Hendrik van Heerden

At this point in time, the development and commissioning of a new autonomous or remote telescope system is easily achievable due to the number of choices available to the builder. The most difficult considerations would be site location and availability of services. Considering the telescope itself, there is such a multitude of technologies such as mounts, sensors, control software and drivers available that it can become a complex exercise to find the best integrated fit. The question that must be asked when considering the automation of an older established telescope include: what are the parameters that needs to be investigated? What are the pros and cons to be considered for the process? What is the current technological state of the telescope? With these questions, and many more, the 1.5 m Boyden Reflector telescope will be examined as to its current state, as well as what would be required to either make it remotely operable, or fully autonomous.

Recently sCMOS sensors have become more popular in astrophysics research due to affordability and availability versus CCDs, but also due to their fast readout speed and low read noise. However, the technology that sCMOS utilize is different than CCD, because of this, full characterization is important to ensure valid reduction and processing for science pipelines. In lab as well as on-sky testing results for the bias, dark current and photo response behavior of the Kepler KL4040 by Finger Lake Instruments will be shown. Analyzed bias frames showed an increase in mean bias counts by 8.24 percent as the temperature increases from -15 to 10 C, indicating a temperature relation. The average dark current as a function of exposure time was investigated, from 0.1 s to 60 s, at an absolute temperatures range of -15 to 10 C, with a clear indication of a correlation between dark current and sensor temperature. The rate of the Dark Noise increase clearly shows linear trends for all temperatures. The photo response curve is linear up to full well depth range, with a similar trend to both low-gain and high-gain modes. Using images with row and column plots, the reduction processing from raw to science images ready for photometric analysis is shown. The results indicates that sCMOS sensors are viable options for astronomical observations given that a thorough understanding of the characteristics and possible drawbacks of sCMOS sensors are understood and compensated for.

Recently the marked improvement and availability of scientific CMOS (sCMOS) cameras has provided an alternative to more expensive CCD based cameras. A Kepler KL4040 sCMOS has been acquired from Finger Lakes Instrumentation to replace the current CCD camera used on the UFS Boyden 1.5 m telescope. Because of the differences between CCDs and sCMOS sensors, the sCMOS camera is currently being characterized and tested. The camera was first mounted to a 14” Celestron CGE 1400 system with an Apogee FW50-7S filter wheel with Johnson-Cousins UBVRCIC filters for the first on-sky and star-light tests. These included absolute photometry of the standard field SA107 in the BVRCIC filters using differential photometry and using the determined colour coefficients. Thereafter the camera was moved to the Boyden 1.5 m telescope and mounted on the Photometer Instrument-pack with a Johnson-Cousins UBVRCIC filter system. After integration into the Boyden 1.5 m telescope systems, additional on-sky tests were performed, including fast photometry of one full orbital period of 3.56 h of the cataclysmic system AR Scorpii at ≈ 6-7 s cadence. All of the results were processed using a custom python pipeline created using libraries including astropy, numpy and ccdproc.

The status of the Boyden observatory and equipment will be evaluated for use in optical counterpart studies of high energy sources. Optical systems include the 1.5~m Boyden telescope which has recently received system and equipment upgrades to the photometer, specifically a new sCMOS camera system. Additionally a state of the art spectro-polarimeter has been commissioned and is in final testing and initial observing phases. Besides the 1.5~m telescope, there is also robotic telescope systems, e.g. Watcher and BOOTES-6. Watcher, was primarily for follow-up of gamma ray bursts, but has also been used for optical counterpart and survey studies, and target-of-opportunity events. BOOTES-6, or Burst Observer and Optical Transient Exploring System, is a new telescope system that allows for much faster target acquisition for Gamma-ray bursts events, but is also available for optical studies of transient phenomena or optical counterpart studies. With these optical systems, various multi-wavelength studies and collaborative efforts are envisioned for the Observatory

SCMOS sensors have become more popular in astrophysics research due to the lower price and availability versus CCDs, but also due to their fast readout speed and low read noise. However, the technology that sCMOS utilise is different than CCD. Therefore, data processing must be performed differently for sCMOS sensors as compared to CCD data. In this proceedings we report on the testing of the bias and dark current behaviour of the Kepler KL4040 by Finger Lake Instruments for use at the UFS-Boyden Observatory. Bias frames were analysed, and it was found that the mean bias counts increase by ≈ 8.24 percent as the temperature increases from -15 to 10 degrees Celsius. The average standard deviation is only 5 counts, the maximum deviation being only 2.34 percent higher. The average dark current as a function of exposure time was investigated, from 0.1 s to 300 s, at absolute temperatures of -5, -10 and -15◦C and the Dark Signal Non-Uniformity (DSNU) was calculated for each series of dark frames. The rate of the Dark Noise increase clearly shows linear trends for all the temperatures.