I have a G8 and G11, G8 has a peak to peak eeror of 20, but guides out at around 2 arcsec, the G11 has 7 but guides around 3 to 4 ... so better unguided worse guided ...
Hi vdb,
Any ideas why these counterintuitive results in your case?
Gale
IEQ45 - an evaluation
Started by
elwaine
, Nov 20 2010 03:49 PM
807 replies to this topic
#551
gdd
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Posted 08 January 2011 - 12:49 PM
Hi vdb,
Any ideas why these counterintuitive results in your case?
Gale
#552
Nocturnal
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Posted 08 January 2011 - 01:47 PM
Very long PE recordings will reveal any local roughness in the gears. That will tell you something about the consistency of the mount.
If a guided PE recording has long excursions then it's possible the guider went haywire. It'll be hard to determine that even if you're watching the whole session closely as it happens. These types of excursions do not necessarily reflect poorly on the mount. It could be caused by any number of factors.
If a guided PE recording has long excursions then it's possible the guider went haywire. It'll be hard to determine that even if you're watching the whole session closely as it happens. These types of excursions do not necessarily reflect poorly on the mount. It could be caused by any number of factors.
#553
vdb
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Posted 08 January 2011 - 02:29 PM
Hi vlb,
Any ideas why these counterintuitive results in your case?
Gale
For the moment not, it seems though the G8 has a larger Peak-to-peak it seems smoother ... not as sudden ... but need more testing.
This is why I'm also interested in PE with guiding.
#554
gdd
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Posted 08 January 2011 - 04:02 PM
For the moment not, it seems though the G8 has a larger Peak-to-peak it seems smoother ... not as sudden ... but need more testing.
This is why I'm also interested in PE with guiding.
Hi vdb,
I think this would be an interesting new thread to compare a high PE GM-8 that guides better than a low PE G-11.
Gale
#555
elwaine
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Posted 09 January 2011 - 12:21 AM
I was able to record the PE during guiding. Results are interesting. (It's late and I'm too tired to post the graphs now, but I will post them tomorrow.)
Maxim DL allows fine adjustments of mount motion during guiding. The general aggressiveness (or guiding responsiveness) of each axis, as well as the backlash control of each axis, can be individually adjusted. Mount motion during calibration can be seen on-screen and makes it easy to see how changes in aggressiveness and backlash affect mount movements.
I ran only two sets of data. The first run was for nearly 3 full worm cycles. No compensation for RA backlash was used but the Dec backlash compensation was set at roughly 4 on a scale of 1-10. The aggressiveness settings for both axes were at the low end of the range. That run reduced the PE from 30 arc seconds peak to peak down to 15 arc seconds peak to peak.
I then increased the DEC backlash compensation and set it to 6. I made no changes in the general aggressiveness settings. The PE droped to only 7 arc seconds peak to peak.
I can probably fine tune the adjustments to lower the PE even further, but for my purposes, a guided PE of + or - 3.5 arc" will work quite nicely.
Maxim DL allows fine adjustments of mount motion during guiding. The general aggressiveness (or guiding responsiveness) of each axis, as well as the backlash control of each axis, can be individually adjusted. Mount motion during calibration can be seen on-screen and makes it easy to see how changes in aggressiveness and backlash affect mount movements.
I ran only two sets of data. The first run was for nearly 3 full worm cycles. No compensation for RA backlash was used but the Dec backlash compensation was set at roughly 4 on a scale of 1-10. The aggressiveness settings for both axes were at the low end of the range. That run reduced the PE from 30 arc seconds peak to peak down to 15 arc seconds peak to peak.
I then increased the DEC backlash compensation and set it to 6. I made no changes in the general aggressiveness settings. The PE droped to only 7 arc seconds peak to peak.
I can probably fine tune the adjustments to lower the PE even further, but for my purposes, a guided PE of + or - 3.5 arc" will work quite nicely.
#556
vdb
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Posted 09 January 2011 - 03:33 AM
Hi Larry,
thanks for being so quick ...
Interesting results, if other owners IEQ45 owners can do the same test, that would give us a goo idea on how this mount would keep up for AP.
(I'm happy to see my G8 can keep up, was wondering if a swap was in order, maybe it still is as I wan't goto back ...)
thanks for being so quick ...
Interesting results, if other owners IEQ45 owners can do the same test, that would give us a goo idea on how this mount would keep up for AP.
(I'm happy to see my G8 can keep up, was wondering if a swap was in order, maybe it still is as I wan't goto back ...)
