DiscMounts DM-6 Alt-Az mount.. first light

snaggs · #1 18-08-2009, 06:48 PM

Well, whilst I wait for my Gran Turismo to arrive, I have been enjoying another fine APO, namely a Takahashi FS-60CB. So how did it go?

The DM-6 has changed my life... why did I persevere with GEM mounts for all those years? and my worries about guiding at high power were unfounded.

Last night I spent much of the evening gazing at Jupiter at 142x (Extender-Q and Zeiss 4mm), saw the 4 moons, banding on the planet etc. Also saw the Eta Carina nebula, M5, Omega Centauri and the jewel box. Just gorgeous! Star resolve to pinpoints like nothing I have seen. The FS-60 has more detail, resolution, everything than the 4" Nextstar I owned (and tracks better by hand with the DM-6!), isn't as good on dim fuzzies as the 6" chinese newtonian I had, but once again, better on planets and much nicer on star fields. Only the 8" Meade LX-90 has given me more detailed views, but I still think I prefer the 60mm Tak and its rendition of the Jewel Box trumps the 8".

Tracking was no problem at all, even at 284x when I stuck the Zeiss 2x barlow in just for kicks (at this resolution the baby TAK did experience some image degradation). I'm glad I ordered the optional handle, it is very convenient to use. Did I mention that the DM-6 has no back lash?

The Sky Commander performs as advertised, and once again I was wondering why I had put up with batteries, cords and whirring motors. The push-to is much faster.

In hind sight, I wish I had just bought a nice Tak or Vixen apo to start with all those years ago on a Alt-Az mount. I would have saved myself alot of chopping and changing.

PS. I have compared the DM-6 to the Tak Teegal, and it is clearly more stable... still I'll put up with a 2s dampening time and be able to take my scope into the country with me on my motorbike. They are different beasts.. and I'd have either over any GEM, never never again..

Daniel.
Perth, Australia

PS. Other photo's of the scope are in the Takahashi FS-60CB first light thread, or in my post on the DiscMount discussion group;

http://tech.groups.yahoo.com/group/discmounts/messages

dannat (Daniel) · #2 18-08-2009, 07:49 PM

great looking mount & scope -280x at 60mm of aperture is a bit of a stretch though.
Is it the zeiss abbe's that you have?

Miaplacidus (Brian) · #3 18-08-2009, 07:58 PM

Well, I'm not sure how to describe the shade of green I've turned, but you get the idea. Congratulations. Where did you source the Discmount???

Cheers,

Brian.

snaggs · #4 18-08-2009, 08:14 PM

Quote:

Originally Posted by dannat

great looking mount & scope -280x at 60mm of aperture is a bit of a stretch though.
Is it the zeiss abbe's that you have?

Yes it is a stretch. 142x is v.sharp though, and does look a like the photo's on the Tasco boxes

Also affirmative to the Zeiss Ortho's, and they make a difference, even with 60mm of aperture.

Daniel.

snaggs · #5 18-08-2009, 08:18 PM

Direct from the maker. The whole mount has been CNC machined from solid steel. Considering the mount (not the legs) can take 7" APO, its a bargain.

http://www.discmounts.com/

They also have a DM-4, I don't know why anybody would by an iOptron when you can buy a mount like this can be had for only $800 US.

The quality difference is like comparing Tasco to Astro-physics.

Daniel.

Quote:

Originally Posted by Miaplacidus

Well, I'm not sure how to describe the shade of green I've turned, but you get the idea. Congratulations. Where did you source the Discmount???

Cheers,

Brian.

JethroB76 (Jeff) · #6 18-08-2009, 08:28 PM

Looks great! I see one of these in my future

snaggs · #7 18-08-2009, 11:06 PM

Quote:

Originally Posted by JethroB76

Looks great! I see one of these in my future

If your interest in Alt-Az, also check out the Tak teegul alt-az mount I have here;

http://www.iceinspace.com.au/forum/s...ad.php?t=48241

It was TG-SK for FS-60 and cost me $750 delivered from Claudio and included rings for the FS-60. You can get versions without rings.

