Page History

This page gives a general overview for visitors and staff

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Updates (and Old Updates)

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title	UPDATE: Ephemeris based pointing and tracking is not currently functional. (2020Jan02)

Ephemeris based pointing and tracking is not currently functional. The cause is understood and it will be fixed with the next release of the telescope control system. Until that happens, we recommend observers who need non-sidereal tracking prepare target lists that include both positions and offset tracking rates, and if the object(s) move quickly enough, consider multiple entries per night. JPL's Horizons and the MPC ephemeris service can provide the necessary rate information. (2020Jan02)

UPDATE: The 2020A staffing schedule for January through March is up. All remote requests for that period are covered. (2019Dec26)

UPDATE: The 2020A schedule has been finalized and released. (2019Dec02)

UPDATE: Winter has set in. DCT has already seen its first large storm. Be prepared for winter conditions.(2019Dec02)

UPDATE: A correction to the correction. The DeVeny grating DV2 is actually blazed at 4000A, not 5000A. This was a long standing mistake here. The grating has been identified as a copy of KPNO #09, which is 300g/mm, 4000A blaze. (2019Sep18)

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title	UPDATE: NIHTS User Manual updated (2019Jan30)

An updated version of the NIHTS User Manual (v1.4 - 2019013) has been released and is available on the DCT confluence pages. Per the authors, NIHTS User Manual v1.4 adds a description of blind target acquisition using LMI.

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title	UPDATE: LMI shutter delay. (2018Dec05)

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. 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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title	UPDATE: DeVeny User Manual updated v1.5 (2018July11)

The DeVeny Spectrograph Reference and Operations Guide has been updated for the new release of the slitviewing camera GUI application. Version v1.5 (10 July 2018) of the manual is now available on the Observing at DCT confluence page.