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Let's Torture the Mach 2

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#76 Ballyhoo

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Posted 25 September 2021 - 01:12 AM

A-P's orientation seems to be much more engineering "Under Promise and Over Deliver", not the marketing orientation of "State Optimistic Case and Get the Sale".

that certainly was the case right when AP had spec'd the Mach 1 at 45Lb capacity. Now it is 65Lb. But what does that mean exactly?

It has been said w premium mounts the number you get is for imaging.

 

 

But who is going to image with a Mach 1 @ a 65Lb load? 

 

Actually who will image a Mach 1 w a 45Lb load?  

 

The Meade 12" ACF weight 32 Lbs. Would you feel comfortable loading it up with a motorized focuser; .6 reducer; a cooled mono camera with filter wheel; guide scope, and image with that big load on an Mach 1?

 

how about the C14? That is whopping 50+ Lbs all loaded with imaging gear. Who will use a Mach 1 to image a C14?

 

edit

 

there is little doubt the Mach 2 could handle the above configurations. after all it is made to handle larger loads.


Edited by Ballyhoo, 25 September 2021 - 01:14 AM.


#77 rockstarbill

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Posted 25 September 2021 - 01:27 AM

This thread isn't about the Mach 1.
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#78 rockstarbill

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Posted 25 September 2021 - 02:51 PM

The Meade 12" ACF weight 32 Lbs. Would you feel comfortable loading it up with a motorized focuser; .6 reducer; a cooled mono camera with filter wheel; guide scope, and image with that big load on an Mach 1?

 

how about the C14? That is whopping 50+ Lbs all loaded with imaging gear. Who will use a Mach 1 to image a C14?

I would be fine with the Meade on the Mach 1 and Mach 2. Just dont use a super heavy camera rig that pushes the overall weight up to 50 lbs or and do NOT use a guide scope. See diagram in post #73. If you do pop a guide scope on top of the Meade you then need to account for that in the OTA height. You would already pull those curves down 10 lbs for the Mach 1, so if you use a little brain juice you can see that doing that becomes problematic. The good thing about the Meade is that it is fairly compact. This makes it easier on the mount. I know you wont look at that chart or really read any of what I am saying here though.

 

No C14 on a Mach 1 or a Mach 2. That is a terrible, terrible idea. For imaging anyhow. 



#79 Ballyhoo

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Posted 25 September 2021 - 11:11 PM

I would be fine with the Meade on the Mach 1 and Mach 2. Just dont use a super heavy camera rig that pushes the overall weight up to 50 lbs or and do NOT use a guide scope. See diagram in post #73. If you do pop a guide scope on top of the Meade you then need to account for that in the OTA height. You would already pull those curves down 10 lbs for the Mach 1, so if you use a little brain juice you can see that doing that becomes problematic. The good thing about the Meade is that it is fairly compact. This makes it easier on the mount. I know you wont look at that chart or really read any of what I am saying here though.

 

No C14 on a Mach 1 or a Mach 2. That is a terrible, terrible idea. For imaging anyhow. 

I look at all the data you provide because you are like the cantankerous wizard and I have to take what you say in earnest.

 

I have no doubt the C14 is discouraged for imaging for a Mach 1. However, it is 46 lbs. So with 5 Lbs. of imaging gear, what does that say about the limits we are given? Specs alone the mach 1 should be able to image with a C14 since the limit is 65Lbs.   I am not doubting but also not clear then on the payload limits. 

 

I know this is not about the Mach 1. but regarding payload specs in general for AP I am not sure.  It is within the spec for a Mach 1 I am surprised that it would not image for a Mach 2.  


Edited by Ballyhoo, 25 September 2021 - 11:11 PM.


#80 rockstarbill

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Posted 25 September 2021 - 11:18 PM

I look at all the data you provide because you are like the cantankerous wizard and I have to take what you say in earnest.

 

I have no doubt the C14 is discouraged for imaging for a Mach 1. However, it is 46 lbs. So with 5 Lbs. of imaging gear, what does that say about the limits we are given? Specs alone the mach 1 should be able to image with a C14 since the limit is 65Lbs.   I am not doubting but also not clear then on the payload limits. 

