hi Jay, Blush... thanks. The line (like a cat scratch), is just another small galaxy up there. But it does not look so good due to excessive sharpening that I had processed into the image (I suspect).

thanks Jay, Planetary tracking is a different animal entirely. I know nothing about that, absolutely nothing. With math and software I imagine the subject can be tracked, (like Jupiter, but I don't if a particular moon is trackable yet).

Anyway though, I suspect part of the secret sauce for processing such a thing is to get tracking shots of the subject and get shots of the moon as well, and separate them, and process them alone, and then composite them back together again.. You are right that the moon since it moves differently than the planet it circles, would I suspect show as a blur or some such depending on how long the exposures add up to and how fast it is moving.

I am sure that I am not saying it well. When I say reduce noise, perhaps it is better to say that it eliminates that which it recognizes as random. And it keeps that which reinforced as being signal. Or valid data if you will. So through the miracle of stacking (math and statistics), you end up seeing deeper and more clearly than you otherwise might.

But yeah, it depends on what you are seeking to see and understand. If you desire to capture the pure moment, rapidly unfolding then the only solution is to improve the resolution of it all. To capture more light more quickly and with greater sensitivity. Stacking is but the poor man's tool to make the most of what we are given.

The cosmos as we view it, it is SLOW and obscenely massively large, and so to be able to see it more fully, the cheating of stacking works very well.

And please don't take my wild rambling about this all to the bank. Like all photography, recognizing the difference between truth and lies requires a connection between the viewer and the object viewed and somehow a mechanical processes touches the soul and becomes Art. Lies and truth, signal and noise, but words that depend on the connection between the seer and the seen.

Or to say the same thing in a more powerful way... the famous quote - "And if you gaze for long into an abyss, the abyss gazes also into you."

thanks Sonny, and
Richard, thanks for asking. Yeah the mount tracks the stars (once it is polar aligned). Without tracking you are hard pressed to have an exposure longer than a couple of seconds for a telephoto lens before stars start becoming elongated. And then there is guiding... which is a smaller lens/sensor that takes photos every couple of seconds and makes small guiding adjustments to the tracking. This allows the larger telephoto lens to stay on target for 300 or 500 seconds. In the image of M51 for example we have about 35 images taken with each exposure being at 300 seconds, and then the software stacks (blends) the images together.

The stacking software is very sophisticated and does a wonderful job recognizing signal and getting rid of noise. For instance, each image taken might have a satellite trail in it, but they are eliminated from the final result because the software recognizes that the trail is not in all the images, so it gets ignored.

thanks Seal, Bruce, Skyking, bwa, and Richard.

Richard, here is my hardware used for this shot:
ZWO 130 mm Apochromatic Quadruplet Refractor Optical Tube (the telescope)
ZWO AM5 mount (mount tracks the stars)
ZWO ASIAIR Plus (computer tells everything what to do and holds the images)
ZWO ASI2600MC-Duo (camera which includes a built in guide sensor)
ZWO EAF (computer uses this motor to put scope into focus)
Optolong L-Pro (filter cuts through light pollution and moonlight)
Jackery battery (gives me two power feeds one used by mount and one used by computer - which feeds juice to camera)
Pixinsight - software used for stacking, image stretching and processing (very hard to learn, I am a noob with it)
Photoshop - used to tweek colors and saturation since I am such a noob with pixinsight.

Learning curve is likely an order of magnitude simpler than it was a decade ago!!!

man that looks cool!

M51 from last couple of nights, and I can see that the space time continuum is starting to rip again...

(Download)

love the color scheme! I tried to get it a few weeks ago but was already struggling with how little time it is there, and I think my exposures were much too long. Beautiful job!! But dag gone it, since you have it star aligned and comet aligned, can you remove stars and but them back in from the star-aligned photo?

thanks so much - just SO MUCH to learn!! Key for me in this leap forward (for me anyway) was recognizing that the color channels had different degrees of "stretchability" available. So I broke the color image into its RGB components and stretched each to my satisfaction looking for additional detail. And then combined them back again and learned a little how to work with masks to control colors here and there.

I revisited Orion and took another stab at it, but using a 1000mm telescope to see what I could come up with. This is around 30 four minute exposures..

(Download)

thanks Ballard

thanks Richard, my eyesight is not as good as it used to be and is getting worse too I fear. Never worry about fooling with an image I put up, I enjoy seeing what you did with it. I really like the colors you worked you emphasized.

Hi Richard, I think your update to the image is AWESOME - and that form/shape/dust of the Nebula is exciting to see. The skill does not belong to me, it is just the technology is really good now-days, things are easier to figure out. The hardware is smarter. I am glad that you enjoyed playing with the image and especially I am enjoying looking at your version.

thanks alberio, everything about it is a compromise. If you get the proper light, you blow out the middle - so this rendition captures some of the detail but it does not capture the bold and violent brightness of it. Our view of Everything is filtered and determined by the lenses we choose to view with.

thank you Bruce - I appreciate your encouragement!