Vespera Raw FITS Files: How to Get Them and Stack Them on a Computer

A Vaonis Vespera stacks on the telescope and shows the finished picture in the Singularity app. It can also keep each single frame as a raw FITS file, and those frames hold more than the picture in the app: they can be graded one by one, the poor ones left out, satellite trails rejected across the whole set, and several nights added together.

This guide covers how to keep the frames, how to get them onto a computer and what to do with them.

Before the observation: keep the raw frames

The Vespera only keeps single frames if it is told to before the observation starts. In the Singularity app, open the image format settings and switch on raw FITS images. The app can also save a 16-bit TIFF of the finished stack; that one is useful on its own, but it is the stacked picture, not the frames.

A session at 10 seconds a frame makes a lot of files: an hour is several hundred. That is what makes careful rejection possible later, and it is worth the space.

Copying the frames to a computer

Vaonis’ own help describes it: you connect to the telescope over FTP, and the files are sorted by observation in a folder called user. Join the Vespera’s Wi-Fi from the computer, open an FTP connection to the telescope (Finder’s Connect to Server on a Mac, or the address bar of File Explorer on Windows) and copy the observation’s folder.

Copy the whole observation folder, then reconnect the computer to your home network.

Which folder to open

Open the observation’s folder of FITS frames. In Akastroid, choose Choose folder on the Deep sky card and select it. It grades the frames, leaves out the poor ones, stacks the rest, removes the light pollution gradient, balances the colour and finishes the picture without any settings.

If you only have the Vespera’s own stacked TIFF, use Choose files instead: Akastroid opens a finished picture as it is and lets you adjust it, but a stack made from the frames will hold more.

Common questions

Why does my dual-band filter nebula look almost black?

Through the Vespera’s dual-band filter most of the light that reaches the sensor is the red light of hydrogen and the green-blue light of oxygen; the stars and the sky are dimmed. A stretch made for an ordinary colour picture leaves a nebula in that light close to black. Akastroid finds the nebula in its hydrogen light and brings it out, and when a picture still stays dim, the report says why.

Can I combine several nights of the same target?

Yes, and it is the biggest improvement you can make: two nights is twice the signal. Copy the FITS frames of every night into one folder and open that folder. Frames taken with and without the dual-band filter are better kept in separate folders, so each set is stacked and coloured for what it holds.

Should I restack the frames or combine the TIFF files?

Restack the frames. Combining stacked TIFFs can only average finished pictures, so a hazy night weighs as much as a clear one. Starting from the frames lets each one be graded on its own and the poor ones left out.

How do I view a Vespera FITS file on a PC or Mac?

A FITS frame holds the raw numbers from the sensor, so most photo viewers show it black or refuse it: the data is linear and has not been stretched for a screen. Open it in software that reads FITS, such as Akastroid, which shows the finished picture.

How do I get a TIFF for Lightroom or Photoshop?

Stack the frames, then export a 16-bit TIFF. Lightroom and Photoshop open it directly and keep every tone for further editing.

Does it work for a Vespera mosaic?

A mosaic observation is a set of panels; open each panel’s frames to stack them, then join the stacked panels on the Mosaic page.

The free copy gives five processing runs and two exports, enough to try it on your own Vespera observation. Download Akastroid. The same approach for other smart telescopes is in the Seestar FITS guide and the DWARF 3 FITS guide.