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CGEM or CG5 - Imaging.

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#1 therocksal

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Posted 11 February 2009 - 07:30 PM

It's not as easy an answer as the title suggests.

I have a few scopes and want to buy a C8, so I can try some imaging with the C8 and my ED80. I figured I'd get the CGEM not only for a solid AP mount but also for future proofing if I want to get a C11 for visual in the future.
BUT, I'm somewhat of a noob and I don't know if I'll get into this that much....and besides, I want to save up for a house and buy a boat sometime soon. And, I might end up buying a 12" dob instead of a C11...half price, more aperature is a good thing.

I'm assuming I can do imaging fine with the C8 or ED80 on a CG5, especially since I've never done it before...I will be using a DSLR only.

So, I guess I have a dilemma cause I would love to future proof a little but really want to save some money...I know I need to make this decision on my own but for anyone using a CG5 with a C8, can you tell me it's a good match for the price?

Thanks.

#2 Patrick

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Posted 11 February 2009 - 10:27 PM

One thing that might be helpful to consider is that used CG-5's seem to hold their value pretty well. If and when you decide to go with a larger scope you can sell the CG-5. At $599, the price is hard to beat and could serve you well as you climb the learning curve. Most of the accessories that make imaging easier will transfer to a larger setup as well, so there's a lot of upside without too much downside!

Regards,

Patrick

#3 HaleBopper

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Posted 12 February 2009 - 07:05 AM

I was a noob last year and I will say that I have had success imaging with my C8 on my CG5. For an entry level AP setup I think it's great. I managed to get some nice "usable" subs unguided up to 2.5 min on very RARE occasions. This is more of an exception than a rule however. I certainly don't think you would have a problem with the 80mm ED. It would most likely perform better.

I recently tried autoguiding with an 80mm Orion ST piggybacked on the C8 with the Orion SS camera and was impressed. I went up to 4 min with round stars at f/6.3. I'll try longer subs when I get a chance to see what limits I can push. Although imaging at f/10 is doable, you should probably get yourself the 6.3 focal reducer. It'll be much easier, but you'll have a bit more vignetting.

If you decide you really want to get into AP one day, then you should get a sturdier mount. For me, I was just starting from scratch, and I didn't have the money to spring for a better mount. I'm happy with my set-up for what it has taught me and for the price I paid.

Having said all that, if you have the money to spend on a CGEM, go for it. The sturdier the mount, the better it'll be for AP. I'm waiting for some of the "bugs" to clear out of the CGEM before I upgrade. In the mean time, I'll keep using my CG5!

#4 Luigi

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Posted 12 February 2009 - 07:40 AM

A heck of a lot of great imaging is done on a CG5 with 4" ED or APO refractors. I think you'll have more fun and get better results more quickly going this route. Get the 12" Dob for visual. BTW, I owned a C11 on a G11 for 10+ years.

#5 therocksal

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Posted 13 February 2009 - 03:34 PM

Jeez...so I spent two of the last three nights up all night going back and forth on this.

Since I've only looked through my C6R twice and haven't looked through the 80ED yet, and these are my first scopes ever....I've decided to buy the CGEM, and forget the C8 or C9.25 for now and just concentrate on using the scopes I have, learning the sky, upgrading the "yard cannon"..etc.

Then, next year I can always buy a used C8 or 9.25 or even buy a C11 for visual...or a 10" newt...or a dob...it will be nice having a decent mount to be able to buy any number of scopes.

And I will have some fun trying some AP with the little 80ED.

What I need to do is keep AWAY from the classifieds...I need no more temptation!

#6 HaleBopper

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Posted 13 February 2009 - 03:38 PM

Good luck with your CGEM! I'm sure you'll enjoy it, and learning the fine art of AP!

#7 therocksal

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Posted 13 February 2009 - 03:57 PM

Thanks Bopper...hope I can be one of those to help get all the "bugs" cleared out! Unfortunately, I have no astro friends around and I've never had a GOTO so it will be interesting..I might now know what is happening or what the certain sounds are. Fortunately, there is an astro shop about a mile from my house with a super nice owner who I have no doubt will help me out.

Clear Skies!

#8 m2434

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Posted 13 February 2009 - 04:42 PM

Good choice!

