In my latest video, I captured a wide-field deep sky object using an impressive little star tracker, the iOptron SkyGuider Pro. Since 2017, I’ve captured several deep sky images with the SkyGuider Pro, with a DSLR camera attached to a camera or small telescope.
In my latest adventures in the backyard, I’ve set up the iOptron SkyGuider Pro once more, but this time I’ve added a rather simple device that makes a critical step of the astrophotography acquisition stage process easier, and more precise.
The iPolar Electronic Polarscope
The iPolar electronic polarscope uses a small camera to understand the mounts positioning, and tell me exactly where it needs to be so that it is perfectly aligned with the north celestial pole. As seasoned veterans will tell you. polar alignment is an essential step of the deep sky imaging process, and it should not be rushed, or skipped.
The iPolar camera is just like the QHY PoleMaster I use on my larger equatorial mounts such as the Sky-Watcher EQ6-R Pro, but this one uses its own dedicated software, and was made specifically for popular iOptron mounts like the SkyGuider Pro.
The iPolar Electronic Polarscope in the RA axis of the SkyGuider Pro.
The version of the iPolar I have came with an adapter to externally mount the device to the SkyGuider Pro. It comes with a USB cable to connect the iPolar to your Windows PC, and the polar alignment is done with using the on-screen instructions of the software.
The system only needs 4 stars to locate the pole, and can do so even if the pole location is obstructed by tree branches or clouds. The field of view of the iPolar is 13-degrees, with a resolution of approximately 30 arc-seconds.
iPolar Compatible Mounts
The iOptron SkyGuider Pro is sure to be a popular mount to add the iPolar upgrade too, but this is not the only telescope mount compatible with this electronic polarscope. In fact, there are currently more than a dozen iOptron mounts compatible with the new iPolar device:
- SkyGuider Pro
- SkyTracker Pro
I know that owners of the iOptron SkyTracker Pro star tracker have been looking for a solution like this for some time now. It will be interesting to see just how far backyard astrophotographers can push the SkyTracker Pro, with the added polar alignment precision the iPolar provides.
The iOptron SkyGuider Pro
As you may already know, the SkyGuider’s job is to accurately track the apparent motion of the night sky for long-exposure astrophotography. It’s RA (right-ascension) motor slowly rotates at sidereal rate to match the skies movement – very simple, yet vital for deep sky imaging.
This lithium-ion battery-powered camera mount was designed for portable astrophotography with a camera lens or small telescope riding on top. This setup usually consists of a DSLR camera and lens, but I’ve seen some incredible little setups using dedicated astronomy cameras, and telescopes as big as the William Optics Z73 mounted (with a 50mm guide scope)!
It can handle up to 14 lbs of gear, which means that small refractor telescopes like the William Optics RedCat 51 are no problem for the SkyGuider Pro. I’ll attach my newly acquired Canon EOS 60Da to the RedCat, with a dual-bandpass narrowband filter inside (2″ Optolong L-eNhance)
I have used the iOptron SkyGuider Pro with the RedCat 51 extensively. I’ve traveled to Costa Rica with this setup in my carry-on bag and set the rig up in 3-feet of snow in the backyard. No matter what the weather conditions or surrounding scenery were, the SkyGuider and RedCat 51 combo have given me some of the most memorable astrophotography imaging sessions of my life.
Images captured using the SkyGuider Pro with the RedCat 51 and DSLR attached.
All of these incredible moments took place using only the built-in, illuminated reticle polarscope that comes with the SkyGuider Pro. As you can imagine, I had mixed feelings about disrupting this proven configuration to upgrade it with the iPolar device.
The SkyGuider Pro has proved to be an incredibly reliable star tracker that only takes a few minutes to set up. The addition of the iPolar electronic polarscope adds time (and additional gear) to this process, which I will discuss further in a moment.
Deep Sky with a Telescope
I’ve fitted a 2″ Optolong L-eNhance filter into the adapter of my RedCat 51. This narrowband filter blocks nearly all light from hitting my camera sensor except for very specific wavelengths emitted from emission nebulae like the North America Nebula.
A William Optics RedCat 51 Refractor mounted to the iOptron SkyGuider Pro.
With a focal length of 250mm (400mm equivalent with a 1.6X crop-sensor DSLR), the RedCat will fit this entire area in a single field of view. Astrophotography at this time of year means limited dark-sky time to collect light on a deep sky target, as we’re almost at summer solstice here in the northern hemisphere.
Late June may have the shortest nights of the year, but it sure beats spending extended periods of time outside in the cold winter months.
Shoot Longer Exposures
Narrow bandpass imaging requires that you collect longer exposures than you would in broadband, especially when using a color camera like a DSLR. The goal is to collect as much signal on a specific wavelength of light as possible.
But longer exposures put a higher demand on tracking accuracy and polar alignment, and that’s where the iPolar comes in.
At focal lengths of 200mm+, capturing an image of 3-minutes or more requires a precise polar alignment of the mount. Even a careful polar alignment routine that is slightly off will begin to negatively affect your images after about 2-minutes.
The iOptron SkyGuider pro includes a built-in polar scope, and you should be able to achieve an accurate polar alignment by eyeballing it. This is more than enough for a sharp 2-minute image using a camera lens with a focal length of 100mm or less.
