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Starting doing guiding to assist with Astro-Photography rather than my usual "up to 30 second exposure".

When I got the guiding going correctly you can see from the image that PHD2 was constantly correcting large errors.

Could this be from wind? Although I i was sheltered, it still felt a little breezey at times so I'm wondering if that was possibly it.

Thanks all

 

My setup is

Skywatcher 200p

Skywatcher HEQ-5 Pro SynScan

QHY5L-II Mono ST-4 on 9x50 Finderscope

PHD2 in On-Camera configuration

(I know that EQMOD is the more common way but I'm not quite there too ditch the SynScan yet and at some point I'll have to purchase a guide scope rather than using the Finderscope but I'm at the limit of the HEQ5 mount with the 2 counter weights)

PHD2 Output.jpg

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I'm by far no expert and have just started out using PHD2, but try looking at you RA Agr and DEC Agr. Try lowering the number down and up Hys to slow things down and smooth things out.

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It looks like combination of seeing and wind and maybe even noise from camera. You should be able to get x2 improvement in total RMS by simply using 3s exposure, and selecting star that has 50 or so SNR (bottom right corner shows 23.2).

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I'm no expert either, I have seen at lot worse :) I woulds agree RA a little to high, and hys to low For my set up Hys is around 20-25. I use 2-4sec exp. But use PHD2 guiding assisstant as everyone's local environment is different, also to look  at min-mo readings aswell. 

I would be happy with your RA Osc being at 0.41

Dean

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I have a similar set up, finderscope/QHY5 and had this problem a couple of weeks ago. The answer; I re-balanced my set up with everything attached and it was instantly fixed!! I use PHD 1.2 as I find it better than 2.0 and keep it separate from APT.

Hope this is helpful?

 

Ron 

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You can also let PHD select the best guide star for you...assuming you didn't already do that..

There are some great basic pointers in the best practices guide along with plenty of other tasty snipits on the PHD2 site....You've probably already seen these, but it really is a great place to start when tuning PHD

https://openphdguiding.org/

Steve

 

Edited by SteveA

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I'd have the exposure time at around 3-4 seconds ,check your balance,run the guiding assistant and apply the settings maybe get the PA errors down abit..

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Try PHD 1.2 instead of 2.0, most folk I know still find 1.2 better!!?

Ron

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1 hour ago, peter w-j said:

Starting doing guiding to assist with Astro-Photography rather than my usual "up to 30 second exposure".

When I got the guiding going correctly you can see from the image that PHD2 was constantly correcting large errors.

Could this be from wind? Although I i was sheltered, it still felt a little breezey at times so I'm wondering if that was possibly it.

Thanks all

 

My setup is

Skywatcher 200p

Skywatcher HEQ-5 Pro SynScan

QHY5L-II Mono ST-4 on 9x50 Finderscope

PHD2 in On-Camera configuration

(I know that EQMOD is the more common way but I'm not quite there too ditch the SynScan yet and at some point I'll have to purchase a guide scope rather than using the Finderscope but I'm at the limit of the HEQ5 mount with the 2 counter weights)

PHD2 Output.jpg

You don’t include the counterweights when working out your payload, if you mount holds say, 15kg, then you could in theory put a 15kg scope on the mount and 15kg of weights....as they balance each other out, although I would not push it right to the limit... just thought I would mention that, as you could get a small guidescope on your setup quite easily.. :)

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With the hardware...

How good is you polar alignment... if it's too far off, it can cause this kind of guide graph... also how good is your backlash compensation setup? does the star move immediately and smoothly in both RA and DEC as soon as you press the direction buttons, all back and forward, forward and back again etc...... or is there a jump or some lag as the gears re latch, that could also cause the kind of graph.

Another feature that you might have is "Max Autoguide rate"... if its set to 100% than it can cause over shooting... lower it, I tend to have my max autoguide rates at 30-50%

Another thing to check is any potential motor clogging... if you have clogging, than the way around it is to move the star a half doze star widths away from the spot to get out of the clogged position.

 

In PHD2 Settings....

Looks too me like the Aggressiveness in RA and DEC are perhaps too high, try dropping them to 50.

The max correction time, if its correcting a short FL for 1600ms than it'll move the star a lot, so try limiting the pulse time to 250-500ms... technically even if the max time is set high, if everything is working than the pulses wouldn't be that long, but in this case try limiting them.

The other problem might be the minimum star movement, it's set to 0.21, try increasing the min mo to 0.5, 0.75 or even 1.

0.2 is good for a long FL, like 2000mm, but for shorter FL it might react too quickly (perhaps to seeing) and too strongly, over shooting the mark and having to correct again.

Try lowering the gain and/or gamma in your guide star (or use a dimmer star) and increase the guide star exposure to 2 seconds, this will lower the possibility of chasing the seeing... Sometimes I use 4,5 and 8 second guide star, if your PA is good, than there should be virtually no drift in that time.

 

Hope this helps..

MG

 

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