Use Your Smartphone to Learn to Star Hop: Star Hop Trainer Pro Review

Astronomy can be a difficult hobby to get into, and it’s common for beginners to become frustrated and call it quits. Star Hop Trainer is an app for Android and iOS (available in free and $4.99 Pro versions) designed to help telescope users practice star hopping from the comfort of their own homes, easing the transition to becoming accomplished amateur observers.


Star Hop Trainer’s interface is clean and simple. Credit: screenshot by Lee Pullen.

Flattening the learning curve

Star Hop Trainer was inspired by the developer’s own experience as a beginning stargazer. The proud owner of a new manual (i.e. not computerized GoTo) telescope, they struggled to navigate the skies and track down objects of interest. This is a common experience, so it’s easy to understand the appeal of an app that can flatten the learning curve by helping beginners practice star hopping – a fundamental skill considered essential by many amateurs – at home during the day before heading out under a starry sky.



Effort has been taken to make things easy for beginners. Credit: screenshot by Lee Pullen.


The interface is reassuringly simple, and it takes just a few clicks to select the type of telescope that will be used. Then it’s on to the Eyepieces section, where a user can input details of the eyepieces they have. It’s all straightforward and intuitive.

Next is the main attraction: the Star Hops. Select a deep sky object and you’ll be presented with a view of a nearby bright star, with your field of view based on the telescope and eyepiece you’ve chosen. It’s easy to scroll around and move this virtual telescope. A little green bar at the side shows progress as you get closer to your target. It does a brilliant job of conjuring that feeling of a cosmic treasure hunt.


Star Hops are categorized by difficulty level. Credit: screenshot by Lee Pullen.


The standout feature is Hop Paths. Tap a button and dotted lines will appear offering a suggested star hopping route to your target. This can be toggled on and off easily, helping you memorize the paths. It’s a good system and works well.

Unfortunately, there’s a catch. At the time of writing, only 20 deep sky objects with Star Hops are available in the app. It feels like the entire Messier catalogue should be represented, along with a selection of Solar System objects. It’s possible to add “User Hops” with target coordinates, but I think it unlikely that beginners will use this feature. Star Hops are categorized by difficulty level, which is a good idea, but note you’ll need to use a different resource to find what objects will be visible based on date or location.


The Star Hops are well thought out. Credit: screenshot by Lee Pullen.


Your guide to the stars?

Star Hop Trainer doesn’t limit itself to indoor use prior to time at the eyepiece. A night mode turns the screen dark red, preserving precious dark adaption under a starry sky. In principle, it’s possible to use the app as a kind of assisted manual / GoTo hybrid system for the Star Hops. With your phone in hand, you can move your telescope to follow Star Hop Trainer’s astronomical dot-to-dot, matching the view through the eyepiece with your phone screen.

That’s the theory anyway, but when I tried this I ran into some issues. First, I wasn’t able to get the number and brightness of stars visible through my telescope to match the Star Hop Trainer view. The app allows you to select one of four light pollution levels, which is commendably simple, but doesn’t offer sufficient granularity for real-life use. I’d like to see a method by which you can adjust the stars to specifically match your telescope view; something that the Desktop version of Stellarium offers with its ability to tweak the Relative and Absolute size of stars.

Second, I found it tricky to know how I should be holding my phone to get the correct orientation. For example, hold the phone normally and Star Hop Trainer may tell you that the first hop is to the left, but if you happen to be holding your phone 90-degrees to the right in landscape mode then it seems that you should be looking up. I thought I could get my bearings by trying the Star Hop for M81, which begins at Dubhe in Ursa Major. This star has a binary companion that was easily visible in my telescope at the 3 o’clock position so all I’d need to do was twist my phone until Star Hop Trainer’s view was a match. Unfortunately, this companion star was not displayed on the app, which scuttled my bright idea.


There’s a lot to like about Star Hop Trainer and I commend its approach of helping beginners to take their first, small steps in telescope stargazing. The interface is simple and accessible, and most features are intuitive. The lack of actual Star Hops and the difficulty using it under the stars prevents me from giving it a resounding thumbs up. The developer has been taking customer feedback and implementing suggestions, though, so I’m hopeful that Star Hop Trainer will gain content and become a very strong product.

Star Hop Trainer is available as a free version or paid-for “Pro” version that unlocks many features: selecting from four levels of light pollution; inputting multiple telescopes and custom eyepieces; tracking your progress across multiple Hops; inputting User Hops; Night Mode; and displaying the dot-to-dot Hop Paths. If you think Star Hop Trainer sounds interesting then there’s no reason not to download the free version and give it a go. If you like what you see, then $4.99 is a reasonable price to pay for the Pro version.


* Simple design suitable for beginners
* Great for practising star hopping before using a telescope


* Lack of official Star Hops
* Difficult to create realistic view

Standard (free):
Pro ($4.99):

Standard (free):
Pro ($4.99):



About Lee Pullen

Lee Pullen is a science writer and communicator from the city of Bristol, UK. He has a degree in Astronomy and a master's in Science Communication. He began his career writing for organisations including the Hubble European Space Agency Information Centre and the European Southern Observatory, as well as becoming Staff Writer for the International Year of Astronomy 2009, the world's largest ever science outreach initiative. Lee runs the website

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