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Issues with guiding


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Thank you, it took me about 30 minutes of going 'Too far past it and back again' to achieve before I finally gave up on improving it

ASIAir may be different, but the PHD2 developers say not to waste imaging time getting tiny PAE figures, no worse than 5arcmins is good enough.

Guiding takes care of the rest.

Michael

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4 hours ago, Iem1 said:

I think I might have misunderstood the Timeout setting :D I thought that was time waited after dithering! Mine was set to 60s originally but moved it to 120s thinking it was increasing the time it allowed the guiding to settle back down!

Is it normal for the guiding to still be disturbed by the dither (or at least appear to be) well into the next exposure being taken? About halfway through the next 3 minutes image the numbers would begun to stabilise.

I still don't understand the timeout setting either and found nothing on the Internet about it yet so just left mine at default. 

Regarding the guide graph it's does show a slight lag but in your case once the guiding goes below 2" for 5 secs the next image will start so I wouldn't pay to much attention and it doesn't affect your images because you are below your stability settings. 

 Once all the dithering settling has cleared the graph it will show the settled figures. I know  you can go into the guide screen and press the clear button to the left of the graph and will start taking the current guide figures but like i say I don't think it affects it, it's just a bit of lag. 

In my baffoonary understanding the better your PA is, the less the Dec has to adjust itself. RA is the one that will need to move the most as it follows the target across the sky due to the way eq mounts work. (well I'm most likely wrong but in my head sounds feasible haha 🤪

Lee 

Edited by AstroNebulee
Grammar
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On 07/08/2022 at 14:28, Iem1 said:

The dove tail of my Z73 is short, too short to balance the DEC without having to shimmy the scope up to the end of the EQ6's clamp. So it is only being held by one of the grips instead of two. It's not massively unbalanced, but definitely not ideal. I chose safety of the rig over perfect balance atm. Need to get that sorted ASAP so both grips hold the bar AND i can balance it properly. Could also be not helping.

 

This statement has me worried.  If you only have the dovetail effectively held by a single clamp then there will always be flexure between the scope and the mount no matter how tight you have the clamp.  I have the same scope and before I bought a losmandy plate I had issues with the supplied vixen interfering with the focus lock screw. Easiest thing was to turn the scope upside down in the rings so I could slide the rings back a bit.  Can you post a photo of your setup please?

Graeme

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3 hours ago, newbie alert said:

Looking at your guidegraph I looking at your Ra peak to peak at at around 3 and the Dec never drops below the trend line.. I fail to see where the air gets those figures from

To be honest I don't know what I am looking at really when looking at the graph (that will come as no suprise I'm sure :D)

im trying to find somd online material to learn from.

3 hours ago, michael8554 said:

Thank you, it took me about 30 minutes of going 'Too far past it and back again' to achieve before I finally gave up on improving it

ASIAir may be different, but the PHD2 developers say not to waste imaging time getting tiny PAE figures, no worse than 5arcmins is good enough.

Guiding takes care of the rest.

Michael

Noted. I usually do my PA around 30-60 mins prior to imaging darkness, so never usually rushed doing it.

2 hours ago, AstroNebulee said:

I still don't understand the timeout setting either and found nothing on the Internet about it yet so just left mine at default. 

Regarding the guide graph it's does show a slight lag but in your case once the guiding goes below 2" for 5 secs the next image will start so I wouldn't pay to much attention and it doesn't affect your images because you are below your stability settings. 

 Once all the dithering settling has cleared the graph it will show the settled figures. I know  you can go into the guide screen and press the clear button to the left of the graph and will start taking the current guide figures but like i say I don't think it affects it, it's just a bit of lag. 

In my baffoonary understanding the better your PA is, the less the Dec has to adjust itself. RA is the one that will need to move the most as it follows the target across the sky due to the way eq mounts work. (well I'm most likely wrong but in my head sounds feasible haha 🤪

Lee 

Thank you for the input! I was absolutely amazed at how effortless that whole process was (once I remembered to actually turn it on!) To be honest, and was very pleased with the results, even as a first try! Those 3 minute subs are better than my 30 second unguided subs I think. Difference is huge!

I believe that is the case too, I read that a bad PA will have the image rotating around the guide star, sounds like basically the reverse of bad back spacing.

36 minutes ago, jacko61 said:

This statement has me worried.  If you only have the dovetail effectively held by a single clamp then there will always be flexure between the scope and the mount no matter how tight you have the clamp.  I have the same scope and before I bought a losmandy plate I had issues with the supplied vixen interfering with the focus lock screw. Easiest thing was to turn the scope upside down in the rings so I could slide the rings back a bit.  Can you post a photo of your setup please?

Graeme

Oh no, that's my poor communication sorry. I meant that if I wanted perfect DEC balance I would need to have the dovetail held by only one clamp, which I do not do for the reasons you stated and I am paranoid it would somehow fall.

As it stands, I have it properly clamped at the expense of perfect DEC balance, that imbalance isn't crazy, but not ideal. I will get a new bar ASAP to rectify it :)

 

Cheers Guys

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5 hours ago, Iem1 said:

To be honest I don't know what I am looking at really when looking at the graph (that will come as no suprise I'm sure :D)

im trying to find somd online material to learn from.

