Seven hours comprising 14 x 30 min subs with Aspen CG16M on 20" PlaneWave CDK. Processed using GoodLook 64.
(The previous night, we'd done another 7 hours, but there were thunderstorms on the horizon, and the seeing was terrible. Even using clever masks to add it only into the faint background, it made things worse, so with running tears and holding each other tight, we waved it goodbye.)
Rather than going for the most contrasty image possible, we've processed this to show detail right down to the core, but also retain the outermost hints of spiral arms.
Unlike say Grus or Indus, there's not a lot happening in the outer field (original image here), so the thumbnail is a tight crop. You can see that the nucleus comprises two dust lanes and five quite separate star-forming regions, all extremely close together.
The structure of the main spiral arm at top right is fascinating. It looks very three-dimensional, curving back inward on itself like a lettuce leaf, or a wave breaking, or like water sloshed out of a bowl, or perhaps like the efforts of a lawn sprinkler.
Hoping to get colour tonight and perhaps H-alpha tomorrow.
I can't help but think something is amiss here...an almost Hubblesque pre-servicing SA light spill pervades the field....as to the cause ?
That said...The depth and scale of this image is indeed impressive ( I am also building some data on this one...but suspect I'll need to remove the focal reducer...galaxies like this need FL! )
P.S. please disregard my initial comment...I just looked at the original in Photoshop....no spill...just even more wonderful depth and scale!
Last edited by Peter Ward; 02-11-2016 at 02:18 PM.
That is an amazing image, and to me, one of the most detailed amateur images of this object I have seen. It may have a soft feel to it, but the details especially including in those faint outer arms is amazing - a multitude of individual nebulae being visible just to name a few.
This is where something like a quality 20 incher makes it all worthwhile!
Excellent image MnT!! The detail in the galaxy is exquisite! I do have to disagree with you on one point however, there are some interesting galaxies in that field
Just back after spending a fortune at Bunnings. Thanks for the supportive comments.
We suspect that using averted imagination, and a glass of armagnac, there just might be thin spiral arms around 2 and 3 o'clock extending out a long way past the obvious edge of the galaxy. One thinks of the tidal tails that show up around NGC 1097 in deep binned stacks, but these look more like just ridiculously faint hints of spiral arms. Perhaps there's nothing there at all, but it might be worth going really deep some time.
We suspect that using averted imagination, and a glass of armagnac, there just might be thin spiral arms around 2 and 3 o'clock extending out a long way past the obvious edge of the galaxy. One thinks of the tidal tails that show up around NGC 1097 in deep binned stacks, but these look more like just ridiculously faint hints of spiral arms. Perhaps there's nothing there at all, but it might be worth going really deep some time.
I can see (imagine?) traces in my skimpy Lum from a couple of years ago too, M&T. Would love to see what pops out if you go deeper.
Fantastic depth M&T! I suspect though that your seeing wasn't optimal for this data either(?) There is a fuzziness about the stars - which Peter perceived initially. It's a relatively minor point compared to the grandeur of the full frame, but some more processing would tighten things up. Can't wait to see the colour version!
I can't help but think something is amiss here...an almost Hubblesque pre-servicing SA light spill pervades the field....as to the cause ?
Quote:
Originally Posted by marc4darkskies
Fantastic depth M&T! I suspect though that your seeing wasn't optimal for this data either(?) There is a fuzziness about the stars - which Peter perceived initially. It's a relatively minor point compared to the grandeur of the full frame, but some more processing would tighten things up. Can't wait to see the colour version!
Thought long and hard about this, and think I have some feel for what's going on. The image is pretty deep - in the sense of lowish noise and longish exposure - and I was able to process to show very faint features, but that meant using an arcsinh stretch with a slope at the origin around 400:1. That (combined with affordable optics and ordinary seeing) is what is causing the stars to look kleenex-soft and fluffy. Marcus's excellent NGC 7424 is showing a similar effect in the stars, for what I suspect is the same reason - Marcus has shown some very faint features in the galaxy and that takes a lot of stretch. In our shot, the sin is compounded by trying to show those five tiny star-forming regions in the central nucleus, rather than letting them burn out to a single clump. The result is to reduce the mid-range contrast. I reprocessed it more conventionally without the super-faint stuff and with the middle burned out, and the stars look fine. Not sure that I can achieve the effect I want without fluffy stars and low contrast. Peter's Alluna scope might be able to do it, as it does seem intrinsically extremely sharp, but one would have to do the actual experiment.
... The image is pretty deep - in the sense of lowish noise and longish exposure - and I was able to process to show very faint features, but that meant using an arcsinh stretch with a slope at the origin around 400:1. That (combined with affordable optics and ordinary seeing) is what is causing the stars to look kleenex-soft and fluffy. Marcus's excellent NGC 7424 is showing a similar effect in the stars, for what I suspect is the same reason - Marcus has shown some very faint features in the galaxy and that takes a lot of stretch. In our shot, the sin is compounded by trying to show those five tiny star-forming regions in the central nucleus, rather than letting them burn out to a single clump. The result is to reduce the mid-range contrast. I reprocessed it more conventionally without the super-faint stuff and with the middle burned out, and the stars look fine. Not sure that I can achieve the effect I want without fluffy stars and low contrast. Peter's Alluna scope might be able to do it, as it does seem intrinsically extremely sharp, but one would have to do the actual experiment.
It's a marvellous image M&T! Yep, extra heavy stretching will have that effect but you should be able to mitigate those effects. I dare say seeing is likely to be the main bugbear in your image.
If it were me, I'd tighten things up a little and you can do that without affecting depth much at all. I had a play and applied some wavelet and star reduction with very good effect.
BTW - seeing is what afflicts my 7424 image - not stretching. I did not do any heavy stretching on that image - ie beyond the norm. The seeing is what killed me.
( I am also building some data on this one...but suspect I'll need to remove the focal reducer...galaxies like this need FL! )
please disregard my initial comment...I just looked at the original in Photoshop....no spill...just even more wonderful depth and scale!
fantastic image Mike & Trish 
