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Using the CG5-GT for imaging

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#1 SanDiegoPaul

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Posted 28 January 2010 - 01:09 PM

I am currently using my refractor on top of my SCT/Wedge combo for imaging. It is unweildy, hard to balance & train and time consuming every time I move the setup from home to the dark sky site.

I am prepared to buy the above mount to use the refractor on. The question is, will it be as good at guiding the imaging scope as the Lx200 is currently?

I am very used to my existing setup and most days, the Lx200 guides well. Certainly enough for imaging up to 8 to 10 minute subframes.

If I spend $600 or so on this CG5 GT mount am I going to be happy or disappointed with it's tracking abilities while I image?

Should I stick with what I have until I can afford a better EQ platform?

#2 jrcrilly

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Posted 28 January 2010 - 01:15 PM

The question is, will it be as good at guiding the imaging scope as the Lx200 is currently?


Not likely. Moving down in quality just to have the German EQ configuration won't keep you at the same performance level. I used a wedgemounted LX200 for years as an imaging mount and I know what it can do. You'd need something along the lines of a CGE to match the quality and performance of the LX200.

#3 rmollise

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Posted 28 January 2010 - 02:17 PM

The question is, will it be as good at guiding the imaging scope as the Lx200 is currently?


Not likely. Moving down in quality just to have the German EQ configuration won't keep you at the same performance level.


Not all LX200s are created equal, however. Some GPS models I've used absolutely HAD to have Pempro applied before they'd autoguide at all. As long as focal length is kept reasonable, 1000mm or less, the CG5 can do just fine.

#4 waassaabee

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Posted 28 January 2010 - 03:02 PM

With that 90mm Raptor weighing in at a whopping 6 lbs., I'd say the CG5 would do fine! I image with my Megrez 90 on a CG5 and have shot 10 minute frames guided.

#5 SanDiegoPaul

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Posted 28 January 2010 - 03:05 PM

The question is, will it be as good at guiding the imaging scope as the Lx200 is currently?


Not likely. Moving down in quality just to have the German EQ configuration won't keep you at the same performance level.


Not all LX200s are created equal, however. Some GPS models I've used absolutely HAD to have Pempro applied before they'd autoguide at all. As long as focal length is kept reasonable, 1000mm or less, the CG5 can do just fine.


Yep I know taht's true. My 8" Lx200GPS never would really guide ~properly~ if I wanted to go deep. This 10" Lx200-R does a much better job but that being said, 10 minutes is about it's limit for subs.

#6 SanDiegoPaul

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Posted 28 January 2010 - 03:06 PM

With that 90mm Raptor weighing in at a whopping 6 lbs., I'd say the CG5 would do fine! I image with my Megrez 90 on a CG5 and have shot 10 minute frames guided.


That's what I'm hoping. The Raptor-90 actually weighs LESS than the 80mm Meade APO (doublet) that it replaced :jump:

#7 galacticphoto

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Posted 28 January 2010 - 05:09 PM

This 10" Lx200-R does a much better job but that being said, 10 minutes is about it's limit for subs.


Having used only GEMs, I'm curious why the LX200 won't guide "forever" if it guides at all? I turn guiding on the MI or CGE at the beginning of a session, and may not turn it off until hours later. The same could be said about the ASGT (CG5), that I used to use, once it was setup properly.

Are Alt/Az mounts "peculiar", or are you saying that star enlongation gets out of hand at 10minutes on individual subs? Maybe just polar alignment, not the LX200?

Robert

#8 rmollise

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Posted 28 January 2010 - 05:47 PM


Having used only GEMs, I'm curious why the LX200 won't guide "forever" if it guides at all? I turn guiding on the MI or CGE at the beginning of a session, and may not turn it off until hours later. The same could be said about the ASGT (CG5), that I used to use, once it was setup properly.

Are Alt/Az mounts "peculiar", or are you saying that star enlongation gets out of hand at 10minutes on individual subs? Maybe just polar alignment, not the LX200?

Robert


First of all, for longer exposures a _fork mount_ telescope can't be set up in alt-az mode. It must be equatorially aligned on a wedge. Why can't it "guide forever"? Various reasons, but quite a few of these drives display some large non random excursions in addition to perodic error. Eventually you'll get trailed images due to misguiding.

#9 galacticphoto

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Posted 28 January 2010 - 07:38 PM



Having used only GEMs, I'm curious why the LX200 won't guide "forever" if it guides at all?
Robert

First of all, for longer exposures a _fork mount_ telescope can't be set up in alt-az mode. It must be equatorially aligned on a wedge. Why can't it "guide forever"? Various reasons, but quite a few of these drives display some large non random excursions in addition to perodic error. Eventually you'll get trailed images due to misguiding.


So are you saying that "some" of these wedge mounted alt/az mounts are no good in general? I have no intention of giving up my GEMS, but I see that there are some, seemingly, excellent eq aligned/mounted alt/az mounts. If fact,some of the biggest, most accurate mounts available today are eq aligned alt/az mounts, so is it just the specific "amateur" mounts under discussion that are deficient?

Robert

#10 guyroch

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Posted 28 January 2010 - 09:35 PM

Maybe I'm the black sheep here but I've never been satisfied with my cg5-gt for imaging, guiding also has issues. It's a very finicky mount and balance is most important with a cg5-gt. But for a grab and go I love it... as long as I'm willing to accept that I'll have to throw away 30% of the frames then I'm fine. Again, not all cg5-gt are created equal but I'm on the fence with this one.

