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Equipment Discussions >> Mounts

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korborh
scholastic sledgehammer
*****

Reged: 01/29/11

Loc: Arizona
Re: 10Micron new [Re: Skunky]
      #6317198 - 01/16/14 07:11 PM

Quote:

I don't think offering software free should determine whether you are a vendor or not..



You are kidding, right? They have to sell something to be a vendor. Free ain't selling.


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orlyandico
Postmaster
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Reged: 08/10/09

Loc: Singapore
Re: 10Micron new [Re: Skunky]
      #6317211 - 01/16/14 07:18 PM

So here's the other thing. How do you even measure fwhm.

I used to use CCD inspector.. until the trial ran out. Deep sky Stacker also provides fwhm (in pixels not arc seconds) but it doesn't agree with CCD inspector...

If you just screenshot the DSS UI after it's done cataloging and grading your images the fwhm is there.

For me more interesting than fwhm is the fwhm of ALL your subs. Because people buy premium mounts for reliability and consistency. Even a CGEM can manage a round sub every now and then... (I exaggerate)

Also, FWHM for short refractors will always be bloated. I think the main reason nobody takes Frank up is that very few people are imaging with long cats or RCs. And those who are, who are by necessity more advanced users, know what they have and can't be bothered to get on this thread.


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Skunky
sage


Reged: 09/16/13

Re: 10Micron new [Re: korborh]
      #6317214 - 01/16/14 07:21 PM

Quote:

Free ain't selling.




Says who?

An idea is free and sold around the world all the time.. yes/no? Am i not trying to sell you on the idea? It's free... take it or leave it..

Frank sells the idea to users to use metaguide.. or he suggests.. isn't that the same thing?

I believe there are many synonyms for sell including advertise, hawk, peddle, hustle, pitch, plug, push, assure or convince..

Are they not trafficking in their specific area of interest?

Does Frank try to "convince" or sell users on the idea of using metaguide?

Does Ed try to "convince" or sell users on the idea of a mount purchase?

Getting satisfaction from giving away an item or idea.. would that not be considered selling?


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freestar8n
Post Laureate
*****

Reged: 10/12/07

Re: 10Micron new [Re: orlyandico]
      #6317242 - 01/16/14 07:38 PM

Quote:

How do you even measure fwhm.




There are many tools for measuring fwhm and the numbers will vary somewhat, especially if the pixels are somewhat big on the scale of the star.

There will be some variability within an image and across subs - but it is unlikely to get a single sub that has both round and very small stars just by luck.

I'm just encouraging what I consider to be a fairly common practice for people doing high res work on good mounts. They aim for small fwhm and they will monitor it in their images all the time - and complain when the "seeing goes south" and will be happy when it is great. "My fwhm was 1.9" last night but now the jet stream is overhead and I am stuck with 2.5" That kind of thing.

People like high end mounts, and tout the priority of the mount for imaging performance - and that does have empirical basis - just like using OAG. They get better results and smaller stars, and the results stand out against the general variability of seeing.

I think many images are limited by focus quality - and that's another reason to track fwhm. Just to make sure the results aren't limited by something under your control and independent of the mount or the seeing.

But this is getting off topic... It's pretty simple - images tell you something about mount performance, and fwhm tells you even more.

Frank


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korborh
scholastic sledgehammer
*****

Reged: 01/29/11

Loc: Arizona
Re: 10Micron new [Re: Skunky]
      #6317265 - 01/16/14 07:47 PM

Quote:

Says who?




CN TOS


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Skunky
sage


Reged: 09/16/13

Re: 10Micron new [Re: korborh]
      #6317465 - 01/16/14 09:40 PM

Quote:

Quote:

Quote:

Free ain't selling.




Says who?




CN TOS




lol. so the CN TOS says, and I quote "free ain't selling"

Would you mind directing me to the exact page and paragraph of that statement in the CN TOS?

Anyways, this is not on topic with the OP. Which is a violation of the TOS. (Thread hijacking is the act of trying to steer a web forum discussion thread off topic by discussing a subject entirely unrelated to the subject at hand. While this can be an intentional act of trolling, it is often accidental - caused by other participants in the discussion responding to a throwaway remark, taking the thread off at a tangent to the original subject matter. The results, whilst sometimes humorous or otherwise interesting, often provoke a feeling of resentment from the author of the original post.)

I've had my say (which the TOS allows: Vendor disagreements should be dealt with via the vendor. Feel free to discuss things here, but please don't beat it to death. Stating your viewpoint once, on-topic and in a civil manner, in a thread is sufficient.) and I will no longer


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korborh
scholastic sledgehammer
*****

Reged: 01/29/11

Loc: Arizona
Re: 10Micron new [Re: Skunky]
      #6317513 - 01/16/14 10:10 PM

"For sale" is not equal to "for free". Read up on who is a vendor according to TOS. That's what I meant. It's simple. If you can't understand this distinction then its your problem.

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David PavlichAdministrator
Transmographied
*****

Reged: 05/18/05

Loc: Mandeville, LA USA
Re: 10Micron new [Re: Skunky]
      #6317532 - 01/16/14 10:20 PM

This threads about mounts in general, 10 Micron in particular. Let's keep it that way.

