[marco (Marco Lorenzi)]

Originally Posted by multiweb

Looks pretty good to me Marco. Lovely colors and good details.

Thanks Marc!

Originally Posted by Tony_

Great image Marco - good to see you back!

Thank you Tony

Originally Posted by strongmanmike

Excellent image of a dynamic field Marco. Your colour processing is remarkably consistent, the colouring here is almost identical to your previous shot of the region with the TEC140, you must have a disciplined work flow

Thank Mike. I have the same processing routine on all my images. In fact the color of the brightest regions (as well as stars) is actually coming mostly from the calibrated RGB image, as it represents the best "reality" IMHO, I just blended in the higher contrast luminance signal coming from Ha and OIII. The faintest regions on the other side takes signal (and therefore color) mostly from the narrow band stacks. I make sure when I combine the NB that the actual color result is consistent with the RGB, to keep the overal feel "natural". I did the same on my older TEC140 image, which, despite having a bit less resolution (yet the Rifast is seeing limited here) and wider field of view, shares a similar overall color balance. Having said that, talking about colors in astronomical images is always a bit of a stretch, since actual "real" colors do not exist

Originally Posted by gregbradley

A wonderful wide and colourful field. A lot of tight small stars there so not sure what the fat FWHM you are referring to is here.
The top right corner stars look a hair out of focus compared to the other 3 corners so a very small amount of tilt.
Also with these scopes, focus will shift despite carbon fibre once the mirror achieves the same temperature +/- .5C. So if you focus when you start and the mirror hasn't achieved equilibrium then you will need to refocus once it does. In my case that takes about an hour.
I also use temperature compensation in case focus shifts with temperature drops. That may not be so critical with a carbon fibre scope but the first is.

Hi Greg, thanks. The FWHM is overall higher than 3" (in particular in the RGB), that is why I had to pay a lot of attention during the stretching to avoid getting the RGB stars becoming too "fat", even if you can still see it, in particular on the clusters. Deconvolution helped but not enough. I agree on your suggestions on the temperature compensation, even if I am actualy focusing every hour. What I am considering now is adding an external Atlas focuser (to install in a field trim in the coming months) in order to get a better sampling of the very narrow critical focus zone. This may help a bit improving the sharpness. Tilting I can adjust remotely, I have already did some tuning, unfortunately with the bad weather and smokes of last weeks I couldn't really test it but I am confident to fix it properly soon.

Originally Posted by Andy01

Hi Marco,
As you know I'm a huge fan of your work - but unfortunately not of this image.

To me it looks very HDR in the core region, too flattened and there's no dynamic range. Maybe it's just me agreeing with Dr. Malin in this case, but to my eye the brightest part of a nebula should appear, well bright!

Wonderful tight stars and the colours are lovely though!

I Andy, fair comment. It is always a difficult balance to keep on these high dynamic range fields, I more or less compensated the brighter parts of the nebula in a similar manner as I did it in my larger fov with the TEC140, however point taken, keeping a bit more brightness difference may improve the overall look of this area..

Thanks again to everybody spending time to comment the image
Clear (and not smoky) skies
Marco