Daniel.

wavelandscott (Scott) · #8 18-08-2009, 11:23 PM

The DM6 is the next bit of gear on my list...except i will substitute in an Argo Navis for the Sky Commander.

I checked them out at NEAF and they sure are finely made!

Congratulations and enjoy!

cohiba (Robert) · #9 19-08-2009, 11:03 AM

Hi Snaggs
What a great mount I have not seen one before I live in Perth and wouldnt mind getting a look at it in the flesh. I have a fixed observatory but am looking for a portable setup I can take out into the bush how do you find the sky comamder ?

snaggs · #10 19-08-2009, 08:53 PM

Sky Commander is very simple and easy to use. Its packed full of more catalogs than I poke a stick at. You can also load in your own lists via Excel Spreadsheets.

Where in WA are you? Next time there is a clear evening on the weekend I want to get up to Orange Grove.

Daniel.

Quote:

Originally Posted by cohiba

Hi Snaggs
What a great mount I have not seen one before I live in Perth and wouldnt mind getting a look at it in the flesh. I have a fixed observatory but am looking for a portable setup I can take out into the bush how do you find the sky comamder ?

cohiba (Robert) · #11 20-08-2009, 02:44 PM

Hi Snaggs
I live in the Vines so if you organise somthing give me a shout and I will come have a look see

Wavytone · #12 20-08-2009, 03:57 PM

If you're looking at a DM6 then maybe you should also investigate the Half-Hitch MkIII as well.

Having had an altaz mount for a year, I'm thinking about upgrading to the Half Hitch rather than the DM6 as I like the really free motion of the HH, provided the scope is balanced.

snaggs · #13 20-08-2009, 10:05 PM

Looks very nice, not sure how it compared to a DM-6 which can handle 6"-7" APO's. Nice none the less, I'd love to compare both side by side.

Either way, GEM's are looking very sad indeed.

Daniel.

Quote:

Originally Posted by Wavytone

If you're looking at a DM6 then maybe you should also investigate the Half-Hitch MkIII as well.

Having had an altaz mount for a year, I'm thinking about upgrading to the Half Hitch rather than the DM6 as I like the really free motion of the HH, provided the scope is balanced.

Wavytone · #14 21-08-2009, 09:42 AM

Snaggs, the real difference will concern how easily you can make small movements at high magnification.

The altaz mount I have currently uses preloaded bearings and teflon sleeves to provide drag with seemingly little or no stiction. In practice this is ok up to about 120X but at 200X its a nighmare for example to locate and track a planet; once lost getting it back in the field means switching eyepieces.

Looking at the DM6 it appears to rely on pre-loaded bearings + teflon between the large disks - and I suspect it suffers from exactly the same issue.

OTOH the HH mount uses free-running bearings and rollers to control its motion, with clutches. If the maker has really managed to make this work as well as it should, the HH should be vastly superior at high magnification. The downside is the scope will have to be well balanced, so it will be desirable to use a set of eyepieces that are all roughly the same weight. I've asked how these work on the CloudyNights forum and all the owners that replied were very happy with them and confirmed they can use high powers on 8" SCT's on the HH mkIII.

As you say it craps all over GEM's.

snaggs · #15 21-08-2009, 01:30 PM

Hey, you might suspect it, and I was worried about that too, but you'd be wrong!

The huge discs make it very consistent, I have tracked at 280x no problem. I have a new toy that arrived today, so soon I'll be able to tell you about higher powers..

Daniel.

Quote:

Originally Posted by Wavytone

Looking at the DM6 it appears to rely on pre-loaded bearings + teflon between the large disks - and I suspect it suffers from exactly the same issue.

DiscMounts, Inc (Tom) · #16 22-08-2009, 07:29 AM

Hi!