David


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Per Frejvall
sage


Reged: 09/28/12

Loc: Saltsjöbaden, Sweden
Re: 10Micron new [Re: David Pavlich]
      #6317800 - 01/17/14 01:40 AM

When I measure the performance of my 10Micron mounts I use PHD guiding in passive mode, just recording the "guide" errors. The FWHM of the subs are also interesting values, but what was 2.2 last night is suddenly 2.8 tonight, but the PHD reported tracking performance is the same.

Unfortunately, I have a black plug in the OAG pickup of the QSI-683 so I have to do it through the actual 8300 chip, which means time will be taken from true imaging.

/per


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freestar8n
Post Laureate
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Reged: 10/12/07

Re: 10Micron new [Re: Per Frejvall]
      #6317875 - 01/17/14 03:51 AM

Yes - I see people often quoting the guide error logs as measures of guiding or seeing performance - and there are many reasons I don't think that is a good idea. The fact that the images are not well correlated with the guide log is direct evidence of that. The guide log just shows what the guider "thinks" it is doing - but what is really happening shows as ground truth in the size of stars in the image. And that size is the one that counts. When a small guidescope is used, it can be a sign of limited centroid accuracy.

There are many reports of people with mid-range equipment who have guide logs that look great and at the limit of the seeing. But eventually they get a high end mount - and their images improve.

I expect that most high end mounts with expensive bearings and gearboxes will guide very well without too much tweaking of the system or the guiding - and it may not be possible to tell one from another in terms of the size of the stars. But I'd still like to know if possible - especially if encoders do in fact improve guided imaging, for example. I'm not optimistic they would - but I consider it possible since there are many subtleties involved.

But I am interested in any numbers for comparison, and I think they would be useful to others considering a new mount like the 10Micron - as long as people know that seeing, focus and other factors do play a role, and that a very small number from one mount doesn't mean it automatically "wins." It's just another performance metric used to gauge a result, and with more people reporting, there is collective evidence for any difference that might show up - just as there is collective evidence that an expensive mount results in smaller stars and improved images.

Frank


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Per Frejvall
sage


Reged: 09/28/12

Loc: Saltsjöbaden, Sweden
Re: 10Micron new [Re: freestar8n]
      #6317903 - 01/17/14 05:05 AM

This is not guide errors, it is the recording of how the guide star moves when the scope is not being guided. Alas, it is a direct measure of how much the mount fluctuates in tracking on its own.

So what you are saying in your first statement is that a centroid calculation (as implemented by Craig Stark in PHD) is not accurate enough, even though it is sub-pixel and the measurement is made through the main imager looking through the scope.

Didn't know that.

/per


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freestar8n
Post Laureate
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Reged: 10/12/07

Re: 10Micron new [Re: Per Frejvall]
      #6317924 - 01/17/14 05:45 AM

I disagree with a lot of claims about how autoguiding works, in particular the accuracy of centroiding. So - even passive logging may not represent what is really going on. It's simple to do sanity checks on how meaningful it is - by comparing logs with a small guidescope and with a long focal length system. If you see any difference - whether in passive or active logs - between different guiding systems on the same mount, or between the guiding system and the image - it loses value as an indicator of imaging performance.

There are strong statements about how accurate centroiding algorithms are - and they tend to be backed by simulation rather than actual measurements. A small guidescope may yield a guidestar with 15" fwhm, and the hope is it will yield accuracy on the 0.1" level. This is optimistic, whereas at long focal length the measured fwhm may be 2" and the centroid value will be more meaningful - but it still doesn't capture exactly what the star is doing on the sensor - for many other reasons. The guider measures a proxy; the image captures the reality.

If you are doing passive logs through the actual imaging system, the result will still depend on the centroiding algorithm and the pixel scale. The stars in short guide exposures are not nice Gaussian spots, as is assumed in estimating centroid errors, and the detectors are not perfect, uniform sensors of light.

Again this more off topic - but relevant for mount performance assessment.

Frank


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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: 10Micron new [Re: freestar8n]
      #6318146 - 01/17/14 09:32 AM

Well Frank, it looks like you aren't successfully talking yourself out of the hole you dug. Time to give the thread back to the OP and pocket the FREE education you just got.

-Rich


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freestar8n
Post Laureate
*****

Reged: 10/12/07

Re: 10Micron new [Re: Starhawk]
      #6318292 - 01/17/14 10:38 AM

I don't think you understand my points - which is perfectly fine. I have been trying to hand the thread back - but people coming back with comments I am obligated to reply to - such as yours, which is content FREE.

Frank


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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: 10Micron new [Re: freestar8n]
      #6318391 - 01/17/14 11:23 AM

Okay, lemme see if I got this right.

1. The 10Micron Mounts seem to be up there with ASA's, AP's and Software Bisque's. So, top-end.

2. The 10Microns do one thing none of the others do: they can go unguided (predictive software guiding with a sky model, etc.) IN THE MOUNT and with no need for a PC. Cool!

