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how to success autoguide?


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hi..

I am try to autoguide for imaging. however, result looks bit smeared stars even 2 min exposure. guide software is PHD2 and polar align is well aligned. the graph is not so good. if you can advice to help enhance autoguide success rate, please let me know. any advice would be welcome.

Thanks

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If you are sure your PA is spot on, have you calibrated PHD when you have a guide star? You can force this by holding down SHIFT and pressing the button to start guiding. Once complete you can view the calibration data which will show a cross hairs with a blue and red trend line showing the corrections made. My understanding is that the closer these are to over-laying the cross-hairs at 90 degrees then the better the alignment/guiding. I can't remember which menu "VIEW CALIBRATION DATA" is, but you'll be able to find it by click on each quickly.

Also, have you entered your guide scope/camera details into PHD2? You can click on the "BRAIN" icon to add that information.

If that is all fine, I may be out of my depth! You could also try drift aligning via PHD, although I have not had to do that myself yet!

As you can tell, I am not an expert, and I am sure more experienced imagers will be along to help soon!

Info about your guide camera/scope and how connected to your mount may also help!

Good luck!

 

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There are a lot of possible reasons for this. You will need to trouble shoot it by eliminating one at a time.

I think the best place to start is to give a bit more description of your gear so we can be more helpful. Also like Marky1973 pointed out - make sure you have your setup properly configured (phd2 camera / guide scope params, and calibration). Make sure your mechanical setup is good - no loose bits, no cable snag, everything is smooth ....

One more thing is really important in pinpointing the cause - is the smear in RA, DEC or some arbitrary direction? You need to establish this.

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On 5/17/2017 at 17:12, Marky1973 said:

If you are sure your PA is spot on, have you calibrated PHD when you have a guide star? You can force this by holding down SHIFT and pressing the button to start guiding. Once complete you can view the calibration data which will show a cross hairs with a blue and red trend line showing the corrections made. My understanding is that the closer these are to over-laying the cross-hairs at 90 degrees then the better the alignment/guiding. I can't remember which menu "VIEW CALIBRATION DATA" is, but you'll be able to find it by click on each quickly.

Also, have you entered your guide scope/camera details into PHD2? You can click on the "BRAIN" icon to add that information.

If that is all fine, I may be out of my depth! You could also try drift aligning via PHD, although I have not had to do that myself yet!

As you can tell, I am not an expert, and I am sure more experienced imagers will be along to help soon!

Info about your guide camera/scope and how connected to your mount may also help!

Good luck!

 

hello.

Thanks for reply. i think i did not try input guide scope/camera details into PHD2. i am interesting drift align you mentioned. i will try this too later. thanks again for your suggestion!

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On 5/17/2017 at 17:50, vlaiv said:

There are a lot of possible reasons for this. You will need to trouble shoot it by eliminating one at a time.

I think the best place to start is to give a bit more description of your gear so we can be more helpful. Also like Marky1973 pointed out - make sure you have your setup properly configured (phd2 camera / guide scope params, and calibration). Make sure your mechanical setup is good - no loose bits, no cable snag, everything is smooth ....

One more thing is really important in pinpointing the cause - is the smear in RA, DEC or some arbitrary direction? You need to establish this.

Hi

Thanks for Suggestion..

i will try look into more carefully RA,DEC direction. another good point to check. Thanks!

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23 hours ago, alacant said:

Hi. You can help us to help by sending a link to the guide log. HTH.

Hi.

I will try capture this later. and issue continues, i'll post guide log. Thanks for suggestion.

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I had to resort to YouTube for help getting my PHD2 working.

It is NOT 'Push Here Dummy' easy.

After that, then fine tweaking will get things working beautiful.

PHD2 Basics 1

PHD2 Basics 2

How I did this was to run the YouTube on one screen, while doing settings in the program on my laptop. Then doing it over to my desktop.

Use the Guiding Assistant in PHD2 (Under 'Tools') while you are learning and setting things for your equipment.

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On 5/21/2017 at 03:35, SonnyE said:

I had to resort to YouTube for help getting my PHD2 working.

It is NOT 'Push Here Dummy' easy.

After that, then fine tweaking will get things working beautiful.

PHD2 Basics 1

PHD2 Basics 2

How I did this was to run the YouTube on one screen, while doing settings in the program on my laptop. Then doing it over to my desktop.

