DiscMounts DM-6: Anyone have this?

Tachyon · Post by **Tachyon** » Tue Sep 20, 2005 12:24 pm

Just wondering if anyone has this: http://www.discmounts.com/why.html

Any comments?

Cheers!

ariefm71 · Post by **ariefm71** » Tue Sep 20, 2005 12:28 pm

I was thinking of quitting astro after looking at their prices...

denebman · Post by **denebman** » Tue Sep 20, 2005 1:14 pm

Not to boast my alt-azimuth mount. In fact one of my previous homemade alt-azimuth mount was sold to a Chinese amateur who was using DM-6 mount for his FSQ106, finally he chose to sale his DM-6.

The link is here: http://forum.xitek.com/showthread.php?t ... genumber=2

The second link is his post to sale his DM 6 mount: http://www.astronomy.com.cn/bbs/viewtopic.php?t=43609

rlow · Post by **rlow** » Tue Sep 20, 2005 3:50 pm

The DM-6 head weighs 7.3kg, can carry 18.1 kg, cost $2016++
The DM-4 head weighs 2.4kg, can carry 6.8 kg, cost $1344++

The Astroslew head weighs 2.7kg, can carry 20kg, cost $410 !!

For me, since I want a lightweight but very stable and cost-effective grab-and-go setup, the choice is pretty obvious. I usually use only two eyepieces anyway and I just tighten the altitude tension knob if I have to.

Tachyon · Post by **Tachyon** » Tue Sep 20, 2005 5:03 pm

Yep. In fact, in a review in 2003 ( http://www.cloudynights.com/item.php?it ... &pr=2x8x35 ), everything about this mount is good except the price!

Still, the attraction of not having to re-balance when I change from eyepiece to camera is tempting...

Cheers!

Post by **VinSnr** » Tue Sep 20, 2005 5:22 pm

Tachyon wrote:Yep. In fact, in a review in 2003 ( http://www.cloudynights.com/item.php?it ... &pr=2x8x35 ), everything about this mount is good except the price!

Still, the attraction of not having to re-balance when I change from eyepiece to camera is tempting...

Cheers!

For that price, I am willing to rebalance any amount of time.

MooEy · Post by **MooEy** » Tue Sep 20, 2005 6:34 pm

rlow wrote:The DM-6 head weighs 7.3kg, can carry 18.1 kg, cost $2016++
The DM-4 head weighs 2.4kg, can carry 6.8 kg, cost $1344++

The Astroslew head weighs 2.7kg, can carry 20kg, cost $410 !!

nothing against the astroslew, just that i'm always skeptic of capacity stated by the manufacturers. the capacity of the discmounts seems very reasonable since they have 4" and 6" bearings on both axis. however the capacity stated by liu ming for the astro slew doesn't seem to be inline with most of the other manufactuers. the stellarvue m6 mount have 4.5" azimuth bearings but only list at 10kg capacity.

another noteable point is that beyond a certain load, giro type mounts tend to require counterweights to balance properly. it seems that the counterweight have always been left out of the equation when calculating weight.

if we consider all factors, the astroslew may not sound as godly as a 2.7kg mount that carries 20kg, but more of a reasonable mount that cost $600+

~MooEy~

denebman · Post by **denebman** » Tue Sep 20, 2005 7:14 pm

MooEy wrote:
rlow wrote:The DM-6 head weighs 7.3kg, can carry 18.1 kg, cost $2016++
The DM-4 head weighs 2.4kg, can carry 6.8 kg, cost $1344++

The Astroslew head weighs 2.7kg, can carry 20kg, cost $410 !!

...however the capacity stated by liu ming for the astro slew doesn't seem to be inline with most of the other manufactuers. the stellarvue m6 mount have 4.5" azimuth bearings but only list at 10kg capacity...
~MooEy~

Good reminder, I will experiment out the upper limit of the stable payload of my alt-azimuth mount before making any formal statement.

In fact, when talking about the dampening ability, the OTA, the mount and the tripod need to be considered as a whole, any weak point will destroy the integrity of the system. In the future, I may get a stable wood tripod to give more test results.

denebman · Post by **denebman** » Tue Sep 20, 2005 7:29 pm

Tachyon wrote:Yep. In fact, in a review in 2003 ( http://www.cloudynights.com/item.php?it ... &pr=2x8x35 ), everything about this mount is good except the price!

Still, the attraction of not having to re-balance when I change from eyepiece to camera is tempting...

Cheers!

Not having to rebalance means altitude friction face is very tight to counteract the unbalancing torque. This is OK if you do a still shot or observe at low power; However at medium or high power, it is very troublesome since the friction makes the manual control very stiff and uncomfortable. This is the lesson I learned when developing another bigger A-Z mount that aims to replace the DM-6. (the mount is being used by a HongKong amateur now)

Tachyon · Post by **Tachyon** » Tue Sep 20, 2005 9:26 pm

denebman wrote:Not having to rebalance means altitude friction face is very tight to counteract the unbalancing torque. This is OK if you do a still shot or observe at low power; However at medium or high power, it is very troublesome since the friction makes the manual control very stiff and uncomfortable. This is the lesson I learned when developing another bigger A-Z mount that aims to replace the DM-6. (the mount is being used by a HongKong amateur now)

Thank you for the insight! So you *do* have a version of the DM-6! How many did u make?

Guess I am back to my GEM...

Cheers!