Avalon M-Zero mount test
by Lorenzo Comolli - written in Dec 2014

The Avalon M-Zero mount has been tested in August 2014 at Colle dell'Agnello, Italian Alps.
Imaging setup: Pentax 75 with Canon EOS 60D, guiding with a 50 mm "finder" and Lacerta Mgen.

Introduction
I've tested this mount thanks to the availability of the manufacturer and friend, Luciano Dal Sasso of Avalon Instruments (for a complete description, see the manufacturer website). He borrowed me a complete mount together with the main accessories, like the X-Guider, polar finder, counterweights, tripod.
I've tested this mount from an imaging point of view, being this the main reason I see for the use of this mount. But obviously you are free to use for visual use.
As a payload I've selected a Pentax 75 apo refractor with a Canon EOS 60D, and a 50 mm "finder" as a guide scope, with the stand-alone Lacerta Mgen camera (thanks Emmanuele for the guiding finder and camera). This complete setup does not need a PC to work, but in order to have go-to pointing, a PC via USB or a Bluethooth device (smartphone or tablet) is necessary. I've decided to use in the simplest way, without any additional device, so I've pointed it manually by using proper friction or small movements trough the hand-pad.
This setup is extremely simple but effective in gathering nice deep sky images. No need for PC is a huge advantage. To power all the setup (mount, camera and guiding camera) I needed only a small 10 Ah Gel-lead-acid battery, that was able to power the setup for all the night.

Tracking
The "fast reverse" technology that is used in the M-Zero (and also M-Uno and Linear mounts) is very interesting because of absence of backlash due to the absence of gears. The transmission and reduction of motion from the motors to the axes is obtained with a four-step reducer via pulley-tooth belt system on ball bearing.
I've verified the absence of a periodic error doing a long tracking test. I've imaged a reference star near the meridian at about 50° height. Polar pointing made with the standard polar finder. To get the video I've used the same camera I've used for imaging, a Canon EOS 60D, set to gather a 30 min video at 100% resolution, crop of 640x480 pixels, 50 fps. Then I've converted the video in fits images and measured the position with Iris software.
The resulting data has been analyzed in Matlab and the results are in the figures below. In the periodogram (or spectrum), the only peaks have periods of 1.1 s, 0.55 s and 0.36 s, with an amplitude of only 0.1", maybe due to the motor steps (1x, 2x and 3x harmonics). No clear signs of longer periods are visible: impressive!
The drift in the "raw" time history is due to polar misalignment, and is nearly 25" in AR and 35" in DEC in the total duration of the video (30 min). Looking at the time history of RA with the trend removed, small "undulations" in the motion are clear, with a peak to peak amplitude of about 12", a value that is really good also for much heavier and bigger mounts.
However for imaging with the selected setup, guiding is absolutely necessary. But thanks to the good intrinsic tracking, and to the absence of backlash, guiding is quite easy.

Raw time history
 Time history with trend removed
Spectrum
 Periodogram
Tracking test of 30 min at 50 Hz (obtained with a video at 100% with Canon EOS 60D)

Long exposures imaging
Using the mount for imaging is very easy.
 Thanks to the good working of the setup, I've been able to gather 10 min long exposures on classical objects of the summer sky, and of a comet. Click on the images to watch the hires and detailed tech data.
Comet C/2014 E2 (Jacques)
27-28 August 2014
Coathanger cluster
 M11 and Scutum star cloud - 2

Conclusions
In this short test I've evidenced the very good behavior of this mount. Thanks to the good tracking, it is easy to guide for long exposures. Being relatively light and compact, it is an ideal solution for the "travel" astroimager. Unfortunately the price is not so popular (about 4 k€ for the tested mount), but quality cannot be cheap. Results proved that this mount is well worth the price when compactness and quality are fundamental requirements.

Images
Here are some images of the setup in the observing field at Colle dell'Agnello, in the Italian Alps, at 2700 m heigth.


Complete view of the mount and tripod (named T-pod)


Detail of the mount head and telescope.


Detail of mount base and electronics box. Note also the small amount of counterweights needed to balance the optics.


Detail of mount base with the Lacerta Mgen stand-alone autoguider.


Front view of the setup


Detail of the electronics box



     
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