Connected telescopes let you photograph the deep sky without having to master every step of astrophotography right away. The instrument handles the pointing, tracking, and stacking of images. As the observation progresses, a galaxy or nebula appears on the phone’s screen.
However, this simplicity does not prevent you from processing the images yourself. To do so, you must first retrieve the files recorded by the telescope and understand what they contain. In fact, the photo available in the app—which is already a stacked image—and the individual exposures do not allow you to perform the same processing.
The purpose of this tutorial is to explain How to retrieve raw files from a Seestar, a DWARF from DWARFLAB, or a Vespera, and then prepare them for processing on a computer. Before moving on to the actual steps, I’d like to revisit a distinction that helps clear up a lot of confusion: the difference between a raw image and a stacked image.
When a connected telescope photographs a deep-sky object, it takes a series of exposures. Let’s take an example: a session consisting of 300 10-second images results in a cumulative exposure time of 50 minutes.
These images are gradually aligned and combined by the telescope. This is what is known as stackingor stacking. This process improves the signal-to-noise ratio of the photographed object in the images.
From that same session, you can retrieve several types of files.
Raw data refers to the individual measurements taken during the observation. They are also called single poses, lights or subframes.
In our example, retrieving the raw data means retrieving the 300 individual frames. This allows you to examine them, discard certain images, and perform your own image stacking.
However, the term «raw» alone does not specify the corrections already applied by the telescope. The behavior of the model used must be taken into account when addressing calibration and processing.
The stacked image contains the result of combining the exposures. It allows you to resume processing without having to restack the images.
This distinction is important because A FITS file is not necessarily a single raw image. At DWARFLAB, for example, an observation file may contain individual frames and a pre-stacked FITS file. At Vespera, the TIFF export feature allows users to retrieve a stacked image for processing. These differences are described in the documentation for DWARFLAB and Vaonis.
In other words, you need to look at the file's purpose, not just its extension.
A JPEG is an image that has already been processed for brightness, contrast, and color. It is generally the most convenient file format for sharing the results of an observation.
To resume processing with greater flexibility, use the files provided for this purpose instead.
| Objective | Files to Retrieve |
|---|---|
| Share the results of the observation | Final JPEG |
| Edit the image without rebuilding the stack | FITS or stacked TIFF, depending on the telescope |
| Sort the poses and create your own stack | Individual Gross Scores |
| Save treatment options for later | Complete session materials |
The procedures described below apply primarily to deep-sky photography. Video, solar, or lunar modes may produce other types of files.
With a Seestar, the first step is to verify that the individual exposures have been saved correctly. Just because you see an image being built in the app doesn't mean that all the data needed for a new stack has been saved.
In the app, look for the option Save each frame, which corresponds to the recording of each image.
The location of this setting has changed. In older interfaces, it appears in the advanced settings, under Advanced Feature or Advanced Settings. Recent interfaces offer this option in the deep-sky observation screen settings, as shown in the Seestar S30 Pro User Manual.
You must enable this option before beginning the acquisition. A stacked image does not allow you to retrieve individual frames that were not saved.
To check the settings, a short session is all it takes: a few exposures are enough to verify that the files are there before starting a longer observation.
USB transfer allows direct access to the telescope's storage.
The source files are stored in the instrument's internal memory. Instructions for retrieving them via USB are described in the Seestar Official File Storage Guide.
Choosing the right cable requires special attention. Some cables are designed for charging only: this means the telescope can receive power without appearing on the computer.
In the Seestar storage, open the folder MyWorks, then search for the poses that match your target.
ZWO describes files with the suffix _sub, for example M42_sub for observing the Orion Nebula. These are the folders you need to look for to retrieve the individual images. The path is shown in the Seestar documentation.
Next, copy the folder to the computer. If multiple observations of the same object were made, check the file dates to identify the correct session.
At this stage, the check is simple: to rebuild the stack, you need a series of individual shots. A final image and its thumbnail do not constitute this series.
It is also possible to use the station mode, known as Fashion Station or STA. The telescope then joins the local network to which the computer is connected.
In the Seestar app, open the Wi-Fi settings, enable access point mode, and select your network. Then note the IP address assigned to the device.
To access the files:
\\IP_ADDRESS in the File Explorer address bar.smb://ADRESSE_IP.Replace IP_ADDRESS using the address displayed in the app. Open Share EMMC Images, then MyWorks. The steps are detailed in the ZWO guides on the station mode and theAccess to storage from Windows and macOS.
At DWARFLAB, the method depends on the model. The DWARF II uses a microSD card, while the DWARF 3 and DWARF mini have internal storage accessible via USB.
The DWARF II and DWARF 3 manuals describe a setting Subframe Format, which lets you choose between FITS and TIFF for individual poses.
The choice should be based on the intended processing. If the tutorial you want to follow uses FITS files, selecting this format at the time of acquisition will make the rest of the process easier.
