As amateur astronomy continues to grow, the demand for high-quality, portable, and user-friendly equipment has never been higher. ZWO, a well-known name in the world of astrophotography, has bought out their line of harmonic equatorial mounts.
In this blog post, we’ll take a deep dive into three of their popular models: the AM3, AM5, and AM5N. We’ll explore their similarities, differences, and help you decide which one might be the best fit for your stargazing needs.
ZWO AM3 Harmonic Mount
The Lightweight Champion
The AM3 is designed for those who prioritise portability above all else. Here’s what sets it apart:
- Payload Capacity: The AM3 can handle up to 8kg (without a counterweight) and 15kg payload (with a counterweight) which is less than the AM5 series and ideal for those who use something like a small, to medium sized telescopes.
- Weight: At just 3.9kg, it’s significantly lighter than its AM5 counterparts.
- Mount Type: Like the AM5, it’s an equatorial mount suitable for astrophotography and can be adjusted to be used as an AZ mount for visual observation.
- Goto and Tracking: Features high-precision goto and tracking capabilities, essential for astrophotography. The periodic error is ±20 arc seconds.
- Latitude Range: The AM3 works from 0° to 90° latitude and the mount can be easily used near the equator if you happen to venture or live there.
- Control: Works like a dream with the ASIAIR, it also works with ASCOM/INDI and with the use of the included hand controller. You can use it over WiFi with a smartphone/tablet.
- Price: The AM3 is the most budget-friendly option in this lineup.
ZWO AM5 Harmonic Mount – (Discontinued Model)
The ZWO AM5 is the original model in this series. It has now been discontinued, but let’s look at its key features it had so we can compare it further down this blog with the ZWO AM5N:
- Payload Capacity: The AM5 can handle up to 13 to 20kg of equipment, making it suitable for a wide range of medium to large telescopes
- Weight: At just 4.8kg, it’s heavier than the AM3 counterpart.
- Mount Type: Like the AM3, it’s an equatorial mount suitable for astrophotography and can be adjusted to be used as an AZ mount for visual observing.
- Goto and Tracking: Features high-precision goto and tracking capabilities, essential for astrophotography. The periodic error is like the AM3 at ±20 arc seconds.
- Latitude Range: The AM5 works from 0° to 90° latitude and the mount can be easily used near the equator if you happen to venture or live there.
- Control: Works like a dream with the ASIAIR, it also works with ASCOM/INDI and with the use of the included hand controller. You can use it over WiFi with a smartphone/tablet.
ZWO AM5N Harmonic Mount – (Current model)
The ZWO AM5N is the newer, upgraded version of the AM5. Here are its key features and how it differs from the standard ZWO AM5:
- Higher load capacity of 15kg (without counterweights) and 20kg (with counterweights)
- Cable management: Added USB type-C port and DC power port have been added to the top of the mount head to help cable management
- Precision Control: Single periodic error within +/- 10 arc seconds
- Multiple functions: Used in AZ mode or in EQ mode
- Weight: Lightweight at 5.5kg
- Control: Hand controller can be used with the hand controller or with the built in bluetooth
- Seamless link with the ZWO ASIAIR
- Power off protection: Electromagnetic brake on RA axis
- Added latitude scale: Is a nice touch
- Altitude fine adjustment knob: Allows for a much more refined and accurate adjustment
- Azimuth fine adjustment grip: Has been removed and springs used to keep the tension, there is no need to lock the AZ bolts when Polar Alignment is complete.
Accessories for the AM3, AM5 and the AM5N
- The ZWO TC40 Carbon-fibre tripod is a perfect match with this mount.
- The ZWO PE200 Pier extension is another accessory to consider that prevents your telescope from colliding with the mount, it can inadvertently cause major damage to the mount and your precious telescope
- The ZWO 12V 5A Power Adapter to power the AM5N is recommended
Choosing the Right Mount
When deciding between these mounts, consider the following factors:
1. Equipment Weight: If you have very heavy telescopes or extensive imaging setups, the AM5N would be the most suitable. For medium-weight setups, the AM5 is great, while the AM3 is perfect for lighter equipment.
