WARNING! NEVER try to image or photograph the Sun unless you do so with an approved solar filter, which reduces light transmission by over 99%. Imaging without a proper filter can cause blindness and/or equipment damage.

Controlling the movements of the mount and collecting the images are essential functions. A laptop computer, tablet, or purpose-built device such as the ZWO AsiAIR is used for both purposes. The specific mount control and image recording device you use will depend on which mount and camera you choose.

SOLAR SYSTEM IMAGING

Sun and Moon:

Imaging is accomplished with single, short duration exposures only AFTER APPLICATION OF SOLAR OR LUNAR FILTERS!

Planets:

1. Choose the Right Equipment

  • Telescope: A telescope with a long focal length is ideal for capturing planets. A refractor or a Schmidt-Cassegrain (SCT) telescope with at least 8 inches of aperture is recommended.
  • Mount: Use a sturdy, motorized equatorial or altitude/azimuth mount for smooth tracking of celestial objects. Tracking is crucial because planets move quickly across the field of view.
  • Camera: A dedicated astronomy camera (like a CMOS or CCD camera) or a DSLR/Mirrorless camera can work. Properly set up, it is even possible with a mobile phone camera. Planetary astrophotography benefits from high frame rates to capture video, which helps to reduce the effects of atmospheric turbulence.
  • Accessories: A Barlow lens can help increase magnification and bring out more detail on smaller planets.

2. Plan the Session

  • Check Planet Visibility: Use a star-gazing app or astronomy software (like Stellarium) to know when a particular planet will be visible and high in the sky, as this minimizes atmospheric distortion.
  • Timing and Season: Plan for times when the planet is at its highest point above the horizon (culmination) or, ideally, when it’s at opposition (closest to Earth).
  • Clear and Steady Skies: Choose a night with clear weather and low atmospheric turbulence (good “seeing” conditions) to capture sharper images.

3. Set Up and Align the Equipment

  • Polar Align: If using an equatorial mount, accurately polar align it to ensure smooth tracking. If using an altitude/azimuth mount, alignment is achieved via training the mount on a few known stars.
  • Attach Camera: Attach your camera directly to the telescope’s focus tube or eyepiece holder.
  • Balance the Telescope: Properly balance your telescope on the mount to reduce strain and improve tracking accuracy.

4. Focus Precisely

  • Use a focusing aid like a Bahtinov mask or your telescope’s focusing knobs to achieve precise focus on stars. Many astrophotographers use live view or camera software for fine-tuning focus.

5. Capture Video or Multiple Images

  • Exposure Settings: Set a fast frame rate, ideally 20-30 frames per second or higher, to capture thousands of frames over a few minutes.
  • Set Gain and Duration of each Exposure : Use a high enough gain and exposure length to reveal details without overexposing the planet.
  • Video vs. Still Images: Capturing a video lets you use a technique called “lucky imaging” (stacking the best frames) to counteract atmospheric distortion.

6. Process the Data

  • Stacking: Import the video or still images into stacking software like AutoStakkert! or RegiStax. This software selects and combines the best frames, enhancing detail and reducing noise.
  • Wavelet Sharpening: Apply wavelet sharpening in software like RegiStax or similar program to bring out fine details on planetary surfaces.
  • Color Correction and Final Adjustments: Use image editing software (e.g., Photoshop, GIMP) for final color adjustments, contrast enhancement, and any additional sharpening to bring out features like Jupiter’s cloud bands or Saturn’s rings.

By following these steps, you will be on your way to capturing clear, detailed images of planets and improve your results over time.

