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CGEM vs. EQ6 Pro

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#1 M54

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Posted 11 August 2009 - 01:16 PM

Hi all

Sorry for this common question - I searched this forum but still wanted to throw this question.

I am in the process of getting one of these mounts - CGEM or the EQ6 Pro (white).

My main target will be astro photography, mainly nebulas and other bigger objects. Mount should take easily 2 lense tubes below 100mm, 2 CCD cameras and motorised focus.

The price and looks (love the white) with EQ6 Pro SynScan makes it a bit tempting one but please give your opinion if this choise is beaten by CGEM. Whic one has better accuracy without guiding.

I've planned to store it outdoors under a light plastic cover an use some heating when stored, a light bulb or so.

Thanks
Ben

#2 Smo

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Posted 11 August 2009 - 01:33 PM

Great question and hope someone can shed light on this, as I am facing the same question atm.

#3 pollux

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Posted 11 August 2009 - 03:59 PM

the major difference to me is nexstar vs synscan

the eq6 has a losmandy saddle option FYI

#4 rmollise

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Posted 11 August 2009 - 04:39 PM

At heart, these are two very similar mounts made by the same company, Celestron's parent, Synta.

Atlas (or EQ6 or EQ6 Pro; these are all the same except for paint):

This is pretty much proven technology and has egendered an add-on industry...tripods, knobs, replacement cradles...there are a lot of Atlases out there, so somebody probably makes the gizmo you want.

Known quantity. Lots of mounts in lots of hands, so there is a large knowledge-base.

EQMOD. This program, which can take the place of the HC is fantastic. Very accurate go-tos, many features, alignment with a planetarium or planner program. FREE!

It is solid, if heavy, easily capable of dealing with a C11.

$$$: you can buy a non-go-to (CURRENT) Atlas, hook a laptop or netbook to it running EQMOD and have go-to on the cheap.

The stepper motors the mount uses are quieter than the servos on the CGEM.

Synta is moving to the Losmandy mount system for the EQ6 mounts, but most are still equipped with Vixen dovetail saddles.

CGEM

More modern design with some improvements, the most noteworth of which are the Losmandy compatible dovetail system (steadier) and MUCH easier to adjust az-alt controls.

NexStar HC. The HC looks a lot like the Atlas Synscan, but the software is much more advanced, and includes an excellent polar alignment routine.

Servo motors, which some folks (not me) like better than steppers.

Looks purtier.

Can use NexRemote in lieu of the HC, which is a crazy good (though usually not free) program.

I like 'em both. I got the Atlas, and am happy with it. It may be my "last" GEM, as I get more decrepit and poorer and more focused on just looking as I approach retirement. If I were to replace it, it would be with a Mach 1 or AP900 or something in that league. Don't plan to unless it goes ti--"belly"--up. :lol:

#5 donsinger1

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Posted 12 August 2009 - 09:59 PM

I agree with all that Rod has said, especially the software for the CGEM/Celestron being more advanced than the Atlas...the Polar Alignment capability for the CGEM works and is worth the "price of admission" so to speak.

Don

#6 neptun2

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Posted 13 August 2009 - 01:22 AM

Also as far as i have read about cgem and from my experience with heq5 pro this mounts are good for astrophotography but with autoguiding. So you should consider this also.

#7 M54

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Posted 13 August 2009 - 04:41 AM


Thanks buys for your great input.

NexStar Polar Alignment? Is this more than 1-2-3 star alignment?

Ben

#8 neptun2

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Posted 13 August 2009 - 06:03 AM

No the idea here is the celestron's all-star polar alignment. It allows you to make good polar alignment using any star you choose. You first make regular goto alignment, then select a star for the polar alignment, center it and then the software moves the star where it should be if your polar alignment was good. Then you use the azimuth and altitude adjustment bolts to center the star and this way you correct your polar alignment.

#9 rmollise

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Posted 13 August 2009 - 07:17 AM

Also as far as i have read about cgem and from my experience with heq5 pro this mounts are good for astrophotography but with autoguiding.


Which is true for almost all mounts, even considerably more expensive ones. ;)

#10 rmollise

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Posted 13 August 2009 - 07:20 AM

Thanks buys for your great input.

NexStar Polar Alignment? Is this more than 1-2-3 star alignment?

Ben


Separate issues. With a GEM, you must do both go-to alignment (1-2-3) and polar alignment. Celestron's software enables the mounts to do accurate go-tos even if the mount is not well polar aligned. For best tracking, and for picture taking, though, you need a good polar alignment. The Allstar (polar) alignment routine Celestron has developed works nicely.

#11 Smo

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Posted 13 August 2009 - 12:35 PM

Well I just bought the EQ6 Pro so here is hoping they continue to upgrade their software and I do not come to regret not getting the CGEM

#12 rmollise

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Posted 13 August 2009 - 05:47 PM

Well I just bought the EQ6 Pro so here is hoping they continue to upgrade their software and I do not come to regret not getting the CGEM


Do yourself a favor and get into EQMOD...it's being continuously updated.

#13 Smo

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Posted 14 August 2009 - 12:15 AM

I will certainly look into that.

