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CG5 - Polar align scope or not

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#1 artcarter

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Posted 02 December 2012 - 10:21 PM

I was considering an iEQ30 mount that comes w/ a polar scope. I have decided instead to get a CG5. So is it worth $48 to get the optional polar scope ?

Thanks
Art

#2 orlyandico

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Posted 02 December 2012 - 10:33 PM

i'd guess no, because you can use the ASPA routine.

#3 Adam E

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Posted 02 December 2012 - 10:35 PM

Having owned mounts both with, and without, a polar scope, my vote goes for 'yes, the $48 is worth it.'

When I lived in a dark area, I was into DSO AP, and a polar scope is a good way to start off on reaching an accurate polar alignment. Now that I'm in a light polluted city, I'm relegated to visual and planetary AP. For planetary AP, I still drift align, but the polar scope gets me that much closer out of the gate. For visual, I just use my polar scope and go. No further polar alignment required.

#4 James74

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Posted 02 December 2012 - 11:10 PM

For visual, all-star polar align feature works well enough.
For astrophotography I have to agree with Adam; get the polar scope. The polar scope is what I call a time-multiplier. Instead of spending an hour and precious DSLR battery power just trying to get in the polar-aligned ballpark you are spending 2 minutes getting into the ballpark and 20 minutes perfecting the alignment.

#5 RTLR 12

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Posted 02 December 2012 - 11:56 PM

I have 3 CG-5s and a CGEM and I do AP with all of them. I don't have a polar scope in any of my mounts. The Celestron "All Star" program is all you need. It is just as accurate if not more so than a polar scope. If you feel the need for an even more precise polar alignment you can do a drift align after the "All Star". I wouldn't waste my time or money on a polar scope.

Stan

#6 spectre

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Posted 03 December 2012 - 09:32 AM

I agree with Stan. I got the Polar Scope with my CG-5 but never use it. The All Star polar align + drift works great.

#7 RTLR 12

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Posted 03 December 2012 - 12:12 PM

I might add that 'All Star' alignment only takes about 30 seconds to perform. I choose my last calibration star close to the Meridian and celestial horizon and then use it as my polar alignment star.

Stan

#8 neilson

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Posted 03 December 2012 - 12:54 PM

I just bought the polar scope myself for my CGEM DX and for the past 4 days I have been using the polar scope then the 2+4 alignment and the all star polar alignment. No matter how perfect I get the polar scope alignment the all star gets it a little closer. If I just did the all star polar alignment and had to move the mount alot then I usually need to do the 2+4 and all star a second time.

But normally I just know the exact spot in my finderscope by using the "Polar Finderscope" software by Jason Dale. It shows you where in your finderscope polaris should be at that exact date and time at your location. Another thing I do is point my laser mounted on my ota just off Polaris towards Kachob. All these things get you close enough for guided imaging but if I'm doing long unguided imaging I still need to do a drift alignment.

I bought my polar scope because I think their neat and I'm old school. But its not necessary.
The All star Polar alignment is very easy and more accurate. And Celestrons polar scope doesn't have an illuminated reticule so you have to shine a red flashlite in the front to see the etchings and that doesn't work very well.

neilson

#9 James74

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Posted 03 December 2012 - 09:37 PM

I haven't had any such luck with my all-star align...

#10 RTLR 12

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Posted 03 December 2012 - 10:10 PM

All Star is only as accurate as your 2 + 4 alignment. If your GoTos are off, so will your polar alignment be off.

Stan

#11 ghataa

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Posted 03 December 2012 - 10:54 PM

Another vote no. ASPA works great for me. Enables me to set up in locations without a view of Polaris. Can guide easily at >630 mm for 8 min or more.

George

#12 DaveJ

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Posted 04 December 2012 - 07:20 AM

All Star is only as accurate as your 2 + 4 alignment. If your GoTos are off, so will your polar alignment be off.


Since we're piling on, I'll add my +1 to ASPA (All Star Polar Alignment) and vote NO to the polar alignment scope. I don't have a CG5, but the same ASPA routine is present in my CGE and CGEM DX and that's what I use with great success.

