Moon – PekDar – Astrophotography Engineering

AutoStakkert! and Lucky Imaging: The Mathematical Battle Against Atmosphere

PekDar — Fri, 15 May 2020 06:27:12 +0000

AutoStakkert 2

Learn the best settings and a step-by-step process to stack your Lunar light frames in AutoStakkert and achieve sharper, high-resolution Moon images.

The Seeing Problem

Why is a single DSLR photo of the Moon rarely perfectly sharp? The culprit is Earth’s atmosphere. Air masses of different temperatures mix, creating turbulence that acts like lenses with varying focal lengths. This phenomenon is called seeing. In classical photography (long exposures), seeing blurs details. The engineering solution is the Lucky Imaging technique.

Mechanism: Statistics and Video

Instead of a single photo, we record thousands of video frames with very short exposure times (milliseconds). Statistically, within a second, there are moments when the atmosphere “freezes” for a fraction of a time and becomes perfectly transparent. The role of AutoStakkert! is to analyze each of the thousands of frames, grade their quality (sharpness), and select only the “lucky” ones (e.g., the best 10-20%).

At first impression, the AutoStakkert user interface does not seem easy to use. However, after getting to know the key options and understanding how the program works, its interface not more to be a secret. We will go through the stacking procedure, processing sample of Moon light frames, which I collected in the early spring of this year.

PIPP (Planetary Imaging PreProcessor): The Essential Step Before Stacking

PekDar — Wed, 22 Apr 2020 11:20:37 +0000

PIPP astrophotography – Why Not AutoStakkert! Immediately? After recording a Moon video (in SER, AVI, or other formats), many beginners skip the pre-processing step in PIPP and directly load files into AutoStakkert!. However, PIPP solves critical recording issues that significantly improve the efficiency and quality of the final stack. Problem 1: Motion and Jitter (Dynamic Tracking) During video recording, even with a perfectly aligned mount, subtle vibrations, tracking errors (PEC), and object shifts (e.g., the Moon drifting out of the center) occur. PIPP’s Role: PIPP analyzes each frame and shifts the image so that the key object (e.g., the Moon disk) remains perfectly centered (dynamic centering) and stable in the X and Y axes. Benefit for AS!: AutoStakkert! performs alignment much faster and more precisely when the target object is not moving chaotically throughout the video. Problem 2: Optimization and Conversion (Frames Optimization) Planetary cameras often record video in formats and resolutions that are not optimal for AutoStakkert! (e.g., 8-bit Y8/MONO format). Conversion: PIPP provides fast and lossless video conversion to the most preferred formats. It allows conversion from uncompressed to efficient formats, as well as converting a monochrome Y8 signal to simulated RGB. Cropping for Efficiency: PIPP allows for precise cropping of the Region of Interest (ROI). If the entire Moon disk takes up 1000×1000 pixels, but the rest of the frame is a black void, PIPP cuts out this unnecessary black area. PIPP Step-by-Step Usage of the PIPP program is relatively simple. It is recommended to follow the step rules – from left to right, going through all the tabs of the program, starting from the Source Files tab and ending with the Do Processing tab. We will go successively through the tabs, processing the Moon with an example light frames that I collected. I will focus only on those options that I need to use. It is not my goal, to describe every available option, that’s why the manual is available on the PIPP page. EXIF parameters, for my light frames you can find below. The camera with default optical configuration. Movie file: file .MOV 1,4GB, RGB Width: 1920, Height: 1080, Duration: 3min. 5 sec., bitrate: 63,5MB/s, FPS: 25 Let’s start processing with movie file. Start PIPP from software list of POL. Source Files tab Click on Add Image Files in the below area of PIPP window. In the file selection window add a movie file and click Open. After you selected the file, the program will open a new, additional window with preview frame of your movie file. The preview image can be enlarged by changing the Zoom value or by clicking the – / + buttons. The Update Image button is used to update the preview after making configuration changes on the other tabs as described below. The Save Image button will save visible image as selected file type .JPG, .PNG, .TIFF, or Windows bitmap. Go to the next tab. Input Options tab The options and functions available on this tab, will apply mainly to video files made by dedicated astrophotography cameras. In the case of DSLR cameras use, usually there is no need to change anything on this tab. Optionally, you can use the available functions: Enable Raw Image Hot Pixel Filter – will remove unwanted hot pixels if the video file has one, Input Frame Colour/Monochrome – set to Color if you know your video is colorful. Go to the next tab. Processing tab On this tab, we can already slightly improve the image visible in the preview window. In the case of my light frames, the image is inverted relative to the real one. I will use the available option to invert the image horizontally. I’m selecting the Flip Horizontally option. In addition, during my camera recording video file, it orientated the image of the moon in horizontal instead of vertical position, so I have to rotate the image in 90° clockwise degree. So, I need to click on the drop-down list in the Flip And Rotate area and choose the Rotate 90 Degrees Clockwise option and then on the Test Options button to see the final effect of the changes. Preview changes below. Go to the next tab. Quality tab None of the options available on this tab will be used with my movie file. Go to the next tab. Animation tab Leave the available options in the default configuration. Output tab The purpose of processing a video file, is to divide it into individual frames that will be stacked later in dedicated software. The best type of photo file saving available in PIPP is .FITS in my opinion and we also choose it. I don’t want the resulting files to have suffix pipp_ attached at the end of their name, so I delete the entry in the Output Filename Suffix field. I want the resulting image files to have a prefix called pipp_ before the name and I entered this prefix in the text field Output Filename Prefix. Go to the next tab. Do Processing tab Click the Start Processing button and wait. Depending on the number of movie frames, processing may take some time. In my case, it took less than 4 minutes to process the video file containing 4637 frames. So, was pretty fast. Now you can proceed, to stacking light frame files in the program, e.g. AutoStakkert, RegiStax6 or Siril. Conclusion: PIPP does not improve sharpness but stabilizes, normalizes, and optimizes the data. This makes it the gatekeeper, ensuring AutoStakkert! receives the best, cleanest, and most organized material for the actual stacking process. Links PIPP main page: https://sites.google.com/site/astropipp/home Download page: https://sites.google.com/site/astropipp/downloads Description about installation process with Linux system, but it’s much different from here: https://sites.google.com/site/astropipp/downloads/installing-pipp-on-linux-with-wine Description about installation process with macOS system: https://sites.google.com/site/astropipp/downloads/installing-pipp-on-macos-with-winebottler PIPP Manual: https://sites.google.com/site/astropipp/pipp-manual PlayOnLinux: https://www.playonlinux.com/pl/

