(privileges may be required)
(privileges may be required)
Note: As of June 2018, we are using a new remote observing procedure. Details can be found here: http://www.chara.gsu.edu/observers/remote-observing and a full description of the remote observing system can be found here: http://chara.gsu.edu/files/chara_technical_reports/tr102.pdf
This guide is intended to focus specifically on remote observing. Please note that the new remote observing procedures for 2017 eliminate operating of telescopes by remote observers. This page will still explain remote operations, but understand you may not be able to do these procedures. A comprehensive overview of CHARA operations can be found here:
CHARA Operating Procedures
Remote Observing Protocol
The current CHARA protocol is that if Remote Observation time is allocated, the Remote Observer should be familiar with Array operations, preferably after having observed in person at the Array before. It is best if remote observers are acquainted with the software manuals and procedures and have reviewed the latest versions of these documents. Also desired for ﬁrst time observers is a visit to Mount Wilson for an accompanying observing run at the CHARA Array to learn observing techniques ﬁrst-hand. It is hard to understand the flow of observing if you have not seen it in person.
As a rule, the observing specialist will handle all the preparations through slewing, acquiring the target, initializing the scopes, and perfoming beacon alignments and sky flats. All slewing of scopes will be done at the CHARA Control Room. Experienced observers who are present at CHARA may be allowed to slew the telescopes when multiple programs are run. Remote observers will no longer slew the telescopes. All remote observers will be limited to operating beam combiners and collecting data.
Modes of Operation
Since several beam combiners can run simultaneously at CHARA, it is important that the remote observers follow the observing procedures correctly and maintain good communication with the Array Operator (or Observing Specialist). The Array Operator will determine the priority and order in which to address problems that arise. Sometimes the Array Operator may be quite busy. If a serious situation occurs with the OPLE carts or the Telescopes, this will require immediate attention and notiﬁcation on Skype. If there is no response from Skype place a phone call to the CHARA Array Control Room.
Please send your configuration request to mailto:email@example.com at least two days prior to the beginning of your scheduled observing time with the following information:
Understand that this email is used to align the lab, set the configuration and get you on sky as efficiently as possible.
It goes to all staff who do alignments and who operate. You do not need to send it to individual staff members.
Failure to provide all of this info can cause a delay in getting on sky so please be thorough when submitting request. Also, be clear about dates when submitting requests for subsequent observing nights. Your nights or days may not match ours and giving UT dates will help avoid confusion.
On the first night of your run, please contact the appropriate Array Operator via skype or email at least half an hour before sunset if you are observing remotely. The observer work schedule is posted in the Online Observing Schedule. The operator can provide an update on the status of the array, current weather conditions, and whether there is a need to go on stand-by status or that the night is being cancelled.
Due to the nature of remote observing, it is beneficial to assess a few things before the evening’s run. First would be the weather. Everything from the Weather Service page, The Clear Sky Clock and the Jet Stream can be checked to have an idea of what kind of night is ahead. Although the Observing Specialist on Mount Wilson will be responsible for these assessments, it's a good idea to check anyway. During the day, maintenance or upgrades may have taken place with the Array so look for updates via email and the Array status from the observing specialist and/or CHARA staﬀ on Mount Wilson. Use the links below
Essential Observing Links
150-Foot Solar Tower Current TowerCam Image (http://www.astro.ucla.edu/~obs/towercam.htm) a live view of the mountain. Check the time stamp when viewing this page as the image can sometimes fail to refresh.
Caltech Millikan Library Camera (http://library.caltech.edu/milcam/) A view of Mt. Wilson from the south, good for watching low clouds and marine layer.
National Weather Service (http://forecast.weather.gov) Mount Wilson weather and 5 day forecast
CHARA telescopes spy cams and weather graph (http://www.astro.gsu.edu) Status of each CHARA telescope. Confirm the date and time on this page as well.
Aerospace Corporation weather station (http://www.weatherlink.com/user/mocam) Another local station at Mt. Wilson Observatory.
Jet stream forecast (http://squall.sfsu.edu/scripts/jetstream_modelsml_fcst.html) Monitors high level winds which degrade seeing
IR satellite loop (http://www.wrh.noaa.gov) Keeps an eye on storms and clouds coming in
California Regional Weather Server (http://squall.sfsu.edu/) A variety of weather links
Clear Sky Clock (http://cleardarksky.com/c/MtWilsonOBCAkey.html) a forecasting tool, but be aware that the humidity forecast is often incorrect on this site as it incorporates the marine layer forecast for the valley below, which does not affect us 80-90% of the time
Remote Observing Setup
The observing specialist on Mount Wilson will run all the servers locally. Before setting up, contact the mountain observing specialist to make sure the Array is stable and ready. At this time nothing by the Remote Observer should ever be turned on unless an “All Clear” has been given by the observing specialist. The ﬁrst order is to set up the remote observing station monitors and or control panel. This is done with a background click to bring up the menu options and drop down choices for the various clients and GUI’S that will be used for the night's observing session.
The clients that we will use are:
NOTE: If a Client does not appear this means that the server is not yet running. Ask the Observing Specialist or standby for more information.
