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  #41  
Old 09-02-2007, 02:45 PM
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ving (David)
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i have heard that g-11s are really bad

hehe
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  #42  
Old 09-02-2007, 02:50 PM
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You need to get your ears cleaned then belle
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  #43  
Old 09-02-2007, 03:14 PM
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Gary,

say the argo is fitted, lets say you are out by heaps in finding the SCP, could you use the AN to precisely find the SCP instead of drift aligning?
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  #44  
Old 09-02-2007, 03:20 PM
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Originally Posted by [1ponders] View Post
Nahh, you don't need a gps for it h0ughy. It's easy enough to input. It's not as though this mount is going to be your normal travel mount
I will be bringing it to sunny QLd
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  #45  
Old 09-02-2007, 03:43 PM
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Maybe you'll want to leave it up here. It is afterall very heavy and you won't be wanting to cart it all over the countryside with your back.
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  #46  
Old 09-02-2007, 03:46 PM
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You need to get your ears cleaned then belle
flattery will get you no where!
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  #47  
Old 09-02-2007, 04:00 PM
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  #48  
Old 09-02-2007, 04:06 PM
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Quote:
Originally Posted by h0ughy View Post
Gary,

say the argo is fitted, lets say you are out by heaps in finding the SCP, could you use the AN to precisely find the SCP instead of drift aligning?

Gemini has it's own Polar Alignment Correction (PAC) and Polar Alignment Assist (PAA) for that.

Cheers

JohnG
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  #49  
Old 09-02-2007, 04:16 PM
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Gemini has it's own Polar Alignment Correction (PAC) and Polar Alignment Assist (PAA) for that.

Cheers

JohnG
Yep, makes aligning to the NCP a almost one step process
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  #50  
Old 09-02-2007, 04:20 PM
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hey it was you who said i was belle!
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  #51  
Old 09-02-2007, 05:51 PM
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Quote:
Originally Posted by h0ughy View Post
Gary,

say the argo is fitted, lets say you are out by heaps in finding the SCP, could you use the AN to precisely find the SCP instead of drift aligning?
Hi h0ughy,

Thanks for the question.

Indeed, Argo Navis can do precisely that.

If you had no idea where to find the SCP whatsoever, there is one procedure
using the ALIGN function alone that will assist you in homing in it.

Once you are within a couple of degress, you can then use the polar alignment
feature of TPAS to further refine the polar alignment,

For example, if you are like me, you simply go outside, naked eyeball the
Cross and the Pointers and plonk the scope down. I can usually plonk the
mount down within a couple of degrees of the SCP. I will then perform
a one-star alignment and sample the position of anywhere between four
to six stars. The system will then report to me the amount of polar misalignment
in azimuth and elevation for the mount. What I then do is tell TPAS
to switch off the polar misalignment errors and I then GUIDE to a star.
The star will not be centered. I then adjust the mount in azimuth and elevation
until the star is centered. I am then polar-aligned.

The problem with a drift test is that it does not take into account the
geometric, gravitational flexure and any eccentric bearing errors within the
mount/OTA. These 'mount fabrication errors', along with polar misalignment
errors are entangled in a very complex way. What TPAS can do is magically
untangle all these errors for you. Most importantly of all, it then reports to
you its results in statistical terms. I cannot over empasize how important
a feature that is in any mount error and analysis correction system.
This statistical information can provide you with degrees of confidence in
the reported results. Without it, you could never be really sure whether
that the reported corrections are to be believed or not.

By way of further background, to use TPAS to its fullest, typically one
devotes one night to performing a long pointing test. For a mount like
a G-11, you might devote one Full Moon night to sampling perhaps 50 to 100
stars. TPAS will then provide statistical information on the mount's pointing
performance as well as what error terms contribute significantly to the
pointing model. Based on the information TPAS provides, you may even choose
to make mechanical corrections to the mount itself. For example, if it reported that
the OTA was not orthogonal to the Dec axis, you might decide to shim the OTA.
(If you don't, there will be a region around the pole your scope will not
be able to point). Alternatively, you may decide to not mechanically adjust
anything and simply let TPAS provide a pointing correction. The system allows
you to save a model from a long pointing run for use on a subsequent night.

