Guiding Improved MASSIVELY With One Simple Step

[wesdon1]

Hi all. Look, I am guessing most folk already know this, but just incase any newbies see this...

My guiding with PHD2 has always been around 1-2 arc seconds per pixel. Anyway, the other night, I let PHD2 do it's calibrating/setting up on my intended target for the night, rather doing what I always did which was finishing the star alignment then setting up PHD2 on the area of the night sky my 3rd and final alignment star happened to be. Well after setting up/running PHD2 on the area of sky I was imaging, my guiding improved massively. I've now gone from 1-2 arc seconds, to 0.12-0.22 arc seconds, the average being around 0.15! I was amazed at the improvement, and cursed myself for not discovering this trick sooner!

So anyone who doesn't know, now you do! Just remember to polar align as perfectly as possible, and balance your rig in RA and DEC, otherwise your guiding will be poor. 

Clear Skies!

Wes.

[Clarkey]

23 minutes ago, wesdon1 said:

Well after setting up/running PHD2 on the area of sky I was imaging, my guiding improved massively. I've now gone from 1-2 arc seconds, to 0.12-0.22 arc seconds, the average being around 0.15! I was amazed at the improvement, and cursed myself for not discovering this trick sooner!

I wish it was always that simple! It is generally better to calibrate near to your intended target, but the improvement is rarely this good. Also, ideally you want to be somewhere near the zenith to calibrate to give maximum effect. My rig is permanently set up and very well aligned (also new bearings, grease, etc), but it rarely that good. Typically 0.5". Hopefully for you it was not a fluke and you have the best tuned HEQ5 in the UK!

[wesdon1]

7 minutes ago, Clarkey said:

I wish it was always that simple! It is generally better to calibrate near to your intended target, but the improvement is rarely this good. Also, ideally you want to be somewhere near the zenith to calibrate to give maximum effect. My rig is permanently set up and very well aligned (also new bearings, grease, etc), but it rarely that good. Typically 0.5". Hopefully for you it was not a fluke and you have the best tuned HEQ5 in the UK!

@Clarkey LOL well to be frank mate, I actually thought it was a fluke too, then the second night outside, I had exactly the same amazing guiding! Interestingly, you say calibrate near the zenith, well my target for last night was close to zenith, NGC7000 North America Nebula! But my target the night before was only around 45 degrees alt., namely IC1848 Soul nebula, and the guiding was exactly the same, 0.15 average, never going higher than 0.22!?

What am I missing?? 

[alacant]

48 minutes ago, wesdon1 said:

from 1-2 arc seconds, to 0.12-0.22 arc seconds

Phew. Really? Are you sure you were guiding on a star? Remember to look at the images, not the numbers!
If you have the benefit of pulse guiding, best to calibrate south, near the intersection of the meridian and the equator, then slew to your target.

Cheers and HTH

[PhilB61]

Amazing guiding figures, the only time mine went that low was when I was accidently guiding on a hot pixel. Just as a sanity check you haven't accidently set guiding to report in pixels rather than arc sec?

[ONIKKINEN]

That does sound too good to be true, way too good in fact. Check the guide logs with PHD2 log viewer and see what it has to say? Its possible you were guiding on a hot pixel, or there was some other issue with your settings leading PHD2 to think it was better than it was.

[Clarkey]

13 minutes ago, wesdon1 said:

What am I missing??

Make sure your FL and pixel size are correct..... 

 

[wesdon1]

12 minutes ago, alacant said:

Phew. Really? Are you sure you were guiding on a star? Remember to look at the images, not the numbers!
If you have the benefit of pulse guiding, best to calibrate south, near the intersection of the meridian and the equator, then slew to your target.

Cheers and HTH

@alacant Yes honestly mate, It was no fluke, the guiding really was that good. Yes my subs were perfectly aligned, albeit only 3 minutes long. I'll make a short video next clear night and post a link on this thread because I really need you guys to see that I'm not fibbing! lol.

[TiffsAndAstro]

1 hour ago, wesdon1 said:

Hi all. Look, I am guessing most folk already know this, but just incase any newbies see this...