#14 mewmartigan

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Posted 14 August 2009 - 07:13 AM

I'll second looking into EQMOD. It is a great program and the more recent release has a polar alignment routine as well. I haven't used my hand controller once since getting EQMOD.

#15 wbrogdo1

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Posted 14 August 2009 - 01:13 PM

The alignment routine they have in place in eqmod doesn't help if you don't have a view of polaris.

#16 Charlie Hein

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Posted 14 August 2009 - 02:15 PM

The alignment routine they have in place in eqmod doesn't help if you don't have a view of polaris.


Give 'em enough time, they'll get that one too. Even without a specific routine you can do a rough alignment and drift for accuracy.

#17 wbrogdo1

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Posted 14 August 2009 - 02:22 PM

I'm sure they will. It is what I currently use also. Just pointing out that compared to the cgem (which can polar align without polaris now ) eqmod still lacks this.

#18 M54

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Posted 15 August 2009 - 06:27 AM



OK - EQMOD will be having PA - good news :)
In this light my eyes are turning towards EQ family.
And being penny wise (?) HEQ5 or 6 "hybrid" (with the modest HC) could be a good choise for me because I'd be using EQMOD remotely from inside the house.

A slight "downgrade" with mount because there seems to be quite a lot hard ware to buy when starting from the scratch. :)

#19 M54

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Posted 20 August 2009 - 03:43 PM

Well I just saw this tubed vid showing HEQ5 Pro PA procedure. http://www.youtube.c...h?v=wh5kipL1mPA

Is this really this jobby? Operating in the freezing temps my nervs might shoot sky high.

Or would CGEM be more user friendly.

Sorry for my stupidity.

Ben

#20 rmollise

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Posted 20 August 2009 - 04:43 PM

Is this really this jobby? Operating in the freezing temps my nervs might shoot sky high.

Or would CGEM be more user friendly.

Sorry for my stupidity.

Ben


Ain't quite sure what "jobby" means, but if you mean, "involved," using a polar scope isn't that hard, as there are workarounds that eliminate using the scales, etc. That said, the alignment routine in the Celestron HC is at least as accurate and at least a little easier.

#21 gnowellsct

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Posted 21 August 2009 - 09:01 AM

Here's one workaround (there are others):

Appendix No. 6. Short cut to putting the “little circle” in your finder scope in the correct position. Polaris is just off true north, as is well known. The SP/GP/CG5 polar scopes come with detailed instructions about how to use the dial on the RA axis to use date and time to move the little circle in the finder to the correct position. This is necessary because Polaris is “off” true north in a different direction (from the Earth) depending on where it has rotated relative to true polar north. Here is a shortcut that works. 1. Find Cassiopeia. Look at the star that is the left-most (when seen as a “W”) or the right-most (when seen as an “M”). 2. Draw a line from that star in Cassiopeia to the horizon. That line points to six o’clock; the left most star of the “W” is the center of the clock. 3. Find Polaris. What hour is Polaris indicating relative to your reference star in Cassiopeia? 4. If Polaris is at 10 o’clock, put your little Polaris circle at 4 o’clock. If Polaris is at 12 o’clock, put the little circle at 6 o’clock. If Polaris is at 4 o’clock, put the little circle at 10 o’clock. The pattern here is that the “little circle” should be set exactly six hours off the “Cassiopeia clock” you established in steps 1-3.

#22 yg1968

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Posted 21 August 2009 - 10:17 AM

Here is another work around. Here is a small software program that locates Polaris' position in relation to the North celestial pole (NCP). Useful for polar alignment.

http://manastro.co.u...re/polar204.zip

You can use this program to place Polaris on the red circle in your polar scope. The HC of the EQ-6 Pro also tells you the hour angle of Polaris. But this software gives you a better visual idea of where Polaris should be.

#23 o1d_dude

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Posted 23 August 2009 - 01:50 AM

I use PolarFinder 2.0 at home as well. Because I use it so much, I put the icon right on my desktop. LOL!

When I'm out and about and my PC is at home, I use Dr. Clay's "Kochab Clock" method an explanation of which can be found H E R E . You'll have to scroll down to see the diagram.

#24 M54

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Posted 23 August 2009 - 05:18 AM


I searched youtube and found few vids demonstrating EQ5/6 mounts. Those seem to be pretty quiet when slewing But there is a significantly nasty sound when starting/stopping slewing (I wonder what that sound would be when operating well below -10C). Is that common with EQs and could changing the lubricants/bearings cure it?

No vid found showing CGEM.
There seem to be some threads here discussing over this noise issue which is pretty important to me (neighbor's bedroom less than 30ft away).
I might accept slightly higher slewing noise but start/stop should be free of extra noise.

BR Ben

#25 WarrenS

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Posted 23 August 2009 - 07:58 AM

Significantly nasty can be a relative term. My Atlas(EQ6) does make the "coffee grinder" noise when starting and stopping slewing but it's so subdued it's only really noticeable compared to the dead silence when tracking. Early on after I first bought the mount I'd have to put my ear right up against it to make sure it was still tracking!
If your neighbors' bedroom window is less than 30ft away I would think you hear a lot more noise coming out of there than they'd be hearing from your mount! YMMV






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