When you take the mount out again on a subsequent night, you then typically
peform a short pointing run of perhaps four to six stars. This allows you
to re-synchronize the model and to re-determine the polar misalignment
terms.

Large professional observatories using nearly identical analysis techniques
as discussed above to improve the pointing performance of their scopes.

Like most users, I find TPAS faster and more convenient than a drift test
as well. There is no need to own a polar-alignment scope nor any
requirement to find Sigma Octanis.

You can read more about TPAS on pp 115-142 of the Argo Navis User's
Manual. See
http://www.wildcard-innovations.com....n/argoman8.pdf

Remember, if you ever see a system that claims to provide mount error
correction or polar correction but does not provide statistical feedback,
treat the results with scepticism. There are many reasons for this, but
one of the most important attributes of a model is its predictive behaviour.
For example, it is one thing to have a pointing model that provides
corrections for the mount on one night. However, ideally the model should
be able to provide corrections for subsequent observing sessions in the future.
Only with statistical results can one have any level of confidence in a model's
worth at some point in the future.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place
Mount Kuring-Gai NSW 2080
Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au
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  #52  
Old 09-02-2007, 06:48 PM
gary
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Hi Gary, long time since I spoke to you.

That is exactly what I am saying, I learnt early in the piece that having encoders with the Gemini was problematic, I found I could never get them to work properly so I abandoned the idea and sold them, since then I have never had further trouble, my opinion was that the encoders were no where the resolution of the Gemini and that was where the conflict was (my opinion only).

As I said in the original post, the encoders are disabled by default in V 4 so the problem may now be fixed.

Thanks for the explanation.

Cheers

JohnG
G'day John,

Great to hear from you again and hope you have been well. Are you still
down at Bermagui? I bet it would be a tough life down there.

I guess only the Gemini designers would know why the encoder port
feature does not work. It's a pity as sometimes some users would just like
to manually push the mount for a while now and then (you mention you
attempted this yourself).

I know with our customers that own the ServoCAT system, which
is mainly seen on larger Dobs, it is an attribute they particularly like
about that system. That is, they can flick the levers and fly manually
for a while, then flick back and go on full 'auto-pilot'.

Once again, great to see you here on IceInSpace and take care.

Best Regards

Gary
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  #53  
Old 09-02-2007, 06:52 PM
snowyskiesau
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Gary,
Thanks for the hint re polar alignment. Something to try when the clouds go away....
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  #54  
Old 09-02-2007, 08:50 PM
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I'll have to have two area's one for the Tak and one for the G11.

Cheers leon
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  #55  
Old 10-02-2007, 05:15 PM
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h0ughy (David)
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OK Gary, what's needed and how much is it?
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  #56  
Old 10-02-2007, 06:00 PM
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OK hOughy, i'll bite

Why would you run a Gemini and an AN at the same time doesn't make sense to me.

Cheers

JohnG
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  #57  
Old 10-02-2007, 06:15 PM
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Yes, good question John.

I thought they both served the same purpose

Someone's going to have stereo go-to!
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  #58  
Old 10-02-2007, 06:35 PM
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h0ughy (David)
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Quote:
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OK hOughy, i'll bite

Why would you run a Gemini and an AN at the same time doesn't make sense to me.

Cheers

JohnG
I delusionally thought that it would help make finding the SCP easier - no problems with me though . I have yet to read the manual on anything and I have just sent away for the upgrade to version 4 for the gemini . Just thought I would ask though. While you are on the biting side at the moment, would a GPS plugged into the mount improve the timing and location calculations????
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  #59  
Old 10-02-2007, 06:38 PM
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[1ponders] (Paul)
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:looks down, put hand to forehead and shakes head ruefully:

Damn don't have that smilie


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  #60  
Old 10-02-2007, 06:41 PM
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h0ughy (David)
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:looks down, put hand to forehead and shakes head ruefully:

Damn don't have that smilie




dinner time , must cook BBq for family
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