#557
elwaine
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Posted 09 January 2011 - 08:41 AM
This was an exercise in POOR PLANNING and loss of concentration. The only lessons I learned from this are 1) that one should plan ahead; and 2), one should avoid conversation with curious neighbors while trying to set up experimental conditions that were not well planned in advance and were not written down!
I used my C9.25. Total load was about 28 lbs. Seeing was just average - maybe 3 on a 1-5 scale. I had intended to bin the guide chip to better match seeing conditions, but I forgot to do so, and wound up using an image scale of less than 1 arc second per pixel - way too high! That alone casts doubts on what the following graphs show.
In each case, the guide star stayed centered within the real-time tracking window. So I'm not sure what the graphs mean. I should have taken an image while I was recording the PE data. The combination of an image and a PE graph would have had much more meaning than the graphs alone. Oh well... next time. (I suppose I am incapable of talking and thinking at the same time. With skills like that, I should have gone into politics!
)
Did you really have any doubts? If you can keep the equipment weight load below 30 lb., a GM8 should out-perform the IEQ45. But you'll spend over $1,000 more for a GM8 that has all the features of an IEQ45. Quality never comes cheap! (Personally, I think that an extra $1,000 - $1,200 is worth the expenditure for those who can afford a complete GM8 package.)
The IEQ45 works OK at least with loads up to about 30 lb. While I haven't tested it at greater loads, I think the 45 lb. stated carrying capacity will prove to be overly optimistic.
I used my C9.25. Total load was about 28 lbs. Seeing was just average - maybe 3 on a 1-5 scale. I had intended to bin the guide chip to better match seeing conditions, but I forgot to do so, and wound up using an image scale of less than 1 arc second per pixel - way too high! That alone casts doubts on what the following graphs show.
In each case, the guide star stayed centered within the real-time tracking window. So I'm not sure what the graphs mean. I should have taken an image while I was recording the PE data. The combination of an image and a PE graph would have had much more meaning than the graphs alone. Oh well... next time. (I suppose I am incapable of talking and thinking at the same time. With skills like that, I should have gone into politics!
) I'm happy to see my G8 can keep up, was wondering if a swap was in order, maybe it still is as I wan't goto back ...
Did you really have any doubts? If you can keep the equipment weight load below 30 lb., a GM8 should out-perform the IEQ45. But you'll spend over $1,000 more for a GM8 that has all the features of an IEQ45. Quality never comes cheap! (Personally, I think that an extra $1,000 - $1,200 is worth the expenditure for those who can afford a complete GM8 package.)
The IEQ45 works OK at least with loads up to about 30 lb. While I haven't tested it at greater loads, I think the 45 lb. stated carrying capacity will prove to be overly optimistic.
#558
Midnight Dan
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Posted 09 January 2011 - 11:11 AM
The IEQ45 works OK at least with loads up to about 30 lb. While I haven't tested it at greater loads, I think the 45 lb. stated carrying capacity will prove to be overly optimistic.
It's been my impression that on any mount, the max capacity rating is for visual use. For imaging, I'm told that the ideal is to use half the capacity, 2/3 at most. Based on that, imaging on this mount should be great at loads in the low 20s and should be acceptable up to around 30 pounds.
Sounds consistent with your experiences so far.
-Dan
#559
elwaine
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Posted 09 January 2011 - 11:24 AM
The IEQ45 works OK at least with loads up to about 30 lb. While I haven't tested it at greater loads, I think the 45 lb. stated carrying capacity will prove to be overly optimistic.
It's been my impression that on any mount, the max capacity rating is for visual use. For imaging, I'm told that the ideal is to use half the capacity, 2/3 at most. Based on that, imaging on this mount should be great at loads in the low 20s and should be acceptable up to around 30 pounds.
Sounds consistent with your experiences so far.
-Dan
I agree with most of what you say, Dan. But there are some top tier mounts (such as A-P's line) that can guide right up to their maximum rated load. Of course, you'll have to pay a premium for that kind of performance. - I wish the IEQ45 performed like a $6,000 mount. Then again, I wish I performed as well as a $6,000 mount.
All one can ask is that we get what we pay for, and I think that the IEQ45 is probably worth its price. (The problem, for me, is that having once owned 2 A-P mounts, I am spoiled.)
#560
TDM
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Posted 09 January 2011 - 04:38 PM
Post deleted by Bowmoreman
#561
elwaine
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Posted 09 January 2011 - 05:13 PM
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#562
TDM
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Posted 09 January 2011 - 05:29 PM
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#563
gdd
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Posted 09 January 2011 - 05:43 PM
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#564
elwaine
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Posted 09 January 2011 - 05:56 PM
I don't know, Gale. I know almost nothing about the IEQ75.
