Centaurus A through a little 5 inch refractor in Sydney
Here is my latest attempt at imaging NGC5128 using my little 5 inch refractor. I am fairly pleased with the result because all of the data were recorded in the heavily light polluted skies of outer suburban Sydney. It has taken me a long time to reach the stage where I can produce images of this quality under such challenging conditions. Driving to a dark sky site is taking the easy way out? Hey?
Thank you all. Mike: the luminance data is based upon 49 exposures of 600 seconds each, all at 1x1 binning with a QSI 683wsg. As you know, the signal is buried on top of and within the sky glow. In principle, one just has to integrate for long enough to average away the noise in the sky glow. However, as the sky glow increases, the integration time required to recover a smooth signal becomes impractically large. I am located in the southern suburbs beside Royal National Park and NGC 5128 passes through the “sweet spot” in my sky, south of zenith, but still high up in the sky where I can make out 5th magnitude stars with the naked eye. I leave the scope running all night and try to record the luminance data when the object passes through the celestial meridian between midnight and 4 am when the sky is darkest. This is a lot of hard work which is something I think you know all about.
that is a fantastic effort, i love that you have picked up so much of the galaxy it reminded me of Paul's version, well done. surely heathcote is not horrible in terms of LP though ...
that is a fantastic effort, i love that you have picked up so much of the galaxy it reminded me of Paul's version, well done. surely heathcote is not horrible in terms of LP though ...
That particular Heathcote is only ~ 35km from the centre of Sydney... Not the Heathcote 120km north of Melbourne.
That is one of the best Centaurus A s I have seen well done Murray and yep Heathcote is quite light polluted I am down in Helensburgh only a stones throw away and can see the glow from Heathcote and Engadine .
you have nailed this thanks for sharing
cheers Pete
You should be well proud of that one Murray. Certainly shows the results that can be achieved with a bit of dedication. It's actually much better than my version of this object taken at Ilford with a Canon 60Da.
That's pretty good Murray for a city image. You have captured the tidal stream and the blue stars. The back ground is smooth. Not sure about the stars in the field though, the halos are a little distracting. Maybe just a tad over sharpened on the dust lanes in my opinion, but a nice image all the same.
Rodney, I bet if you integrate for 8 hours on Centaurus A at Wiruna your raw data will be 4 times deeper than mine. I would prefer to integrate for 8 hours at Wiruna rather than Sydney any day.
Paul, I don't fully understand why the halos are so strong ... I suspect that it is something to do with intense stretching of the amplitudes to pull out the wanted signal which is barely detectable on top of the bright sky glow. I suspect the halos would be weaker if the data were recorded at a dark sky site. I can go 4x times deeper at Wiruna versus the darkest part of the sky above my home located ~30 km from the Sydney GPO. I guess I should repeat the imaging run with the same gear at Wiruna one day to test the hypothesis.