My guiding with PHD2 has always been around 1-2 arc seconds per pixel. Anyway, the other night, I let PHD2 do it's calibrating/setting up on my intended target for the night, rather doing what I always did which was finishing the star alignment then setting up PHD2 on the area of the night sky my 3rd and final alignment star happened to be. Well after setting up/running PHD2 on the area of sky I was imaging, my guiding improved massively. I've now gone from 1-2 arc seconds, to 0.12-0.22 arc seconds, the average being around 0.15! I was amazed at the improvement, and cursed myself for not discovering this trick sooner!

So anyone who doesn't know, now you do! Just remember to polar align as perfectly as possible, and balance your rig in RA and DEC, otherwise your guiding will be poor. 

Clear Skies!

Wes.

Gonna give this a go tonight but not convinced

[wesdon1]

14 minutes ago, PhilB61 said:

Amazing guiding figures, the only time mine went that low was when I was accidently guiding on a hot pixel. Just as a sanity check you haven't accidently set guiding to report in pixels rather than arc sec?

@PhilB61 Interesting? Tbh I'm not sure?? I'll have to fire up my Laptop and check that Phil! ( Oh I really hope it's really as good as I have believed it to be, my bubble will get burst open! lol )

[wesdon1]

1 minute ago, TiffsAndAstro said:

Gonna give this a go tonight but not convinced

@TiffsAndAstro LOL please let me know if you see any improvements! Most guys on here are thinking I'm mistaken and/or misreading my guiding! LOL

[wesdon1]

Oh my goodness I just realised I actually have a picture of the guide graph I took last night!!!! I forgot I took it to show my brother Rob how good my guiding had become!!

I'll post it in 2 mins, you'll see!!

[TiffsAndAstro]

4 minutes ago, wesdon1 said:

@TiffsAndAstro LOL please let me know if you see any improvements! Most guys on here are thinking I'm mistaken and/or misreading my guiding! LOL

My guiding could be better, no harm me trying

[wesdon1]

here's two pics I took last night. The guiding was around 0.17 to 0.18 in the moments I took the pics!

TOLD YOU I was being honest!! Haha!! 

[TiffsAndAstro]

What mount you using btw?

[Skipper Billy]

You are measuring RMS error in pixels - try changing it to the more usual Arc Seconds and see what happens!!

[TiffsAndAstro]

Just now, Skipper Billy said:

You are measuring RMS error in pixels - try changing it to the more usual Arc Seconds and see what happens!!

FFS how did I not notice this

ty

Edited September 19 by TiffsAndAstro

[wesdon1]

4 minutes ago, TiffsAndAstro said:

What mount you using btw?

Skywatcher HEQ5 Pro @TiffsAndAstro

[wesdon1]

3 minutes ago, TiffsAndAstro said:

FFS how did I not notice this

ty

@TiffsAndAstro Oh no I just noticed in my own pic!!?? It's in pixels not arc secs!! LOL

[wesdon1]

I'm so sorry for my mistake!! I'm really showing my amateurishness with this one!! 😫😂

[wesdon1]

Shall I delete the post??? 

[Vroobel]

No, keep it for others. Who didn't do that mistake in their history? 

Edited September 19 by Vroobel

[TiffsAndAstro]

16 minutes ago, wesdon1 said:

Shall I delete the post??? 

Like vroobel said, still useful info. I've done same mistake myself and was gutted when I found out my mount wasn't actually competing with observatories

[Vroobel]

One wise guy said "Graph is graph, show the stars." Recently my total RMS oscillates around 1", but the stars are still OK, round and sharp. So, don't think too much about the guiding, you may chase the seeing. 

 

Edited Sunday at 08:32 by Vroobel

[Clarkey]

13 hours ago, Vroobel said:

One wise guy said "Graph is graph, show the stars." Recently my total RMS oscillates around 1", but the stars are still OK, round and sharp. So, tont think too much about the guiding, you may chase the seeing. 

Very true. My guiding on my HEQ5 has been the worse it has ever been recently. However, my star HFR and 'roundness' was spot on.

You also need to consider that with short FL guidescopes, any little movement gives a large arc second movement. Due to the approximation of star centres in PHD2, it can exaggerate guiding error. For my guide scope 1/4 of a pixel is 1" - so tiny fluctuations look awful.