Aggression settings in MaximDL for guiding

[Paul Haese]

I have finally given PHD the flick. Great program and I highly recommend it for the beginner, but I have moved onto using MaximDL for all my camera control.

Strangely everything worked right from the start. That is good so I am happy with that.

I do wonder though what aggression settings I ought to be using. I have the PME and it is guided by the SSAG through the QSI OAG. I changed it from the default to 5 on both axis. The guide graph looks pretty reasonable, but how can I tell what is good and what is not? It is a little different to what I am accustomed to using, so I would welcome any imput. It might also be a good discussion for the record too.

[Tandum]

Paul, I'm running aggression at 6 on both with 3 sec exposures binned x2 on the qhy5 and orion oag. That seems to give me a smooth graph, no sudden/violent corrections. I'm getting round stars with that, so if it ain't broke ... :)

[Paul Haese]

Yep interesting. I think I was using 2 second exposures, not binned but 5 on the aggression. That gives a pretty smooth looking graph, almost non existent with movement especially neat the zenith. Do you have an image of the graph? I should have done likewise myself really.

[Tandum]

No, haven't screen grabbed a graph at all, I tend to just look at the error numbers coming from the camera these days. I started binning as I was having trouble getting a clean star image from the camera through the oag. I do think binned x1 is the better option though.

[Paul Haese]

That is interesting Robin. I had some trouble with a star the other night, then I selected another and it calibrated straight away. It must have been slightly brighter.

I'll take read of the manual tonight and see what I can pick up from that.

[White Rabbit]

How are you guys finding maxim for guiding? I've been thinking of making the plunge myself but was wondering if it's worth the bother?

Thanks

[pvelez]

I had similar problems for a while.

My guide camera is the Orion SSAG. There is a setting box that comes up in Maxim - one reduces noise and the other smooths guiding. I keep the smooth guiding setting off till I have calibrated. This does mean that the SNR can be a bit lower so subs may need to be longer depending on your set-up. With both on, I found that the stars would move on screen but Maxim couldn't pick it up.

Aim for SNR of at least 30 - I shoot for 40+. It seems to work fine for me now (touch wood)

Pete

[richardo]

Hi Paul,
I've been using Maxim for a long time for both acquisition and guiding.
IMO it has a lot more control than most out there.
I pretty much leave the advance settings these days to default. Use fine aggression control in the main window.
While every mounts response will be different depending on the speed of relays/ guider interfaces and ports, I use around 6.6 in Ra and Dec using 3 sec exposures. Robins around the same mark, at least on a ball park setting.
I found binning the guide camera made guiding so much more efficient.
A thing to watch, as you've been doing is the corrections. Make sure it's not too aggressive and over shoot. So a big jump from - to + will indicate this unless it's a shocker of a night and you're on a faint guide star.
Keep watching the accumulative guide error with the graph... of course lower the better... but this will take a little time to fine tune your aggression settings that will work for you. Too harsh a setting, getting up over 7 will basically be chasing the seeing and really take away control from a well behaved mount
Also when just calibrating, (I select my own when guiding for imaging) let maxim find its own guide star (just select calibrate) I've found this works best. If you find calibration is not working, (ie guider moved <5 message) increase the calibration time up to 20. This has always worked for me.
If you have pulse guide with your PME, turn it off on your mount control while calibrating as this causes all sorts of weird stuff to happen.

Other than that, all trial and error as long as you have the basics down.

I've been doing exactly the same thing last night myself with my new SX OAG... certainly nice to see the stars in the same place without drift anymore :), and 8min subs, yea haaa.. this is the way to go for sure!
Now for a decent night..

Hope this will help a little and plus reinforce what you're already doing.:thumbsup:

Rich

[Paul Haese]

Thanks guys, these comments pretty much confirm what I thought. leave the defaults and use small aggression settings.


White Rabbit, so far I have found it works great, some slight calibration issue as I said, but overall it just works. Worth using I reckon, the whole program is great but for image capture I have not seen anything that tops it so far.

[RobF]

It sounds like you're hardly struggling Paul, but for such a great mount any tracking movement is much more likely to be seeing than mount. So in general, would suggest the following rules of thumb:

- go for longer exposure times (2-5 secs perhaps)
- work out how much guider movement will show on your main camera/OTA and consider adjusting min movement accordingly
- agressiveness of 5 is 50% so tweak up or down depending on seeing


For my trusty HEQ5 which obviously doesn't have anything like your PME for engineering I'm much more inclined to increase the min movement settings and decrease the max move, keep the agreesiveness down (4-5 usually) and find a short FL guidescope to be a big help with seeing (200mm) which is probably along the same lines as Robin describes with binning.

There is a multi-star guiding plug-in for Maxim that theoretically should be the bee-knees, but I haven't been smart to get it going must confess :rolleyes:

I've spent many a moonlit night tweaking individual settings back and forth to get a feel for what they do, and think it's all been time well spent getting every last bit of performance out of my rig. Seemed to be much harder to get right under the bonnet like that in PhD, but only my 2 cents.

[Paul Haese]

Thanks Rob, I heard from a mate tonight that setting around 2 and 3 worked really well with his PME. So maybe 50% is way too high.

Must take a look at the multi star plug in, that sounds interesting.

[richardo]

Just an update Paul on my settings in Maxim with an OAG.
With a ST80 F5 guide scope I used 3 sec exposures. This made for nice round stars till flexure kicked in.
Now I find with the OAG, if I use the same 3 sec exposures with 6.5 aggression, my stars are elongated. I'm sure it has to do with the iffy conditions at the moment, the moon and also guiding at the main image systems FL now.
I've just found tonight that if I shorten my exposures to 1 sec., decrease my aggressiveness to some where in between 3-4 I'm getting nice round stars out to 7- 8min subs.

I thought I'd share this with you as it seems to be working this way for me.
Might give you a new set of figures to test out.

Rich