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Common Guiding Accuracy

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#1 Bill001

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Posted 20 April 2019 - 12:44 PM

Hi,

 

I would like to know what sort of guiding accuracy do folks see graphicly displayed on an ‘average’ night. So I’m not refering to your ‘best’ guiding under ideal conditions, I mean a clear sky, no twinkle in stars, maybe a light breeze at times, perhaps occasional high altitude wisps of cirrus clouds.... what on average do people encounter in performance?

 

It doesn;t have to be Phd or Ekos or any particular software just how good is your ‘common’ night performs?

 

I have a ZWOASI178MC on a 240mm focal length Orion 60mm guide scope on a C8.

 

Thanks again,

Bill



#2 kathyastro

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Posted 20 April 2019 - 12:56 PM

On a decent night, I get around 1.5" RMS.  On a really good night, I'll get under 1".



#3 schmeah

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Posted 20 April 2019 - 01:08 PM

Around 0.6" - 0.7" on a typical night. But a "typical" night for one may be drastically different between individual users, selection bias rampant. For instance, I am reluctant to image (since I do mostly long FL imaging) if the little boxes in CSC aren't at least light blue and wind less than 8-10 MPH. If I were imaging more with my refractor, I would be more tolerant of sub par seeing nights.

 

Derek


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#4 Stelios

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Posted 20 April 2019 - 01:16 PM

Typical for me is 0.7", but that's an average depending on object elevation. Low target elevations will do a bit worse, approaching 1". Under low wind and higher target elevations 0.5" is typical.


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#5 Bill001

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Posted 20 April 2019 - 01:17 PM

On a decent night, I get around 1.5" RMS.  On a really good night, I'll get under 1".

What is the image scale of your guide scope assembly?

 

Thanks

B



#6 Bill001

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Posted 20 April 2019 - 01:21 PM

Around 0.6" - 0.7" on a typical night. But a "typical" night for one may be drastically different between individual users, selection bias rampant. For instance, I am reluctant to image (since I do mostly long FL imaging) if the little boxes in CSC aren't at least light blue and wind less than 8-10 MPH. If I were imaging more with my refractor, I would be more tolerant of sub par seeing nights.

 

Derek

Yes my criteria of common or average is very imprecise.  I don’t recall which software uses the little boxes in CSC. What app is that?

Thanks

Bill



#7 kathyastro

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Posted 20 April 2019 - 01:30 PM

What is the image scale of your guide scope assembly?

 

Thanks

B

Guide scope and camera is 6.62"/px.  Imaging scope and camera is 1.20"/px.



#8 Bill001

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Posted 20 April 2019 - 01:31 PM

Typical for me is 0.7", but that's an average depending on object elevation. Low target elevations will do a bit worse, approaching 1". Under low wind and higher target elevations 0.5" is typical.

If one is tracking along (within 1”), then both RA & DEC guiding deviates in unison sustaining that devistion for a minute or so and recovers, what sort of things cause that?  It was generally calm out.

 

Thanks

Bill



#9 Bill001

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Posted 20 April 2019 - 01:37 PM

Guide scope and camera is 6.62"/px.  Imaging scope and camera is 1.20"/px.

At 1.5” RMS does that translate to about .23 pixels for you? 

1.5” divide by 6.62”/px ?



#10 Astrola72

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Posted 20 April 2019 - 01:43 PM

Yes my criteria of common or average is very imprecise.  I don’t recall which software uses the little boxes in CSC. What app is that?

Thanks

Bill

Clear Sky Chart: http://www.cleardarksky.com/csk/



#11 Astrola72

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Posted 20 April 2019 - 01:52 PM

I've been surprised/pleased with how solid my newish AT115EDT is on my CEM60. Using an LX2 and Celestron OAG I get RMS 0.6"-0.7" average for a whole night, pretty reliably. This is just around 0.3 px, which is well within the capacity of PHD2.

