ZWO Seestar S50 Smart Telescope – now available for WAS members to borrow

In his March 2024 Sky & Telescope review of ZWO’s Seestar S50 Smart Telescope, Dennis di Cicco recalled Arthur C Clarke’s Third Law: “Any sufficiently advanced technology is indistinguishable from magic”. And what a magic little instrument this is! So easy to use – such fine images in no time! WAS has just bought one and it is now available for any member of WAS to borrow!

Our new Seestar C50 Smart Telescope

(Picture by Sandy Giles)

How I recall my early steps in astrophotography and the business of setting up my scope – aligning it, attaching a camera, persuading a target to fit onto the camera’s chip and getting it to focus, and then sitting outside in the freezing cold for an hour or two, fussing over the scope’s tracking, capturing what one hoped would be a recognizable image of something. My first efforts left me wondering whether this was the hobby for me!

But with barely twenty minutes of setting up my i-phone to talk to the Seestar I was outside taking very acceptable images of the Sun

Images of the Sun using the Seestar at three different magnifications (Pictures by Sandy Giles)

The Seestar is a GoTo 50mm f/5 telescope and astronomical camera, all in one. You don’t look through it, rather you see the image it is capturing on your phone. For deep sky images it does this in 10 second shots, stacking each image as it goes, the image improving after each shot is added to the stack. The scope comes equipped with a dual band OIII/Hα filter, an autofocusser, a dew heater and a solar filter so in addition to deep sky work it can deal with lunar and solar imaging, and also terrestrial work.

1 hour of 10 second exposures of M51

Image by Jon Jewitt)

30 minutes worth of 10 second exposures of M81 & M82

(Image by Sandy Giles)

Setting up this easily transportable little instrument is easy. You take it outside, plonk it on the tripod and turn it on. Then you fire up the App on your phone and connect to the scope. It takes location and time/date information from your phone and also works out which way it’s pointing. After that you select what you want to look at, either from its list of what’s good now, or searching a database it accesses. Once you have chosen, you hit Go and the scope slews to the selected target, takes a preliminary image which it then plate solves, making further pointing adjustments till your chosen target is in the centre of the frame. You hit the Start button and away it goes taking its 10 second shots. You can customize this to 20 second or 30 second subframes, but I found they tend to produce streaky stars; because it doesn’t track in the conventional sense – rather when the image is added to the stack, if the amount of movement it detects in the target is excessive, it moves the scope a little before taking the next set of images. There is some kind of algorithm it uses to decide whether an individual image is of sufficient quality to stack; as I discovered this is not perfect – I captured an aircraft streak in my stack of M82 for example. You even don’t have to babysit the instrument – you can turn off the App, go inside and let it get on with it.

8 minutes worth of 10 second exposures of M27, the Dumbbell Nebula

(image by Shawn Macfarlane)

The stacked deep sky image is displayed on your phone and when you have finished imaging it, say after 10 minutes or longer, the image is saved as a JPEG file in your phone’s photo library (yes, in a separate Seestar library). It should be said that the JPEG image is noisy – and it’s only 8 bit. However, this little instrument has a trick up its sleeve – it can save the individual 10 second images in the telescope’s memory as 16 bit FITS files which can be downloaded from the instrument to a computer (Windows or a Mac) for image selection, stacking and processing in the likes of PixInsight. And it’s well worth the trouble as the images of M31 here show.

M31 Unprocessed (from Seestar)

M31 Processed with PixInsight

Left, unprocessed 30 minute image of M31 straight from the Seestar Right, processed with PixInsight (images by Sandy Giles)

And if this isn’t enough, it will also take videos of the Sun and Moon so those who are used to Autostakkert and Registax to process lunar and solar files are catered for as well.

The Moon

(Image by Jon Jewitt)

This instrument will be very useful for outreach work and we’ll certainly use it for that. But it is as an introduction for WAS members to astroimaging and image processing that I see as its greatest benefit. We plan a workshop for the use of the Seestar and PixInsight and hopefully this will encourage yet more contributions to our annual Astroimaging Exhibition.

Finally, if when you’ve borrowed it you fancy getting one yourself (as I and four other WAS members

have already done!) you might be very pleased with the price you have to pay – less than £500 if you

buy carefully.

Hey! – an easy-to-use complete Astroimaging set-up for less than the price of a posh eyepiece? What’s

there not to like?

Sandy Giles