[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Re: [APML] Comet Machholz 1/31/2005
Hi Wade,
Well, I guess I am not the correct person to answer your question <g>, but
both versions look fine to me. Indeed you removed vignetting very well with
DBE.
Perhaps I can help with what you are complaining about. I have downloaded
your first version (done with PI) and the background is very flat, but it is
not neutral. After background subtraction, this is the first problem that
must be fixed. It is very easy with curves. Look at the histogram of the
image. The green maximum is a bit too low, so the background has an overall
magenta cast. You can decrease red and blue a bit on the shadows to achieve
a nice neutral background.
On the other hand, the image can be improved a lot on the midtones. With a
single curves transform, both tasks (neutral background and midtones
enhancement) can be carried out very easily. This is my result with a curves
transform in PI:
http://pleiades-astrophoto.com/tmp/machholz_wade/Comet-Machholz11_01-31-2005.jpg
and this is the process icon with the curves used:
http://pleiades-astrophoto.com/tmp/machholz_wade/Comet-Machholz11_01-31-2005.pi-psm
Load the .pi-psm in PixInsight LE (right-click on the workspace, choose Load
Process Icons...) and apply the icon to the image. Perhaps with your
full-res image the curves should be adjusted a bit differently, but this is
the idea. Probably, better results could be obtained playing with luminance
and saturation curves.
Again, a very nice image.
Regards,
Juan
__________________________________________________________________
Juan Conejero, Pleiades Astrophoto Team
PixInsight Home Page: http://pleiades-astrophoto.com/pixinsight/
__________________________________________________________________
----- Original Message -----
From: "Thomas W. Earle" <twade@bmi.net>
To: <astro-photo@seds.org>
Sent: Sunday, March 20, 2005 9:09 AM
Subject: [APML] Comet Machholz 1/31/2005
>I have "completed" another one of my images of Comet Machholz. The
> vignetting associated with the Pentax 67 165 mm F/2.8 lens was
> "easy" to remove, but very difficult to get an acceptable image.
> The first image was created using PixInsight LE. I like how the
> nebulas stand out a little better with this version; however, the
> comet is pretty weak. The second version I used Photoshop to remove
> the vignetting. I like the comet better; however, the nebulas are
> weaker. Is there a way to have both worlds? I'm just learning the
> art of removing vignetting in an image so I'm sure there are better
> techniques. Any help would be greatly appreciated.
>
> Which version do you like the best?
>
> As you can tell, I'm not completely satisfied with either. Perhaps,
> a little more experience with PixInsight LE will allow me to fine
> tune the image (e.g. perhaps my "FLAT" is not ideal). Nevertheless,
> I'll continue my trek towards perfecting my technique.
>
> Here's the link:
>
> http://www.northwest-landscapes.com/html/comets/comet_machholz2.html
>
> You can find a higher resolution shot by clicking on the appropriate
> image.
>
> Thanks,
>
> Wade
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo