whats the best method to guide with, pulse or st4 ?

[red dwalf]

hi all,

i`ve been having alittle trouble with PHD 2 and guiding my mount, neq6, over the last few days, and i use the eqmod and pulse guiding, haven`t had alot of trouble with it before but was wondering if people prefer the st4 cable method, is it easier or better than pulse guiding ?

any thoughts please. 

[Thalestris24]

Hi

It shouldn't make any difference which you use. But if you've been successfully pulse guiding, I see no reason to change.

What problems have you been having?

Louise

[red dwalf]

i upfdated the firmware and drivers on my zwo asi 120mm camera and then tried guiding with it and on the phd graph showed the dec blue line going up and down like a heart monitor and the ra red line hard moving along the graph at all, the green box around the star started to move to the left along the green cross hair line almost straight away, not 100 percent if it was the camera updates or something else going on but strange that it happened after i had done the upgrades.

i also read that st4 guiding was recommened by the zwo website as it sends commands faster to the mount, but whats in a 100th of a second L.O.L. 

[russp]

Isn't it the theory that pulse guiding is more efficient because the correction is applied to the tracking and a single move command sent to the scope rather than a move and a correct command .. aiui this is even more pronounced if you use PEC (which just seems like a complete black art).

[Thalestris24]

i upfdated the firmware and drivers on my zwo asi 120mm camera and then tried guiding with it and on the phd graph showed the dec blue line going up and down like a heart monitor and the ra red line hard moving along the graph at all, the green box around the star started to move to the left along the green cross hair line almost straight away, not 100 percent if it was the camera updates or something else going on but strange that it happened after i had done the upgrades.

i also read that st4 guiding was recommened by the zwo website as it sends commands faster to the mount, but whats in a 100th of a second L.O.L. 

Hi

You updated firmware on the cameras? Are you using a PC (rather than a Mac)? I think you have to be careful that firmware updates correspond to the right computer type, so I would double check you updated correctly. As you say, it's suspicious that you've had problems since. Do you know if other asi users have had problems since firmware/driver updates?

Louise

[Merlin66]

I use the QHY5 II for guiding my NEQ6pro/EQmod/CdC under PHDV2.3 for spectroscopy...no issues, no drama.

[Gib007]

In theory there should indeed be no difference in performance, though I favour ASCOM PulseGuiding to do away with that ST-4 cable. One less cable and all that. Works really well. I set both the ASCOM PulseGuiding speeds to 0.30x on EQMod for my Avalon M-Uno, but a friend uses 0.10x for his Skywatcher NEQ6 Pro. 

[Thalestris24]

In theory there should indeed be no difference in performance, though I favour ASCOM PulseGuiding to do away with that ST-4 cable. One less cable and all that. Works really well. I set both the ASCOM PulseGuiding speeds to 0.30x on EQMod for my Avalon M-Uno, but a friend uses 0.10x for his Skywatcher NEQ6 Pro. 

Hiya

Just wondering what difference the pulse guiding speed settings make? I've no doubt your mount tracks exceedingly well compared to my heq5!

Louise

[red dwalf]

not heard anyone else have issues with updating, these cameras have always been funny when plugging them in to active usb cables or usb hubs but i`ve only noticed when i wanted to do high frame rate imaging of planets with it, it didn`t like my windows xp pc although it worked fine on my windows xp laptop, so i thought the firmware update might improve things in the usb department as it says on the website, with new drivers also, surely newer drivers had to be a good choice, or so i thought.

[red dwalf]

I use the QHY5 II for guiding my NEQ6pro/EQmod/CdC under PHDV2.3 for spectroscopy...no issues, no drama.

mag5 star on slit.PNG

do you pulse guide or st4 route ?

[Thalestris24]

not heard anyone else have issues with updating, these cameras have always been funny when plugging them in to active usb cables or usb hubs but i`ve only noticed when i wanted to do high frame rate imaging of planets with it, it didn`t like my windows xp pc although it worked fine on my windows xp laptop, so i thought the firmware update might improve things in the usb department as it says on the website, with new drivers also, surely newer drivers had to be a good choice, or so i thought.

Ok. I read somewhere about recent updates for ASI only being for usb 3.0 but I may be wrong. I believe most people who run eqmod pulse guide - saves having to use another cable. I take it you don't connect via the Synscan hand controller? Oh, just thought, I have heard of people having guiding problems and finding it was their RA connection on the mount that was the problem - connector or wire loose or something. Can you slew the mount normally in RA (and DEC) via eqmod? If so, that at least tells you the mount and connection is ok. In fact thinking about it a bit more, with pulse guiding you are just using the guide camera as a camera. PHD is just monitoring the movement of a guide star. Any commands to speed up or slow down the mount's motors go out via the serial cable. So your camera driver updates could be a red herring. If you can't slew via eqmod then maybe you just have a serial cable problem. I suspect in that case eqmod would come up with an on-screen error message though I'm not certain. Anyway, try the slewing check first.

Louise

[Gib007]

Hiya

Just wondering what difference the pulse guiding speed settings make? I've no doubt your mount tracks exceedingly well compared to my heq5!

Louise

Hi Louise,

Experimentation is key but I believe 0.10x, the default, is the way to go for most people with most mounts. I only tried higher speeds because Avalon recommended 0.20x to 0.50x. I basically guided on a decent guide star on a night with no wind and monitored the graph as I changed speeds from 0.20x all the way up to 0.50x. It seemed to me that for my mount, 0.30x was the best compromise as it provided the mount with the ability to quickly correct errors but not so much that it over-shoots and re-corrects the other way. Basically the RMS of the graph on PHD Guiding was the lowest number with 0.30x, for my mount. Keep in mind my mount has no wormgears and instead uses pulleys. As a result, it also has no backlash. The characteristics are therefore different to the EQ5 and EQ6 series of mounts by Skywatcher/Celestron. 

[Thalestris24]

Hi Louise,

Experimentation is key but I believe 0.10x, the default, is the way to go for most people with most mounts. I only tried higher speeds because Avalon recommended 0.20x to 0.50x. I basically guided on a decent guide star on a night with no wind and monitored the graph as I changed speeds from 0.20x all the way up to 0.50x. It seemed to me that for my mount, 0.30x was the best compromise as it provided the mount with the ability to quickly correct errors but not so much that it over-shoots and re-corrects the other way. Basically the RMS of the graph on PHD Guiding was the lowest number with 0.30x, for my mount. Keep in mind my mount has no wormgears and instead uses pulleys. As a result, it also has no backlash. The characteristics are therefore different to the EQ5 and EQ6 series of mounts by Skywatcher/Celestron. 

Hmm... Both RA and DEC rates are set to 0.5 on mine. I think I do get a lot of overshoot and re-correction so maybe I should try reducing a bit...

Thanks

Louise

[perfrej]

Isn't it the theory that pulse guiding is more efficient because the correction is applied to the tracking and a single move command sent to the scope rather than a move and a correct command .. aiui this is even more pronounced if you use PEC (which just seems like a complete black art).

Nope. ASCOM pulse guiding uses the specific pulse guide commands, not the move command. I would guess that pulse guiding is more consistent as it is applied with more precision than electronics or small relays can provide, but the difference should be marginal. Given the "quality" of RJ12 connectors, I would choose pulse guiding over ST-4 any day.

The internal implementation of pulse guiding in the driver and in the firmware may vary from one brand to another, as will the firmware implementation of the ST-4 input. So, we can't really tell which is best across the board, can we?

/per