#13 dickbill

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Posted 04 December 2012 - 10:43 AM

I say: it depends. for example at star parties when you may want to set up as quickly as possible, a look in the polar finder is faster than (3 star-align + ASPA Polar align).
With the polar finder, you can set your mount, still unpowered, in ONE minute on Polaris, then power ON and do a 2 star-align (maybe 5 minutes) and you are good to go with OK tracking and GOTOs. Other advantage of the finder: While the mount is still OFF, you can move it directly from its feet (lets say you use the north leg as a pivot) to recenter the azimuth knob and prevent excessive tension when you align either with the finder or the ASPA.

Personnaly i have a polar scope and I use it, even if i do an ASPA later, because i prefer to make small corrections in the mount'station with the ASPA rather than having to turn the knobs like crazy to their extreme range. Also, starting close to the pole guarranties that your initial 3-star align will be close (with small corrections), which in turn means you can trust your ASPA. On the other hand, if, using ASPA alone, my mounts tells me to move one degree, i wouldn't trust that with high precision and, after correction (poor knobs), I would redo another ASPA later. So, better be close first, you save time and potential trouble later.

#14 orionn1

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Posted 02 April 2013 - 09:45 PM

How do I find out more about this all star polar alignment?
How do you do it?

#15 mclewis1

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Posted 02 April 2013 - 11:11 PM

It's described in the CGEM and CGEPro manuals in the Astronomy Basics section.

The function is in firmware gem4.15/nxs4.18 and higher but you won't see it called All Star polar alignment in the firmware ... it's now just the default polar alignment routine.

#16 dickbill

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Posted 03 April 2013 - 08:34 AM

How do I find out more about this all star polar alignment?
How do you do it?


ASPA is the All Star Polar Align routine that is available in all Hand Control for the cg5, cgem/dx and most likely Vx. So you don't need Polaris to align your mount with this routine.
You can download the manual from Celestron/Downloads web site.

#17 dragonslayer1

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Posted 03 April 2013 - 09:32 PM

I downloaded a neat ipad program "THEODOLITE" is true north alignment. Use it for my CPC 9.25 Wedge and tested it with my new purchased (unused yet) CG-5. Works great and was $4.99 max I think. Just hold IPad against legs and get north no matter where I am..
Kasey

#18 Tom Andrews

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Posted 05 April 2013 - 10:15 PM

How do I find out more about this all star polar alignment?
How do you do it?


Here's the directions on how to use it:

All Star Polar Alignment

#19 budman1961

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Posted 06 April 2013 - 02:15 AM

I graduated from a fork-mounted LX200 Classic 10", to a smaller 8" LX3 OTA, on a Celestron CG5-GT. I read just about everything I could find on alignment procedures, and here is what works for me.

Assuming that your tripod is level, and is set to true north:

I do a 2 star alignment.
Add 4 calibration stars.
Perform the polar alignment routine...note, many say you have to power off the mount before proceeding, I never have. I do have the latest hand control/motor control firmware loaded.

Once that is done, don't kid yourself, "eyeballing", or doing the fine alignment without a illuminated-reticle eyepiece, or camera (I use a Mallincam or DSLR, it makes the fine align easier), you might as well quit. Look in the classifieds here or elsewhere, an EP with illuminated reticles are fairly cheap.

The last step involves manually adjusting the RA/DEC screws or bolts, get it centered, it is so important.

Using this as my setup, it takes mo no longer than 10-15 minutes after my tripod is set up.

I can generally achieve 90-110 second UNGUIDED exposures.....it all comes down to being careful, and getting a good polar alignment.

In other words, pass on the polar scope......this is a lot easier, and becomes second nature quickly.

Sorry for being long-winded, I hope this helps!

Andy

#20 DaveJ

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Posted 06 April 2013 - 07:56 AM

The last step involves manually adjusting the RA/DEC screws or bolts, get it centered, it is so important.


You mean the Altitude and Azimuth adjustment screws/bolts rather than the RA/DEC screws. There aren't any RA/DEC adjustment screws!

#21 budman1961

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Posted 06 April 2013 - 08:11 AM

Yes Dave, up too late last night! Alt/AZ adjusters.

Andy

#22 roscoe

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Posted 06 April 2013 - 08:12 AM

I just look through the hole where the scope would go.....fast and easy......
R






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