DEEP SKY IMAGING

Astrophotography of deep-sky objects (DSOs) like galaxies, nebulae, and star clusters requires careful planning, the right equipment, and specific techniques. Here’s a step-by-step guide:

1. Choose the Right Equipment

  • Telescope: A wide-field refractor telescope with a shorter focal length (400-800mm) is ideal for deep-sky objects. Larger aperture telescopes gather more light, capturing fainter details. Some products, such as Starizona’s HyperStar device, can reduce the focal length and widen the field of view of Schmidt-Cassegrain Telescopes to make them suitable for deep sky objects.
  • Mount: An equatorial mount with tracking capabilities is essential for keeping the object centered during long exposures. For deep-sky photography, a GoTo equatorial mount (which automatically tracks objects) is highly recommended.
  • Camera: A dedicated astronomy camera (CMOS or CCD) or a DSLR/mirrorless camera can work well. DSLRs are great for beginners, while cooled astrophotography cameras reduce noise and capture faint details better. Mobile phone cameras are unlikely to be used successfully for these targets.
  • Accessories: A field flattener can correct distortions at the edges of wide-field images, and a light pollution filter helps reduce urban light interference. Narrowband filters permit passage of light of only certain wavelengths to reach the camera sensor and can be critical for imaging some deep sky targets, such as emission nebulae.

2. Plan the Session

  • Target Selection: Use star-gazing apps or software (like Stellarium or SkySafari) to decide which objects will be visible and well-positioned in the night sky.
  • Moon Phase: Try to photograph during a new moon or when the moon is below the horizon to avoid its light washing out fainter details.
  • Weather and Sky Conditions: Look for clear nights with minimal atmospheric turbulence (good “seeing” conditions) and transparency to capture sharper images of faint objects.

3. Set Up and Polar Align

  • Polar Alignment: Align the equatorial mount with the celestial pole (using tools like a polar scope or software-assisted alignment) to ensure accurate tracking.
  • Balance the Telescope: Properly balance your telescope on the mount to reduce strain and allow for smoother tracking. This step helps to minimize vibrations and improve image sharpness.

4. Configure the Camera and Focus

  • Camera Settings: Set your camera to manual mode. Use a low ISO setting (around 800-1600 for DSLRs) to balance sensitivity and noise, and use RAW format for capturing the maximum detail.
  • Exposure Length: Start with 1-3 minute exposures. Longer exposures capture more light, but tracking accuracy and noise management are critical.
  • Focus: Use a Bahtinov mask or live view to achieve precise focus. Focusing on a bright star near your target and then locking it in will yield sharp results for the entire field.

5. Take Multiple Exposures

  • Subframes: Take multiple exposures or “subframes” of your target to increase detail and reduce noise. Deep-sky imaging often requires dozens, if not hundreds, of exposures (e.g., 50-100 shots).
  • Dithering: Slightly shift the mount’s position between frames (dithering) to reduce sensor pattern noise. Many astrophotographers use guiding software (like PHD2) to automate this process.
  • Calibration Frames:
    • Dark Frames: Capture a series of dark frames (with the lens cap on) to record sensor noise and thermal noise.
    • Flat Frames: Take flat frames to correct vignetting and dust shadows. Flats are captured with a uniform light source like a flat panel.
    • Bias Frames: Quick exposures with the camera covered to capture read noise; often optional for beginners but improves image quality.

6. Stack the Images

  • Import to Stacking Software: Use software like DeepSkyStacker, Astro Pixel Processor, or PixInsight to stack your images. Stacking averages out noise and enhances the signal (details) in your images.
  • Stack Calibration Frames: Load the dark, flat, and bias frames into your stacking software to correct for noise, dust spots, and sensor artifacts.

7. Post-Process the Image

  • Image Stretching: Adjust the levels and curves to brighten faint details without overexposing brighter parts. This “stretches” the dynamic range to reveal more features.
  • Noise Reduction: Use noise reduction techniques to smooth out the background while preserving details. Astro-specific software like PixInsight has advanced tools for this.
  • Color Balancing: Adjust color channels to achieve a natural look and highlight the true colors of stars, nebulae, or galaxies.
  • Final Enhancements: Add subtle sharpening, saturation adjustments, and any other fine-tuning necessary to bring out specific features, like the color in nebulae or the detail in galaxies.

8. Review and Improve

  • Each deep-sky target may require different approaches. Experiment with exposure lengths, number of subframes, and processing techniques. Reviewing past images will help you identify areas for improvement and refine your process for future sessions.

By following these steps and continually practicing, you’ll be able to capture impressive and detailed images of deep-sky objects.