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#26 jchaller

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Posted 11 June 2013 - 12:32 PM

It shows off if not aligned and alt-az after alignment.
If it tracks, but tracking is off, make sure your time/site info is correct.

#27 dragonslayer1

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Posted 11 June 2013 - 12:43 PM

This might apply to you, Prior page post,, and yes I have folded LOL
""Just a FYI, just before I deforked my 9.25 I had upgraded handset and seem to remember that for one mode to stay locked in (alt/az?) the scope has to be aligned. Put it into just a quick or fake align and see if it changes""
Kasey
And as previously posted, spent much time on phone with 3 people and third one said needed to be aligned for Alt/AZ to work

#28 brucepech

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Posted 11 June 2013 - 12:54 PM

Once again, Monadnock, I dunno. I just replicated your result by doing a mock one-star alignment to Betelgeuse and tracking(?) a faux Jupiter. When I returned to tracking mode, ALT-AZ was, surprisingly, on (as you noted). However, the menu doesn't allow you to do a manual two star alignment w/o turning the scope off (I tried) -- and when you turn it off the ALT-AZ mode also reverts to off. Which means that the scope won't track during a manual two star alignment making it darned near impossible to center the alignment stars in the eyepiece and, therefore, extremely difficult to complete the alignment procedure.

Taking into account the near impossibility of doing a real, non-auto two star alignment, I remain persuaded that, unlike my LX-90, the scope doesn't track *during* a two star alignment or that the tracking rate isn't (even though it's set to it in the Nexstar+) sidereal. I'm basing my supposition on the serially more inaccurate gotos I experienced after each (imprecise) two star alignment.

Since most experienced observers say that the manual two star alignment is more accurate than other procedures (which was my experience with my LX-90) I ordered another Nexstar+ from "that river place" (at *half price*). I'll report back if it performs differently.

#29 brucepech

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Posted 11 June 2013 - 11:25 PM

Well, page 10 of the Celestron Manual explicitly says that tracking doesn't begin until the scope is aligned (at least when doing a manual two star alignment, but probably with all alignment procedures):

"Once the second star alignment is completed properly, the display will read Alignment Successful, and you should hear the tracking motors turn-on and begin to track."

How you're supposed to accurately center a star moving at 15 degrees/hour in a 12mm illuminated reticle eyepiece like Celestron's Crossaim (or any high or moderate power eyepiece for that matter) remains a mystery to me. In my experience, the star will traverse the non-tracking eyepiece's FOV pretty quickly making centering problematic,

The Manual suggests adjusting the directional arrow slew rate to facilitate centering, so I suppose you could adjust it to a sidereal or 2x sidereal rate by pressing the "Motor Speed" (or "Rate") button followed by buttons "2" or "3," chase the star across the sky until it appears centered, then quickly mash down the "Enter" and/or "Align" buttons. But this procedure is almost guaranteed to be inaccurate unless the direction of the star's motion and the direction of the slew are precisely aligned with one another. (See all the threads about the importance of accurate centering to proper alignment in the Cats and Casses Forum.)

C'est la vie I suppose. If that's the way Celestron designed the scope, that's the way Celestron designed the scope. (BTW Dragonslayer and Jchaller are correct: the handbox won't lock in "ALT-AZ" until the scope has been aligned.)

#30 cn register 5

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Posted 12 June 2013 - 02:35 AM

How would the mount know what direction to move until it's aligned?

In practice it's quite easy to position the star just in front of the cross hairs and press the Align button as it passes them.

Chris

#31 brucepech

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Posted 12 June 2013 - 04:40 AM

cn, all I can say about my 2003 LX-90 is that it does -- perhaps because alignment begins in what Meade calls the "Home" position: w/ the OTA level and pointed at a reasonable approximation of celestial north.(Easily accomplihed by orienting the tripod so that the front two legs are at the 10:00 and 2:00 positions and the rear leg is at the 6:00 position in relatio to a N-S line, manually pointing the OTA at Polaris by loosening the AZ and ALT clutches, tightening the AZ clutch, leveling the scope, tightening the ALT clutch, and beginning the alignment procedure. I can't visualize the geometry, but I suspect that it then tracks at a sidereal rate roughly aligned with the celestial paths of the target alignment stars. (Perhaps this was the precursor to Meade's later, automated LNT technology and its successful patent infringement suit against Celestron.)

If my intuition about starting an alignment in Home position is incorrect (as well it might be), then I don't have the faintest idea why the target stars remain comparatively stationary in the LX-90's eyepieve's FOV while I center them.

In any event, I guess I was wrong when I initially said that I had a "problem." I think I'm just suffering from cognitive dissonance as I try to reconcile Meade's familiar alignment procedure w/ Celestron's.

#32 rmollise

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Posted 12 June 2013 - 07:49 AM

How you're supposed to accurately center a star moving at 15 degrees/hour in a 12mm illuminated reticle eyepiece like Celestron's Crossaim


Not much of a problem IMHO. I've been doing it for over a decade without a problem, anyhow. The GPS series of scopes worked exactly the same way: tracking off till aligned, then alt-az tracking kicks in. ;)

Alt-az tracking requires different motor speeds depending on _the position the scope is pointed to in the sky_, so until the alignment is done, there's not much point in starting tracking.

#33 KerryR

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Posted 12 June 2013 - 08:07 AM

I've had no issues aligning either. It's been pretty easy to slowly guide the star to the center, finishing movements in the same direction goto's finish to absorb any backlash, and hit "align".

I believe there's a bit of wiggle-room built in to the software-- things can be a LITTLE off and the computer can still figure out the alignment accurately.

