Celestron NexImage camera review: astrophotography made easy
Whether you already own a telescope or are looking to buy one, it’s definitely worth considering whether you would like to be able to take photographs of what you can see through your telescope in the night sky. This type of photography is known as Astrophotography and if you love to look at beautiful photos of the moon, planets, galaxies and nebulae, you might be interested to know that you could do it yourself … even on a modest budget!
There are two main types of cameras for astrophotography: multi-use digital SLR cameras and specialist CCD & CMOS cameras designed specifically for use with a telescope. In this hub, I’m going to look at telescope-specific cameras, specifically Celestron’s NexImage.
NexImage is a compact CCD camera which is similar in shape, size and weight to a webcam (I believe it is actually similar to a modified Toucan webcam). It has a CCD (Charge Coupled Device) sensor which is ideal for astrophotography and can take pictures up to 640 x 480 resolution. NexImage fits directly into any telescope that takes 1.25” eyepieces and can be used in conjunction with magnification accessories such as Barlow lenses. It comes bundled with an instruction manual and two bits of software: one for capturing video clips or still images and another for ‘stacking’ video frames into a still image (more on that later!). You DO need to be able to attach NexImage to a computer, so you would ideally need to take a laptop outside unless you are lucky enough to have an indoor observatory with power sockets and can use a desktop PC!
To get started, all you need to do is locate the feature you’d like to capture using a normal eyepiece – it’s usually best to start with something easy to find, such as the moon. Once you have the telescope pointing in the right direction, swap the eyepiece for the NexImage camera and connect it to your laptop via the USB cable. Start up the supplied video capturing software and use the telescope controls to focus the image. There are various settings within the software which you can modify to improve the image you are capturing, which are explained clearly in the instruction manual. Once you have everything looking perfect, you set the video to record for a set time – e.g. 20 seconds – and you’re left with an AVI video recording.
From that video recording, you can use the ‘stacking’ software which is fantastic for producing brilliant still images – even if your video didn’t look all that brilliant, you’ll be amazed by what you can produce using the stacking software. All you do is load the video file and select a reference point in the frame, such as a particular crater (or several craters) in the moon’s surface. Then the software aligns all the frames, ignores the frames that don’t look very good, and merges all the others into the perfect still image. There are various settings to adjust which can improve your picture and really bring out the detail, so it’s worth spending some time practicing with it.
The very first recording I did of the moon was actually done shortly after sunset so it was still very light outside and therefore there wasn’t a great contrast in the moon’s features. Not only that, but due to the position of the moon in the sky at the time, I had to do it through my sitting room window – and doing any kind of photography through glass is never very impressive! Despite that, I still managed to come up with this video recording and the image below, which was created by stacking the video frames. You can see how much the stacking software improves the image!
Since then, I have managed to capture the moon from outside on better nights and recently captured the shot at the top of the page. This is the video footage from it:
I’ve also managed to capture my first image of Jupiter – and this was captured in poor seeing conditions with lots of light pollution from street lights etc. so I’m very pleased with how it came out!
NexImage is perfect for lunar photography and planetary photography and is an excellent low-cost entry to astrophotography. The instructions are simple to follow and you’ll be taking brilliant pictures in no time!