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Running a remote observatory entails some risk; the situation with TMO is not the same as with remote observations at APO, where there is an observing specialist that keeps an eye on the telescope and weather. Please be conservative with TMO.


If you notice any issues with TMO while operating please notify Jon and Zach via the email alias so that we can address it.

If there is an immediate issue that presents potential danger to the telescope, call Zach (TA's should have Zach's phone number) or Jon.

Observatory location

TMO is located at a latitude of 32°17'35“ N (32.293048), a longitude of -106° 41'53” (-106.698056), and an altitude of 1505m (4937ft) MSL.


Prior to observations, check the weather -

Clear Dark Skies -

Weather Underground -

Please recall that you are using a remote observatory and are not physically present at the dome/telescope. It can take a significant amount of time to get to the telescope. Please keep this in mind when checking the weather for the night. If, for example, the weather becomes unsafe and the dome refuses to close this could cause serious damage. Don't use the facility if there is a significant risk of precipitation.

If for some reason the dome does not close, position the telescope in the stow position to keep potential precipitation from reaching the mirror. Position the dome so that it points in a different direction than the telescope to make sure sunlight won't go through the telescope. If that's not possible, position the telescope to be pointed somewhere where the Sun can't be (i.e., at high declination).

Operating interfaces

There are several possibilities for observing interfaces:

- you can use ACP's built-in web interface from a browser. This is relatively simple, but perhaps somewhat limiting

- you can open a remote desktop on the control computer and get access to the individual control programs: ACP, MaxIM DL, FocusMax, Scitech, etc.

- you can schedule observations using ACP Scheduler

Note that you can only connect to TMO (either web interface or remote desktop) from within the NMSU network.

Desktop interface

You can connect to TMO's computer via VNC Viewer; free viewers are available for all computer platforms. You should connect to - Jon and Zach have have the password for this connection. Again, you must be on the NMSU network or connected through VPN to be able to access tmo.

Sometimes the connection can be slow and there is not immediate feedback when you press a button. Only press a button once.

Please Note - VNC uses port 5900 to connect to a computer. If too many people are connected at once, this can cause the connection to run slowly. Make sure you disconnect when done for the night. And if someone else is using TMO please limit the number of connections to what is required. Zach will occasionally go through and kick lingering connections on port 5900 (during the day).

Using the webcams

There are two webcams in the dome, one looking at most of the dome (it can be steered), and one looking at the telescope dials (note that only HA and DEC will be correct, not RA which depends on a clock!). They are accessed using the Internet Explorer (only!) browser by going to the addresses (dome/telescope) and (dials) using the browser on the TMO desktop (which is actually Microsoft Edge but running in Explorer emulate mode for these addresses). The user is admin.

Use these generously! They have built-in LED lights that you can turn on. These shine at ~8000 A, so can even be on while you are taking exposures, unless you are working in the I or z band.

If something does not look right in the webcams, stop! In particular, if the telescope does not appear to be pointing where the coordinates in the software think it is, you should stop, to avoid running the telescope into the limits.

Note that the dials tell where the telescope really is, not the software!

Start Up

Usually, software is left running. The software consists of:

  • FocusMax v5 : focussing software
  • MaximDL : camera control software (science and guider)
  • Scitech controller : telescope controller
  • ACP : master control program
  • Clarity II : weather station program

If all is up, check the Scitech controller program to confirm that it says “Scope Parked”. If it says “Not initialized” or “Bad scope communication”, then the program may need to be restarted, and the telescope position will need to be initialized (for now, contact Jon or Zach).

If you are starting observation from an empty desktop (please inform Zach of this) and follow these steps:

  • Open FocusMax v5 using the desktop icon
  • FocusMax *should* automatically open MaximDL
  • In MaximDL - click the 'Observatory Toggle Control' (the icon is a little observatory) and click to 'connect all'. This should automatically open the Scitech control program.
  • Open up ACP using the desktop icon.
  • If doing manual observations - in ACP go to both 'Telescope' and 'Camera' to connect both the telescope and camera
Dome Control

The Dome Control is done via ACP (note, 'NOT' ASCOM Dome Control, although this is an alternative interface in case of issues). In the ACP control box - in the bottom left click the button - 'Dome Control' to access the controls.

