The Mesu Mount
| Benefits of the lack of a meridian flip : |
| - | No interruptions while observing or imaging objects going through the meridian. | |||
|---|---|---|---|---|
| - | No need to search for a new guide star because of the 180-degree image rotation going through the meridian. | |||
| - | No 180-degree image rotation during stacking of long exposed sub frames. | |||
Especially for astroimaging, which the Mesu-Mount is designed for, these are great advantages. Especially the 180-degree image rotation in combination with loosing the guide star are often irritating during astroimaging sessions.
Something about PE (Periodic Error)
| The Mesu-Mount with a typical instrument setup is seeing limited for many minutes of open loop tracking (without optical feedback from the object). Measurements are done to demonstrate the Mesu-Mount periodic error over a long period of time under heavy load conditions in open sky conditions. As written in the DFM article more properties than PE are important for a telescope mount. The Smoothness of tracking is more important than the low frequency periodic error. This is because even a fairly large amplitude periodic error can be guided out using optical feedback (from a guide star) if the frequency is low. If the frequency is high you need expensive systems to guide it out. So it is desirable to have a smooth running mount that does not has high frequent tracking errors. Optical feedback from a celestial object is what is needed to expose a deep-sky object for a long time. A feedback from the mounts axis to make it rotate very constant will not be enough. This will cost a high resolution encoder to measure the rotation on arc second level and will not help to make a good deep-sky picture. Much better is to use auto guiding and use a celestial object as reference. Auto guiding can be done for a low price and needs to be done anyway also when the mount has a close loop control system on the RA axis. This is because there is variation in atmospheric conditions and flexure in the mechanical parts of the telescope. This factors are becoming more important when exposure times increase. This cannot be compensate by feedback from the mounts RA axis to the servo controller alone. Another property that defines the mounts quality is the stiffness. Typically telescope structures are stiffer than the drive stiffness, the drive system needs to either have inherent stiffness or develop stiffness through the servo motor controller. Any gear system require lubrication. The lubrication film between the gear teeth will significantly lower the stiffness. The Mesu-Mount is very stiff because it has no gear system that need a lubrication in the drive train. Furthermore is a high efficiency drive desirable. It requires less power and it allow the drive system to remove energy from the moving telescope setup. Removing energy allows faster deceleration and significantly improves telescope response to position changes. Worm gears with high gear ratio have very low efficiency and must be decelerate very slowly increasing the time required to respond to a position change command. |
The original ServoCat motors including gearhead generated an overall PE of 30" peak-to-peak. Therefore these motors including gearhead are replaced by Maxon motors including gearhead which improved the overall PE dramatically to 4" peak-to-peak (see below graph).
The first Mesu Mount with ServoCat/ArgoNavis control is already delivered to Rob Kantelberg. For more details see his website.
Download here a review of this mount.
Download here a brochure of this mount.
Images of different Mesu-Mounts
click on the thumbnails for enlargement
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Images made with several telescopes mounted on the different Mesu-Mounts
click on the thumbnails for enlargement
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| Before you decide which telescope mount you buy : Compare! | Bevor Sie sich entscheiden welche Astro-montierung Sie kaufen : Vergleich! | Voordat u beslist welke telescoop-montering dat u gaat kopen : Vergelijk! |
| Our mount | Unsere Montierung | Onze montering |
| Mobile high end telescope mount | Mobile high-end Montierung | Mobiele high-end montering |
| No meridian flips | Kein Meridian Umschlag | Geen Merediaanomslag |
| Easy separation in two 25 kg parts within minutes | Einfache Zerlegung in zwei 25 kg Teile in wenige Minuten | Eenvoudig op te delen in twee delen van 25 kg in enkele minuten |
| Siffer construction then German mount on tripod | Steifer Konstruktion wie German Montierung auf dreibein | Stijvere constructie dan Duitse montering op driepoot |
| Friction drive 1:150 primary reduction on both axles (300mm diameter) | Friktionsantrieb 1:150 Reduktion auf beide Achsen (300mm Durchmesser) | Frictieaandrijving 1:150 reductie op beide assen (300mm diameter) |
| Drive: no backlash | Antrieb spielfrei | Aandrijving zonder speling |
| Latitude range from N to Z polar circle | Latitude bereich von N bis Z Poolcirkel | Latitude bereik van N tot Z poolcirkel |
| No measurable periodical error | Kein messbaren periodischen Fehler | Geen meetbare periodieke fout |
| Very smooth guiding speed | Sehr gleimasige lauf | Zeer eenparige volgsnelheid |
| High dynamic speed range | Hohe dinamische geschwindigkeit bereich | Hoog dynamisch snelheids bereik |
| Craddles of your telescope size | Teleskopesattel fur Ihr Teleskop | Telescoopzadel voor uw telescoop |
| Contra weight up to 20 kg included | Kontragewicht bis 20 kg ist inklusiv | Inclusief contragewicht tot 20 kg |
| Advanced servo controller (ask info StellarCat) |
Advanced servo controller (Versuch info StellarCat) |
Geavanceerde servobesturing (Vraag info StellarCat) |
| Advanced D.S.C. (Ask info ArgoNavis) |
Advanced D.S.C. (Versuch info ArgoNavis) |
Geavanceerde D.S.C. (Vraag info ArgoNavis) |
| Cost: €7495,00 | Preis: €7495,00 | Prijs: €7495,00 |
Find here a performance overview of many more mounts.
| Comparison of mounts | Vergleichung von Montierungen | Vergelijking van monteringen | ||||
|---|---|---|---|---|---|---|
| Brand/ Hersteller/ Fabrikaat |
Max. Load/ Max. Last/ Max. Last |
Max periodic Error/Fehler/ Fout |
Meredian Flip/ Meredianspiel/ Merediaanspeling |
No backlash/ Spielfrei/ Spelingvrij |
Mobile/ Mobil/ Mobiel |
Cost/ Preis/ Prijs |
| Mesu Mount | 2 x 65kg | 4" peak-to-peak | No/Nein/Nee | Yes/Ja/Ja | Yes/Ja/Ja | €7495,00 |
| Losmandy Titan | 1 x 45kg | 10" peak-to-peak | Yes/Ja/Ja | No/Nein/Nee | Yes/Ja/Ja | €8295,00 |
| Astro Techniek CP180 | 2 x 100kg | 4" peak-to-peak | No/Nein/Nee | No/Nein/Nee | No/Nein/Nee | €10000,00 |
| 10 Micron GM2000 | 1 x 45kg | 8" peak-to-peak | Yes/Ja/Ja | No/Nein/Nee | Yes/Ja/Ja | €10950,00 |
| Astro Physics 1200GTO | 1 x 63kg | 8" peak-to-peak | Yes/Ja/Ja | No/Nein/Nee | No/Nein/Nee | €13000,00 |
| Paramount |
1 x 60kg | 4" peak-to-peak | Yes/Ja/Ja | No/Nein/Nee | Yes/Ja/Ja | €13750,00 |
| Vixen Gajax | 1 x 44kg | 10" peak-to-peak | Yes/Ja/Ja | No/Nein/Nee | Yes/Ja/Ja | €14956,00 |
| Gemini Mountegra | 1 x 70kg | 4" peak-to-peak | No/Nein/Nee | No/Nein/Nee | No/Nein/Nee | €16000,00 |