NGC6188 Ha

DJScotty (Scott) · #1 24-07-2016, 02:01 PM

Working on a HaRGB of this area. Nearly finished. Just need some more B and G data. Hopefully the clouds will stay away up here in Brisbane.

This image is 5 hours of 15 minute Ha subs. have been experimenting with selective sharpening. I have a question to you all. Is it best to selective sharpen each layer or the finished colour image?

Done with PSCS6 and Astra Image plug in.

Any advice and criticism welcomed...

Cheers,

Scott

RickS (Rick) · #2 24-07-2016, 02:24 PM

Looks good, Scott.

Dunno how you have your layers set up but usually you only want to sharpen the luminance and not the colour.

Cheers,
Rick.

DJScotty (Scott) · #3 24-07-2016, 02:57 PM

Quote:

Originally Posted by RickS

Looks good, Scott.

Dunno how you have your layers set up but usually you only want to sharpen the luminance and not the colour.

Cheers,
Rick.

Thanks Rick. I will have to experiment.

gregbradley · #4 24-07-2016, 04:45 PM

Nice image there Scott. You've got the ridge nicely standing out.
In this case its a mono image but I do it both ways.These days though I tend to spend more time on the individual layers like luminance or Ha and get it to where it would stand as a standalone image before adding it together. But you can sharpen the final image selectively. Part of selective sharpening though is to block out any of the stars in the areas you do sharpen. With Photoshop that means painting the stars black to hide the sharpened layer so only the neb ridges are sharpened and not the stars.

A little bit of a sort out needed on your camera and tilt. The top right corner shows some coma and the bottom left look a little out of focus yet the middle and other areas are in focus. Tilt is a bit like collimation and when you get it right the images will look suddenly crisper and sharper as an overall impression.

Greg.

Atmos (Colin) · #5 24-07-2016, 06:19 PM

Lovely detail showing up, definitely looking forward to the finished version!

DJScotty (Scott) · #6 24-07-2016, 06:51 PM

Quote:

Originally Posted by gregbradley

A little bit of a sort out needed on your camera and tilt. The top right corner shows some coma and the bottom left look a little out of focus yet the middle and other areas are in focus. Tilt is a bit like collimation and when you get it right the images will look suddenly crisper and sharper as an overall impression.

Greg.

Thanks Greg. I am going to do both I think, sharpen all the layers selectively and then combine and also try combine and selective sharpen. See which is better.

In regards to the camera tilt, yes top right corner. The bottom left looks out because of meridian flip and associated flip of the camera position. Short of a tilt adjuster, not a lot I can do, and unfortunately I have run out of room in the imaging train. I guess I am stuck with it.

Once again, thanks Greg.

DJScotty (Scott) · #7 24-07-2016, 06:52 PM

Quote:

Originally Posted by Atmos

Lovely detail showing up, definitely looking forward to the finished version!

Thanks Colin. So am I!

gregbradley · #8 24-07-2016, 08:50 PM

.

In regards to the camera tilt, yes top right corner. The bottom left looks out because of meridian flip and associated flip of the camera position. Short of a tilt adjuster, not a lot I can do, and unfortunately I have run out of room in the imaging train. I guess I am stuck with it.

Once again, thanks Greg.

[/QUOTE]

What you do is first establish the orientation of the camera with respect to the images. So top right corner of the image is which corner of the camera? I used focus images and a dim torch to establish which corner of the image was which corner of the camera. In my case both top and bottom of the image was inverted and also swapped left to right. So top right on my images is bottom left on the camera looking at it from behind the camera.

Then I would pack out that corner with brass shims or spark plug feeler gauges. Usually its about .2mm or less that needs to be packed out.\You can do focus images at 1x1 binning and check the images in that corner until its corrected and then check the other corners to make sure they are all good and you are done.

Perhaps an hour to do.

Greg

DJScotty (Scott) · #9 25-07-2016, 06:30 PM

Quote:

Originally Posted by gregbradley

.

Then I would pack out that corner with brass shims or spark plug feeler gauges. Usually its about .2mm or less that needs to be packed out.\You can do focus images at 1x1 binning and check the images in that corner until its corrected and then check the other corners to make sure they are all good and you are done.

Perhaps an hour to do.

Greg

About to give that a crack tonight inbetween clouds. The camera screws directly into the filter wheel via a 5mm m54 thread. So if I pack shims inbetween the front flange of the camera and the FW at the appropriate corner that should do the trick right?

gregbradley · #10 25-07-2016, 07:42 PM

Quote:

Originally Posted by DJScotty

About to give that a crack tonight inbetween clouds. The camera screws directly into the filter wheel via a 5mm m54 thread. So if I pack shims inbetween the front flange of the camera and the FW at the appropriate corner that should do the trick right?

Yes that would probably work. In my case the camera inserts with a dovetail so you can pack it to some degree before it affects the other corners.

You may have to hold the shim when screwing it in as at some point its going to grab and spin the packer with it.

Alternatively you could put it before the filter wheel if there is a dovetail fitting in your system.

Greg.

DJScotty (Scott) · #11 25-07-2016, 09:03 PM

No dovetails anywhere in the train unfortunately. Plus it is completely cloudy. So will have to wait until tomorrow night. Thanks for the help Greg.