GIOTTO flat field generator

The GIOTTO flat field generator is designed to produce calibration frames for astrophotography by delivering consistent and even illumination across the telescope's aperture. It works with a variety of telescope types and sizes, as long as the selected model provides a panel diameter larger than the external tube diameter of the telescope. This ensures that the entire optical path is evenly lit, which is required to correct for vignetting and dust shadows in image post-processing.

The device uses a series of LEDs with a color temperature chosen to resemble daylight. A built-in light diffuser ensures that the brightness is distributed uniformly across the illuminated panel. Flat frames created this way allow astrophotographers to remove unwanted gradients and optical defects from deep-sky images, especially when combined with dark and bias frames during calibration.

GIOTTO flat field generator

Each GIOTTO model includes a control panel with a USB-C port for wired connection to a computer, including the PrimaLuceLab EAGLE system or any Windows PC. The generator also includes WiFi capability, allowing remote operation through a Virtual HandPad interface. Light intensity can be adjusted in 100 steps, from 0% to 100%, giving users precise control over the brightness of the panel for use with various filters and sensor sensitivities.

The unit mounts to the front of a telescope using plastic thumbscrews, which are included with each model. These screws are used to grip the dew shield or outer tube without damaging the finish. The fit is adjustable, allowing for quick attachment and removal as needed. The thumbscrew system avoids the need for handholding or repositioning the scope to aim at a white surface, streamlining the calibration process.

Compatibility extends to a wide range of telescope designs. As long as the telescope’s external diameter is smaller than the GIOTTO’s illuminated panel, the device can be securely mounted. This includes refractors, Schmidt-Cassegrain designs, aplanatic SCTs, Ritchey-Chrétiens, and other common formats. Additional accessories may be needed to achieve proper positioning on telescopes with short mounting bars.

The GIOTTO system integrates with PrimaLuceLab’s PLAY software, which includes tools specifically for flat frame acquisition. Users can create and manage calibration files directly within PLAY, or they can connect GIOTTO to other imaging platforms using the provided ASCOM driver. This flexibility allows integration into a variety of imaging workflows without requiring exclusive use of one software environment.

The Virtual HandPad interface allows for control without a computer. By connecting a phone or tablet to the GIOTTO WiFi network, users can power the unit on, adjust brightness, and save preset settings for future use. This is useful when operating in the field without a computer, or when managing multiple filters that require different lighting levels.

For remote or automated systems, GIOTTO can be converted into a motorized telescope cap with the addition of the ALTO telescope cover motor. This optional add-on attaches to common dovetail rails such as Vixen or Losmandy style bars and allows users to open or close the generator remotely. When integrated with automation systems, this feature supports full hands-off operation, including calibration file capture and telescope protection during idle periods.

GIOTTO, end of the struggle with dust and vignetting

GIOTTO flat field generator models

• GIOTTO 120
• GIOTTO 150
• GIOTTO 185
• GIOTTO 220
• GIOTTO 255
• GIOTTO 285
• GIOTTO 320
• GIOTTO 430
• GIOTTO 560
• GIOTTO for Origin (designed for Celestron Origin telescopes)
• Custom GIOTTO (for observatory-class telescopes)
   

GIOTTO flat field generator specifications

• Illuminated Panel Diameter: Varies by model, ranging from 120mm to 560mm.
• Compatible Telescope Aperture: Each model is designed for telescopes with apertures up to its respective illuminated panel diameter.
• Mounting: Thumbscrews included for securing the generator to the telescope's front tube or dew shield.
• Light Source: LED lights with a color temperature similar to sunlight.
• Light Diffuser: Specially designed for even illumination across the field.
• Light Intensity Adjustment: Adjustable in 100 steps from 0% to 100%.
• Connectivity:
• USB-C Port: For connection to EAGLE or standard Windows computers.
• WiFi: Allows wireless control via smartphone or tablet using the included Virtual HandPad.
• Power Supply: Operates on a 12V power source.
• Software Compatibility:
• PLAY Astrophotography Software: For controlling the generator and capturing flat frames.
• ASCOM Driver: Allows control through third-party software.
• Optional Accessory: Compatible with the ALTO telescope cover motor to convert the GIOTTO into a remotely controlled motorized cap.
   

PrimaLuceLab: How to attach GIOTTO flat field generator to the front of your telescope

The GIOTTO flat field generator is used to produce evenly illuminated calibration frames, which are necessary for correcting optical vignetting, sensor dust, and other variations in astrophotography. The device attaches to the front of a telescope and provides a consistent light source across the entire aperture. Proper attachment ensures flat field frames are captured accurately and can be used in post-processing to clean up image artifacts.

To install the GIOTTO generator, it should be positioned directly in front of the telescope’s aperture. The unit comes with thumbscrews made of plastic. These screws are used to fasten the generator to the telescope’s dew shield or front tube without damaging the surface. The screws should be tightened just enough to hold the unit in place without shifting or applying too much pressure. Centering is important. The flat field light must cover the full diameter of the telescope opening to avoid uneven illumination.

The size of the GIOTTO model must match the scope correctly. The diameter of the white illuminated panel should be larger than the outer diameter of the telescope tube or dew shield. This ensures the light source covers the entire front opening. A panel that’s too small can cause shading at the edges, which ruins the purpose of the flat frame.

There is a version of the GIOTTO made specifically for the Celestron Origin telescope. This model does not use thumbscrews. It’s shaped to match the front of the telescope and fits directly onto it without adjustment. The fit is mechanical and relies on alignment with the Origin’s outer casing. Once pressed into place, it's ready to use.

After installation, the GIOTTO generator can be used to capture flat field frames as part of a normal astrophotography workflow. These frames are later combined with light frames and other calibration images during image processing to remove defects caused by optical issues, sensor dirt, and field illumination gradients.

GIOTTO, the smart flat field generator

The mounting system is designed to work with a wide range of telescope types. The thumbscrew method allows flexible fitting without requiring tools. The plastic material prevents damage to painted or metal surfaces. Installation takes only a few minutes and doesn't require any prior experience with calibration tools.

Using the correct size model is the only key decision required before setup. Measure the external diameter of the telescope or dew shield and choose a GIOTTO unit with a larger light panel. This approach ensures that the entire field is illuminated uniformly, which is necessary for effective flat correction. The generator provides a flat light source when activated, but how it is powered or triggered isn’t covered here.

In short, attaching the GIOTTO generator involves placing it against the front of the telescope, tightening the thumbscrews just enough to hold it firmly, and ensuring it’s centered. For the Celestron Origin version, it is pressed into place with no tools or alignment required. The device is used for capturing flat frames to correct image flaws during processing. Selecting the correct model size based on the scope’s outer diameter is critical for proper function. No special tools or adjustments are needed beyond this.

How to attach GIOTTO flat field generator to the front of your telescope

GIOTTO, the smart flat field generator

Buy the GIOTTO flat field generator