 

Joe


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#12 Gipht

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Posted 20 April 2019 - 02:04 PM

With my 70 mm refractor about 0.8" on an average night.  With my 10" reflector, just over 1".  This is with a CEM-60. 



#13 scadvice

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Posted 20 April 2019 - 02:08 PM

Just checked the logs...My CEM60 with PHD2 is from .40 to .66 (.33px) average. Tough nights .85 to .95 (.40 px). Average run time around 3hrs +/-.


Edited by scadvice, 20 April 2019 - 02:12 PM.


#14 Bill001

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Posted 20 April 2019 - 02:18 PM

Just checked the logs...My CEM60 with PHD2 is from .40 to .66 (.33px) average. Tough nights .85 to .95 (.40 px). Average run time around 3hrs +/-.

What would be the image scale (seconds/px) of your guide scope assembly?  .33px is how many seconds on your rig?

Thnaks,

Bill



#15 overnight

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Posted 20 April 2019 - 02:22 PM

Yet another CEM60 user:

 

.5" - .7" arcsec with anything from a 80mm refractor to 8" newt, with a ZWO OAG and ASI-290MM.


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#16 scadvice

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Posted 20 April 2019 - 03:14 PM

What would be the image scale (seconds/px) of your guide scope assembly?  .33px is how many seconds on your rig?

Thnaks,

Bill

Are you referring to camera exposure time?  3 seconds. Camera - Specific properties 3.75 px sz. Search region 15 px.

 

Guiding with a WO Zenith star 66mm f5.9. Guide camera ALTAIRGP130M


Edited by scadvice, 20 April 2019 - 03:22 PM.


#17 Bill001

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Posted 20 April 2019 - 03:19 PM

Are you referring to camera exposure time?  3 seconds. Camera - Specitic properties 3.75 px sz. Searce region 15 px.

No, I’m referring to guide scope systems image ‘scale’. (Guider camera pix size/guide scope focal length)*206. Get seconds/px for image scale.



#18 scadvice

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Posted 20 April 2019 - 03:49 PM

No, I’m referring to guide scope systems image ‘scale’. (Guider camera pix size/guide scope focal length)*206. Get seconds/px for image scale.

I added detail to post 16...



#19 View2

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Posted 20 April 2019 - 03:57 PM

Same, around 0.6" to 1".  ES127 on an iEQ45p. 60mm ZWO GS and ASI120mm. PHD2


Edited by View2, 20 April 2019 - 03:58 PM.


#20 View2

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Posted 20 April 2019 - 04:00 PM

Yet another CEM60 user:

 

.5" - .7" arcsec with anything from a 80mm refractor to 8" newt, with a ZWO OAG and ASI-290MM.

80mm refractor on a CEM60, that ought to be stable!



#21 betelgeuse91

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Posted 20 April 2019 - 04:00 PM

80mm refractor on AVX with 50mm guidescope I get 1.3"~1.5" rms. 


Edited by betelgeuse91, 20 April 2019 - 04:01 PM.


#22 Bill001

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Posted 20 April 2019 - 04:13 PM

So it tends to look like around 1”, hopefully/sadly +/- .5”

good number.

B



#23 overnight

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Posted 20 April 2019 - 08:31 PM

80mm refractor on a CEM60, that ought to be stable!

There's no such thing as overmounting wink.gif



#24 Bill001

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Posted 20 April 2019 - 08:38 PM

There's no such thing as overmounting wink.gif

I’ve started keeping my cem25 scope tripod low ( which does hurt ) and I’ve added 25 lbs to hang on the tripod. It is much more stable, but not as cool as overmounting



#25 scadvice

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Posted 20 April 2019 - 11:10 PM

No, I’m referring to guide scope systems image ‘scale’. (Guider camera pix size/guide scope focal length)*206. Get seconds/px for image scale.

Sorry to many outside things going on. I misread the question. idea.gif  

 

0.85 asec/pix




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