[Moderator edited to remove off-topic material related to earlier TOS violation - but NOT posted by THIS poster]
(Yet to be established is the long term history of the IEQ45. How will it perform a year or two from now? Is anyone willing to invest in a product that costs nearly as much as the mount itself when the longevity of the mount is unknown?)
[Moderator edited to remove off-topic material related to earlier TOS violation - but NOT posted by THIS poster]
(Yet to be established is the long term history of the IEQ45. How will it perform a year or two from now? Is anyone willing to invest in a product that costs nearly as much as the mount itself when the longevity of the mount is unknown?)
#565
TDM
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Posted 09 January 2011 - 06:11 PM
Post deleted by Bowmoreman
#566
elwaine
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Posted 09 January 2011 - 08:38 PM
Attila,
OK - Now I understand. Based on the pictures of the IEQ45, you, and me, and many, many others also thought that the IEQ45 was a clone of an A-P mount. In appearance, it is a clone. In build and in performance, it is not. Believe me. I owned an A-P 1200 GTO up until a few years ago, when I retired and sold most of my large equipment because I had no room to keep all that wonderful 'stuff' in my new house.
If you were to buy a Ferrari body, and placed it over a Volkswagen, you could impress all the ladies until either you started the engine, or they got to look inside. And that's about how close a "clone" the IEQ45 is to an A-P 900 or 1200.
My mother tried to teach me that looks can be deceiving... but I fall for good looks each and every time.
The IEQ45 is a good mount for the money - but in my honest opinion, it is not "deserving" of an upgrade as fine (and as justifiably expensive) as a TDM.
Based on iOptron pictures I feel iEQ45 can be an AP clone.
OK - Now I understand. Based on the pictures of the IEQ45, you, and me, and many, many others also thought that the IEQ45 was a clone of an A-P mount. In appearance, it is a clone. In build and in performance, it is not. Believe me. I owned an A-P 1200 GTO up until a few years ago, when I retired and sold most of my large equipment because I had no room to keep all that wonderful 'stuff' in my new house. If you were to buy a Ferrari body, and placed it over a Volkswagen, you could impress all the ladies until either you started the engine, or they got to look inside. And that's about how close a "clone" the IEQ45 is to an A-P 900 or 1200.
My mother tried to teach me that looks can be deceiving... but I fall for good looks each and every time.
The IEQ45 is a good mount for the money - but in my honest opinion, it is not "deserving" of an upgrade as fine (and as justifiably expensive) as a TDM.
#567
John P
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Posted 10 January 2011 - 09:00 AM
I have had my mount for about a month and a half and while I finally have it set up and aligned, the weather here, south of Rochester, NY has not been good. The one night I managed polar alignment was clear but not transparent enough for imaging.
So far the mount has been a dream with no problems...everything just as it should be out of the box. Polar alignment in particular, was both easy and quick. Can't wait to try imaging.
My question is regarding the "stiff" movement of the declination axis. I don't like it and am thinking of trying to find a thin thrust or needle bearing to eliminate it. I can see that this might require re-drilling and tapping for the clutch retainning screws so they maintain their position in the clutch housing. I can also see where this will create an entry space for dirt and dust. But do you think it's possible, assuming the correct size bearing is available of course?
So far the mount has been a dream with no problems...everything just as it should be out of the box. Polar alignment in particular, was both easy and quick. Can't wait to try imaging.
My question is regarding the "stiff" movement of the declination axis. I don't like it and am thinking of trying to find a thin thrust or needle bearing to eliminate it. I can see that this might require re-drilling and tapping for the clutch retainning screws so they maintain their position in the clutch housing. I can also see where this will create an entry space for dirt and dust. But do you think it's possible, assuming the correct size bearing is available of course?
#568
Bowmoreman
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Clear enough skies
Posted 10 January 2011 - 09:37 AM
Moderator Comment:
I've had to delete several posts that started from a Vendor TOS violation, and then a back and forth that occurred prior to my ability to delete it.
In addition to the TOS violation, we were getting off track from the main point of this very valuable thread.
Vendors are reminded to please review the CN TOS, and refrain from activities such as product pushing and commenting on quality (or lack thereof) of products which are NOT the specific vendors.
Thank you all for your understanding!
I now return you to this "Best of Mounts" thread!
