Is this PHD graph etc any good?

[beamer3.6m]

I dont really understand PHD graphs although my guiding is ggod for 10 min subs so I assume it is all working as it should.

Does this mean anything to anyone?

PHD2 Screen print.doc

[Uranium235]

Could you post a screenshot instead please? You will probably get more feedback if its easily viewable.

If your stars are round, then you can proabably assume its ok - but there is always room for improvement!

[Ant]

Looks pretty good to me, but as Rob says if the stars are round - it doesn't matter what the graph looks like.

 

screen grab attached...

 

ant

[kens]

The numbers look good but the proof is in the pictures.

BTW Posting the guide log is generally more useful than a screen shot as it contains a lot more information. For example, you're using the largest scale on the graph and it only shows 50 seconds of data and does not show the guide pulses.

[libraryman]

That's not a good set up for guiding, I would say that your stars will be oval because you Dec rms is quite a bit higher than your ra rms.

up the exposure to 2 secs if you can and perhaps lower the min motion, but......run the guiding assistant to check.

 

Ray

[Uranium235]

Looks alright to me, I'd be happy with that!

[johnrt]

The graph looks fine because the scale is huge, the bullseye tells a very different story, but even then it is not much help as we do not know what resolution your guiding camera and imaging camera are.

[beamer3.6m]

Ok thanks Guys

Will have a play

[beamer3.6m]

How do you get the guidelog?

What is a good RMS Error 'score' etc?

In simple terms please.

For clarity I am guiding with a QHY5 as a finderguider

[libraryman]

Your rms is independent of your guiding arc sec per pixel ratio if you are reporting in arc secs, so...depending  on your imaging scale..you should try to get half or less than half your imaging Arc sec per pixel scale. I.e. If your imaging scale is say..3 arc sec per pixel then a good rms might be 1.0  but really good guiding would be half an arc sec or just over I.e. 0.7 rms depending on seeing.

some imagers do get less than this but it needs a very good mount and set up, the longer your focal length the more difficult it is to achieve.

your Osc looks good at 0.35 but ideally you need to get your Dec guiding under control.

The guide logs are in the PhD folder usually in c drive documents

Ray

[beamer3.6m]

44 minutes ago, libraryman said:

Your rms is independent of your guiding arc sec per pixel ratio if you are reporting in arc secs, so...depending  on your imaging scale..you should try to get half or less than half your imaging Arc sec per pixel scale. I.e. If your imaging scale is say..3 arc sec per pixel then a good rms might be 1.0  but really good guiding would be half an arc sec or just over I.e. 0.7 rms depending on seeing.

some imagers do get less than this but it needs a very good mount and set up, the longer your focal length the more difficult it is to achieve.

your Osc looks good at 0.35 but ideally you need to get your Dec guiding under control.

The guide logs are in the PhD folder usually in c drive documents

Ray

Hmmm... too complicated to me.

Thanks for the help though. I think this level of detail is not for me. I'm going to stick to the maxim of 'if it ain't broke don't fix it'.

[michael8554]

Okay, but I would at least increase the exposure time as Ray suggests, so that you're not chasing "seeing".

Michael

[Andyb90]

I don't have an option to delete this post so removing the content, as I realise it is better etiquette to post as a separate topic.

Andy.

[cfpendock]

There has been some good advice here.  But you need to be able to see what is happening.  I suggest you start by reducing the y axis to a maximum of 4 secs instead of the 16 you are on.  From the graph you show, you might even be able to reduce this more.  Then you should increase your exposure time.  I use 5 seconds.  You should find many more stars appear, and as Michael above suggests, you won't be chasing the "seeing".  You x axis should then show a decent length of time - hopefully enough to detect any periodic error.  I use 400, and at 5 second exposures, this gives around half an hour of immediately visible guiding history which is much more useful for identifying problem subs due to wind, clouds, earthquakes etc.

Whatever, from the RMS figure, your guiding seems to be pretty good for an HEQ5. 

Chris

[Freddie]

Although it is often said to just look at your stars and if they are round all is good, I really don't think this is a good guide (sorry) to how good your guiding is. If you have random errors in DEC and RA then your stars will still be round bit not as tight as they could be. Don't therefore think just because you have round stars you have good guiding.