This is just the price we 'pay' for not having to start in a 'home' position, as I must with my LX90.

#34 Monadnock

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Posted 12 June 2013 - 09:04 AM

I agree with KerryR. I'm not even sure the scope cares if the first 1 or 2 stars, depending on your alignment method of choice, are centered in the FOV. I believe its just an identification thing for the scope to get it's bearings. The last star is the "money" star as far as centering goes, and it can be tweaked after alignment WHILE the scope is tracking. I believe what is far more important is choosing good alignment stars as described in the manual. These choices can make or break a successful alignment, or cause somewhat poor tracking.

Out of the 10 or so (ya, wow, that many) times I've used my CPC, I've never had an issues aligning the scope or tracking an object, providing I've chosen bright stars. Never actually left the scope on one object longer than a couple hours but it has always tracked virtually flawlessly.

#35 brucepech

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Posted 12 June 2013 - 09:28 AM

Rod, Monadnock, and Kerry ... as I said in my post to cn, what I thought was a firmare issue appears instead to be cognitive dissonance after several years if experience aligning a Meade LX90 and no experience whatsoever in aligning Celestron scopes. At least I've learned a good deal about my new CPC from your explanations. I apologize for any confusion I've caused.
Bruce

#36 dwitek

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Posted 15 June 2013 - 01:55 PM

And I apologize, too, for starting this whole thing if it is in fact just a misunderstanding on my part. The CPC is a bit of an anomaly for me as I am used to using equatorial scopes. I just don't remember having any drift when doing an alignment with the CPC. I've reset the original hand controller and pushed the CPC software into another with the same results.

If I do a mock Two Star alignment I now get tracking in Alt-Az and I can do GoTos to anything in the sky. Perhaps I did have a software issue initially because after getting Align Success in the field it still wouldn't track. So, maybe the resets cleared that up but I was fixated on the Tracking Mode rather than going through the whole process.

I think the discussion was a good one and I thank everyone who stepped in. I'll move the scope back up to it's home next weekend and try it again weather permitting, of course.

#37 rmollise

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Posted 17 June 2013 - 08:38 AM

No need to apologize...stuff happens. I have run into a scenario like this using an older version of Bisque's TheSky. Tracking would just freaking go OFF. I finally realized it was a hiccup with the program, but I was going koo-koo for a while. :lol:

#38 Jon Isaacs

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Posted 18 June 2013 - 09:02 PM

Not much of a problem IMHO. I've been doing it for over a decade without a problem, anyhow. The GPS series of scopes worked exactly the same way: tracking off till aligned, then alt-az tracking kicks in.

Alt-az tracking requires different motor speeds depending on _the position the scope is pointed to in the sky_, so until the alignment is done, there's not much point in starting tracking.



Is this the case with all Nexstar mounts? The scope knows that it is hopefully close to the intended alignment star so it should be able to track with reasonable accuracy...

Jon

#39 brucepech

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Posted 19 June 2013 - 12:26 AM

Jon, to quote from a post by cn register 5 on the Cats & Casses Forum where I raised the same question I raised here:

"Part of the reason that the Celestron AltAz mounts don't track before they have aligned on at least one star is because of the Meade patent on starting at a known terrestrial alignment. Without that the scope doesn't know which way to track. If it makes some assumption about which way to track it could be said to be infringing on the patent."

So, yes, it's probably true of all post-patent Nextar mounts.

#40 Jon Isaacs

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Posted 19 June 2013 - 06:12 AM

Jon, to quote from a post by cn register 5 on the Cats & Casses Forum where I raised the same question I raised here:

"Part of the reason that the Celestron AltAz mounts don't track before they have aligned on at least one star is because of the Meade patent on starting at a known terrestrial alignment. Without that the scope doesn't know which way to track. If it makes some assumption about which way to track it could be said to be infringing on the patent."

So, yes, it's probably true of all post-patent Nextar mounts.


Bruce:

Thanks for the info...

I better be careful when I align my non-GOTO mounts, make sure I align them on Polaris before turning on the drive.. My property and house are within in less than a degree of being aligned north-south/east-west so I can align very closely just by looking that the house or fence.

Of course maybe Meade doesn't have the patent on aligning to a building, fence or road...

It does seem like a strange patent, no creativity there, it's a no-brainer and people have been doing it forever, I would guess from the invention of the tracking drive. It's not GOTO but its alignment.

jon

#41 mclewis1

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Posted 19 June 2013 - 01:48 PM

Just a warning for those who are are trying out NexRemote and using an EQ oriented mount (gem or on a wedge). If you do your initial alignment from the real hand controller and then with NexRemote on your PC you just do something simple like adjust the settings (no initial alignment or anything like that) it will set the real hand controller tracking to OFF.

It would be interesting to see if the Alt Az oriented mounts with NexRemote do the same thing.

Since you're supposed to only use one or the other "controllers" in practice this situation shouldn't come up but if you happen to have NexRemote loaded on you PC and you're looking at this tracking On/Off issue it might get quite confusing.

#42 rmollise

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Posted 20 June 2013 - 10:27 AM


Is this the case with all Nexstar mounts? The scope knows that it is hopefully close to the intended alignment star so it should be able to track with reasonable accuracy...

Jon


Yes, this is the case with all the _fork_ mounts, Jon. Whether it knows where it is in the sky, roughly, depends on the alignment method. The old GPS north-level? Yes. The newer modes like Auto-two-star? Not at all. At any rate, tracking does not begin with the fork mounts until alignment is complete. ;)






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