User Manual

This is the user manual portion of the OpihiExarata software package for reducing and analyzing Opihi data.

The Opihi telescope is a smaller telescope mounted on the side of the IRTF. It primarily provides asteroid view-finding and photometric calibration services.

It was conceived to assist the IRTF telescope and its instruments in finding asteroids and other near Earth objects on the sky. This is needed when the positional uncertainty in the ephemeris of these objects are greater than the field of view of the IRTF’s current acquisition and tracking instruments (about 1 arcminuite). This can often be the case for newly discovered objects with a small number of observations. With Opihi’s 32 arcminuite field of view, these objects can be spotted and the telescope pointing can be corrected, thus greatly reducing the overhead time of finding the target.

However, a minority of time allocated by the IRTF are for these types of targets. Having Opihi only operate a few times a semester when it is needed for acquisition is inefficient. In addition to the asteroid view-finding capabilities, the Opihi telescope also serves as a source for photometric monitoring and calibration. By continuously taking pictures and determining the photometric solution for each, the photometric conditions (as measured by the zero point magnitude) can be monitored over time. Moreover, this photometric data can also be used to assist with photometrically calibrating science targets observed by other IRTF facility instruments (e.g. SpeX, MORIS, SPECTRE, etc).

A more detailed description of the physical and optical specifications of the Opihi telescope can be found in Opihi Telescope.

It is typical for the asteroid view-finding to be done manually by either a telescope operator or an observing astronomer; for this reason, we may refer to this view-finding mode as the Manual Mode of operation for Opihi and OpihiExarata.

The photometric monitoring mode does not require the constant input from a user, it only requires instructing the Opihi camera to continuously take images and for the software (OpihiExarata) to continuously solve for their respective photometric solutions; for this reason, we may refer to this photometric monitoring mode as the Automatic Mode of operation for Opihi and OpihiExarata.

Photometric monitoring may be done manually if the user desires more control over the process. However, asteroid view-finding cannot be done automatically. It is currently beyond the scope of this software to implement automatic asteroid/transient finding.

An astronomer or other user interacts with the Opihi telescope and the OpihiExarata software by connecting to a VNC session; this is common to all IRTF instruments. The Opihi camera controller has an interface and data viewer independent of the interfaces of OpihiExarata.

For the general user, the OpihiExarata presents itself with helpful graphical user interfaces (GUIs). However, a command-line interface is provided to open these GUIs. It is likely that most users do not need to worry about this interface as the GUI may already be open for them in the VNC session, however, the command-line interface and its usage is documented in Command Line.

See Manual Mode or Automatic Mode for usage instructions depending on the desired mode of operation. Both of these have some technical jargon better described in System Framework. See Configuration for the available configuration options of both modes. If you are having trouble, see Troubleshooting for more information and possible solutions. If you believe you found an issue or bug with the software, please report it to the appropriate IRTF staff member(s).

If you used the Opihi telescope or the OpihiExarata software, please acknowledge your usage in any projects or publications; see Citations for assistance and for our own references.