Great view. I viewed this field just last week at culmination about 10 degrees above the horizon. Seems to be an object I missed when observing from the Southern Hemisphere. Similarly I wasn't certain if I saw any of the dust near the center in the 20-inch, but I think it was a smaller dark feature closer to the nucleus that I was going for. Didn't make a sketch - too low.
Sorry I missed your reply. I dunno, a 20" is plenty powerful aperture. Low altitude might be enough to make detail that much more difficult in any aperture. I cannot say for sure. I cannot avoid the vision of something being there. Not clearly seen, but often hinted at or glimpsed (maybe). Believe me, I held no hope of seeing anything so exotic as those dust features near the core. I thought I was seeing the edge of the halo where some images show a bit of a sharp drop off. But, as it turns out, I do not think I was seeing as much of the dimmer halo that extends much closer to NGC 1317 or any of the very low contrast that would result form such a dim halo. About the best I can do it to see the brighter portions of the galaxy. So, I am left with only one option.
I think I may have made the same mistake with NGC 1365, never hoping to see anything near it's fine dust features pinching into the core. Really, that's too much to ask of me and a modest 8" aperture, surely. Still, I cannot escape the fact something was teasing my eye (thus my brain) in the vicinity of the brighter bar. Again, some images show some sharp drop off of it's halo in about that same place, too. So, my first guess was a sharp drop off instead of a fine dust feature. Just seems the easier of the two features to see.
Still, it's hard to use filtered and processed digital images to replicate the visual appearance. So, it's really hard to select one image over another that seems to describe what we are seeing. So, upon verification of some sightings, I kind of have to mix and match some images to get a feel for what might have been seen. And I do not mean actually seen so much as detecting something as being there. It's just not at all clearly defined, as I am sure we understand. Almost an artifact, but one that is somewhat consistent in its location. Something that is teasing us and we read the "behavior" of the image as it comes and goes.
So, truthfully, I do not know which detail I actually got an impression of. Thinking about it, the higher contrast of a darker feature against a brighter core makes more sense than the very low contrast of a sharp edge to an invisibly dim halo. Maybe not. Maybe the latter is easier for some unknown reason. But something crept into the image letting me know something was trying to be seen. I really could not make it out other than to know somethign was there, and turns out there is something there. Question is, what was it? My imagination?
Also, truthfully, I really didn't think much about the finer dust features, they were not on my mind. So, I do not believe I was trying to see something I didn't think I could see nor a detail I paid no mind to. I never know what to expect even if I know what the galaxy looks like. Something that seems easy in a digital image, sometimes is not even remotely visible. And visa versa. Sometimes things that look impossible or we have little expectation and hope of seeing it, sometimes we do. Just a weak undefined signal tickling our optical nerve and registering on the brain undefined and unseen...but, in a way, it is seen. Especially when some feature is there and may well have caused the impression we register in our mind. It's those difficult clues I pay attention to trying to read very faint signals.
I paid attention to notoriously faint M74 for two hours each over two nights. I cannot say I ever saw the spiral arms in the way we say we see things. I did actually catch some dimming and one brighter knot in the faint fuzzy halo. But, even without seeing the arms, I knew where they were and which way they were oriented. I made notes, and upon verification (flipping and rotating a digital image to match my FOV and field stars, I had no preconceived idea of it's orientation) I was absolutely astonished I got it right. They were probably nothing more than a slight variation in the background noise and somehow my brain picked up on it. Other than a soft darkening and a brighter knot, I have absolutely no visual recollection of having seen the spiral arms in the way we remember seeing things. Not even close to remembering a digital image we've seen. All I remember seeing is a faint fuzzy, a slight and fleeting dimming, and a rare glimpse of a brighter knot. That's my mental image.
I understand the importance of seeing something and confirming it by actually seeing it. I've seen enough effects of some features on the image of a galaxy that I do not strive to see the feature itself to know it's there, rather to recognize the effect it has on the very dim image we do see and the weak signals we pick up on. Over time, I've learned to trust those weak, tantalizing, and nearly unseen effects. And I try to understand that, often enough, there is something present just below our perception of it to cause an effect we can barely detect as a very vague something in the image. Fleeting. Glimpsed. All those words apply. We just have to learn to trust them and ourselves. And, of course, verify.
Edited by Asbytec, 10 January 2020 - 03:25 AM.