It is also important to distinguish between the format used for the exposures and that of the final result. DWARFLAB specifies that individual images can be saved in TIFF format, while the stacked image is saved in FITS format. This process is explained in the manuals for the DWARF II and DWARF 3.
The session folder contains the individual images as well as files generated during the observation. The goal, therefore, is to identify the sequence of exposures without confusing it with the stacked result.
Other files may also be present: CALI_FRAME contains calibration files, DWARF_DARK individual Darks that have been captured and Restacked the results of Mega Stack. DWARFLAB explains this structure in its DWARF 3 File Guide.
Initially, keeping the complete file allows you to postpone sorting until the time of processing.
With the DWARF II, you can retrieve files directly from the microSD card:
This method works on Windows and Mac.
On Windows, a USB connection is also possible by leaving the card in the DWARF II. To do this, you must turn on the device and enable MTP Mode in Settings → Advanced Settings of the app. Storage becomes accessible from This PC.
Both methods are described in the Official Guide to DWARF II.
The DWARF mini can also be connected to a computer using a USB data cable. It appears as a storage device on Windows and macOS.
DWARFLAB notes that recently captured files may require you to log out and then log back in before they appear. This step should be performed after all current transfers have completed. See the DWARF mini File Recovery Guide.
According to Vespera, the first step is to identify the instrument's generation. The presence of a USB-C port does not mean that all models use this connection to transfer images.
According to the Vaonis documentation, the methods are broken down as follows:
| Model | File Transfer |
|---|---|
| Vespera Original, Vespera II, Passengers, X Edition, and Vespera Pro | Wi-Fi via FTP |
| Vespera III and Vespera Pro 2 | USB-C |
You select the files to save within the app Singularity.
This selection is described in the Vaonis Guide to Image Formats.
Here again, the choice depends on the work you plan to do. The TIFF file allows you to begin processing the observation data. The individual FITS files allow you to resume the stacking process.
For models that use Wi-Fi, Vaonis provides a procedure that involves FileZilla Client. FTP is simply the protocol used to transfer files between the telescope and the computer.
Install FileZilla before connecting to the Vespera's Wi-Fi network, then:
10.0.0.1 in the field Host.The Vaonis guide does not require you to enter personal account information for this login.
Once you're logged in, open USER, then the folder for the session you're looking for.
The subfolder 02-initial-images contains the images from the observation. 01-initial-pointing corresponds to the initial count.
Select a destination folder on the computer, then right-click the remote files or folder and select Download. Wait until the operation is complete and check to make sure there are no failed transfers.
The File SYSTEM contains data specific to the instrument; the observations to be retrieved are located in USER. The entire procedure is outlined in the FileZilla Tutorial by Vaonis.
These models use the USB-C transfer technology announced by Vaonis.
On a Mac, the manufacturer notes a specific requirement: an adapter or connector with a USB-A port is required to establish the connection. If the direct USB-C connection does not work, see the Vaonis Connection Diagram for Mac.
Singularity allows you to save JPEG and TIFF images to your phone or tablet. To retrieve individual FITS frames, you must access the instrument's storage.
This difference explains why exporting a photo from the app does not necessarily mean saving the raw files from the session. Vaonis outlines the options in its Vespera Image Recovery Guide.
Once the copy is complete, you'll need to verify that the expected data is actually there. Open several images and compare the number of files and the folder size with those on the telescope.
Do not discard the originals until you have checked the copy. A second backup is also useful for sessions you want to keep.
To organize your observations, a descriptive folder name is sufficient, for example:
2026-09-10_M31_Seestar-S50_10s
This filename identifies the date, subject, telescope, and individual exposure time. Inside the folder, keep the original files and place your processed images in a separate folder.
If you need to combine multiple nights of data, keep the sessions separate at first. You can then review the settings and select the appropriate data for the same stack.
This may be the image that has already been stacked. Check the folder containing the individual frames and the recording settings used during acquisition.
If the poses have not been saved, they cannot be reconstructed from the final result.
A dark image at the start is not necessarily empty. Data may be present without the brightness stretching used to display faint details.
Specialized software allows you to scale the display to inspect the image. Vaonis explains this behavior in particular for the TIFF files exported by Vespera.
Siril allows you to continue with stacking and processing. In particular, the project offers a tutorial on Seestar images.
You must choose a procedure that is appropriate for the model and the acquired data. The steps required for a set of raw images are not the same as those for an image that has already been stacked.
It depends on the corrections that have already been applied to the files. Therefore, you should check that the telescope is functioning properly before running a calibration.
In Vespera Pro, for example, Vaonis notes that automatic calibration does not modify the individual FITS files, although it may affect the TIFF file intended for processing. This point is documented in the Vespera Pro FAQ.
Saving the raw data allows you to revisit an observation later, with greater control over the processing. This requires more storage space, but makes it possible to compare different stacks without having to repeat the acquisition.
Before the next long session, it’s therefore most helpful to test the entire procedure on a few exposures: check the recording settings, transfer the files, and then open them on the computer. This check lets you know exactly what data will be available at the end of the observation.
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