There are several possible ways to communicate with your telescope at a remote site. The most popular is to use the Internet. We are located at a remote site to obtain dark, transparent skies with good seeing. As a result, our area is not served by cable TV, DSL telephone service, or other inexpensive high speed Internet services capable of consistently high throughput rates going out.
We have installed one DS1/T1 line capable of megabit per second data transfer rates in each direction full duplex for the shared use of all our customers and ourselves.
Despite this relatively high speed line, we support only pre-programmed, robotic observing, in which our customers download a schedule and their computer at our site executes the schedule by directing their telescope where to point, and moves a filter wheel or sends whatever other commands are needed to execute an observation. There is absolutely no human intervention at any point during the observation, either here in Sonoita, or at a remote site.
We do not support remote, real-time operations. This is because the T1 line is shared by our current customers to send their images back to their home institutions, and does not have adequate bandwidth to do this and to provide adequate response for real-time operations. We experimented with this a few years ago with a customer using a satellite system dedicated to their exclusive use. Between the painfully slow uplink speeds inherent in all satellite systems and the time delay caused by the fundamental limit of the speed of light and the distance from the Earth to geostationary satellites, simply moving a mouse on a screen from a remote location proved to be confusing and frustrating. Once that organization moved their operation to a different site with a high speed Internet connection, their operations improved dramatically, so we are led to believe. Until we can provide each of our users with more than a relatively small fraction of a T1 line, we simply cannnot accept remote operation customers into our observatory, based on the hard lessons learned from this past experience.
In a typical robotic observing scenario, each afternoon, a telescope control computer obtains a set of objects to observe from its home institution from a command or script file. That evening, these objects are observed robotically, under the control of the computer while the astronomers sleep. The resulting data files are trasferred back to the home institution over the Internet connection, and when the home institution computer automatically acknowledges receipt, the data files are deleted from the computer in Sonoita.
For example, the University of Iowa maintains a Web site
on the
Iowa Robotic Observatory at which pre-approved users
can request images using their Web-based request form. A
student who schedules the telescope (a 14.5-inch R-C
Cassegrain with a Finger Lakes CCD camera) receives all
the observing requests and assembles them each day into
an overall schedule for the telescope that is placed into
a file named telrun.sls. The file is then
transferred to the telescope control computer at the
Winer Observatory in Sonoita. The computer opens it, makes
sure the date and time are correct for that evening, then
waits for the time of the first observation.
When the Sun is 1° below the horizon, a Winer
Observatory computer automatically opens the roof
(we signal all the telescope control computers whether
the roof is open or closed using a Web page;
we dissiminate weather data the same way). The Iowa
control computer then begins processing the
telrun.sls file. Each entry in the file
specifies the name of the observer, the name of the object
to be observed, its sky coordinates, the filter to be used,
the length of the exposure, and other items needed to make
the observation. The computer slews the telescope to the
object, begins tracking, moves the proper filter into
place, opens and closes the shutter with the proper exposure
interval, reads out the camera, stores the data in a file,
and moves the telescope to the next location while it begins
moving the image file back over the Internet to Iowa City.
The data files in Sonoita are erased only when receipt is
acknowledged from Iowa City.
For only the cost of postage or courier service and
the storage media, Winer will support the writing of
DVD's, CDROM's, tapes, or removable hard drives at its
facility and the transportation of those volumes to your
home institution. Large amounts of data handling could incur
additional charges.
Last modified: January 1, 2010.