#9 MrKrink

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Posted 09 March 2009 - 02:28 PM

Does the CG-5 have the NEw ALL-Star polar alignment like the CGEM?? I can find if it does or not. Is that what the "Auto-align" is??

#10 Chris Rowland

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Posted 09 March 2009 - 03:00 PM

Yes it does, you need the 4.15 HC version.

Chris

#11 waassaabee

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Posted 09 March 2009 - 04:10 PM

I tossed around the idea of a CGEM for quite a while, then I had to put my CG5 in the shop and the CGEM got even more interesting. But my scope/guidescope setup rides very comfortably on a CG5, so it looks like I'll be getting another one. For a 5 pound increase in capacity and unproven technology, $800 is quite a hit for me. I've only been in this 'hobby' for a bit over a year, so I don't know if it's a long term or not. If it is, I'll be heading towards a CGE class mount.

#12 Dave H.

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Posted 09 March 2009 - 06:44 PM

The CGEM is a very good choice, and if this is your first GOTO mount, I think you will find it very inutitive. The CG5 uses either the same or almost the same Nexstar software I have not used a CG5 for about a year, but both are very easy to use.

I think for imaging the C8 will work, but you may want to pick uo a focal reducer for that F10 OTA. OTOH the short focal length of the ED80 makes that a very good imaging OTA, many great astro photos have been taken with the ED80.

I think you will be very happy with the CGEM, who needs a house and stinking boat!!! It is a simple matter of priorities :foreheadslap:

Enjoy! :grin:

#13 waassaabee

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Posted 09 March 2009 - 08:18 PM

It is the same firmware update. I had 4.15 on my CG5 before I shipped it off and the goto's were even tighter than before. Better choice of alignment stars, and the All Star is awesome!

#14 MrKrink

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Posted 10 March 2009 - 08:01 AM

OK, so what are the major differences in the CGEM and the CG5-GT?? I have looked at both online and other than size is it the PEC, what ever that is being the only difference?? Is it worth $500 more dollars??

#15 Blixx

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Posted 10 March 2009 - 09:26 AM

I am not sure if the cg5 has this, but the CGEM has the ability to tell the mount that you are using a side by side setup. This is what I am going with as soon as I get my CGEM. I found a setup pretty cheap at scopestuff that I can use. I wont have to buy all new dovetails and the side by side rail. It uses the Losmandy dovetail but has the shoes for the vixen dovetails. I think that it will work for me, and I will save a few bucks. If it works I will be a very happy camper. :jump: :jump:
Dan

#16 waassaabee

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Posted 10 March 2009 - 10:18 AM

I would think that the CG5 being able to utilize the 4.15 update, would have this option as well.

Stuart, I too am asking the same question. The PPEC seems to be the major difference, but the hardware must be more robust on the CGEM and hopefully tighter tolerances as well. The payload difference sure doesn't warrant the price point, and my calulations (CG5 @ $700 / CGEM @ $1400) put the spread at twice the cost of a CG5. My CFO has authorized a new CG5, but if I can determine the CGEM is just as good 'bang for the buck', I may have to resubmit my proposal. :whistle:

#17 Patrick

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Posted 10 March 2009 - 10:27 AM

OK, so what are the major differences in the CGEM and the CG5??



Higher payload capacity, internal wiring and quieter motors, not only PEC...but PPEC (permanent PEC), and retractable counterweight shaft to name a few. It's a great looking mount and definitely a step up from the CG5-GT.

The question still remains though...what is the intended application? I'd love to have a CGEM, but can't really justify it since the CG5 at this point in my astrophotography career does everything I want it to do.

Patrick

#18 waassaabee

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Posted 10 March 2009 - 10:53 AM

Patrick, Correct me if I'm wrong, but CG5 visual payload 35 pounds and CGEM is 40 pounds. Or even if it is 30 & 40 pounds, equals 15 & 20 for imaging... Personally, internal wiring and quiter motors are 'nice to haves'. PPEC would indeed be very nice, but I think I've gotten some very nice images with my CG5. I'd 'like to have' a CGEM, but I'm not sure I 'need' one...

#19 mclewis1

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Posted 10 March 2009 - 11:20 AM

First neither the CG5 nor the CGEM understand the dual saddle 90° orientation. Neither mount cares and when using a dual saddle you simply attach it, rotate the DEC axis 90° and start your alignment (ignoring those index markets on the CG5). That feature (OTA Orientation) is in the 4.15 code to handle the CGE which does need to understand the orientation of the DEC axis for alignment because it has position switches ... the CG5 and CGEM do not have those switches.