Each GUI has a STATUS button. The Status gives the observer information about the current status of that particular system. Since the servers are all run from the Mountain, it is essential that the STATUS GUI be run on the following systems that have a STATUS GUI option to use. A STATUS GUI should be used for the following:
Cosmic Debris - The Sequencer
Cosmic Debris is the main sequencer or control panel for the Array. This is a tabbed interface and what we use to execute the commands to observe and collect data. Cosmic Debris also gives the necessary information needed for observational targets. Inputting the stars designated number, then hitting the corresponding catalog name next to the the star (for example HD, HR, SAO, IRC), and clicking WHEN, will give the AZ & EL plus sky availability and the hour angle in the CD display window. The remote observer may use Cosmic Debris to follow along with the observations. It also will list information about the observing session. For example, when going to a star it will give the status of the acquisition procedure and also any error messages. Remote observers will not use Cosmic Debris to slew.
Cosmic Debris Setup
• To set up Cosmic Debris , click on the background (or the Applications menu bar on GNOME environments) and, depending on which observing slot you fall into, click
Cosmic Debris →Primary, (PAVO is always primary) or
Cosmic Debris →Secondary
• Check the TIPTILT STATUS GUI. If it reads that the selected beams are correct for the combiner you’re using, then all is well.
• If not, notify the Observing Specialist so that they can run the TIPTILT COMM sequence again. [TIPTILT COMM] is a button on Cosmic Debris. When selected, Cosmic Debris will put 7 items in the job queue and then run them. If the communication is established there will be messages in the status window of the Cosmic Debris indicating signal rates for tiptilt for the chosen telescopes.
Synchronizing the Clocks
Will be done by the observing specialist at start up using [SYNC CLOCKS] function on Cosmic Debris.
The observing specialist on the mountain will have opened up the telescope enclosures, dome slits, and optics covers, as well as have things powered up. Set up can be continued as beacon alignments and sky flats are performed.
6.7 Slewing with Cosmic Debris Note: Remote observers will no longer be slewing telescopes
Check with the Observing Specialist to find out if it is safe to slew to your first target. Often the Observing Specialist will slew and initialize the telescopes on the first target and will let the remote observer take over after all systems have been checked. For completeness, here is a list of instructions for slewing and aligning on the first target:
Acquisition Laser Alignment
Finishing the slew sequence
Automatic Acquisition Sequence (This function has been removed)
6.8 OPLE Cart Operation
While operating the OPLE carts, the remote observer should keep an eye on the delay lines as much as possible. Do not change the direction of the carts too quickly. When moving them, click STOP, wait, and then restart them. Also watch for warnings on the OPLE server STATUS display. If the FH= Front Hard or BH = Back Hard lights up it means the hard limit switch has been contacted by the cart, and the observer needs to notify the Observing Specialist and turn the carts OFF. If you suspect that the carts aren’t moving, or are stuck, or are not moving at the correct speed, IMMEDIATELY stop and notify the observer.
Checking the Cart Positions
• The reference cart is stationary. Astrolib will give a TARGET position of where the Ref cart should be. When this position is set the other cart should come into range leaving plenty of delay space to slew through. If not, recheck or reset the REF position.
• For example, Astrolib gives a TARGET position of 30 Meters. The reference cart should be set to that position give or take. The moving cart then needs to be placed to allow room for it to slew between 0-44m. If the moving cart is out of this range, change the reference cart position to accommodate the moving cart.
• On Cosmic Debris, type in the reference position in the empty ﬁeld next to the ‘REF’ input. The empty space next to this is for controlling the speed of reference cart, which we shall leave alone for now.
• The position that was just set will register in about 10 seconds on the OPLE server STATUS display under ‘Target’.
• Once the REF position has registered, the carts can go into place by clicking TRACK on the OPLE GUI.
• Once each cart has reached its position and the ERRORS are low, everything is set.
• Also once the carts are tracking, click the ‘MAN’ and ‘OL’ buttons for the moving carts and the OL button for the ref cart.
6.9 Routine Observing
It is at this time that you can settle down to the standard, and sometimes mundane, part of observing. Not to be taken for granted, data means WINNING!!! As soon as the carts are tracking and the Tip Tilt beams are locked, the Remote Observer can start taking data. Remember the Array is made up of many systems and at anytime one could falter. As Array Observers, it is most pertinent that we keep watch 100% of the time. If problems occur, notify the observer. When trouble arises proceed slowly and carefully. Don’t forget to check the CHARA Array Control Software Manual or in the worst case scenario call the CHARA Control Room.
6.10 PoP changes during the night
It is proper protocol for the PI's or remote observers to announce any PoP changes 10 minutes before needed so the operator can bring up the required windows for the change. Please give the PoP's for only the telescopes that need changing. Use this format: E1 → 1, E2 → 2, W1 → 3, etc. Give only the final PoP.
6.11 Configuration changes during the night
It is also proper protocol for the PI's or remote observers to announce any configuration changes 30 minutes before needed so the operator can open telescope domes and have the scopes ready for the change. Failure to announce changes causes observing time to be lost. Please also include additional configurations in your set up request.
6.12 Nightly Observing Report
The Observing Report is automatically generated by Cosmic Debris at the end of the observing. Check the report for completeness and accuracy and inform your observing specialist if there are notes which you would like to have added to the report.
Last updated 2020-1-27