Revisiting a Still of Jupiter with Photoshop.

The day before Thanksgiving I went to the Plymouth Astrophotography SIG group.  It was an interesting meeting, but there was not to much instruction on the basics given to any of the newer people.  I actually missed the first 20 minutes or so of the meeting, so it's difficult to say if they gave any basic instruction.  They usually go over photoshop skills and photoshop demos where we can walk along with our laptops and a test image.  That didn't happen.

There was a showing of a photo being worked on and some work that some of the imagers did.  My images are far less technical and far less detailed as I usually shoot basic images with basic equipment.

There was also a slideshow about a trip one of the members took out west, which was interesting, inside a mirror factory that builds very large telescopes and an astronomy show. . . but I don't have photos of that presentation.

The topics were varied. . . just sitting around and looking at the photos others were working on gave me the desire to open up the simple Jupiter stills I took and play with them a bit in photoshop to see if I could improve them a bit more.

I choose a single still, a JPEG image.  I shot this in RAW and JPEG, but downloaded only the JPEGS to play with.  The Raw image might give better results, but I'm basically just learning how to enhance images a bit and this image is far from perfect in getting a good still image of a planet.  In practice it's better to take VIDEO recordings of planets and process these.  For the planets and moon an AVI file can be processed if you record an AVI file using a basic WEBCAM based astronomy camera on a telescope or use a dedicated camera, like the FLEA3 which can record AVI files which are much better for getting planetary images.

What usually happens at HJRO is I show up with a couple of cameras but not the Stellacam.  I usually have my iphone and Canon EOS t1i, which don't require a computer to control them.  Because I'm not using the Stellacam or the Meade Deep sky camera, I'm not capturing AVI files.  We will setup the HJRO computer for the Meade camera soon and fix it for the Stellacam, but right now I have to haul a laptop with me to control these and capture from these.  So to be quick, and not mess much with imaging, I'm usually not setup for Stellacam imaging.  After all I'm usually opening up for visual observing and imaging is often an afterthought, not a planned activity.  Deep sky imaging requires long exposures with our setups and we often don't dedicate the telescope for images. . . there more details to discuss but I'll spare you that in this post.

So I loaded up some JPEG images and found one that looked to have some pretty good detail.  I decided to tweak the image using photoshop, and we normally use curve controls to bring out details of faint objects.  Curve adjustments can do more than this, sometimes it can balance an image.  The curve filters most Astronomers use adjust the entire picture and we usually adjust the RGB curves all at the same time.  This to have a balanced color adjustment.  We don't want to alter the color balance much, but sometimes some will add color saturation to bring out details.  Most astronomers who post process, won't put in to much saturation or overly push the image, because they don't want over-saturated colors of levels to blow out the image and make it to bright and lose detail.

Most use curves for fainter images and bring up levels.  For a high exposed image, you may use curves that are "negative" which pull down levels.  This is usually suggested to get rid of sky glow, in the "Nebulosity manual" for example.  Most Astronomers don't use negative curve settings much to bring down brightness settings.

In this Jupiter image I used curves at first and then found out as I opened and worked on other images, that the HDR settings for an image offer a lot more control and tweaking ability.  I revisited a curved adjusted image of Jupiter and loaded that back into Photoshop and did some HDR processing.  I found that the DETAILS setting to bring out more details in the HDR filter could work some wonders.

The exported image was quite bright and over-saturated.  I brought down some of the color in Apple Preview and brought down the exposure a bit.  I was fairly happy with the result considering not a lot of detail was going to come out of one single still image of Jupiter.  You have to use many images and stack to get rid of noise and bring out more details.  Since I didn't have an AVI file for REGISTAX to work with I'd have to settle with bringing out detail from this single still.

The resulting image was over-saturated and had more color than some would like to see in a Jupiter image.  The color details bring out more detail that might not be present in a black in white image in this case, so pushing the color information helps bring out interesting features.

The resulting image looked pretty nice and sharp, with some nice details, but it's still far short of efforts others show with AVI recordings through a 2.5x barlow on a C14.  I shot this JPEG handheld using a Canon EOS through a 25mm eyepiece and 2x barlow.  That kind of image will never compare to an image taken in an AVI file and processed in Registax with the same C14 setup and sky conditions.

The final image had a little bit of noise in it that I thought might be cleaned up using Neat Image Noise reduction.  I loaded it up in Neat image and it cleaned up the image nicely.  I made some adjustments.  Usually noise reduction will take out some details in the image, if noise is inside the image itself.  For example the noise that might be in part of the image of Jupiter near the top pole in this photo may be reduced, but some band details might get a bit more fuzzy when that works.  Usually image processing on an astronomy image may reduce noise in the sky that is not the detailed information you have elsewhere in the photo.  I attempted to adjust noise in the planet's detail area.  This made the image a little softer than I would like it to be.  A few tweaks of the many settings in Neat Image Noise reduction and I was able to add back some details, using a detail enhancement setting inside the image program.

Many use softening to soften the noise in a photo of Jupiter or Saturn.  This may reduce fine details in the bands of gas in a Jupiter photo.  I don't like softening the photo to much.   To me Gaussian blurs are usually overkill and reduce detail in Jupiter images, especially near the edge of the planet's disk.

Here's the result.  It's far from perfect, but it gives you an idea of how much detail was visible in the eyepiece.  A human viewer would see an image that had a lot less color, but you would see some color in the eyepiece for Jupiter.

This image looks better on my Macintosh than on my iphone.  The image was over-processed to bring out details and that makes it look a little bit more like a painting than a photo.  You can see cloud band details however that were not clearly evident at the eyepiece.  The seeing conditions, stillness of the air was good enough for brief flashes of detail to appear at the eyepiece, but this was perhaps for only 5% of the time and most of the time the image would look a little more blurry than shown below and you'd catch the sharp image from time to time at the eyepiece.