I've had to delete several posts that started from a Vendor TOS violation, and then a back and forth that occurred prior to my ability to delete it.
In addition to the TOS violation, we were getting off track from the main point of this very valuable thread.
Vendors are reminded to please review the CN TOS, and refrain from activities such as product pushing and commenting on quality (or lack thereof) of products which are NOT the specific vendors.
Thank you all for your understanding!
I now return you to this "Best of Mounts" thread!
#569
elwaine
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Posted 10 January 2011 - 10:39 AM
Thank you, Dave.
_________
John,
I can't answer your excellent question as my skills as an engineer are limited to operating model trains. But I just wanted to comment that in spite of the stiffness (which annoys me, too), the mount works. While I would love to learn of an easy modification to improve the Dec axis stiffness, I am reminded that sometimes the enemy of 'good' is 'better.'
_________
John,
I can't answer your excellent question as my skills as an engineer are limited to operating model trains. But I just wanted to comment that in spite of the stiffness (which annoys me, too), the mount works. While I would love to learn of an easy modification to improve the Dec axis stiffness, I am reminded that sometimes the enemy of 'good' is 'better.'
#570
TDM
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Posted 10 January 2011 - 12:51 PM
Okay, Dave, I understand.
Good bye,
Attila
Good bye,
Attila
#571
John P
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Posted 10 January 2011 - 02:48 PM
Larry, just for giggles I emailed iOptron and bounced the idea off them. I got a response from a technical representative literally within an hour. That alone speaks well for the company.
He included a couple photos for my reference and indicated the "stiffness" (my word not his) was normal and only 2-3 pounds. He stopped short of advising me not to try the modification but didn't encourage it either.
My decision is to wait and see and as I have yet to try the mount while imaging, give it several opportunities hopefully over the next few weeks. It's a simple exercise to weigh a few things and run some quick moment-arm calculations if I get too nervous and jerky about the stiffness, and can always do the modification at a future time should I choose.
He included a couple photos for my reference and indicated the "stiffness" (my word not his) was normal and only 2-3 pounds. He stopped short of advising me not to try the modification but didn't encourage it either.
My decision is to wait and see and as I have yet to try the mount while imaging, give it several opportunities hopefully over the next few weeks. It's a simple exercise to weigh a few things and run some quick moment-arm calculations if I get too nervous and jerky about the stiffness, and can always do the modification at a future time should I choose.
#572
elwaine
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Posted 10 January 2011 - 02:54 PM
Hi John,
Sounds like a good plan.
(And yes, iOptron tech support has been first class.)
Sounds like a good plan.
(And yes, iOptron tech support has been first class.)
#573
John Miele
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Fly Me to the Moon
Posted 10 January 2011 - 06:24 PM
Hi Guys,
One way you can completely get around the DEC stiffnes sissue is to set up uour OTA just as it would be for use. For example, I set up my C8 with finder, guider, dew shield, and camera at the position of focus and then set it on a table and balanced it one a wood dowel. Marked the spot on the dovetail bar and I just slide it to the balance point when I place it on the mount. DEC stiffness never enters the equation. Some OTAs may not lend themselves well to this but I suspect most refractors and SCT's will...John
I also have a couple more images taken with the ieq45. This is the horsehead. It's still in work and needs a lot more data. But these were all 5 minute subs and did not have to throw out one due to guiding issues.
One way you can completely get around the DEC stiffnes sissue is to set up uour OTA just as it would be for use. For example, I set up my C8 with finder, guider, dew shield, and camera at the position of focus and then set it on a table and balanced it one a wood dowel. Marked the spot on the dovetail bar and I just slide it to the balance point when I place it on the mount. DEC stiffness never enters the equation. Some OTAs may not lend themselves well to this but I suspect most refractors and SCT's will...John
I also have a couple more images taken with the ieq45. This is the horsehead. It's still in work and needs a lot more data. But these were all 5 minute subs and did not have to throw out one due to guiding issues.
Attached Thumbnails
#574
John Miele
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Fly Me to the Moon
Posted 10 January 2011 - 06:34 PM
Here is M37. Again, all the subs were usable. The ieq45 is guiding quite well IMHO and I am using all the stock PHD settings except for the calibration step which I increaeed to 1500 but that was more due to my using a very short fl guide scope (kwiq guider @200 mm fl). I have not taken any time to fine tune settings or use PEC correction...John
Attached Thumbnails
#575
elwaine
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Posted 10 January 2011 - 08:18 PM
Excellent, John. Thanks for posting those photos.
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