UPDATE:Call for Proposals for 2025B released. (2025Apr09) UPDATE: LMI is back on-line as of Jan 30. (2025Jan31) UPDATE: DeVeny is back on-line as of Jan 14. (2025Jan14) UPDATE: The 2025A LDT Schedule has been released. (2024Dec06) UPDATE: Check your VPN settings before your next remote observations (2024May14)
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title | UPDATE: The LMI User Manual updated. (2023Sep27) |
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| The LMI User Manual has been updated. |
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title | UPDATE: The DeVeny Spectrograph User Manual has been updated. (2023Nov16) |
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| The new version (v1.8 – 16 November 2023) updates to the PypeIt instructions and introduces the LDT Observer Tools python package. It is available on the LDT Observer Information Confluence page. |
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title | UPDATE: NIHTS User Manual updated. (2021Apr26) |
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| An updated version of the NIHTS User Manual (v1.7) has been released and is available on the LDT confluence pages. Per the authors, NIHTS User Manual v1.7 includes a couple of revised figures from the NIHTS Commissioning paper. |
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title | UPDATE: LDT Observer Information Pages released. (2021Mar22) |
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| The new LDT Observer Information Pages were released, replacing the prior DCT Observer Information Pages. |
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title | UPDATE: LMI shutter delay. (2021Sep09) |
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| We have looked into quantifying the delay between when a user requests an image with LMI, and when the shutter actually opens. Details can be found in the write up under the LMI link about the shutter delay (last done 2021Sep). The bottom line is that: The exposure times are as recorded to within a few hundredths of a second, based on the star streaks. The shutter throw time in each direction is between roughly 0.1 and 0.2 seconds, meaning that there is also a temporal gradient across all the images. Formal uncertainty on the measured time offsets are an underestimate of the true variation. The shutter throw time alone means the mid-time varies across the frame systematically by at least 0.1second (added as the systematic uncertainty below). The shutter opens 2.05 +/- 0.06 (ran) +/- 0.1 (sys) seconds later than the UTCSTART in the image header. The shutter closes 0.19 +/- 0.06 (ran) +/- 0.1 (sys) seconds earlier than the UTCEND in the image header.
Exposure times should be computed as: Start time = UTCSTART + 2.05sec End time = UTCEND - 0.19sec Mid-time = UTCSTART + 2.05 + EXPTIME/2 or Mid-time = [(UTCSTART + 2.05) + (UTCEND-0.19)] / 2
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