Even if the clouds ruined the details on the Moon, the colors variation introduced by their halos can transform a modest shot in an appealing image

 

 

This paper can be considered as another paragraph of the recent tutorial dedicated at the Moon rising along with Venus that you can read at this link:

http://www.dariogiannobile.com/blog/2014/3/Moon-and-Venus-rising-together

At the end of the night I decided to try some new shots using a Samyang lens (F 500 mm, f 6.3). The idea was to catch the earthshine on the Moon and Venus at the same time.

In spite of the clouds that made the image quite soft (the Moon details above all) I was determined to try in any case. I hoped to take advantage of them to increase and put in evidence the colored halos cast by the two celestial objects.

So let’s see the shooting conditions whose result can be seen in fig1:

• Canon 7D + Samyang 500 mm f6.3, iso 800, 1,6 sec

 

To decrease the noise induced by high iso, I stacked 10 shots in PS and the result can be seen in fig.2.

 

Moon and Venus averageMoon and Venus average fig.1

 

Moon and Venus cloudsMoon and Venus clouds fig.2

 

 

Both the shots have strength and weakness.

• The averaged shot (fig.2) has got low noise on the Moon, a pleasant light blue halo around Venus ma has not clouds texture. Further-more the Moon has got a cyanish halo mainly in the high-light that risks “to blow up” during the color saturation;
• The single shot (fig.1) presents an interesting clouds texture along with a red halo but has got high noise and an unpleasant lens flare that needs to be reduced before increasing color saturation.

 

For these reasons, the final image needs to be a merge of the two such as to put in evidence their best peculiarities.

 

 

Moon Sharpening

Let’s start from the Moon averaged image in the attempt to pick the details on its surface:

 

1. Duplicate the background layer;
2. Apply on it the UnSharpening Mask filter (USM) with the following values for amount, radius and threshold: 500, 5, 2 (fig.3A);
3. Apply on it a white mask and by means of a small black brush let’s mask  the white halos on the edge of Moon and Venus;
4. Duplicate the background layer and put it on top;
5. On this new layer, apply the USM with the following values for amount, radius and threshold: 200, 30, 0 and change opacity @ 50% (fig.3B);
6. Use a mask if need to stop the unwanted halos;
7. Merge down the layers and duplicate the resulting image;
8. Apply the USM with the following values for amount, radius and threshold: 300, 30, 2;
9. Modify opacity @ 50% in blending mode lighten.

 

Remember to mask Venus and not desired halos around the Moon’s edge. The final resulti is fig.3C and can be compared with the starting point fig.3D.

 

Moon and Venus USM1Moon and Venus USM1 fig.3

 

 

Color Correction

Once that the image for the Moon is ready, it is the moment to blend it with the ones that brings the clouds texture. The latter need the application of  the noise reduction filter (this is a single shot not an average) with amount 10 and color noise reduction 100%.

The final result can be obtained merging three layers: one for Moon’s details, one for Venus’s halo (in color blending mode) and one for clouds’ texture. Simple masks created by means of the brush tool can be used.

Now we need to color correct the lens’s flare and the cyanish halo around the Moon:

1. Apply a layer curve to correct the cyanish halo with a white mask;
2. Apply the b inverted channel of Lab to the mask;
3. Fill with grey @50% and then auto-tone;
4. Apply a curve to the mask until you close the shadows and eventually mask even Venus;
5. Blur with a radius of 20 - 30 pixel (fig.4A);
6. At this point we can use the layer curve to reduce the cyan;
7. Repeat the steps from point 1 but use the a channel of Lab instead of “b inverted” until you get the mask in fig.4B;
8. Use the layer curve to reduce the magenta and the luminosity.

 

Moon and Venus mask1Moon and Venus mask1 fig.4

 

 

The color corrected image is shown in fig.5

 

Moon and Venus Color correctionMoon and Venus Color correction fig.5

 

 

Boosting Color and Creating Color Variations

To boost the colors and create color variations I used two well-known technics from Dan Margulis:  the Modern Man from Mars and the Color Boost both launched by the Dan Margulis’s PPW panel (free download from internet).

I made the following adjustments:

• MMM color opacity from 30% to 50%   
• Group opacity from 100% to 45% (Fig.6).

 

Moon and Venus CB and MMMMoon and Venus CB and MMM fig.6

 

 

Final Retouch

The clouds’ texture can be improved by an HiRaLoAm (high radius – low amount) USM.

To do that just apply the Davide Barranca’s little hammer action with  amount 300, radius 30 and threshold 3 and reduce the opacity to 33% then merge down.

Eventually, if some noise appears after the USM, apply the noise reduction filter only to the clouds (fig7).

 

Moon and Venus adjusting cloudsMoon and Venus adjusting clouds fig.7

 

 

The very last retouch were aimed to increase the color and luminosity contrast by means of a “S” curve to the L channel of Lab and an increase in the blue saturation in the sky (fig.8).

 

Moon and Venus final contrast and colorMoon and Venus final contrast and color fig.8

 

 

I even used the dodge tool on the little stars on the left hand side of the picture to give it depth (fig.9).

 

Moon and Venus conjunctionMoon and Venus conjunction fig.9

 

 

This is the comparison between the final image and the original shot (fig.10).

 

Moon and Venus before - afterMoon and Venus before - after fig.10

 

 

I think that, even if the clouds ruined the details on the Moon, the colors variation introduced by their halos can transform a modest shot in an appealing image. Even in this case the use of the action MMM and CB along with the power of Lab color space can be considered the crucial step in the workflow.

Do not forget that even the best shot you can do will not compete with the nature show itself!!

 

If you think that this Tutorial could be useful to other astronomy and astrophotography amateurs, please feel free to share it!!

Paint the Sky, Share your Knowledge!!

Ciao

Dario