I’m Tom Peters the designer and manufacture of DiscMounts products. I have been in the hobby for over 50 years. Some years ago, I bought a TV NP-101 to use as a terrestrial and astronomical telescope when camping. The three things I demand in a mount, rigidity, smoothness, and being able to change eyepieces without the telescope moving, wasn’t available, so I designed and built my own. After prods from my friends and family to produce a similar mount, I started DiscMounts, Inc. Even though the rewards from manufacturing a very high quality mount has been great, the friends I have made all over the world has been even better. DiscMounts, Inc. has been nothing but fun!

Just some general comments about the DM-4 & DM-6!

The DM-4 and DM-6 are close coupled designs, with no struts or arms to vibrate. When vibration is considered the axis are just very big and short shafts (6” for the DM-6 and 4” for the DM-4). The design also allows the two axis to be very orthogonal, which DSC’s require to be accurate and consistent.

The friction discs are not Teflon! Teflon is soft, cold flows, has stiction problems, and wears out fairly quickly. The material I use (selected after years of experimenting. The first friction mount I designed and still use is 40 years old), is very tough (must be machined), has no stiction, and will last the life of the mount.

The DM-4 and DM-6 have two moving parts, and will last many years, with care, a lifetime. There is no maintenance! All our products are Type-3 hard anodized, which is very scratch resistant. Type-3 is not the same as the anodizing most manufactures use. There is no paint! There has been only one design change to the DM-6, the addition of two spring washers. None to the DM-4! The first DM-6 and DM-4 look and operate the same as what I’m shipping now. The design is very simple, and works.

The DM-4 is a down sized version of the DM-6, designed for the 4” and under grab & go scopes. It can handle a light 130 very well. It weighs, 6 pounds with saddle and is not much bigger than your hand.

The friction system is made adjustable so it can be tailored to the accessories being used, and can be changed easily when accessories change. Most owners find the adjustments they like and leave it there. I advertise 0-2.5 pounds for the DM-6 and 0-1.5 pounds for the DM-4 without changing the balance or adjustments. Some customers are going beyond these limits.

When tracking by hand the friction, unlike bearing mounts, actually helps. There is no over shooting the object then having to compensate. The mounts are so smooth and ridged, tracking is easy.

The advantage of the Sky commander over other DSC’s for the DM-6 &DM-4 is it’s small size, long history (15 years), easy use and Vic the Manufacture is a friend and local to me. That said, Gary (Argo Navis) and I have worked out cables for the Argo. The Encoders and cables must be sent to me and for a nominal fee I will install them. We have done many! Both DSC's are great!

Thanks for letting me shoot my mouth off! Hope I haven't come across to strong. Please visit out website at www.discmounts.com If you like to see pictures of telescopes, be sure to visit the “Galleries”!

Tom

Dennis · #17 22-08-2009, 09:52 AM

Hi Tom

Welcome to Ice In Space and thanks for the details on the DM-4 and DM-6, they sure look sweet and I can see one or other of these in my future! Daniel (snaggs) sure makes these sound like a must have mount!

Cheers

Dennis

snaggs · #18 22-08-2009, 12:35 PM

I'll get Cohiba to post his thoughts once he has had a play!

Daniel.

cohiba (Robert) · #19 25-08-2009, 08:49 PM

Snaggs
Look forward to an invitation

casstony · #20 19-02-2010, 11:23 AM

Thought I'd add my 2 cents to this old thread since I recently purchased a used DM6 from Astromart. I can track fairly easily at low to mid powers and there is no tendency to lose the object (the mount doesn't run away from you at all). The altitude axis is very easy to control while the azimuth is a little less so - just a touch jerky for minute adjustments, though I may not have the tension set perfectly yet. I may couterbalance the azimuth axis, particularly if I end up putting a C11 on it, which should make it perfect. I easily tracked a couple of satellites across the sky in a low power eyepiece - I use a laser pointer as a finder so it's easy to point the scope ahead of the satellite and catch it in the eyepiece. If you don't have the cash for these expensive mounts don't worry - a dob does a similar job for a lot less money - just depends on your preferences.

It'll be interesting to see how the DM6 compares to the new T-Rex mount when it's available.