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Lowell Discovery Telescope

(formerly the Discovery Channel Telescope)

[some fancy script-logo here, or something]Observer Information Pages

Warning
titleCOVID-19 Note:

For the duration of the COVID-19 outbreak, all observing at the LDT will be done remotely.  See Continuing in 2023B and 24A, limited in-person observing will be supported at LDT.  For those observing remotely, see LDT Remote Observing Notes.

Current Semester Observer and Telescope Operator Calendar

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Image courtesy: TJ. Ellsworth-Bowers Fernandez (Lowell)

Brief Overview:

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.

Lowell Observatory operates the LDT in partnership with Boston University, University of Maryland, Northern Arizona University, University of Toledo, and Yale University.  The telescope is scheduled by semester, with the current being 2020B2023B.

The current call for observing proposals is available linked in the sidebar at left for Lowell Observatory and Partner Institution members:  2021A LDT Call for Proposals

Instrumentation available on the LDT (all mounted to the cassegrain instrument cube):

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titleDeVeny (Optical Spectrograph)

Operational - Facility Instrument

Summary

Web Page:

Manual: DeVeny_Manual_v1.5_10July18.pdf

Additional Information: DeVeny_Ops_Appendix.tar

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titleDSSI / QWSSI (Optical Speckle Imager)

Operational - PI instrument

Summary

Web Page: the instrument page at Gemini-N is mostly applicable and very informative

Manual:

Additional Information: DSSI/QWSSI is available part time at LDT. For information, contact E. Horch or G. van Belle.

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titleEXPRES (Optical Spectrograph)

Operational - PI Instrument

Summary

Web Page: EXPRES web page

Manual:

Additional Information:

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titleLMI (Optical Imager)

Operational - Facility Instrument

Summary

Web Page:

Manual: LMI User Manual

Additional Information: LMI Exposure time calculator, LMI Filter Information, LMI shutter delay

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titleNIHTS (Near-infrared Spectrograph)

Operational - Facility Instrument

Summary

Web Page:

Manual: NIHTS User Manual (v. 1.4 - 20190130)

Additional Information: Overview of NIHTS (2018 Proc. SPIE 10702, 107023E)

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Facility Instruments:

LMI (Optical Imager)

DeVeny (Low- to Medium-Resolution Optical Spectrograph)

NIHTS (Near-infrared Low-Resolution Spectrograph)

Visitor / PI Instruments:

EXPRES (High-Resolution Optical Spectrograph)

QWSSI (Optical Speckle Imager)

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RIMAS (Near-infrared Spectrograph / Imager – Under Development)

Coming Soon

Summary

Web Page:

Manual:

Instrumentation Main Page

List of LDT Scientific and Technical Publications

Additional Information:

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Updates (and Old Updates)

UPDATE: The DeVeny spectrograph is back in operation. (2020Nov062024A LDT Call for Proposals has been released.  (2023Oct12)

UPDATE: The 2021A 2023B LDT Call for Proposals Schedule has been released.  (2020Oct092023Jun08)

UPDATE: NIHTS is again available for use.  (2020Oct08)

UPDATE: The GG495 blocking filter has been replaced in the DeVeny spectrograph.  (2020Oct02)

: The change over to the new confluence server https://confluence.lowell.edu has happened.  Please let us know if you run across problems with these pages. (2022Mar07)

UPDATE: DeVeny Image Quality Issue: See the DeVeny Instrument Page for more information.  (2021Nov15)

UPDATE: The new VPN platform is now required for connection to the Lowell network.  All remote observers MUST update their VPN settings: Watchguard SSLVPN Installation.  (2021Sep06UPDATE: The LMI User Manual has been updated to reflect modified focusing instructions and information about fringing when using the z' filter.  (2020Sep30)


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titleUPDATE: TCS The DeVeny Spectrograph User Manual has been updated, ephemeris tracking is again working.   (2020Feb192022May10)

The 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 (v1.7.1 – 10 May 2022) includes corrected confluence links and updates to the PypeIt instructions.  It is available on the LDT Observer Information Confluence page.

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titleUPDATE: NIHTS User Manual updated. (2019Jan302021Apr26)

An updated version of the NIHTS User Manual (v1.4 - 20190137) has been released and is available on the LDT Observer Information confluence pagepages.  Per the authors, NIHTS User Manual v1.4 adds 7 includes a description of blind target acquisition using LMIcouple of revised figures from the NIHTS Commissioning paper. 

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titleUPDATE: 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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titleUPDATE: The LMI User Manual updated.  (2020Dec20)

The LMI User Manual has been updated.

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titleUPDATE: 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:

  1. The exposure times are as recorded to within a few hundredths of a second, based on the star streaks.

  2. 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.

  3. 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).

  4. The shutter opens 2.05 +/- 0.06 (ran) +/- 0.1 (sys) seconds later than the UTCSTART in the image header.

  5. 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:

  1. Start time = UTCSTART + 2.05sec

  2. End time = UTCEND - 0.19sec

  3. Mid-time = UTCSTART + 2.05 + EXPTIME/2 or

  4. Mid-time = [(UTCSTART + 2.05) + (UTCEND-0.19)] / 2

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titleUPDATE: 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.

Facility Information:

Planning Your Observing Run:

At the Telescope: