Department of Physics AstroLab

DRACO

Example Results

This V-band light curve was derived from 256 60-sec exposures taken over a six hour period on 2004 March 14 of the asteroid (129) Antigone. The data has been folded about the known period of 0.20655 days.

Introduction

We had developed a remote/robotic observing facility for our undergraduate AstroLab. The facility is built around a 10-inch Meade LX200 and RoboDome from Technical Innovations. The initial detector was an SBIG ST7 CCD but now we have upgraded to an ST9E. The control of telescope/dome/ccd etc has been developed with python + Tkinter under Fedora linux. DRACO acquired over 50,000 images.

 

We have a concrete base (about 5 inch height). A small ring structure is bolted onto this concrete base along with the wedge for the telescope mount. The dome is then bolted directly onto the ring structure. Control and power cables are connected via a small pipe which leads to our Far-East dome which houses the control computer, dome control box, etc. All the cables have now been connected (see here for a set of random pictures of our technicians, Wayne Dobby and George Teasdale hard at work). We have two dome spy cameras. One is internal and is used to view the LX200 mount including the power panel. The other is external and gives a wide-angled view of the dome and the Durham skyline.

 

Software Control

A screenshot of our Python LX200 control GUI is shown below. The N, E, W, S buttons offset the telescope from the current position. The size of the offset is fixed by the slider button and the selection of the appropriate radio button. The GUI also has a park command in the Set menu.

There is a separate "Object Finder and Loader" GUI. As well as loading bright stars and planets, object positions can be manually entered or downloaded from SIMBAD or from NASA's Ephemeris Generator.

A wide angle (7 x 7 degree, to 8th magnitude) chart is displayed when the telescope arrives at a target. The box shows the size of the video finder (see below). Clicking on a star in the chart loads the position into the telescope control GUI.

We have a video finder that is used for the initial acquisition of bright stars and the initial "coordinate-match" of the telescope to a selected object. The video finder has recently been upgraded to a StellaCam. This gives a field of about 7 x 5 degrees. The video camera is mounted on an angled bracket in order to align the long axis of the camera with the E-W direction.

The camera output is piped into a Grandtec Multi Capture Card and viewed with xawtv. We use "xawtv -remote" to display in a remote X-window. With the ×128 mode, stars to 10th magnitude are easily visible. The outline of the finder field is shown in the make_chart.py display.

The initial dome control was developed by Tim Morris in Perl/Tk. The program design was based loosely on the Digital Domeworks software supplied with the dome. A screenshot of the current Python version is given below.

A short video of the dome is available from this link - domea.avi (692Kb)

The ST9 CCD is controlled via a Python/Tkinter interface to a c++ programme using Jan Solan's excellent driver. This is currently being converted to SBIG's linux driver.

Peter Draper's superb GAIA (Graphical Astronomy and Image Analysis Tool) programme is used to assess the images. This programme is part of the Starlink collection.

A JMI NGF-S focuser unit modified in-house by Andrew Hunter to include a digital position readout is used to move the detector over a range of 1cm to achieve a good focus, e.g.

DRACO Observing Information

DRACO movies

Additional information on DRACO can be found here.

DRACO is located at 01 34 24 W, 54 46 01 N, height 75 m.

Useful links


Back to the AstroLab Home Page jrl 2013-Dec-22 23:54:22 UTC