#11 SanDiegoPaul

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Posted 29 January 2010 - 01:17 AM

I didn't get the smaller one as I was expecting - picked up a CGEM instead. Now I have room to grow to get a larger refractor if I decide to sell the Lx200-R

But I can't get the new CGEM to connect to The SKy Pro. Does the serial-to-handbox adapter cable (included) not allow this?

#12 rmollise

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Posted 29 January 2010 - 08:53 AM



So are you saying that "some" of these wedge mounted alt/az mounts are no good in general? I have no intention of giving up my GEMS, but I see that there are some, seemingly, excellent eq aligned/mounted alt/az mounts. If fact,some of the biggest, most accurate mounts available today are eq aligned alt/az mounts, so is it just the specific "amateur" mounts under discussion that are deficient?

Robert


Not necessarily. I am saying that:

1. You will be limited in exposure in alt-az setup due to field rotatation.

2. Almost any mount will top out on exposure length due to gear noise, wind, need to do a meridian flip, etc.

3. Some Meade fork mounts are not as easy to autoguide as they should be.

;)

#13 rmollise

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Posted 29 January 2010 - 08:55 AM

Maybe I'm the black sheep here but I've never been satisfied with my cg5-gt for imaging, guiding also has issues. It's a very finicky mount and balance is most important with a cg5-gt. But for a grab and go I love it... as long as I'm willing to accept that I'll have to throw away 30% of the frames then I'm fine. Again, not all cg5-gt are created equal but I'm on the fence with this one.


Balance _is_ important with these mounts...but if that's watched, then they are pretty effective for imaging (don't go out imaging if there are gale force winds). My own CG5 will do 10 - 20 minute subs without complaint autoguided by my ST2000 at about 800 - 1000mm.

#14 rmollise

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Posted 29 January 2010 - 08:57 AM

I didn't get the smaller one as I was expecting - picked up a CGEM instead. Now I have room to grow to get a larger refractor if I decide to sell the Lx200-R

But I can't get the new CGEM to connect to The SKy Pro. Does the serial-to-handbox adapter cable (included) not allow this?


It should.

Make sure your comm ports are right, that you have plugged the cable into the base of the hand controller, and have the appropriate driver selected in TheSky.

#15 waassaabee

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Posted 29 January 2010 - 10:03 AM

Atta boy Paul!! You're going to like the CGEM!!

ASCOM driver?

#16 SanDiegoPaul

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Posted 29 January 2010 - 10:18 AM

I didn't get the smaller one as I was expecting - picked up a CGEM instead. Now I have room to grow to get a larger refractor if I decide to sell the Lx200-R

But I can't get the new CGEM to connect to The SKy Pro. Does the serial-to-handbox adapter cable (included) not allow this?


It should.

Make sure your comm ports are right, that you have plugged the cable into the base of the hand controller, and have the appropriate driver selected in TheSky.


That is one of the problems - the docs don't tell you which driver to choose. I tried three different ones and all failed. I do know the port is #3 - but that's all I know right now.

#17 Richard Scott

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Posted 30 January 2010 - 01:45 PM

I started out imaging with my trusty CG5
And I had a C11 and an ED80 mounted on it at the same time
It required 5 11lbs counterweights, but I balanced carefully and if the wind was not blowing it could track for 2 to 4 minutes with most subs usable.
One issue I ran into more than a few times was a failure of PHD to successfully complete it’s calibration, and it was always the north/south half of the calibration that failed.
I think it was excessive dec backlash coupled to grossly overloading that poor mount.
But my point is, I and lots of other guys, have made that mount work for them

Clear Skies to all
Richard

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#18 mclewis1

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Posted 30 January 2010 - 03:14 PM

A C11 AND an ED80. Oh that poor CG-5 ... and that poor dovetail bar. Richard you were a braver man than I relying on that CG-5 saddle bolt. I'll bet you're glad you've got an EQ-6 now.

Oh and very nice shots too.

#19 clydet

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Posted 30 January 2010 - 05:45 PM

I started out imaging with my trusty CG5
And I had a C11 and an ED80 mounted on it at the same time
It required 5 11lbs counterweights, but I balanced carefully and if the wind was not blowing it could track for 2 to 4 minutes with most subs usable.
One issue I ran into more than a few times was a failure of PHD to successfully complete it’s calibration, and it was always the north/south half of the calibration that failed.
I think it was excessive dec backlash coupled to grossly overloading that poor mount.
But my point is, I and lots of other guys, have made that mount work for them

Clear Skies to all
Richard

Hi Richard
How much did your C11 and an ED80 total assembly weigh, to require 5 11#?
Oh, were those 4 shots with your old CG5 or new NEQ-6 Pro?
clyde

#20 Richard Scott

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Posted 30 January 2010 - 07:14 PM

The total OTA weight was a shade over 43 lbs. Dew heaters, electric focusers etc
And those 4 shots were acquired auto guiding my CG-5

With a bit of patients and a good balance, that mount works quite well at it’s price point
Particularly when you think that the next step up in mounts is twice the money

Clear Skies to all
Richard






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