 

I know this is not about the Mach 1. but regarding payload specs in general for AP I am not sure.  It is within the spec for a Mach 1 I am surprised that it would not image for a Mach 2.  

We would need to know the height of the C14 scope as measured in the diagram above. 



#81 Ballyhoo

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Posted 25 September 2021 - 11:26 PM

We would need to know the height of the C14 scope as measured in the diagram above. 

well the diagram is for the Mach 2 so I presume the Mach 1 is quite a bit lower in the curve.

 

however, are there heavy OTA's like 45Lb + that are less in height than an SCT?  

 

This really does illustrate to the novice that weight payload is only part of the story on what a mount can load.

(edit) yeah I know you say that in your post too about weight not being everything.)


Edited by Ballyhoo, 25 September 2021 - 11:29 PM.


#82 rockstarbill

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Posted 25 September 2021 - 11:33 PM

well the diagram is for the Mach 2 so I presume the Mach 1 is quite a bit lower in the curve.

 

however, are there heavy OTA's like 45Lb + that are less in height than an SCT?  

 

This really does illustrate to the novice that weight payload is only part of the story on what a mount can load.

You would pull the curve down 10lbs for the Mach 1. Might want to double check with Roland if the approximation is valid. I would assume so though.

 

There are a number of a very heavy telescopes out there that are not as fat as a large SCT like the C14. 

 

That diagram really shows two things. The effect the height of a scope has and the effect the length of a scope has. Both of them are important considerations. You cannot just look at the weight capacity and move on. You need to consider the effects of both. In the case of my "Torture Test" of the Mach 2, it was fine in terms of length. The height is what pushed it a little into the Red considering the weight of everything attached, 11lbs of which is my camera, wheel, and OAG. 



#83 Ballyhoo

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Posted 25 September 2021 - 11:36 PM

 why won't balancing the RA and DEC axis assuage the effect of the OTA geometry? 



#84 Ballyhoo

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Posted 25 September 2021 - 11:41 PM

Also I am not sure about the illustration of Karen bc she is sticking her arm out but our rigs, again, are balanced. If Karen had her second arm going opposite the first with the counterweight, wouldn't she be balanced out? Well her wrist elbow and shoulder joint would get tired but I am not sure how analogue a human is to a mount. but maybe that is the answer.



#85 Peter in Reno

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Posted 25 September 2021 - 11:48 PM

Why are you so concerned about balancing. Simply respect the manufacturer's capacity weight limit and the length of scope used and balancing won't be a problem. Why are you asking this?

 

A-P describes very clearly about their mount loading capacity at their web site not only based on the loading capacity weight but the length and size (i.e. diameter) of the scopes. They even give great examples of different types of scopes maximum weight as well as sizes and lengths. It's all there, you just have to find them and they are not hidden.

 

Peter



#86 Ballyhoo

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Posted 25 September 2021 - 11:52 PM

Why are you so concerned about balancing. Simply respect the manufacturer's capacity weight limit and the length of scope used and balancing won't be a problem. Why are you asking this?

 

A-P describes very clearly about their mount loading capacity at their web site not only based on the loading capacity weight but the length and size (i.e. diameter) of the scopes. They even give great examples of different types of scopes maximum weight as well as sizes and lengths. It's all there, you just have to find them and they are not hidden.

 

Peter

sounds good.



#87 rockstarbill

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Posted 25 September 2021 - 11:58 PM

 why won't balancing the RA and DEC axis assuage the effect of the OTA geometry? 

The graphic answers this. Read the text box and the printed text on the length graph. 


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#88 SilverLitz

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Posted 26 September 2021 - 08:41 AM

 why won't balancing the RA and DEC axis assuage the effect of the OTA geometry? 

No that is not enough.  Read up, ideally in physics text, "Moment of Inertia".  It is a higher order effect.  It impacts the force need to accelerate (speed up or change direction) movement.  With lower inertia, the mount will respond and correct quicker, with greater ease.