2. Portability Needs: If you frequently travel to dark sky sites, the ultra-light AM3 might be your best bet. The AM5 is also portable, while the AM5N might be slightly heavier due to its increased capacity.
3. Future Plans: If you’re planning to upgrade to heavier equipment in the future, the higher payload capacity of the AM5N provides more room for growth.
4. Budget: Consider the price differences between the models. Generally, the AM3 is the most affordable, followed by the AM5 and the AM5N (which are at the same price at the time of publishing this post)
Specifications
| Features | AM3 | AM5 | AM5N |
| Mount type | Alt-Az/Equatorial | Alt-Az/Equatorial | Alt-Az/Equatorial |
| Payload Capacity without the counterweight | 8kg | 13kg | 15kg |
| Payload Capacity with the counterweight | 13kg | 20kg | 20kg |
| Mount weight | 3.9kg | 5.5kg | |
| Drive | Strainwave gears & sync. belt | Strainwave gears & sync. belt | Strainwave gears & sync. belt |
| Reduction ratio | 300:1 | 300:1 | 300:1 |
| Periodic Error | <± 20 arcsec, 288 secs | <± 20 arcsec, 288 secs | <± 10 arcsec, 288 secs |
| RA Drive | NEMA35 stepper motor & brake | NEMA42 stepper motor & brake | NEMA42 stepper motor & brake |
| Dec Drive | NEMA35 stepper motor | NEMA35 stepper motor | NEMA35 stepper motor |
| Latitude adjustment range | 0° – 90° | 0° – 90° | 0° – 90° |
| Azimuth adjustment range | ±6° | ±10° | ±10° |
| Dovetail saddle | Losmandy & Vixen | Losmandy & Vixen | Losmandy & Vixen |
| Counterweight Shaft | M12 | M12 | M12 |
| Stepper motor resolution | 0.17″ | 0.17″ | 0.17″ |
| Max slew speed | 6°/S | 6°/S | 6°/S |
| Power port | DC 5.5 x 2.1 12V 3A | DC 5.5 x 2.1 12V 3A | DC 5.5 x 2.1 12V 3A |
| Power consumption | 0.386A standby, 0.58A tracking, 1.7A GOTO | 0.386A standby, 0.58A tracking, 1.7A GOTO | 0.386A standby, 0.58A tracking, 1.7A GOTO |
| Guide port | ST4 | ST4 | ST4 |
| Communication interface | USB / Wifi / Bluetooth | USB/Wifi, ASCOM, INDI (LX200) | USB C/ Wifi / Bluetooth, ASCOM, INDI (LX200) |
| Zero position | Mechanical | Mechanical | Mechanical |
| Operating temperature | -15º – 40º C | -20°C – 50°C | -20°C – 50°C |
| Power failure protection | Yes | Yes | Yes |
| SKU | ZWO-AM3 | ZWO-AM5 | ZWO-AM5N |
Conclusion
All three mounts – the AM3, AM5, and the AM5N – offer excellent performance in a portable package. The AM5 provides a great balance of payload capacity and portability, the AM5N offers enhanced payload capacity for demanding setups, and the AM3 stands out with its ultra-lightweight design.
Whichever you choose, you’ll be getting a quality mount that combines ZWO’s innovative technology with user-friendly design, helping you to explore the wonders of the night sky with ease and precision.
Remember, the best mount for you is the one that fits your specific needs, equipment, and observing style.
Optics Central has these mounts readily available:
ZWO AM3 Harmonic Drive Mount
https://www.opticscentral.com.au/zwo-am3.html
ZWO AM5 Harmonic Drive Mount (discontinued)
https://www.opticscentral.com.au/zwo-am5-harmonic-equatorial-mount.html
ZWO AM5N Harmonic Drive Mount
https://www.opticscentral.com.au/zwo-am5n-harmonic-drive-mount.html