We recommend watching the dome webcam when opening and closing the dome, to ensure it is doing what you expect. The dome is opened with the Open button. *Note that when open the dome, it will automatically slew to the telescope, so beware! Make sure the telescope isn't pointed somewhere you don't want it to be, e.g., in the direction of the Sun!* Note that you can click the Stop Dome Motion button to stop the dome.

Slew to an Object

Slewing can be accomplished through the ACP program, which provides a deep sky catalog and various bright stars, or through the !SciTech telescope controller. The “Nudge” window in ACP allows you to offset the telescope in any direction.

To go to an object, click 'Slew or Sync (catalog)' in the bottom left of the ACP box. This will bring up an option to allow you to slew the scope to a given object. There are four options:

  • Coordinates (RA and Dec) : note, however, that ACP does not seem to take J2000 coordinates in the slew window. To slew to coordinates, you may need to use the Sidereal Technologies telescope window Goto tab, with the J2000 box checked
  • Deep Sky Object : can be entered by name, but note it is picky about spacing in Messier and NGC catalog 'M 44')
  • Major Planet
  • Alignment Star: set of bright stars, you need to know your constellations to know where they are!

There is also an ACP !FindBrightStar script to find a relatively bright star near to where the telescope is currently pointing: use Select the Script in the upper right of the ACP window to find it, then click the Run button in the lower right. After starting up, it will prompt you for a filter to use, which you will enter in the Console window: here the filter is specified by number, 2 will use SDSS r.

Taking exposures

You take exposures manually using MaxIm DL, using the Camera Control window (the icon to the left of the observatory icon). Use the Expose tab, where you can set the filter and the exposure time. The science camera is Camera 1, while the guide camera (no filters) is camera 2.

The raw pixels in the science camera subtend about 0.24 arcsec on the sky. We typically run the detector in 2×2 binning to better match the seeing and reduce image size. The chip can also be windowed to only read out a portion of the detector: you can select Subframe and choose the area using the mouse.

You can either take single images or set it up to take images continuously. The latter is useful, in conjunction with windowing the detector around a star, for focusing the telescope. Remember to switch back to Single mode when you are done.

The guide camera is mounted on the 6“ finder scope and is pointed in about the same direction as the main scope/camera. If you just take exposures using Camera 1, they will be unguided. This is probably fine for most observations. If you wish to try autoguiding, use the Guide tab, click the Track button, and start exposing. If the software cannot find a guide star in the guide camera, it may try to guide on noise and may make the image much worse than without guiding.

Image display in MaximDL

The science camera has a lot of pixels, so if you display it at 100% it will be far larger than the image window, even with 2×2 binning, and you will need to use the scroll bars to see everything. To see the whole frame at once, use 12.5% view.

The Screen Stretch window is useful for adjusting the brightness and contrast.

You should be able to center an object in the field of view using the right mouse button when the cursor is on the object you wish to center, the find Point Telescope Here near the bottom of the menu. Sometimes it seems that this goes the opposite direction in one axis, so you may need to figure out where you need to click!


In general, the ACP AutoFocus script works well. You will need to select a filter, this time by name, but it seems that it will focus in SR no matter what you input!

To focus manually, point the telescope at a moderately bright star (use the !FindBrightStar script works well). Take an image with MaxIm DL. Use the cursor to drag a box across the star so that you can display images at 100% but just see the region around the star. Adjust the exposure time so that the star is well exposed but not saturated. Adjust the greyscale so that you can see the intensity structure near the star center. Start taking continuous exposures by clicking the Continuous button (instead of Single), then hit Start.

In !FocusMax, open the Jog window. You can use the In and Out buttons to move by the amount specified in the box. If you are near focus, using a step size of 25-50 should be good. Do a focus run from out of focus on one side to out of focus on the other and choose the best focus value.

ACP Scripts

There are several scripts in ACP (for example, auto focus) which can be very useful. These are located in the ACP box in the top right - click on 'select the script…' and it'll open a list of scripts that you can run.

Useful Scripts:

  • AutoFocus.vbs
  • AutoFlat.vbs
  • CenterScope.vbs
Closing Up for the Night

Make sure that both the dome and the telescope are parked. In the Dome Control window you can simply click “park” and it will tell the dome to go its resting position. In the telescope control box, click “park” and it will do the same for the telescope.

Please visually ensure that both the dome and telescope are parked using the IPCam Client: (Must be used with a window computer, usually Jon and Zach keep a browser opened with the camera. If it asks you for the password, Jon and Zach can provide it).