The Moon’s First Quarter: A Theater of Shadows and Detail

PekDar — Wed, 15 Apr 2020 15:30:41 +0000

Moon first quarter

Why Not the Full Moon? Beginner observers often wait for the Full Moon, thinking it’s the best time for photography. In reality, a Full Moon appears “flat” because sunlight falls perpendicular to the surface, eliminating shadows. The First Quarter is a magical moment—the Sun illuminates the Moon from the side, bringing out monumental mountains and deep craters along the terminator line.

The Terminator: The Boundary of Light and Dark

The terminator is the line separating the illuminated part of the Moon from the part shrouded in night. This is where the action happens. Due to the low angle of sunlight, even small elevations cast long shadows, allowing us to perceive the three-dimensionality of the terrain.

What to Photograph During the First Quarter?

During this phase, some of the most spectacular formations appear along the light line:

The Crater Triad (Theophilus, Cyrillus, Catharina): An impressive group of three large craters with varying degrees of erosion. Theophilus has prominent central peaks that cast sharp, long shadows across the crater floor during the first quarter.
Albategnius Crater: A large, ancient crater with a distinct central peak that is among the first to emerge from the darkness.
Mare Serenitatis (Sea of Serenity): Along its shores, systems of ridges and faults are visible, appearing like ripples on a water surface under side-lighting.

Technical Tip: Exposure Time

During the first quarter, the dynamic range of brightness is immense. Bright highlands are very high-contrast compared to the dark “maria.” During your session, try not to overexpose (blow out) the bright edges of the craters—it’s better to slightly underexpose and recover shadow details during post-processing (e.g., during the stacking process in AutoStakkert!).

Moon – first quarter

My first photo of the Moon. It took me a long time to finally snap a picture of it—I just couldn’t bring myself to dive into the topic. Once I had gathered the photo and video material, I procrastinated again when it came to processing it. Maybe it’s because photographing the Sun, Moon, or planets is a completely new subject for me. Eventually, I sat down and the fun began. While wrestling with AutoStakkert and editing the images, some side projects emerged—let’s call them… oh never mind. When they’re ready, you’ll find out right here on this page.

Light Frames:

114 x ISO 12.800, 0,00025[s],
RAW files of .CR2 with conversion to .TIFF (16-bit) file type, 5488×3662 [px].

Processing:

AutoStakkert v. 2.6.8
RawTherapee v.5.8
Gimp v. 2.10.14