 

This also why you want to have use more counterweights, but have the heaviest weight higher up.


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#89 WadeH237

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Posted 26 September 2021 - 08:52 AM

I know this is not about the Mach 1. but regarding payload specs in general for AP I am not sure.  It is within the spec for a Mach 1 I am surprised that it would not image for a Mach 2.  

You seem to have it in your head that whether a payload is acceptable or not is a binary thing.  It's not!

 

A configuration that works perfectly on a calm night might be shaky on a windy night.  A mount that works fine with a shorter focal length scope might be unsuitable for a different scope of the same size and weight, but a longer focal length.

 

I saw a Mach1 once that was carrying about 100lb.  This is obviously far over the rated capacity, and I would not suggest that you do this, but the user was happy with the performance they were getting.


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#90 rockstarbill

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Posted 03 October 2021 - 12:52 PM

Here are 2 subs, a regular HA stack, and a drizzle HA stack:

https://1drv.ms/u/s!...MHew8Q?e=geq6bf

Data looks very solid to me.

Circling back on this thread. Open to feedback on the data quality as there's been some commentary from folks in other threads that suggest the data was not good and the mount being overloaded was the problem. I disagree with that assertion but welcome the discussion.

More data to come shortly. This data was taken before the Collimation of the scope was adjusted and a baffle issue was fixed.

Edited by rockstarbill, 03 October 2021 - 12:55 PM.


#91 RogeZ

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Posted 03 October 2021 - 12:59 PM

Thanks RSB for coming back to this thread. Hopefully we all learn a bit.

Couple of questions:
-Did you include all the frames on the dats you presented here?
-Did you run subframe selector on raw, calibrated or registered frames?

#92 rockstarbill

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Posted 03 October 2021 - 01:01 PM

Here are some data stacks before the collimation was adjusted using SkyWave and after the collimation was adjusted and an issue with the baffle was identified and resolved.

 

https://1drv.ms/u/s!..._qiC-A?e=wqSNNp

 

Note the Before and After in the frame names. In a moment I will run the individual subs for the after data through analysis.



#93 rockstarbill

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Posted 03 October 2021 - 01:19 PM

Attached are the individual sub grades from Subframe Selector in CSV format. All of the calibrated subs were uploaded to the same share link above. Feel free to download the data and explore. Do note that the system I calibrated the data on did not have the column defect map, so I did not fix those in the calibration. In a real process pass, those would be fixed. 

 

The FMHME Script gives the following grade of the stack of data:

 

FHMWE_Stack_AfterColl.JPG

 

At 0.87"/px we can see the stack is 2.14" FWHM with an extremely low eccentricity of 0.2. I dont know the world in which this data is bad, or the mount is overloaded. I do not believe either of those are true statements at all. If the mount was overloaded it certainly would have shown up, as the subframes are 20 minutes long each. That was not the case, and did not occur. The mount guided incredibly well, at around 0.2-0.3" RMS. Also, it is important to know that I image in the Pacific Northwest, and data that good in terms of quality is not common for us. 

 

Looking forward to hearing peoples thoughts on the data.

Attached Files


Edited by rockstarbill, 03 October 2021 - 01:20 PM.


#94 RogeZ

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Posted 03 October 2021 - 01:41 PM

Attached are the individual sub grades from Subframe Selector in CSV format. All of the calibrated subs were uploaded to the same share link above. Feel free to download the data and explore. Do note that the system I calibrated the data on did not have the column defect map, so I did not fix those in the calibration. In a real process pass, those would be fixed.

The FMHME Script gives the following grade of the stack of data:

FHMWE_Stack_AfterColl.JPG

At 0.87"/px we can see the stack is 2.14" FWHM with an extremely low eccentricity of 0.2. I dont know the world in which this data is bad, or the mount is overloaded. I do not believe either of those are true statements at all. If the mount was overloaded it certainly would have shown up, as the subframes are 20 minutes long each. That was not the case, and did not occur. The mount guided incredibly well, at around 0.2-0.3" RMS. Also, it is important to know that I image in the Pacific Northwest, and data that good in terms of quality is not common for us.