I’ve been extremely satisfied with the results I’ve achieved using this method of polar alignment, but it’s time to push the SkyGuider Pro mount even further.
An electronic polar scope uses a camera to plate solve an image of the area of sky around the celestial poles – and provide useful feedback to guide your adjustments to the Altitude and Azimuth controls.
No matter how good you are at manually aligning the mount through the polar scope with your eyes, I think it’s safe to say a camera has got you beat.
It’s this level of accuracy that users of the SkyGuider Pro have been asking for.
Installing an iPolar to the iOptron SkyGuider Pro
Until the iPolar, SkyGuider Pro users were left to improvise and create a custom adapter to mount a QHY PoleMaster. If you haven’t yet gone down this road, it’s worth looking into the new iPolar.
I must say, the iPolar experience and software felt very familiar, which isn’t a bad thing considering how much I love the PoleMaster. You simply download the iPolar software and calibrate the camera on the RA axis of the mount.
The iPolar installation process was… interesting. Now, I am not overly technically sound, so it was a bit unnerving to open the SkyGuider up with a screwdriver. The process involves removing the control board and unplugging a few small cables.
The process of removing the stock illuminated polar finder scope inside the iOptron SkyGuider Pro.
No big deal for those that like to tinker with electronics, but definitely an adventure for people like me. All in all, it took about 15 minutes to remove the standard polar scope and install the iPolar on the SkyGuider Pro.
The included casing adapter to package the SkyGuider back together matches up nicely, and it looks like the iPolar was there all along.
Polar Alignment using the iPolar Software
The iPolar software is available to download on the iOptron website. After a quick installation of the software on my Windows 10 laptop, I connected the device via the included mini-USB cable.
The device was recognized in my device manager, and I connected the camera by clicking the “connect” button at the top left-hand of the screen. For anyone that has used the QHY PoleMaster, this experience should feel very familiar and comfortable.
The first thing you’ll need to do is take a single dark frame for camera calibration purposes, which I did by covering the RA axis with my hand. (did you catch that in the video?)
From here, it’s a matter of adjusting the camera settings so that the iPolar can pick up enough stars to plate solve the image. I attempted this process at the early onset of dusk, and found that I had better results waiting until it got a little darker. Just change the gain adjustment and exposure length until about 10 stars are detected.
Unlike the PoleMaster, the stars are displayed as exaggerated black and white blobs that the software uses for plate solving. For a more “normal” looking view through the camera, simply click on the RAW image button. You’ll need to un-check this for the software to calibrate properly.
The iOptron iPolar Polar Alignment Software.
You’ll need to enter in the lat-long coordinates of your location, which you can easily find online or using the GPS on your phone. You also need to set the rotation center of the mount, which can be calibrated after clicking the “clear rotation center” button on-screen.
Rather than going through the rotation center calibration process (that involves confirming 3 positions of the mount), I opted to enter the rotation center using the manual input rotation center button. The official iPolar manual states the following:
You may also manually enter the rotation center, X=480, Y=640, for rough alignment if you are sure the iPolar center is not far away from the mount RA axis.
Once the plate solve has succeeded, you should see a red cross, and a red dot on the screen. Your job is to align these two indicators with each other by making adjustments to the alt-az adjustments knobs on the mount wedge. You may have noticed that I am using the upgraded William Optics wedge to mount the SkyGuider Pro, and this certainly makes this process a little more enjoyable.
As you get closer to being perfectly polar aligned, the red dot and cross-hair will enlarge. When the red dot fully covers the red cross, you are all done.
With the polar alignment dialed-in thanks to the iPolar, I was able to shoot 4-minute exposures at ISO 1600 on the North American Nebula and surrounding area. These are unguided sub exposures at 250mm (that’s actually 400mm when you factor in the 1.6x crop factor).
Here is a look at the image I was able to capture using the iPolar for polar alignment on the iOptron SkyGuider Pro:
Results using the iPolar for polar alignment of the iOptron SkyGuider Pro.
The final image includes 62 x 4-minute exposures for a grand total of 4 hours and 8 minutes. The lack of dithering was evident in the data, and would have helped to reduce noise in the final integration. Regardless, I used each one of the 62 (240-second long) sub-exposures for my final image.
That’s some incredibly impressive data acquisition from a star tracker that fits in your hand.
The iOptron iPolar was developed because of a demand for polar alignment accuracy. Owners of the SkyGuider Pro looking to push the mounts capabilities further now have a dedicated device for this critical aspect of astrophotography.
Check out those round stars! I used all 62 x 240-second exposures in my final image.
I enjoy the simple setup and dead simple software to polar align the mount – however, I’ve now lost some of the portability of this mount. I’m now connected to a laptop for polar alignment, as I’ve removed the visual polar scope completely.
Seeing as how this mount was designed for portability and simplicity, it’s an upgrade that may not make sense for you. You add performance at the cost of more set-up time.
So, if the SkyGuider Pro is your main deep-sky imaging rig, the iPolar is a no-brainer, especially if you’ve had trouble with polar alignment in the past. But if it’s your travel/quick setup rig – remember that you have given up your ability to polar align the mount without software assistance.
If you have found this review helpful, please let me know in the comments. If you would like to know more about the iOptron iPolar, I would be happy to answer.