Q: Can I view what I see through my telescope on a tablet or PC screen?
A: Yes. There’s a number of ways to do this. Let’s explain how.
This is one of the most asked questions we encounter!
The process of attaching a digital camera to a telescope instead of an eyepiece and then directly viewing on a screen of some kind is often called EAA or Electronically Assisted Astronomy. (There’s other terms and acronyms for this process as well.)
You might want to display the image on a phone or tablet like an iPad. You might prefer to view through a PC setup away from your telescope. A common use of EAA is to present views through a telescope to a group of people via a large monitor or TV screen.
At BINTEL we’ve also helped setup telescope systems to assist folks with disabilities that prevent them directly looking through a telescope eyepiece.
There are a few other ways to use a camera with a telescope. Astrophotography is where a camera captures the light from the telescope, and this is processed into an image to be viewed later via a computer or printed out. Long exposures, filters and other techniques bring out details in the images that you can’t see with your eye through a telescope. Astronomers have been using long exposure photography with telescopes since the 1850’s, so it’s hardly a new technique. Digital imaging has almost entirely replaced film cameras for both amateur and professional astronomers, much in the same way that this has happened for traditional photographers.
There’s also electronically enhanced viewing. This uses an eyepiece similar to a night vision device to view through. Finally, a new generation of telescopes like the Stellina from Vaonis replaces the entire separate telescope, camera and mount combination with a single piece of technology purely designed to produce images for viewing and sharing on a computer.
The simplest way to do it.
The simplest way to view images from your telescope to a screen is to use a mobile phone holder like the Celestron NexYZ. This inexpensive gizmo makes the fiddly job of holding your phone over the telescope eyepiece a straightforward process. Images can be viewed on the phone or sent to a large TV for live viewing using Google Chromecast or Apple TV.
You will often find a control on your phone to adjust the brightness of the image, and this might need to be wound down a bit to get the best views of the Moon.
This is probably the easiest way to show a group of people telescopic views of something like the Moon. If you don’t have a motor drive on your telescope mount, you will need to nudge it occasionally to keep the image in the field of view.
Telescope mount with a motor drive
EAA using a telescope with a motor or GOTO features drive opens up a much wider range of objects.
The Celestron NexStar range has been used successfully for EAA as well as the Meade LX90 and LX200 telescopes. Lower cost options would be GOTO Dobsonians from Sky-Watcher. You don’t need to use a large or expensive telescope.
It’s also highly likely that you’ll need to refocus between your eyepiece and camera, so a telescope with full GOTO capabilities will make life much earlier for you. Similar choices apply for telescopes for EAA as they do for imaging in general. A wide-field, short focal length refractor would be great for viewing large nebulae like the Great Orion Nebula (M 42) or the Carina Nebula, whereas an SCT is great for planetary viewing.
Camera
We’d suggest a “one shot” colour astronomy camera. They start at just $229 for the ZWO ASI120MC-S. Other low-cost options would be the ZWO ASI224MC and the ZWO ASI385MC.
These cameras replace the telescope’s eyepiece. There are other options and have a chat to us at BINTEL to help you with the best camera for EAA.
While you can use monochrome astronomy cameras for EAA, they won’t be able to show colours in live views of deep-sky or Solar System objects. The images will be purely black and white. (When used for astrophotography, monochrome cameras take a series of images through coloured filters and these are combined later on to produce colour images.)
You can also use your existing DSLR camera if it has a live view output via USB. This attaches via a T-ring to suit your camera body type (ie Nikon, Canon, Sony etc) and then a standard camera adapter. BINTEL stocks these parts.
Computer
For EAA you will need a computer. Astronomy cameras like those from ZWO or DSLR cameras will generally not be able to put deep-sky images onto your phone or large screen without some form of computer.
The most popular option is to connect your camera to a notebook computer. This will let you see the live output from the camera connected to the telescope. If you want to display onto a large screen, the notebook will need a HDMI output or support HDMI via USB-C. These are common features on modern notebooks.
If you don’t want to connect to a PC or notebook, then you can use a ZWO ASIAIR Plus or possibly a Raspberry Pi based solution running a bundle of software like Stellarmate.
Image via Sky & Telescope
It’s possible to connect a ZWO camera directly to your phone or tablet using the ASICAP app, but this doesn’t offer live stacking and more aimed at Lunar or Solar System images.
ASICAP Shown viewing the Moon
Software
ZWO cameras can use the powerful ASISTUDIO package. This is a complete system which is under constant development for image capture and processing and can be also used for EAA. It’s free to download and offers live stacking. Please note this only supports ZWO cameras.
Another extremely popular software package for EAA is SharpCap.
You can download SharpCap from here
The free version works fine, but we highly recommend you pay an annual subscription of just 12 pounds a year which unlocks several additional features. These include polar alignment support, more memory for live stacking and additional support for multiple monitors, ie show the app’s controls on your notebook screen and just the image on another. Very handy for EAA!
BackyardNIKON and BackyardEOS are handy for capturing and displaying images from Nikon and Canon EOS cameras. Their website contains a list of what cameras support live output which is needed for EAA.
Focusing
With any kind of imaging you will find spot on focus will contribute greatly to getting the best from your camera. Apps like the paid version of SharpCap have tools to assist with focussing or you can use a low cost Bahtinov mask to make sure your focus is extra sharp.
Live Stacking
A very cool feature of many apps is Live Stacking.
After only a few moments, the extra data received will sharpen the image
As you watch an image on the screen, additional information from the camera arrives and adds to the detail and colour. It’s effectively a long exposure astrophotograph arriving and being built in front of your eyes in real time.
Conclusion
Electronically Assisted Astronomy (EAA) is where a camera is attached to your telescope to view what you see through the telescope on a screen.
This starts with something as simple as viewing the Moon on your phone which can be displayed onto a TV, through to adding an astronomy camera for views of more Solar System or deep-sky objects. Using additional programs you can even watch a long-exposure image with extra colours and details form in front of your eyes using Live Stacking.