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(Formerly the Discovery Channel Telescope)

[Some cool tagline or motto of the LDT... need to ask Marketing to come up with something?]

Warning

title	COVID-19 Note:

Continuing in 2024A, limited in-person observing will be supported at LDT. For those observing remotely, see LDT Remote Observing Notes.

Partner Institutions:

SectionQuick Links: LDT Science Observing Schedule LDT Remote Observing NotesLDT Staff Current Call for Proposals (2021A)

Warning

COVID-19 Note:

For the duration of the COVID-19 outbreak, all observing at the LDT will be done remotely

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Current Semester Observer and Telescope Operator Calendar

Facility Overview

List of LDT Scientific and Technical Publications

The 4.3-m Lowell Discovery Telescope (LDT) is Lowell Observatory's flagship facility at a dark-sky site approximately 40 miles southeast of Flagstaff on the Coconino National Forest. The telescope is classically scheduled by semester, with the current being 2024A. See the current call for observing proposals for Lowell Observatory and Partner Institution members.

The facility was constructed as the Discovery Channel Telescope, and was renamed in 2019 in cooperation with Discovery Communications.

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NIHTS is again available for use. We have been monitoring a consistent shift in the detector position over the course of a couple years whereby the slit location has moved toward the bottom of the detector. If you notice anything untoward with the detector during use, contact LIG. (2020Oct08The GG495 blocking filter has been replaced in the DeVeny spectrograph. (2020Oct02

UPDATE: LDT resumed 7 night per week operations the week of June 22, 2020. We plan to continue full operations during semester 2020B, assuming things go smoothly. (2020Jun25)

LMI User Manual has been updated to reflect modified focusing instructions and information about fringing when using the z' filter. (2020Sep30) TCS , ephemeris tracking is again working2020Feb19 telescope control system (TCS) has been updated, and several issues fixed. One item of particular note to observers is that ephemeris based pointing and tracking is now functioning again. If you plan to use an ephemeris, please be in touch with staff ahead of your run to ensure that things work as expected. The ephemeris file format has changed slightly. For ephemerides extracted through the TCS, there shouldn't be an issue; if you generate your own ephemeris file, then you will need to make sure it conforms to the revised format. (2020Feb19)

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. (

2019Jan304 - 2019013 Observer Information page4 adds description of blind target acquisition using LMI

couple of revised figures from the NIHTS Commissioning paper.

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title	UPDATE: LDT Observer Information Pages released. (2021Mar22)

The new LDT Observer Information Pages were released, replacing the prior DCT Observer Information Pages.

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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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Facility Information:

title	UPDATE: DeVeny User Manual updated v1.5 (2018Jul11)

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 LDT Observer Information confluence page.