3. They are not made in the USA, so shipping them for fixing could be a problem, BUT, the USA-based distributor happens to be a mount-fixer kind of guy, so this may not be a big deal (as opposed to a distributor who just forwards the mounts on to the mother company). This wouldn't bother me under these conditions, as opposed to some obscure Mongolian mount that had to be shipped by yak back to get fixed.

4. The 10Microns work on 24v, as near as I can tell. That's a small but important detail for some of us (me) who have put some funds into some kickazz LiFePO4 batteries. Don't want to get a whole 'nother set, but not a determining issue. Just something to know in case one already has some batteries.

5. There's a guy out there (Per?) who's coding some fine software for the 10Micron mounts.

6. The 10Micron mounts don't have a power/usb hub built in like the ASA's and Paramounts do. (Another small detail, but isn't that what decides a Ferrari from a Lambo?) Do they have through-the-mount cabling? I need to check.

7. I do not think anyone would kick a 10Micron mount out of bed if they won one for free.

So, any other differences or comments that one should know about the 10Micron mounts?

Paul


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dawziecat
Carpal Tunnel
*****

Reged: 10/20/10

Loc: Rural Nova Scotia
Re: 10Micron new [Re: psandelle]
      #6318575 - 01/17/14 12:47 PM

Quote:

opposed to some obscure Mongolian mount that had to be shipped by yak back to get fixed.






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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: 10Micron new [Re: dawziecat]
      #6318597 - 01/17/14 12:56 PM

To clarify a couple of points I made:

1. 10Micron has a 12VDC converter of their own (again: not a big deal, but good to know).

2. The larger 3000 & 4000 mounts have through-the-mount cabling. The smaller ones don't, but they do have their motor/etc. cabling inside the mount (Dec & RA motor cables).

There was a time I was thinking of getting a modded DSLR, one of them PC-less guiders (which I still haven't heard are that great) and head out to the wilds with a smaller battery and a solar charger, and voila: the ultimate survivalist rig.

I went the way of the PC, etc., but the 10Microns, aside from their other sterling points, would make really fantastic super-mobile setups that still gave unparalleled tracking (without guiding). That's pretty great if you need that (and I think there are quite a few that would like it).

Anyway, just some points on the points.

And, for Terry, I have tried to find a way to stabilize a yak to get some quick sub 5 minutes pics...no go. The yak ate the stabilizers.

Paul


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: freestar8n]
      #6318611 - 01/17/14 01:02 PM

Frank,

I think that there is definitely an interesting topic for discussion here and I would highly recommend that you start a new thread to discuss the differences between error measurements and FWHM measurements in evaluating mount quality. I suspect that the result will be that neither method should be used alone and they in fact complement each other.

Ed.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: dawziecat]
      #6318649 - 01/17/14 01:23 PM

Quote:

Quote:

opposed to some obscure Mongolian mount that had to be shipped by yak back to get fixed.









I think that in December all of the shipping services must have switched to yak-back transport. That would explain why everything took so much longer in shipping.


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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: 10Micron new [Re: psandelle]
      #6318650 - 01/17/14 01:23 PM

I have spent some time with one of these, and I can answer a couple of things for this:

1. There were both 120V-24V and 12V-24V converters with the one I used. Note, the main difference is the conversion from 12V to 24v means half the current upstream of the conversion. The original batteries should be OK.

PC-versus on mount: The 10 Micron controller is instantly mount-aware. So, while a fine pointing model won't survive a power outage, as soon as the controller is started again, it has awareness of how the mount is pointed due to the absolute encoders, so you don't have to worry it will think driving into the pier is the right thing to do. I did this experiment by accident when I inadvertently pulled the 120V adapter off the plug adapter.

The other thing is there is no delay to getting to a point where you can invoke a pointing model. What I mean by that is no booting up the mount, booting up the PC, going through a couple hoops to get them to talk, getting all the pieces of software running, then starting a routine in one and watching to see if it is working.

In the field, a GM1000HPS comes up with the pointing model as part of the basic alignment process- go as far as you like, then use it.

-Rich

Quote:

To clarify a couple of points I made:

1. 10Micron has a 12VDC converter of their own (again: not a big deal, but good to know).

2. The larger 3000 & 4000 mounts have through-the-mount cabling. The smaller ones don't, but they do have their motor/etc. cabling inside the mount (Dec & RA motor cables).

There was a time I was thinking of getting a modded DSLR, one of them PC-less guiders (which I still haven't heard are that great) and head out to the wilds with a smaller battery and a solar charger, and voila: the ultimate survivalist rig.

I went the way of the PC, etc., but the 10Microns, aside from their other sterling points, would make really fantastic super-mobile setups that still gave unparalleled tracking (without guiding). That's pretty great if you need that (and I think there are quite a few that would like it).

Anyway, just some points on the points.

And, for Terry, I have tried to find a way to stabilize a yak to get some quick sub 5 minutes pics...no go. The yak ate the stabilizers.

Paul




Edited by Starhawk (01/17/14 01:25 PM)


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