As for value between the CG5 and CGEM, the CGEM has larger and presumably more precise bearings, larger motors and I believe larger gears (with more teeth) than the CG5. While the manufacturers spec says 35lbs of carrying capacity for the CG5 and 40lbs for the CGEM, for imaging it's probably (based on Atlas/EQ-6 experience) more like 20 vs. 30+lbs, at least a 50% increase.

I'm sure once all the initial CGEM folks have spent some time with their mounts that we'll start to see averaged PE figures below those of the CG5. In general I'd be leery of basing any PE comparison on a single example of either the CG5 or CGEM.

If you're on a tight budget there is not much choice between them. If you've got a fairly light weight imaging setup then the CG5 will be fine, but if you have the money and feel that you want "better" then the CGEM is the way to go. If you are planning to image with more than 20lbs of gear you'll be happier with the CGEM. If you're going visual and you've got a larger scope (like a refractor or newt) in the 25-30lbs + class then you'll be happier with the CGEM.

Patrick - "retractable counterweight shaft" ... I know the EQ-6 has this, are you sure the CGEM does as well?

#20 Charlie Hein

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Posted 10 March 2009 - 11:30 AM

Patrick, Correct me if I'm wrong, but CG5 visual payload 35 pounds and CGEM is 40 pounds. Or even if it is 30 & 40 pounds, equals 15 & 20 for imaging... Personally, internal wiring and quiter motors are 'nice to haves'. PPEC would indeed be very nice, but I think I've gotten some very nice images with my CG5. I'd 'like to have' a CGEM, but I'm not sure I 'need' one...


Bear in mind that pretty much everything about the mechanics of the CGEM is substantially more robust than a CG-5. The worm gears and worm wheels are much larger. The bearings carrying everything are much larger and more robust. IMO the actual capabilities of these mounts are farther apart than you're thinking that they are.

That said, if the CG-5 is working well for you then don't fix it if it 'aint broke.

Charlie

#21 Takman

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Posted 10 March 2009 - 11:50 AM

Having owned a CG-5GT mount, it is quite a bargain for what you get. An 8" SCT with astrophotography trimmings (guidescope, autoguider, etc...) is probably the maximum you will get on the mount. Something you may want to consider if you even get aperture fever.

#22 waassaabee

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Posted 10 March 2009 - 12:15 PM

The CG5 does work good for me .... but it's in the shop because 'it's broke'... So if I'm looking down the road a bit, maybe a CGEM would be in order.

But I'm also going through imaging withdrawls as I've been without a mount for close to a month. Anyone have CGEM's in stock?

#23 Patrick

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Posted 10 March 2009 - 12:59 PM

Patrick - "retractable counterweight shaft" ... I know the EQ-6 has this, are you sure the CGEM does as well?



Sorry...my bad.

HERE's One disassembed.

Patrick

#24 MrKrink

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Posted 10 March 2009 - 03:33 PM

Patrick, Correct me if I'm wrong, but CG5 visual payload 35 pounds and CGEM is 40 pounds. Or even if it is 30 & 40 pounds, equals 15 & 20 for imaging... Personally, internal wiring and quiter motors are 'nice to haves'. PPEC would indeed be very nice, but I think I've gotten some very nice images with my CG5. I'd 'like to have' a CGEM, but I'm not sure I 'need' one...


That is what I am trying to justify. If you have had good results with teh CG5 on AP then that is what I am looking for, but then again if I am going to make a first investment for a starter scope then I look at it this way: If I can get good results for $1500+ accessories+/- $2000 then why spend $2000+accessories +/- $2500 and get roughly the same results.

Also if I ultimately want to stack an APO guide scope will the CG5 be heavy enough to support the weight? I figure it will be close to 20-25lb on a 30lb mount, will that be too much weight??

#25 waassaabee

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Posted 10 March 2009 - 04:18 PM

Stuart, This thread has made me think out loud so to speak, and absorb some very good information. Currently I am checking availability of a CGEM and it looks like the soonest anyone will have them is towards the end of the month. Everyone is pricing identically (but Astronomics does have a CN discount).
Now to polish up the presentation to the CFO.... :flower:






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