ASI Air Plus Review

I am a fan of astrophotography equipment manufactured by ZWO.  I use several of their astro cameras, filter wheels, and recently started using their focus motors.

I was recently selected to be a part of a program in which ZWO recruited astrophotographers to be "Experience Officers" who are to test and review a device called the ASIAir Plus.   The "Plus" is a microcomputer-based device that performs several important functions that make capturing images of deep space objects easier.

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Experience Officers received a moderate discount on a purchase of the Plus in return for testing and publishing a review or reviews on their findings but there were no requirements for either a positive or negative review.   So here goes:

The Plus is a refresh of the ASIAir Pro, which I have owned for a year or so.  I hadn't used the Pro very much, because both of my other astrophotography rigs included non-ZWO devices.  The ASIAir devices (Plus and Pro) only control ASI cameras, filter wheels, and focusers.   I had other devices in my rigs so relying totally on ASIAir to capture astro photos was not possible.

However, coincident with the announcement of the Plus, I had put together a new rig which included two ASI cameras and, so far, didn't have an autofocuser or filter wheel.  The new rig included:

- SpaceCat telescope (focal length 250 mm, f4.9)

- Ioptron Sky Guider Pro Tracking Mount

- ZWO ASI183MC Pro Imaging Camera

- ZWO ASI120MM Mini Guide Camera (on a ZWO guidescope)

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I was planning to take the new rig to the Black Forest Star Party at Cherry Springs State Park in Pennsylvania, USA. 

I didn't really care about autofocus because I would be there to check focus throughout the event and didn't need a filter wheel with the One Shot Color (183MM) camera.   Instead, I had incorporated a 2 inch filter drawer into the image train.

The user interface for the Plus hasn't changed much from the Pro, at least for the functions that I used during the party (notably not including autofocus or automatic filter changes).

In the days leading up to the party I tested the new rig in the configuration I would be using in the field (from my Bortle 8+ skies).

I had no problems registering the new Plus unit and it connected to all of my devices on the first try.  Since the rig included the tracker, the one difficult part is finding targets and getting them framed.  I have developed a method of doing this using the fast plate solving ability of the ASIAir.  I use a telrad to visually place the scope near the target by star hopping.  Then I take an quick image, plate solve it, and then compare the resulting RA and DEC values against their actual values.   I then use the tracker to slew in RA and a manual knob on my rig to move in the DEC direction.   I have become very adept at this such that it only takes about 3 iterations to get the target centered in the sensor and then I make any rotations needed to get the final framing.

After this, I can take some additional images to assess what gain and exposure I want and get them dialed in using the Air.  Then I create the exposure plan and start imaging.

The first target was the North America Nebula.  The resulting image:

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I was very pleased with this outcome and headed out to the PARTAY!!

The weather generally cooperated even though there were some clouds one night that resulted in a quite striking sunset:

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I also took my narrow field rig (Losmandy G11, Celestron EDGE8 SCT) and ran both rigs and also took some static star trails with my DSLR.  (I was pretty busy.....)

Once again, the Air Plus worked essentially flawlessly for the functions that I exercised.  I was able capture a few more targets, including:

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OK, so here are my impressions and summary of this review:


- For the functions I've tested, the Plus has been flawless.

- After returning from the party I've also tested the ability to communicate with the Plus through my home wifi network.   This works well so far.  So at dark sites I will use the direct wifi connection to the Plus and at home I will use my network so that I can use my iPad anywhere in the house without worrying about disconnects.

- I really like the speed of the plate solving.  As mentioned above, on my tracker rig finding targets is a little difficult.   But the speed of the plate solving and display of the resulting RA and DEC makes this process more efficient than it would be with some of my other imaging software tools.

- As a result of the testing so far I decided to purchase a ZWO Focuser (EAF) to this rig.


- None so far.


- This review had a deadline so I have not been able to test some functions, including filter changes using a ZWO (EFW), and autofocusing (EAF).  As mentioned, I ordered an EAF for this rig and I already have an extra EFW so I will be doing more testing in the weeks to come.   My local astronomy club has a star party scheduled for next weekend so I may be able to get some more testing completed there.

- My main intention for the Plus is for trips away from home.  However, I will also be testing my other rigs using the Plus for control as well to see how well the Plus handles my Losmondy G11 mount.  I will likely take a lot to get me to replace N.I.N.A. as my home control software, but who knows?

I guess maybe the best indication of my impression of the Plus is that since trying it I have purchases two additional focus motors from ZWO.  This means that, if desired, I can control all three of my rigs with the ASI Air Plus (which means I have a lot of ZWO devices......).

Thanks to ZWO for the opportunity to get an early Plus unit.

Clear skies everyone.

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