Use the Guiding Assistant in PHD2 (Under 'Tools') while you are learning and setting things for your equipment.

Thanks much for your good tutorial. i should learn about drift align more. thanks again!

here are my PHD statues which i capture screen. i realized that i should input guidescop's focal length.

gra.jpg

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Wow,  that guide graph photo shows RA and DEC rms not far from 0.5arcseconds!  

 

I wish i could could achieve that accuracy with my eq3!

 

i suppose it depends on the imaging scale/scope magnification.   With my setup, I end up with 6megapixel photos on a 750mm long telescope, which works out at about 2 arc seconds per pixel.  So, my guiding doesn't need any more accuracy than that.

 

Maybe you are imaging a much tinier patch of sky and therefore need more accurate guiding.

 

the PHD authors can offer specific help if you post on their google group   Also, the PHD support site has links to several troubleshooting  guides.   Well worth a visit!   

 

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On 5/25/2017 at 03:22, mikey2000 said:

Wow,  that guide graph photo shows RA and DEC rms not far from 0.5arcseconds!  

 

I wish i could could achieve that accuracy with my eq3!

 

i suppose it depends on the imaging scale/scope magnification.   With my setup, I end up with 6megapixel photos on a 750mm long telescope, which works out at about 2 arc seconds per pixel.  So, my guiding doesn't need any more accuracy than that.

 

Maybe you are imaging a much tinier patch of sky and therefore need more accurate guiding.

 

the PHD authors can offer specific help if you post on their google group   Also, the PHD support site has links to several troubleshooting  guides.   Well worth a visit!   

 

Hi. thanks for information. i will try

I wonder did your guide make smeared star shape? even my rms is around 0.2 arcsecond my result always smeared.

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11 minutes ago, jkm13 said:

Hi. thanks for information. i will try

I wonder did your guide make smeared star shape? even my rms is around 0.2 arcsecond my result always smeared.

If what you mean is the displayed star in the Star Profile target window, it is usually fuzzy. The important thing is it shows your guiding is holding that one guide star. It is also magnified in that view, so that tends to make it fuzzy. And you don't want perfectly focused stars for guiding anyway.

All in all, I'd say you are doing great. Don't be afraid to try refining your RA and DEC setting, and also try adjustments to your hysteresis. Do one thing, and observe your guiding results. Tiny steps, because you will be refining your guiding to your mount and your telescope. Maybe keep a scratch pad with your changes.

Pretty soon, things settle in and you have the best results guiding for your mount and telescope. I haven't changed my RA or DEC or Hysteresis setting is a very, very long time. Months or maybe years now.

When everything comes together for you and your equipment, you can get down to the .25 pixel guiding Craig Stark designed into PHD2. I do. It takes patience and some dedication observing the guiding and your imaging results. Because the end game is those imaging results.

You're doing fine.

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Guest Tuomo

Are you sure you have problems with the guiding? It might be the polar aligment. How about flat field? What kind of scope/flattener you have? If you dont have flattener, your edge of field will always have egg-shaped stars even you had the best guiding

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After doing your calibration steps in PHD2, run the Guiding Assistant.

This runs for a couple of minutes and suggests possible values to minmo for both RA and DEC.

However, the display also give an indication of polar alignment error; that my help you decide if yo need to redo PA.

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On 5/27/2017 at 14:53, Tuomo said:

Are you sure you have problems with the guiding? It might be the polar aligment. How about flat field? What kind of scope/flattener you have? If you dont have flattener, your edge of field will always have egg-shaped stars even you had the best guiding

Hi..

Yes i did polar align good with polemaster. i will check for flattner. thanks

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18 hours ago, iapa said:

After doing your calibration steps in PHD2, run the Guiding Assistant.

This runs for a couple of minutes and suggests possible values to minmo for both RA and DEC.

However, the display also give an indication of polar alignment error; that my help you decide if yo need to redo PA.

Hi..

I never did Guiding Assistant before. i will try next shoot. thanks for suggest.

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On 5/27/2017 at 14:11, SonnyE said:

If what you mean is the displayed star in the Star Profile target window, it is usually fuzzy. The important thing is it shows your guiding is holding that one guide star. It is also magnified in that view, so that tends to make it fuzzy. And you don't want perfectly focused stars for guiding anyway.

