Quick Jump Menu
Info Ask a Question
Advanced Search Search the Knowledgebase
RC16: Dome Control
Views: 4789 Last Updated: 2012-02-09 19:40

Note: Dome control is not available on the telescope server. Please access the NM-Dome1 computer for dome control.

The dome control software is not your typical user-friendly bit of software. It's an engineering interface. For routine daily control of the dome, only a small part of the software should be used. 

Please avoid using any parts of the software you are not thoroughly familiar with. You can cripple the software, or damage the dome. 

The dome control software operates an Astro Haven clamshell dome. There are a pair of east shutters, and a pair of west shutters. 

Run the dome software from the Start menu ("TMF Dome Control"). Here is what the dome control software looks like:

Use only the controls at upper left: Easp Up/Down, West Up/Down, Stop, and Move Duration. If the information showing in the software doesn't make sense, contact Ron Wodaski immediately for assistance. Some of the other software features are described in the latter sections of this document; they are for advanced use only.

The first thing to note is that there are situations where you should NOT open the dome, and the dome control software tries to help you with that. But keep in mind that you need to check weather conditions yourself before making a decision about opening the dome. See the page RC16: Weather Rules for information. Basic rule is: "Do not open the dome unless you are 100% sure it is safe to do so."

Error and Weather conditions

There are certain indications in the above sample that show that the dome should not be opened:

  • There are position sensors for the East and West shutters. In this example, the east shutter is not reporting - it is marked as LOST, and the position is '999'. This means that the east shutter cannot be operated because we don't know what position it is in. Always verify that you are getting valid position values for both shutters before operating the dome. If you must do an emergency close but the shutter position is LOST, follow the "Emergency Close" instructions below.
  • The red box says "Please close now" - this means that the software sees conditions that indicate the dome should be closed. In this case, the roof at New Mexico Skies (next door) is closed, so the software expects the dome to be closed. If you need to open the dome anyway (for example, for maintenance, and that will usually be done by someone on-site, inside the dome), you can check the "Override NMS Closed" checkbox. 
  • The red box will also indicate weather conditions that the software believes mean the dome should not be open, such as very cloudy conditions or rain. There is a summary of detected weather conditions available; the software is using this information to make the weather decision. 
  • If the software cannot get recent (within the last 10 minutes) weather data, it will close. If you know for sure that the weather is OK, you can override this type of closer using the checkbox. You should only do this if you have reason to believe it's going to be clear, low wind, and no clouds until the indicated auto-close time. Never use that checkbox if you have the slightest doubt about conditions remaining optimal.
The bottom line: carefully look at the information on the dome control app, the current weather, predicted weather for the night - anything you can lay your eyes on - before deciding if you are going to open the dome.

Operating the Dome

Once you have made your decision about opening the dome, the actual mechanics are pretty simple. Again, this is an engineering interface, so you need to follow a precise procedure for both opening and closing. When in doubt about what is happening, click the Stop button and evaluate.

Note: you can get information on using video to see what's going on in the dome here.

To open:

  1. Check the current dome position using the east and west values. You would expect these values to be 90 and 90 when the dome is fully closed. You can also verify dome position with the video camera. You can verify that the dome is closed if "East up limit REACHED" and "West up limit REACHED" appears in the list at center left. This means that the physical limit switches that cut off power to the dome have been engaged and the dome is fully closed.
  2. Determine the move duration. For a normal open operation, that is 7 seconds (7000 milliseconds). Chose this from the drop-down list. This will not open the dome all the way; for normal operation, the minimum elevation for imaging is about 30 degrees. We do this in part to block wind, and in part to avoid moving the dome fully into the limit switches.
  3. Click the E or W Open button, and observe that the move is what you expect. The dome should open to about 30 degrees, but this may vary somewhat. During the move, the white bars will partially fill with green to indicate the rate of motion. You can verify that the dome is fully if "East down limit REACHED" and "West down limit REACHED" appears in the list at center left. This means that the physical limit switches that cut off power to the dome have been engaged and the dome is fully open. You can use moves of 500ms or smaller to fully open the dome if it does not reach the limit switches on the first big move.
  4. Make sure that the dome stops moving. Record the total time you used to open the dome; you will need it for an easy close.
  5. Repeat for the other side.
  6. You can use the video camera as well as the position indicators and limit switches to verify dome position.

To close:

  1. Verify dome position. Turn on lights if needed to see dome details clearly.
  2. Select a move duration that will close one side of the dome. The shutters move up more slowly than they move down, so in general, to close, use 1-2 seconds more for the up move. It's OK to use a time that is too long; the limit switches will cut power when each side reaches the correct position for fully closed. If you do not know or remember the time to open, then use the video camera and the limit switch text to keep track of the shutter's position with respect to 'fully closed'.
  3. Click the E or W Close button, and observe that the move is what you expect. If it stops short, and the position I > 80 degrees (or if it simply looks close to fully up in the video), open it again - you want a move of at least a full second to allow the shutter to speedup enough to firmly seat itself at the fully closed position.
  4. Repeat for the other side.
  5. Verify full closure using the video camera; it should look like this:

Rss Comments
  • There are no comments for this article.
Info Add Comment
Nickname: Your Email: Subject: Comment:
Enter the code below: