It's been quite a while since I've posted, thought I would write a bit on the differences involved in imaging in Singapore (at the balcony) and in Melbourne CBD (also at the balcony).
It took a while of getting used to, initially. Setting the mount at mid-latitude instead of 1 deg N. Also, having made the mistake of aligning the mount north in Australia the last time, it was interesting to mount it south (where the mount axis is pointing). It would have helped to have a polar scope, but no one would have one coming from Singapore/Malaysia. So the process of drift alignment would follow, in any case it still should, with polarscope or no polarscope. The mount electronics had to be switched over too, and having the RA motor running in the opposite direction. When mounting the OTA on it, it was a little more challenging too, since the dovetail plate holder is no longer in the near-horizontal position and angled instead, which means one cannot simply rest the OTA on the plate without fearing it would drop off. Next, the drift alignment process is similar to that done in equatorial countries. Chosing a star near meridian and another closer to the western or eastern horizon. Like all things done for the first time, drift alignment took quite a while, but with practice, it was done more quickly during subsequent sessions. Oh! A word about general conditions.... before every imaging session done at the Melbourne balcony, it would be wise to check how the outside temperature is. One cannot simply do the imaging in slippers and bermudas, singlet, what-nots like back home, comfortably. Normally, it would be wise to wear socks (the concrete is chilly!), jeans, inner shirt, and jacket. Quite a feat I would say initially, but again with time, it became like clockwork, and a routine. Luckily, one would not need to be physically at the balcony while imaging, drawing the doors a little closer, and pulling the blinds down, the imaging session would commence with as little outside air flushing into the room interior and with the imaging laptop inside the room. But all is not inconvenienced with the colder climate, the camera is very happy! Infact, it is working so well at lower temperatures, that I could image with the camera functioning at -6 degrees with twice as low of noise as taken as usual at 0 degrees back in Singapore. But so far, I have not tried it yet, cause it will also mean taking a whole new collection of dark frames at -6. Being imaging from the light polluted conditions of Melbourne, it would not have been as rewarding as doing it under actual dark skies. But I would probably have a go on rebuilding the dark frame library for -6 before heading to the star party in 2 weeks time. WOuldn't want to miss the opportunity to shoot at -6 under darker conditions! Here is one preliminary luminance image mosaic of the Tarantula region taken from the balcony (here!). Not a perfect seamless mosaic I would say, and also assembled over data taken of varying nights, and greatly varying seeing conditions. Some were taken when the nights had thin clouds too and with the moon present. What surprised me was the seeing conditions seem to affect the image capture more over here than in Singapore. Perhaps it could also be due to the steeper temperature changes/gradient as well. Focus would vary as the night progressed, more over here than in equatorial countries, where the night temperatures do not vary so much. At times, during autoguiding, the star would be "lost" because the seeing varied so much that from a pinpoint star, it becomes a featureless diffused big blob that render the autoguiding algorithm confused, and sometimes halting prematurely. Nevertheless, after several attempts, I could gather enough data to assemble a partial mosaic like this. With the star party nearing, I hope to take this object in colour, but only with enough clear sky time, could I attempt a colour mosaic, and that is assuming if there are no other interesting southern objects to capture, which one would doubt so!
