MLAstro SAL-33 Mount Review: A Capable Strain Wave Mount at a Competitive Price

Introduction

The MLAstro SAL-33 is a strain wave gear mount that aims to deliver performance comparable to more expensive options at a significantly lower price. With a 15 kg payload capacity without counterweight, expandable to 20 kg with a 5 kg counterweight, it positions itself as a serious contender for astrophotographers looking for a capable mount without the premium price tag.

Priced at $1,100, the SAL-33 undercuts many of its direct competitors while offering features like an open-source firmware, a unique zero-shift polar alignment system, and a striking silver anodized finish designed for long-term durability in direct sunlight. This review explores the mount’s design, performance, and overall value.

Design and Build Quality

The SAL-33 immediately stands out with its silver anodized finish. This is not just an aesthetic choice; the special anodizing process is designed to withstand prolonged exposure to direct sunlight without discoloration or degradation. This makes the mount particularly well-suited for solar photography, a natural fit given the brand’s background in spectroheliographs.

The entire mount is machined from aluminum, giving it a solid and robust feel. The prominent screws visible across the housing are intentional, designed to make the mount easily serviceable by either the manufacturer or the end user. This focus on repairability is a welcome feature, aligning with the right-to-repair philosophy.

The dual saddle supports both Vixen and Losmandy standards. A thoughtful design choice keeps the two saddle parts independent, allowing you to tighten one side securely before the other, preventing any awkward angles when mounting a telescope. The mount also includes a level and a graduated scale for rough altitude adjustments on the polar alignment base.

Polar Alignment Performance

The standout feature of the SAL-33 is its zero-shift polar alignment system. With the altitude and azimuth knobs locked down, you can move the mount around, even with heavy payloads, without losing your polar alignment. This system works as described, making the polar alignment process notably easier.

The altitude adjustment screw is exceptionally fine, allowing for very precise adjustments. The azimuth adjustment is standard but functional. Overall, the polar alignment experience is rated as better than the AM5N, placing it at a similar level to the EM31 Pro, a highly regarded mount in this category.

The only minor drawback is that large altitude adjustments require the use of the provided wrench to loosen and reposition elements on the base before making final fine adjustments. This is a small inconvenience for what is otherwise an excellent polar alignment system.

Guiding Performance and Results

The SAL-33 was tested with a setup controlled via NINA on a Windows computer, and also worked fine with other popular control systems like the ASI Air, Toptech Astro Station, and Stellar Mate Pro. The guiding results were consistently good, with total RMS error figures typically around 0.7 arcseconds, and right ascension error around 0.55 arcseconds, even under less-than-ideal seeing conditions with some wind.

A frequency analysis of the guiding data revealed a periodic error peak at around 280 seconds, in addition to the expected 430-second peak. The predictive PEC algorithm effectively handled the 430-second peak, while the 280-second peak remained a minor contributor. The mount’s motor settings are accessible and adjustable via the web interface, offering potential for further optimization.

The mount’s performance was comparable to a WD20 mount imaging alongside it, which had a slightly heavier payload. No oscillations or other issues were observed in real-time star views. The SAL-33 proved to be a very competent and reliable performer.

Software and Open-Source Ecosystem

The SAL-33 is driven by OnStep X, an open-source firmware. The implementation here is notably smarter than other OnStep mounts. When powered on, the mount creates a Wi-Fi hotspot that you can connect to, and a browser-based control system allows you to change all settings, including important parameters like meridian flip behavior.

The default settings for meridian flips are good, which is a significant improvement over many other OnStep mounts. The mount also comes with excellent documentation, including a series of videos that thoroughly explain how to use the mount, understand OnStep’s characteristics, and optimize guiding.

The open-source nature extends to the pin layouts and electronics, allowing users to modify or improve the system. Any firmware enhancements are contributed back to the OnStep project. This openness is a stark contrast to some other major players in the astrophotography market and is a major plus for users who value long-term support and customization.

Buying Advice

The MLAstro SAL-33 is an excellent choice for astrophotographers who want a high-performance strain wave mount without the premium price. Its $1,100 price point makes it significantly more affordable than comparable mounts like the AM5N, while offering similar or better performance in key areas like polar alignment.

It is particularly well-suited for those interested in solar photography, thanks to its durable silver finish, and for users who appreciate open-source hardware and software. The lack of through-the-mount cabling and saddle plugs are minor omissions, but they are easy to overlook at this price.

Conclusion

The MLAstro SAL-33 is a very competent and impressive mount. It offers solid tracking, excellent polar alignment, full compatibility with AM5N tripods, and a considerably lower price than its main rivals. The open-source design and focus on serviceability are significant advantages for long-term ownership.

While it lacks some luxury features like through-the-mount cabling, its performance and value are hard to beat. For anyone seeking a reliable and capable strain wave mount, the MLAstro SAL-33 is a compelling option that deserves serious consideration.