Winer ObservatoryUsing a Remote Robotic Telescope and Receiving Data
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 two DS1/T1 lines capable of ~3 megabits 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 connection, 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 lines are shared by our current customers to send their images back to their home institutions, and we do 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 higher 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 two T1 lines, we simply cannot 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 transferred 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 disseminate 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.
Page last updated on: February 1, 2014
