observatory

Thermal analysis of the LLR optical telescope tube assembly based in Hartebeesthoek Radio Astronomy Observatory

LCROSS (Lunar Crater Observation and Sensing Satellite) Observation Campaign: Strategies, Implementation, and Lessons Learned

Recent astronomical tests of general relativity

Contact Info

Product

Resources

About