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Re: [ccd-newastro] Looking for new portable mount

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  • Ron Wodaski
    Interesting points. I won t disagree about what the mount can handle , but I do recommend leaving some headroom, and staying short of the can handle point
    Message 1 of 40 , Jun 8, 2013
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      Interesting points. I won't disagree about what the mount 'can handle', but I do recommend leaving some headroom, and staying short of the 'can handle' point for _any_ mount.

      A C9.25 is a great match.

      I chuckled at your point, that someone going from a CGEM to a Mach 1 would be astonished at the relative lack of features. True enough, but I would look at it from this point of view: the CGEM has an astonishing lack of features that matter for someone after precision.

      And you are right - absolute encoders are wonderful. Removing periodic error is valuable. But it's not a perfect solution. At longer focal lengths, you still need to have a good tracking model even with very high quality absolute encoders - there are still physical elements contributing to error (both periodic and jitter). Even a direct drive telescope with absolute encoders needs a good model to perform really well. But we're talking very small errors; they often don't even come into play until you get out to half-meter focal lengths or longer.

      Basically, absolute encoders, placed at the active surface of moving parts, have a great deal more lever arm than things like servos. They are not cheap. Still, all things being equal, they are a delight to use. Basically, your mount is not longer steering blind.

      Ron Wodaski



      On Jun 8, 2013, at 10:40 PM, Orlando Andico <orly.andico@...> wrote:

      > Let me chime in on this.
      >
      > 1) Roland states that the Mach1 can handle a C11 without issue; I imagine
      > you will still need an off-axis guider.
      >
      > I am using a C9.25 with a separate guide scope (a 560mm focal length, 60mm
      > refractor). This works just fine up to 10 minute guided subs.
      >
      >
      > 2) I have a CGEM. You will be astonished at the (relative) lack of
      > features in the AP GTO controller. There is no alignment procedure (e.g.
      > no need to put the mount in home position and wait for it to slew to
      > alignment stars). Because the AP GTO controller only does 1-star aligns.
      > You turn on the mount, point it at a star across the meridian from the
      > telescope tube, select the star from the list, and Sync. That's it.
      >
      > What this makes obvious is that the pointing will be severely off unless
      > your polar alignment is perfect.
      >
      >
      > 3) Another option is the 10Micron GM1000HPS. Ed Thomas from Deep Space
      > Products is the US distributor. It weighs more than the Mach1, has the
      > same capacity (45lb) as the Mach1.... and costs $1000 - $1500 more. BUT -
      > it has dual 10-million tick absolute encoders on both axes. I'll leave the
      > real experts like Ron to tell you what dual encoders bring to the table...
      >
      >
      >
      >
      > On Sun, Jun 9, 2013 at 9:32 AM, Mark Acker <markacker@...> wrote:
      >
      >> **
      >>
      >>
      >> (I know you meant the other Mark.)
      >> With the PASILL4, I can get very good alignment. I was going to order the
      >> new RAPAS scope, but with the alignment I already get, I just could not
      >> justify it. You can always use PEMPro as well to do a drift alignment with
      >> a CCD or a finder and use the modified drift align. I've never done that
      >> as the polar scope always got me close enough. The longest subs I do a are
      >> typically 20 mins for Ha. I used the same PA routine as you when I had the
      >> CGE, but with the PASILL4 scope, it's way faster, easier since the scope is
      >> easier to adjust and every bit as accurate if not more so.
      >>
      >> I image with both a 10" ACF and 12" SCT and both work fine, as long as
      >> there is no wind. That's always the main variable with either of these.
      >> The TOA-130 handles wind just fine.
      >>
      >> Mark
      >>
      >> ________________________________
      >> From: Mark Striebeck <mark.striebeck@...>
      >> To: ccd-newastro@yahoogroups.com
      >> Sent: Saturday, June 8, 2013 7:28 PM
      >> Subject: Re: [ccd-newastro] Re: Looking for new portable mount
      >>
      >>
      >>
      >>
      >> Thanks everybody for the endorsements of this mount. Mark, I like what you
      >> pointed out: that this mount "just works". With my CGEM, I can make it
      >> work, but it's a lot of work and I'm constantly messing around with it to
      >> just get it a little bit better.
      >>
      >> A few more questions:
      >>
      >> Right now, I'm using and 8" EDGE scope - I'm sure that it can handle that
      >> easily. But I am considering to buy an 11"-ish scope in the future where
      >> the load can go beyond 20 kg. Would this mount be able to handle that? (or
      >> is there any portable mount that could handle that load)?
      >>
      >> What I like about the CGEM scope is its polar all-star alignment. It allows
      >> me to get polar alignment good enough for 10min subexposures. Does the
      >> Mach1 mount have something similar? How accurate can you polar align it
      >> with the polar alignment scope?
      >>
      >> Thank you!
      >>
      >> MarkS
      >>
      >> On Sat, Jun 8, 2013 at 10:19 AM, Ron Wodaski <yahoo@...> wrote:
      >>
      >>> **
      >>>
      >>>
      >>> We have two of the Mach 1 mounts at Tzec Maun Observatory, as well as a
      >>> bunch of other AP mounts. All of them are excellent performers.
      >>>
      >>> If I recommend a mount to someone who's starting, or starting to get
      >>> serious, about imaging, this is what I recommend for smaller scopes. If
      >> you
      >>> have medium to large scopes, then the larger AP mounts are also an
      >>> excellent choice.
      >>>
      >>> Not that there are also other good mounts, such as the Paramount. In the
      >>> end, thought, if you want to image without grief, then you are going to
      >>> need to spend somewhat generously on a mount.
      >>>
      >>> Ron Wodaski
      >>>
      >>>
      >>> On Jun 8, 2013, at 10:31 AM, daniele malleo <d.malleo@...> wrote:
      >>>
      >>>> Hi Mark,
      >>>> another strong vote of confidence for the Mach1. This is the mount that
      >>> "changed my life". It is simply outstanding. Prior to this mount my
      >> nights
      >>> were all about Periodic Error, biasing the balance this way or the other,
      >>> freaking out when wind was blowing...
      >>>> After this mount, all of that is gone. I set it up in the field, polar
      >>> align it, first roughly with the polar scope, then finely by CCD
      >> drifting,
      >>> and I'm done for the night. It will track with sub-arcsec accuracy
      >> through
      >>> the night.
      >>>> I would argue that its price is fair, given its performance.
      >>>> As far as I know there was no waiting list for the Mach1 when I bought
      >>> it new, about a year ago (I received from AP inside of a week of my
      >> order).
      >>> Not sure if things have changed since then.
      >>>> Best of luck,
      >>>> Daniele
      >>>>
      >>>>
      >>>> --- In ccd-newastro@yahoogroups.com, Mark Striebeck <mark.striebeck@
      >> ...>
      >>> wrote:
      >>>>>
      >>>>> Hi,
      >>>>>
      >>>>> I am starting to consider getting a new mount. I'm mostly imaging from
      >>> my
      >>>>> backyard. But I have to move my mount into the house and often I am
      >>> taking
      >>>>> my mount to other (less light polluted) places.
      >>>>>
      >>>>> I was looking for reviews of the various mounts. From the few that I
      >>> found,
      >>>>> it seems as if the Astro-Physics AP Mach1 GTO mount is an amazing
      >> mount
      >>> -
      >>>>> but also for a pretty steep price (and apparently quite a long waiting
      >>>>> time).
      >>>>>
      >>>>> I'm pretty sure that some folks on this list have this Astro-Physics
      >>> mount
      >>>>> and would be interested in your experience.
      >>>>>
      >>>>> Is there somewhere a good comparison between mounts?
      >>>>>
      >>>>> Thanks
      >>>>> MarkS
      >>>>>
      >>>>>
      >>>>> [Non-text portions of this message have been removed]
      >>>>>
      >>>>
      >>>>
      >>>>
      >>>> ------------------------------------
      >>>>
      >>>>
      >>>>
      >>>>
      >>>
      >>>
      >>>
      >>
      >> [Non-text portions of this message have been removed]
      >>
      >> [Non-text portions of this message have been removed]
      >>
      >>
      >>
      >
      >
      >
      > --
      > Orlando Andico
      > +65.6436.1577 | +65.8139.0251
      >
      >
      > [Non-text portions of this message have been removed]
      >
      >
      >
      > ------------------------------------
      >
      >
      >
      >
    • CurtisC
      Who is AT? Astro-Physics website lists four US dealers. OPT says out of stock. Anacortes doesn t say if they have it in stock, and I haven t
      Message 40 of 40 , Jun 10, 2013
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        Who is "AT?" Astro-Physics' website lists four US dealers. OPT says "out of stock." Anacortes doesn't say if they have it in stock, and I haven't investigated Company7 and Starizona. Also, Mach1s show up on AM pretty regularly.

        --- In ccd-newastro@yahoogroups.com, Mark Striebeck <mark.striebeck@...> wrote:
        >
        > Again, thanks for all the feedback and info - super valuable.
        >
        > ... but now where I got my hopes up, I received a response from AT that
        > they won't have new units until next year :-( So, I have to decide to
        > either keep tuning my CGEM and deal with it for many, many more months. Or
        > to go with one of the alternatives that were mentioned here. Unless
        > somebody here (or anywhere else) wants to sell his Mach1.
        >
        > MarkS
        >
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