ACP Web interface

ACP Scheduler

For typical remote observing we tend to go one step higher, and start ACP Scheduler. This also opens a weather station window. Clicking the checkbox for “Dispatcher Running” will begin operation. Scheduler will only start observing once conditions are right (weather is OK, it's dark, etc.), so you can start it during the day and it won't do anything until nighttime. Startup and dome opening occurs 60 minutes after sunset, and object observation begins once the sun is 12 degrees below the horizon. In the morning, Scheduler will also take sky twilight flats. However, be aware that the scheduler will keep running every night (assuming conditions are okay) until you tell it not to. We don't really want this behavior, so in the morning following an observation run you need to pull up the webcam, make sure the dome is closed, and uncheck the dispatcher box. Problems and such should be stored in the logs; the only major emergency is if the dome does not close.

Scheduler is organized via “programs”, which contain objects of interest. Objects contain observations, which is where exposure time, binning, etc. is specified. Scheduler can be accessed via the desktop program, or via the ​webpage.

Potential Problems

When in doubt, consult Zach or Jon and/or stop!

'Windows Log-In Screen' -Jon and Zach always aim to keep TMO's desktop logged in. If, when you connect via VNC, you notice that its asking for the windows log-in. Please notify Jon and Zach. This indicates the computer has restarted and Zach will need to investigate “why”. Ask Jon or Zach and they will log in.

'Bad Telescope Connection' - This usually happens after the telescope has been sitting for a while without use. If the telescope has a bad connection - you might have to disconnect the telescope in ACP (and possibly MaximDL) and reconnect them. If this doesn't work, you can disconnect everything, then exit out of all the desktop programs then start them back up using the instructions above for starting from an empty desktop.

'Dome Stops Follow Scope' - this may happen if you are manually operating the telescope and you start controlling the dome separately. It also may happen because the dome drive wheel starts to slip. If this is the case, the wheel may need physical adjustment, and you will need to stop.

'Dome pointing in wrong direction' - if the dome seems to be lost, you can try to Home it, which moves it until a sensor, whose position is known, is triggered. You can then Unpark/Unhome the dome and see if things are better. But t also may happen because the dome drive wheel starts to slip. If this is the case, the wheel may need physical adjustment, and you will need to stop.

'Trailed Images' - Possible that images become trailed if there is some balance issue, which may depend on location in the sky. It also might happen if you are trying to autoguide, but the autoguider isn't working well, perhaps because of a faint guide star or intermittent clouds. This can also happen if conditions are poor.

'Camera Connected but exposure fail' - If the camera is connected but fails at exposing, you might need to power cycle the camera using tmopower2. It is also possible that FocusMax v4 and MaximDL aren't talking correctly - restarting other applications and reconnecting will fix this.

Calibration of AutoGuider

Data and logs

If observing manually, you should keep a log of your observations to make finding your .fits file easier. When taken with MaxIm DL, the images are automatically named “” which is usually not helpful for identifying objects. When taken through the web interface or in robotic mode, the images are organized by program and have more meaningful names.

Data are stored on the local computer at TMO, but is automatically synced to the NMSU Astronomy servers every 15 minutes. On the Astronomy computers, it is located at /home/tmo/, which can be accessed via the web at ​

ACP stores logs per object; this can be pretty inconvenient if you just want an idea of what it did all night. Therefore we have a script that runs each morning that concatenates these logs into summary logs for each night, helpfully stored in /summary_logs/.

Logs contain a lot of information; here's a quick guide. The software attempts to “plate solve”, which looks at the image and tries to correlate it to a star catalog to make sure the pointing is okay. Pointing information is also included in the log; after slewing pointing error may be as high as half an arcminute, but will (hopefully) quickly be corrected with subsequent exposures. The software will also do occasional focus runs, and calculate other values of interest including plate scale, focal length, FWHM (seeing), and field of view.

Other useful locations:

/Images/[date]/AutoFlat/ contains any flats taken on that date.

/ACP_Astronomy/Scheduler_Engine_Logs/ contains scheduler logs, detailing every object's availability and whether it tried to observe them or not.

/Logs/ contains autofocus routine logs.

/Logs/AutoFlat/ contains auto-flat routine logs.

/ACP_Web_Data/Doc_Root/images/TM61/[date]/ contains any manual observations taken on that date (as long as they were taken through the ACP webpage).

howto.txt · Last modified: 2023/09/18 23:30 by holtz

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