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Equipment Discussions >> Mounts

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Fortress
member
*****

Reged: 03/25/11

Loc: Kansas City
CG-5 with ADM Replacement Head
      #5471142 - 10/15/12 09:31 AM

After 10 years using nothing but an Alt-Az mount, I decided to pick-up a CG-5 Goto mount and immediately found the mount head to be unacceptable (I understood going into this a complete mount for $645 will have some issues to overcome). I replaced it with the ADM CG-5 replacement head, which, by the way, is a real nice mount head and saddle. On my first night out (last night) I found that the pointing accuracy was way off. So I have a few questions for those who, unlike myself, know what they are doing:

1. Do I need to make any further adjustment now that I replaced the original mount head with the ADM replacement head?

2. How critical is aligning/squaring the polar scope to the mount itself for visual work, i.e., would this alone account for very poor accuracy?

3. In the start-up alignment process, does "daylight savings time," mean living in an area with daylight savings time or whether we have actually moved our clocks ahead an hour for daylight savings time (I assumed the later)?

Any other pointers would be greatly appreciated and thanks for your help!!


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psu_13
sage


Reged: 05/30/10

Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5471178 - 10/15/12 09:56 AM

When I tried this saddle I found that it affected the balance of the mount to some degree because it is a lot heavier than the piece it replaces. So consider that.

But, the real question is: when you say that pointing was "off" do you mean before or after doing the whole alignment procedure? The two+four star alignment is pretty critical for getting good pointing with this mount since the mechanics are pretty sloppy even on the best of nights. In the early stages of this process the mount will usually be pretty far off (more than a finder field) but as you add stars it should get better and better until finally it starts to hit in a medium power eyepiece.

The only other issue I can remember from using this saddle is that it can be hard to find the "zero" position on the mount which will make the initial pointing even further off but otherwise is not a huge deal.


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Fortress
member
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Reged: 03/25/11

Loc: Kansas City
Re: CG-5 with ADM Replacement Head new [Re: psu_13]
      #5471206 - 10/15/12 10:13 AM

Yes, psu 13, you are correct in that the ADM is much heavier and I will need to see how that changed the balance of the scope. Regrading your other question, perhaps I am being a little too impatient. I did the intial two-star alignment and then added a third. It sounds like I may need to a couple more. I'll focus on these two items the next time I am out under the stars. Thanks!!

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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5471291 - 10/15/12 11:02 AM

1) Polar alignment accuracy generally does not affect goto accuracy. Goto accuracy is dependent on how well you do the initial 2+4 alignment (what stars are chosen, how well they are centered and any physical issues like excessive backlash inherent in the mount).

2) It is very beneficial to use a consistent approach direction when centering the alignment/calibration stars, for example always approaching an alignment star from the bottom and right and if you overshoot during the alignment procedure, slewing back a bit so that this approach procedure is followed. This really helps reduce the effects of backlash in the gears. This should also be followed up with the Goto Approach setting in the hand controller (they should be the same).

3) Polar alignment and the date/time/location/DST info does affect accuracy of the pointing to the initial alignment and calibration stars.

4) When you perform the initial alignment it is quite normal for the first star to be quite far off, but the second should be closer, and with each of the 4 calibration stars closer still. By the 3rd or 4th calibration star I rarely have to do much adjustment, the stars tend to be virtually centered in a 30mm eyepiece.

5) Starting off from a consistent location (the index marks for example) is also important for the accuracy pointing to those initial alignment stars. What you use for this initial location really isn't as important as continuing to use that location. This isn't a big deal but it does mean that you have to move around less when doing the initial alignment.


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Fortress
member
*****

Reged: 03/25/11

Loc: Kansas City
Re: CG-5 with ADM Replacement Head new [Re: mclewis1]
      #5471309 - 10/15/12 11:10 AM

Clearly I need to spend more time with alignment stars and pay more attention to my approach with each. Thanks, Mark!

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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5471321 - 10/15/12 11:18 AM

Yes, but don't obsess over it ... just try and be consistent.

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rmollise
Postmaster
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Reged: 07/06/07

Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5471470 - 10/15/12 12:36 PM

Quote:


1. Do I need to make any further adjustment now that I replaced the original mount head with the ADM replacement head?

2. How critical is aligning/squaring the polar scope to the mount itself for visual work, i.e., would this alone account for very poor accuracy?

3. In the start-up alignment process, does "daylight savings time," mean living in an area with daylight savings time or whether we have actually moved our clocks ahead an hour for daylight savings time (I assumed the later)?

Any other pointers would be greatly appreciated and thanks for your help!!




1. No.

2. Don't use the polar scope. The polar alignment routine in the HC (either AllStar or the Polaris routine of the older firmware) is easier and more accurate.

3. It means "Is Daylight Savings Time currently in effect?"

I don't know how far off "way off" is, but what mostly matters is centering the correct alignment/cal stars and using up and right keys for final centering.


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Fortress
member
*****

Reged: 03/25/11

Loc: Kansas City
Re: CG-5 with ADM Replacement Head new [Re: rmollise]
      #5471606 - 10/15/12 01:45 PM

Rod, I trust you mean the "Align Mount" function to polar align the mount under the "Utilities" feature of the HC. I just figured either way one is still having to locate Polaris. Will certainly give it a shot. Thanks!

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DaveJ
Carpal Tunnel
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Reged: 01/07/05

Loc: NE Ohio
Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5471687 - 10/15/12 02:31 PM

Quote:

Rod, I trust you mean the "Align Mount" function to polar align the mount under the "Utilities" feature of the HC. I just figured either way one is still having to locate Polaris. Will certainly give it a shot. Thanks!




I'd recommend that you update your HC firmware to 4.21 and the MC firmware to the latest. By using the latest HC firmware, you'll have the ASPA (All Star Polar Align) which is accessed by pushing the "Align" button on the hand controller and selecting the polar alignment function.


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rmollise
Postmaster
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Reged: 07/06/07

Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5471770 - 10/15/12 03:30 PM

Yep, the new function is under the Align button (the old polar align procedure was in utilities). It does work better than the polar scope b-u-t...

You don't need to use it for visual work, just centering Polaris in the hollow bore where the polar scope goes is good enough. Or if you've got the polar scope in there, just center Polaris in it...no need to worry about polar scope alignments or reticles.


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Fortress
member
*****

Reged: 03/25/11

Loc: Kansas City
Re: CG-5 with ADM Replacement Head new [Re: rmollise]
      #5472165 - 10/15/12 07:26 PM

Excellent! Thanks to all.

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wolfman_4_ever
Pooh-Bah


Reged: 07/15/11

Loc: El Segundo, Ca, So. Cal
Re: CG-5 with ADM Replacement Head new [Re: Fortress]
      #5472683 - 10/16/12 02:21 AM

I run the ADM saddle. I also run a side by side setup on my cg5.

What did Forest say? Balance is as balance does..


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