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Old 24-04-2019, 08:46 PM
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Nikolas (Nik)
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Can someone please explain what this graph means in phd2

I tried a little guiding and got the graph up on phd 2
No idea what it all means and how good or bad the tracking/guiding is. I read the manual but it meant nothing to me as I don't understand Nerd talk. Can someone simplify it for me?
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Old 24-04-2019, 09:13 PM
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multiweb (Marc)
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Do you have details about your guider chip pixel size and the focal length of your guiding scope. At first glance that guiding graph looks "alright" but it could be a little tighter if the display is in pixels.
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Old 24-04-2019, 09:28 PM
glend (Glen)
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Also the scale compresses the variations, your lines are at steps of +-2, try changing it to 1.

Your RMS numbers look ok anyway. Important thing is, are your stars round?
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Old 24-04-2019, 09:30 PM
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Nikolas (Nik)
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it's the zwo 224mc using the zwo guide scope
I think the display was in pixel settings


Guide scope is 280mm focal length
You'll need to explain in laymans terms as I really don't understand any technojargon
Cheers


Pixel Size3.75µmSensor Size


4.8mm*3.6mm
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Old 24-04-2019, 09:31 PM
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Nikolas (Nik)
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Quote:
Originally Posted by glend View Post
Also the scale compresses the variations, your lines are at steps of +-2, try changing it to 1.

Your RMS numbers look ok anyway. Important thing is, are your stars round?

They were round

What are good rms numbers?
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Old 24-04-2019, 09:40 PM
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multiweb (Marc)
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Looks similar to me guiding through an ED80 with a QHY5 so if your stars are round it's good enough.
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Old 24-04-2019, 09:44 PM
Imme (Jon)
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So your stars are round? Perfect, the graph is fine.
Don’t get too wrapped up in trying to dissect the graph or you will go nuts.....as long as it be stars are good then you’re going well.
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Old 24-04-2019, 09:49 PM
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Nikolas (Nik)
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Thanks guys
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Old 25-04-2019, 12:07 AM
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set the graph to show things in arc seconds. pixel graph is relative to your pixel scale.
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Old 25-04-2019, 07:58 AM
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The_bluester (Paul)
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When setting up for arc seconds, have you put your guidescope focal length in to the guider settings window? If you created the guiding profile using the new profile wizard it would have asked for it and the focal length you need there is the guider scope length, unless you are using an off axis guider, in which case it is the focal length of the main scope.

Pretty much what others have said, it almost does not matter what the graph looks like if your stars are round and tight. If they are round but bloated for instance then you are probably using a short guide exposure and the system is trying to guide out the seeing (Which is not possible)

More or less the graph is just a pointer for if it is all going OK and a place to start looking if you are having problems. I wish mine looked that smooth but I am guiding at 2200mm which is a lot more demanding.
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Old 27-04-2019, 09:16 PM
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Quote:
Originally Posted by Nikolas View Post
I tried a little guiding and got the graph up on phd 2
No idea what it all means and how good or bad the tracking/guiding is. I read the manual but it meant nothing to me as I don't understand Nerd talk. Can someone simplify it for me?
I did a snapshot of my guiding graph tonight. The guider is an old SX lodestar. 752x580 with a pixel size of 8.2um. The focal length I'm guiding at is 2630mm so the image scale on the guider is ~0.65 arcsec. Tonight is better than yesterday. This graph is also typical of what I get when I guide through my C11 at 2800mm. It could be tighter but the stars are still round(ish). when I guide through the old Q at 530mm the graph is almost flat but that's because the image scale goes to over 3 asp so one graph row with the FSQ is ~6 rows with the CN-212 or C11. The zoomed stars are the ones in the white box insert.
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  #12  
Old 27-04-2019, 09:34 PM
Startrek (Martin)
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Nik
These are my best guiding figures in PHD2
Imaging the Centaurus A galaxy with 4 minute subs
This is about the best guiding I can do with a big scope 8” f5 newt
Seeing conditions mostly determine how well you guide
Make sure you set your graph to read out arc seconds ( “ ) instead of pixels

A general gauge in guiding below -
Bad guiding + 2 arc sec
Average guiding 1.5 to 1.8 arc sec
Good guiding 1.0 to 1.5 arc sec
Excellent guiding 0.50 to 1.0 arc sec

Cheers
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  #13  
Old 28-04-2019, 08:00 AM
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Nikolas (Nik)
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Thanks for the images, it's a great Centaur by the way.
Next clear night I'll have another look.
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Old 28-04-2019, 08:51 AM
Startrek (Martin)
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Thanks Nik
Some good advice is to read the manual that comes with PHD2 it gives you tips on improving your guiding
I read it from time to time to cross check all my settings
Plus there’s heaps of YouTube clips to view
A good one is the Astro imaging channel where they had a guest speaker Andy Galasso from PHD2
Try and set up an auto calibration ( dark pixel map and darks ) when you get more confident it saves time, I can usually start guiding in 5 seconds
Best of luck with your guiding you will love it and so will your images
Cheers
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Old 28-04-2019, 09:54 AM
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Merlin66 (Ken)
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Marc,
I see you're still using PHD1....
Any reason why you don't go for PHD2???
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Old 28-04-2019, 11:33 AM
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Quote:
Originally Posted by Merlin66 View Post
Marc,
I see you're still using PHD1....
Any reason why you don't go for PHD2???
It works for me. I know what you're saying, PHD2 is probably loaded with loads of other cool features but I'm pretty minimalist when it comes to guiding and data capture.
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