All in all, I'd say you are doing great. Don't be afraid to try refining your RA and DEC setting, and also try adjustments to your hysteresis. Do one thing, and observe your guiding results. Tiny steps, because you will be refining your guiding to your mount and your telescope. Maybe keep a scratch pad with your changes.

Pretty soon, things settle in and you have the best results guiding for your mount and telescope. I haven't changed my RA or DEC or Hysteresis setting is a very, very long time. Months or maybe years now.

When everything comes together for you and your equipment, you can get down to the .25 pixel guiding Craig Stark designed into PHD2. I do. It takes patience and some dedication observing the guiding and your imaging results. Because the end game is those imaging results.

You're doing fine.

Thanks for suggest. i think i should study PHD far more. thanks again!

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Are you using a guide scope?? if you are and your main scope is mirror based, like a SCT or a Newt, make sure that it is not caused by mirror flop.

 

Edited by MarsG76
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11 hours ago, jkm13 said:

Thanks for suggest. i think i should study PHD far more. thanks again!

PHD Basics 1, PHD Basis 2. Loved these video's, got me going.

Cutting to the quick, here I will take to the part extraordinaire... By all means enjoy the entire thing, but sometimes it's just nice to stick a fork in the roast beast. :icon_biggrin:

I found great guiding consisted of a lot of patience and observation, small changes, and not moving my mount. Not moving my mount has resulted in speeding up the entire process because the mechanical part is the same as the night before. (Very close anyway...) So I can get away with covering my mount and merely carrying my telescope in the house.

It took a while to get the setting to where I like them now. But once there, things seem to run very, very well. Best of luck to you as you venture forth. :icon_biggrin:

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On 5/31/2017 at 19:52, MarsG76 said:

Are you using a guide scope?? if you are and your main scope is mirror based, like a SCT or a Newt, make sure that it is not caused by mirror flop.

 

Hi

Yes i use 9X50 finder as guide scope and main reflector is SCT. i'll checkmirror flop too. i didn't concern too much because mirror lock.

Thank

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On 6/1/2017 at 01:48, SonnyE said:

PHD Basics 1, PHD Basis 2. Loved these video's, got me going.

Cutting to the quick, here I will take to the part extraordinaire... By all means enjoy the entire thing, but sometimes it's just nice to stick a fork in the roast beast. :icon_biggrin:

I found great guiding consisted of a lot of patience and observation, small changes, and not moving my mount. Not moving my mount has resulted in speeding up the entire process because the mechanical part is the same as the night before. (Very close anyway...) So I can get away with covering my mount and merely carrying my telescope in the house.

It took a while to get the setting to where I like them now. But once there, things seem to run very, very well. Best of luck to you as you venture forth. :icon_biggrin:

These days i feel your point. and it's really big bless who has good observing place. i always move to go dark place with car. you are lucky :)

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On 6/1/2017 at 23:56, jkm13 said:

These days i feel your point. and it's really big bless who has good observing place. i always move to go dark place with car. you are lucky :)

That I am. But lucky or not, it takes gobs of experience with your own equipment. The more time spent, the more you will learn, and the more confidence you can gain.

It is a rare night I can just plunk down and go to imaging at a strange spot. It happens, but it usually takes more. For Light Pollution, there's filters to help. Perhaps a LPF could make your location more friendly for you?

I think I learn something new every time I start out. But consistency with your routine will help hone your abilities. Even if it's a short session, there are things to learn. (Concerning you and your mount and your confidence, the skies come in time.) :wink:

I know you can. You need to realize you can, too.

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On 2017-5-31 at 11:52, MarsG76 said:

Are you using a guide scope?? if you are and your main scope is mirror based, like a SCT or a Newt, make sure that it is not caused by mirror flop.

 

I've never got that...its not guiding thou the scope so mirror flop isn't an issue surely?

Guiding at 2000mm + would cause it's own issues surely..

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Actually if it's not guiding through the scope but through the 9x50 finder than the flop will most likely cause "drift" like trails since the mirror is moving while the guider is carrying on guiding on the original path.

If you were guiding through the scope, through a OAG for example, than any mirror flop would be corrected for by the guider. 

The best way I found to check if its mirror flop that is causing your problem is to let the scope and camera image for a extended period of time like 2 hours or longer, or stack the subs gathered in that time without alignment and see if the trial are straight lines or arcs/curves. Curves indicate that it is mirror flop.

 

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