PHD2 Multi Star Guiding

[Startrek]

Just come across some info on the new PHD2 Multi Star guiding released in version 2.6.9 dev 2 and 3 back in December

Read through the details in PHD2 manual and looks very promising to say the least.
Its in development stage so I suppose their trying to iron out all the bugs from different manufacturers and models of guide scopes, guide camera models and capture software etc... So far it is very stable



A lot of folk on CN with various types of rigs have commented about improving their total guiding error by up to 20% which is amazing.
From my understanding there are no guarantees that your guiding will improve as there are numerous factors that determine your guiding error but it does offer another layer of certainty and reliability when locking onto a good guide star.


I'll probably wait until the development phase is completed and then give it a try in a few months

You have nothing to lose I suppose and may improve your guiding to a level you never thought possible.


Comments Welcome

[mswhin63]

I have been using it for a while now and it is a game changer. The only problem I have (not PHD2) is Ekos interface, sometimes it reverts to single star guiding.

There is a difference in the output, My latest ETA carina is the best I have ever seen from my camera. I am now doing a HEQ5 Supertune now, hopefully get even better.

[brisen]

I am using it with an EQ8 and whilst the guiding has traditionally been good with this mount, I have noticed a significant improved over what I normally get. From the few part nights that I have had in between clouds, the improvements would be around 20% overall, with the RMS down around the 0.25 - 0.3 arcseconds and remaining consistently low throughout the session until the clouds visit.

In the latest development release (dev 3) they have fixed the bug that was automatically turning off the multistar function in the UI so it now stays on. I just have to remember to tell PhD2 to autoselect the star as opposed to what I used to do and select the stat manually.

Brian

[peter_4059]

I've been using it since the development snapshot was released. Seems to work without any issues. It should help with improving guiding when seeing is not great as it is averaging the centroid over multiple stars.

[Startrek]

Peter,
Did you notice your guiding error numbers improve compared to not using it ??
Thanks
Martin

[peter_4059]

I havent tried switching between during the same session and it is impossible to compare one night to the next. It certainly isnt any worse.

[Startrek]

Thanks All
Some positive feedback so far
The word “game changer” has been mentioned a few times on various other forums
Anybody else using PHD2 multi star guiding !!

[muletopia]

Folks,

The idea is surely appealing so I downloaded and installed the dev 3 version.
When the program tries to execute the message
'PHDGuiding2\VCRUNTME140.dll is not for Windows or contains an error.'
I tried downloading again but the message persists.


Has anyone else hit this hurdle?
On one good night PHD2 gave me an RMS error of .25 arc seconds
so an improvement of 20% to .2 would be interesting to see.


Chris

[kens]

That's a known issue with 32bit installations. Check this thread on the PHD2 support forum for how to work around it:
https://groups.google.com/g/open-phd-guiding/c/MIonWl6ignk

[peter_4059]

Looks like there is a new build that might fix that:
v2.6.9dev4 - 8 February 2021
Windows installer: fix 32-bit Windows incompatible version of vcruntime140.dll added in v2.6.9dev3
Multi-star: change display when primary star is lost
Multi-star: reduce aggressiveness of dropping lost secondary stars
Guide stats: fix incorrect max deflection calculation
ZWO cameras: update SDK to V1.16.3 (Windows, Mac, Linux)

[kens]

As I understand it from Andy's instructions, you still need to manually delete the faulty vcruntime140.dll installed by dev3 before installing dev4

[muletopia]

Thank you Peter and Ken for your advice.
Last night I downloaded and installed dev 4 on my 32 bit Windows desk top, no problems. I did not have to uninstall the old VCRUNNTIME140.dll. So I only saw the problem as I wanted to look at the program inside whilst it was raining.


Then dev4 installed dev4 on my observatory 64 bit laptop.It installed and ran without any problems.
Between clouds I ran only this new version of PHD2 and my mount software ,despite the very poor seeing, just to watch the guiding.


I did not see any improvement over single star guiding but it was a crook night.


Chris

[Startrek]

From these discussions I might wait until the development phase is completed and a stable regular version is available

[kens]

The dev releases are not beta - they are all thoroughly tested. They should really be called a dot release. The distinction from major releases is for people who don't want to update more than once or twice a year.
The problem discussed above was specific to people running 32bit Windows so if you run 64bit Windows you should find it works with no issues. The only bugs found in dev2 were that manually selecting a star caused the multi-star option to be reset and the guide star distance was incorrectly reported to some imaging apps. These were fixed in dev3 but the actual guiding with multi-star had no issues.

[Wilsil]

I am using the Dev3 version and don't see too much improvement, but that might be that i still not 100% sure how to set it up. Guiding is good, but not much better as I can tell.
I know others I know say it has improved heaps for them.

[mswhin63]

I am getting guiding figures of 0.89 arcsec on my really old HEQ5, was getting ~2 arcsec before. really happy with the results. I believe there maybe other improvements I have made but I did a test before then and saw an improvement of about 0.8 arcsec.

Quite happy with the results.

[Andy01]

If you're using Ekos, the internal guider supports multi star guiding and works brilliantly :)

Andy

[xa-coupe]

I finally ticked the box and gave it a go. Went from 6.-.7 error to .5-.6 (all over a number of hours) with the occasional foray into .4 .. so it is definitely an improvement.

[Startrek]

Some great feedback so far !!
Looks like most folk are getting some sort of improvement in their guiding which is very pleasing to see
I looked back in some archives on CN ( 2013 / 2014 )and the PHD2 developers Andy and Bruce had some users and testers suggesting multistar guiding at that time but it didn’t develop or eventuate into anything serious
Thanks All for responding
Martin

[Karlz]

I read about the multi star guiding and it's benifits, I downloaded the up to date software and changed all I had to make it work. Last night's guiding sat around the 0.22 arc sec mark if not better the worst was about 0.3, a big difference to 0.48-0.6 the night before. I would recommend to anyone to get the newer version.

Clear skies
Karl

[Startrek]

That’s great Karl
I would be handy to know your make / model mount and scope / payload too that accompany those great guiding numbers. That information put the whole thing into perspective
I’m sure that Multistar guiding will provide some benefit for us AP’ers with the lower end mounts ( me included ) not the premium high end mounts as they are already getting incredible guiding
Martin

[Karlz]

Martin I have an older EQ6 mountbelt driven, 8in F/4 scope, a little piggy back guide scope, dslr and cables. I use Sharpcap to do my polar aligning and had it excellent last night too. In saying that I've had it excellent before as well and was still producing those higher numbers. Whatever settings you have for PHD2 carry over to the new version, only thing you have to do in settings is hit use multi star guiding.

Hope that helps.
Karl

[Startrek]

I upgraded to PHD2 V 2.6.9 Dev 4 a few weeks ago and have guided in both Bortle 8 Sydney skies and Bortle 3 South Coast dark skies
So far my guiding has been unbelievable compared to the conventional single star guiding , at least a 20% improvement in both Ra and Dec numbers
Even in poor to average seeing conditions the improvement is still at around 20% improvement
IMHO a definite “game changer”
My EQ6-R with 8” f5 newt and all AP gear , dew control gear etc... ( 15kg on board) has never been as low as 0.65 total rms
Gives you a lot of confidence in your imaging sessions !!

[mswhin63]

I may give it a go, although pretty happy with PHD2 so far now getting a really stable 0.7 arcsec throughout a whole imaging session now after tuning the EQ5.