You will only find that out from the full package of PhD..... I've no faith in the air... But it's not my setup so nothing to do with me..so good luck hope it works for you

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5 hours ago, Iem1 said:

To be honest I don't know what I am looking at really when looking at the graph (that will come as no suprise I'm sure :D)

im trying to find somd online material to learn from.

Hopefully you'll find all you need here, I used to use it all the time to help and still do at odd times. Lots of useful explanation and tutorials. 

https://eastwindastro.blogspot.com/?m=1

Lee 

 

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On 08/08/2022 at 22:15, AstroNebulee said:

Hopefully you'll find all you need here, I used to use it all the time to help and still do at odd times. Lots of useful explanation and tutorials. 

https://eastwindastro.blogspot.com/?m=1

Lee 

 

Thanks for the link, that had a ton of useful info in it! Going to try implememt the method of working out ideal exposure times it discusses...only ever used 30 second exposures prior to this, so over exposing as never actually been an issue I don't think :D

Went out last night for another go, targeted the Elephant trunk nebula. The data is not very good, but I think that is due to conditions more than anything. Old DSLR running 3 minute exposures during warm and moonlit nights. Noisy and low dynamic range data, I live and learn.

But, here was the guiding graph at various points through the night after some adjustments;

Screenshot_20220810-030449_ASIAIR.thumb.jpg.1ae7e0463ae94fb6d1d46885b8e48a34.jpg

Screenshot_20220810-002406_ASIAIR.thumb.jpg.6f1b5285c9ffb808abdcfc4a28b4f072.jpg

Screenshot_20220809-233055_ASIAIR.thumb.jpg.10e66be7f23d3dc580ecc4b411d6dc3e.jpg

Screenshot_20220810-002323_ASIAIR.thumb.jpg.4100e38f939df0a856a53b9714b1ffde.jpg

Screenshot_20220810-002338_ASIAIR.thumb.jpg.a288321407aa5e4b02ad5bc7635ad8ad.jpg

 

I think I will bump dither to 30 pixels next time, apprently that is recommend for DSLR's. Also lowered aggr to 85% and upped calibration steps from 2000 to 8000 for my 120 mini guide scope.

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1 hour ago, Iem1 said:

Thanks for the link, that had a ton of useful info in it! Going to try implememt the method of working out ideal exposure times it discusses...only ever used 30 second exposures prior to this, so over exposing as never actually been an issue I don't think :D

Went out last night for another go, targeted the Elephant trunk nebula. The data is not very good, but I think that is due to conditions more than anything. Old DSLR running 3 minute exposures during warm and moonlit nights. Noisy and low dynamic range data, I live and learn.

But, here was the guiding graph at various points through the night after some adjustments;

Screenshot_20220810-030449_ASIAIR.thumb.jpg.1ae7e0463ae94fb6d1d46885b8e48a34.jpg

Screenshot_20220810-002406_ASIAIR.thumb.jpg.6f1b5285c9ffb808abdcfc4a28b4f072.jpg

Screenshot_20220809-233055_ASIAIR.thumb.jpg.10e66be7f23d3dc580ecc4b411d6dc3e.jpg

Screenshot_20220810-002323_ASIAIR.thumb.jpg.4100e38f939df0a856a53b9714b1ffde.jpg

Screenshot_20220810-002338_ASIAIR.thumb.jpg.a288321407aa5e4b02ad5bc7635ad8ad.jpg

 

I think I will bump dither to 30 pixels next time, apprently that is recommend for DSLR's. Also lowered aggr to 85% and upped calibration steps from 2000 to 8000 for my 120 mini guide scope.

Pleased you found some useful pieces of information and it's looking better already, with my Canon 600D I only dithered 10 pixels but give 30 a go and see how it goes. 

You could still lower your RA aggression a bit more to help smooth the graph line a it more, think of the aggression settings as a fine tune to your guiding rate. 

I'll look forward to your images, good luck. 

Lee

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You can see from the graphs that corrections aren't applied until the guide error reaches over 1 arcsec.

I assume that ASIAir doesn't have the Minimum Move setting that PHD2 has ?

That setting would allow corrections to start at a smaller error.

There are no overshoots, so it would be worth trying increasingly more RA Aggression, to bring those over-1-arcsec deviations back more quickly.

Overshoots would indicate too much, so try each increase for a few minutes, and see if the RA error figure is better or worse.

Michael

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22 hours ago, michael8554 said:

You can see from the graphs that corrections aren't applied until the guide error reaches over 1 arcsec.

I assume that ASIAir doesn't have the Minimum Move setting that PHD2 has ?

That setting would allow corrections to start at a smaller error.

There are no overshoots, so it would be worth trying increasingly more RA Aggression, to bring those over-1-arcsec deviations back more quickly.

Overshoots would indicate too much, so try each increase for a few minutes, and see if the RA error figure is better or worse.

Michael

Would the minimum move setting be these settings? Still learning about guiding.

Screenshot_20220812-094841_Gallery.thumb.jpg.cd779f094fba8392ff7fe4a694692041.jpg

 

Will test out increased RA Aggression and see how it fares, thank you for the response :)

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