Looking forward to hearing peoples thoughts on the data.


This data set is different than the previous one and you did not answer my questions on the previous data set.

How many sub frames did you toss?

#95 rockstarbill

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Posted 03 October 2021 - 01:45 PM

This data set is different than the previous one and you did not answer my questions on the previous data set.

How many sub frames did you toss?

Zero subs were discarded. I was quite clear that the data was taken after collimation work. It is not the same subject matter, as that project was done and I wanted to get data on this subject. In terms of the mount performance, that is irrelevant though.

 

All of the data is uploaded to the share above. If you have any other questions that looking at the data yourself does not answer -- let me know. The mount performed excellent. No questions about that at all. It was not overloaded either. The manufacturer supported what I was doing and was confident it would work fine, and it did.

 

So question back to you -- what in this data tells you the mount was overloaded and the results show it?



#96 RogeZ

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Posted 03 October 2021 - 01:52 PM

On the first data set, the eccentricies reach 0.50-0.57 in some frames which as roundness goes you are by definition oblong and have tracking errors. Combine this with the large pixels you are using, and this is nothing expectacular.

By definition anything over 0.42 is oblong.

Also, in the first data set there seem to be images that were discarted (due to clouds or something else) and therefore the data set is incomplete.

#97 RogeZ

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Posted 03 October 2021 - 01:52 PM

Also, are the frames you are using for this analysis, raw, cal or registered?

#98 rockstarbill

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Posted 03 October 2021 - 01:56 PM

On the first data set, the eccentricies reach 0.50-0.57 in some frames which as roundness goes you are by definition oblong and have tracking errors. Combine this with the large pixels you are using, and this is nothing expectacular.

By definition anything over 0.42 is oblong.

Also, in the first data set there seem to be images that were discarted (due to clouds or something else) and therefore the data set is incomplete.

Stop moving the goalposts. I told you why the off axis eccentricity was high. It was not the mount.

 

What in this data tells you the mount was overloaded and the results show it?

 

Also, are the frames you are using for this analysis, raw, cal or registered?

All of them are uploaded in the link I shared above. Here it is again:

 

https://1drv.ms/u/s!..._qiC-A?e=wqSNNp

 

This question has nothing to do with the quality of the mount under the load it was under. This topic is not about Pixinsight processing techniques. Still waiting for this insight of yours that suggests the mount was causing a problem with image quality. 



#99 RogeZ

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Posted 03 October 2021 - 02:04 PM

Stop moving the goalposts. I told you why the off axis eccentricity was high. It was not the mount.

What in this data tells you the mount was overloaded and the results show it?

All of them are uploaded in the link I shared above. Here it is again:

https://1drv.ms/u/s!..._qiC-A?e=wqSNNp

This question has nothing to do with the quality of the mount under the load it was under. This topic is not about Pixinsight processing techniques. Still waiting for this insight of yours that suggests the mount was causing a problem with image quality.


Thats not the way image analysis works.

If collimation rises (and it does) your average eccentricity values it does it on all frames but you have variation among your frames which is significant.

Also, which frames you measure do affect the subframe selector measurements. Hence my question.

I just don’t reach the same conclusion you do based on the data available.

#100 rockstarbill

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Posted 03 October 2021 - 02:08 PM

Thats not the way image analysis works.

If collimation rises (and it does) your average eccentricity values it does it on all frames but you have variation among your frames which is significant.

Also, which frames you measure do affect the subframe selector measurements. Hence my question.

I just don’t reach the same conclusion you do based on the data available.

All of the data is there for you to look at and if you want to draw conclusions from it, please share the analysis and your data with the thread so we can all see it. All of the data, every single sub used to stack the post-collimation adjustment frame has been provided. 

 

Not sure what conclusion you are arriving at, as you have not provided anything objective to review. You have evaded the question twice now. 

 

What in this data tells you the mount was overloaded and the results show it?




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