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Seeking Advice: Would an ASA DDM60 be an upgrade from a Vixen AXD?

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#1 AnakChan

AnakChan

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Posted 23 October 2021 - 07:37 AM

I have an opportunity to pick up a used ASA DDM60 Std built around 2013 that has been firmware updated. Aside from it being a direct drive mount that ASA no longer makes, I'm wondering if it'll be considered as an upgrade from my 6 year old Vixen AXD. My intended payload will be my Takahashi µ250CRS used for imaging with my ASI6200MM camera - a combination that's 0.31"/px at Bin1x1. My payload is < 20kg which is well within the reach of my AXD's 30kg payload, and the DDM60's 25kg payload.

 

Currently with the AXD I'm guiding a wide range from 0.23 -> 0.7" RMS depending on environmental conditions, and I do have some slight teething issues with the Vixen's ASCOM driver not fully supporting AsyncSlewing (more precisely the Slewing property isn't accurate) which the maker hasn't acknowledged it as a fault yet. What I am hoping to gain from the ASA DDM60 is from it's encoders and from it's lighter weight to save my ageing spine.

 

However all I have are just the specs of the DDM60 and am not certain if in practice if it'll be a marked improvement over my Vixen AXD from a guiding perspective. I mean if my AXD is able to provide a more consistent 0.2-0.35" RMS, in guiding, I'd probably wouldn't be so anxious in looking for an alternate mount. A such I'm wondering if the DDM60 with it's encoders will provide that.

Anyone care to share their thoughts/opinions?

I've attached 2x PHD2 files, one where I do have good guiding the whole night, and another is just average. Scope/payload setups the same for both instances.

Attached File  PHD2.zip   266.94KB   5 downloads



#2 AnakChan

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Posted 29 October 2021 - 01:28 PM

Giving this a bit of a bump.

I've been following up with various ASA DDM owners in the past few days and it seems that from a stability perspective (no pun intended), the DDM60 would have some benefits over the Vixen AXD from the perspective of truly eliminating any ambiguity I may have with Vixen AXD's performance, may it be tracking accuracy, susceptibility to wind, periodic errors, OTA flexure, etc. This makes the DDM60 even more tempting.

However it seems with ASA mounts, they are tightly coupled with the AutoSlew and Sequence software that runs on a PC. i.e. ASA mounts cannot operate standalone. I'm a N.I.N.A. user and I'm aware AutoSlew supports ASCOM. However it seems I might not be able to benefit from the point modelling and MLPT unless I also bu MaximDL & PinPoint.

Has anyone used N.I.N.A with their ASA mounts? If so any recommendations on workflow? Would I need to buy MaximDL/PinPoint just to perform MLPT and sky modelling first, then have AutoSlew replay and just have N.I.N.A running after to interface with the mount?

I don't have an observatory so it'll be a nightly setup/daily teardown approach.



#3 AnakChan

AnakChan

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Posted 13 November 2021 - 01:02 AM

A little update to this. I've decided to go ahead and take the plunge into the ASA DDM60. When I get it I'll perform a side-by-side comparison for myself and decide if it'll be the AXD replacement.

Meanwhile, I'm still seeking folks who have ASA's AutoSlew/Sequence/MaximDL/PinPoint experience. My understanding is :-

1) I need Sequence (which in turn depends on MaximDL and PinPoint) for building the sky model. MaximDL is used merely as an interface to the camera as all the actual brains/logic is in Sequence. Similarly Pinpoint is just used for plate solving (an alternative to ASTAP)

upon building the sky model

2) I just need AutoSlew to replay it (kinda like replaying PEC), and thereafter with AutoSlew's ASCOM interface, I can use my favourite acquisition/scheduling software (in my case N.I.N.A.) to mange the image acquisition scheduling.

Is my understanding of the use of AutoSlew/Sequence/MaximDL/PinPoint correct?




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