About the OCA Anza Site Sky Monitor

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The OCA Anza site sky monitor page displays an all-sky view of the sky and current weather conditions as sampled at the observatories of Bruce Waddington (weather) and Jim Windlinger (sky view). The page accessible from the OCA's address ( http://anza.ocastronomers.org ) is essentially a "mirrored" display of a page which is accessible at the Anza site. More about that below...


The weather information is updated every 5-minutes, and the sky image is updated every 15-minutes. Because both types of information must be uploaded from the Anza site via a sometimes unreliable satellite link, there may be gaps in the information or the data may not be current. Check the time stamps to verify that the data is current. Because the sources are not tied together, the times of the displayed data may not always be in sync.


Please note that this information is being informally provided by individuals and that both hardware and software are still being developed and tweaked. If you note any problems or have comments or suggestions, your feedback is appreciated, but please post them in the OCA's discussion groups on Yahoo:



Do not send complaints to the OCA's board members! If you are at the site and think you see a problem with the sensors, please do not attempt to clean or fix the problem yourself! Just post a message on the Yahoo group so that everyone knows of the problem and doesn't inadvertently flood someone with email.


All-Sky Camera View


When the page is first loaded, the sky view shown will be the latest one received, but an animation of the last 50 frames (12.5 hours) can be viewed by placing your mouse cursor inside the picture. There is no need to actually click there. When you remove the cursor from the animation, it will freeze on the current frame. The time stamp for the image is at the upper left corner.


The gray "scroll" bar of rectangles below the sky image represent individual frames and allow you to selectively view a frame or scroll through the captured sequence by moving your cursor over the frames (no need to click). The animation of the images should help you spot trends and see if there are any thin clouds which might interfere with your observing plans.


Once you have loaded the web page, all of the images you are viewing are cached on your local PC. To get the latest images, hit the refresh/reload button on your browser, but remember that it's not necessary to do so very often because the sky view data is updated once every 15-minutes (on the quarter hour) and weather data every 5 minutes. Please do not "lean" on your reload button!


As mentioned earlier, there may be missing frames or gaps in the time stamps, because of communication link problems, or one or more of the site data servers may be down. Minimizing lost data due to the satellite link is a problem that is currently being worked on and will hopefully be improved in the future.


If you see something interesting on the sky camera's images, please post the time stamp on one of the Yahoo group discussions. The next time Jim has a chance to go to his observatory, he may be able to take a closer look at it as he is archiving frames at his observatory which are taken at a higher rate.


Weather Conditions


The weather conditions displayed are updated every 5 minutes. Because of the small amount of data in every update and the higher frequency of updates, this is most likely close to the actual current conditions. To see historical data in graphical form, visit Bruce Waddington's Weather Underground site.


Accessing Sky Conditions from the Anza Site


When at the Anza site, high-speed access to a local "mirror" site is available. In addition, the sky images may be viewed at either a 5-minute frame rate or 15-minute rate. If you find your autoguider warning going off, it's convenient to check the sky views to see if clouds are encroaching, or the humidity has gone up. CCD users may also find the temperature monitor handy to insure you have enough cooling margin on hot summer nights.


This project was undertaken mainly to provide on-site Anza observers with a local source of information so that the slow access to the internet could be avoided for them and more bandwidth would be available for other uses. When connected to the Anza site network by wired connection or via the club's wi-fi connections, a similar set of sky-monitor pages should be used at this address:


This address is an internal address on the club's network out at the Anza site, and cannot be accessed over the internet. Using this address when you are on-site will speed up your access to the data as well as reduce the load on the slow satellite link. Please note, however, that if you are out at the site using your cell phone or tablet's 3G/4G connection, you are not on the club's internal network. If you switch to using the club's wi-fi connection, you will be able to access the internal web page. If you are confused about this, you could always just try using the address above. If you can't get to it, you're on an external network.