Part two of the Celestron NexStar series.

This guide is intended to help first time users and those who are experiencing difficulty with the Celestron SkyPortal (previously known as Celestron SkyQLink) Wifi module.

Introduction

In our previous blog we reviewed Celestron’s top-selling Celestron NexStar Evolution 8 Computerised Telescope. Now, this blog will go through the ins and outs of how to use the Celestron SkyPortal app that is used to control the Celestron telescope (and any telescope using the Celestron SkyPortal WiFi adapter).

These telescopes are just examples of some that are compatible with the Celestron SkyPortal Module:

Celestron NexStar 90 SLT Computerised Cassegrain Telescope	Celestron NexStar 6 SE Computerised Cassegrain Telescope	Celestron NexStar Evolution 8 Computerised Cassegrain Telescope

The Celestron NexStar Series

The NexStar is a computerised telescope mount, which is specifically an alt-azimuth (alt-az) mount. This is the type that moves left-right and up-down. It’s the most common type of mount and differs from more serious telescopes, or ones meant for astrophotography.

The alternative to the alt-az is the equatorial mount. Before you can use one of these, you have to carefully align the mount to the Earth’s axis of rotation. This tricky procedure is called polar alignment. One of the great things about the NexStar is that you don’t need to do this.

It’s also computerised

A computerised (or “go-to”) mount is one that will move itself to show you whatever you ask it to. No, this isn’t magic, but it does require a computer with a large database of targets along with co-ordinates. When you ask for the Jewel Box, Jupiter, or NGC 6188, the mount looks up a database, does some calculations, and determines where to point.

It also needs a bit of a set up procedure.

Setup guide

The benefit of the Celestron NexStar Evolution over the NexStar SE, and any non wi-fi enabled mount for that matter, is its ease of use thanks to its intuitive interface and convenience. Computerised mounts are easy to use as they are built to find targets very quickly, given it’s brain-the-size-a-planet computer. But it requires some information to get it going, such as the time, time zone, date, longitude, latitude, altitude, and spatial coordinates. Without a bit of basic information, it’s a blind man stumbling around in a cellar. The NexStar Evolution, which is wifi-enabled AND computerised, can extract that valuable information on its own, further reducing the amount of input you need to provide.

The time, time zone, longitude and latitude is information that is readily available either using the Compass app on your phone, by using an actual physical compass, or by simply Googling your location. But spatial co-ordinates? Imagine you’re in a space capsule with no windows. Your commander tells you to fly towards Mars, but you’ve got no idea which way your craft is pointed. Clearly you can’t just blast off in any direction. You don’t know which way is up, down, left or right. Funnily enough, this was one of many problems the astronauts on Apollo 13 had to solve. Your telescope is in a similar situation, and to get it to understand which direction it is facing, we need to do a “bright star alignment”.

Star alignment

The Apollo 13 astronauts were able to peek out of their capsule and see the Moon. This gave them just enough information to be able to get home. Your mount needs similar information, in a process called a “star alignment”. Don’t worry, it’s quite different to a polar alignment, and you’ll be glad to know it’s a lot easier.

You’re going to help your mount point its telescope exactly at a bright star. You’ll do this by confirming that you can see the star right in the middle of the eyepiece. Once you’ve got that, the mount will know what’s in that direction, but not how to point to other stars. After you point the scope at a second bright star, the mount will know roughly where everything is. This is called a two-star alignment.

Pointing to a third star will really nail it. This is what we’ll do and it’s called a three-star alignment.

Having said all of that, if you’ve got your mount fully optioned with a Celestron StarSense, the star alignment is even easier – all you do is stand back and watch it work.

Celestron SkyPortal vs. SynScan

You’re in for a treat. I’ve mentioned the competition between Celestron and SynScan before. Both companies have great and very usable mount control software, and in some respects, they’re as good as each other. But in the case of star alignment of computerised alt-az mounts such as the NexStar range, I think Celestron has the edge. (This hurts, because I’ve been a Synta man for ages.)

Get this – with the Celestron software you don’t need to know the names or locations of any bright stars! Just point the scope and it’ll figure it out for you! Awesome!!

Now go outside

I’m going to describe the star alignment procedure as done through the SkyPortal app. Doing it through the handbox is very similar, don’t worry.

For the alignment procedure, pop your longest eyepiece into the telescope (I used a 40mm) so you are on the lowest magnification.

Step 1: Align your finderscope

It’s now time to go outside, set up your scope, including (and this is important) aligning the finderscope, because you’ll be needing it. If you don’t know how to do this, read How to Align a Finderscope.

Step 2: Connect your smart device

After you’ve turned on the scope, you need to connect your device through the mount’s built-in WiFi. IOS users, go to your WiFi settings and you should see a network called SkyQLink. Connect to this (you may have to disconnect from your home WiFi network first).

Step 3: Open the SkyPortal app

Once you have connected your phone to the mount’s WiFi, open the Celestron SkyPortal app. It’ll look like this if you hold your phone sideways (in “landscape”).

Touch “connect and align”. The mount will get time, date and location information from your phone and immediately start the star alignment procedure. This is the screen you’ll see. (I’ve added a couple of extra labels.)

Stop for  a second and look up. Choose three of the brightest stars. If it’s in the late evening, you should see a few stars around the place, and you can choose the first three you see, as they’ll be the brightest ones visible. If it’s actually at night there won’t be any shortage of stars, but you’ll still need to choose the brightest few.

The first star

Now, you need to slew the scope to the first star you’ve chosen. This is in two phases.

First, you’ll slew (move the scope) fast and look through the finderscope. The arrows on the left and right of the app screen are the slew buttons. You’ll notice that the app sets the slew rate to 4 (that’s the fastest), and that the instruction says to use the scope’s finder. Once you’ve got your star in the crosshairs of the finderscope, touch enter in the app screen. It will then move to the second phase.

In this second phase, the rate automatically drops to 2, meaning you’ll slew slowly. The app will tell you to look through the eyepiece. If you’ve aligned your finderscope accurately, you should see your star somewhere in the field of vision. Use the slew buttons to make sure the star is right in the very centre of the round field you can see. (Sometimes it’s a little difficult to tell where the field ends, as the black sky doesn’t really contrast with the black inside the scope, but that’s a problem you’ll have to solve yourself!) Once the star is right in the middle, press enter on the app screen.

The second and third stars

Now, the procedure is exactly the same as the first one. Use your finderscope to slew quickly to the star, hit enter, and then use your eyepiece to centre it in the field and hit enter. Simple.

You’re done

I’d like to say that the alignment is now complete. However, occasionally it will fail, and you’ll have to do it again. This can be due to a number of reasons, including (and I’m definitely guilty of this one) not finishing the procedure quickly enough, or choosing a star that isn’t in the database (see if you can choose the brightest stars).

Once you have finished the star alignment, you can use the app to do what you want. This includes touching a target on the app screen and going there, selecting a target from a find list, or taking a tour.

Enjoy your observing!

Related reading

How to set up an equatorial mount

Common disasters in selecting telescope mounts

Bill is Optics Central’s expert on astrophotography, telescopes and bird watching. You’ll find him in the Mitcham store on Fridays and Saturdays. Come in for advice on how to get the best out of your current telescope, what your next telescope should be, how to take photos of the sky, or even how to see some rare birds.