SX lodestar & Eqmod PulseGuide?

[RyanParle]

I have been an eq mod user for a while and have found using pulse guide to be the best method for guiding, in the past i have used either my Atik 16IC-S mono or a SC3 modified logitech webcam as the guide camera, the webcam can be a little flaky from time to time so I prefer to use the Atik.

The only problem with the Atik is that it is quite bulky, and now that i use an OAG i find that it limits the positioning of the camera.

A few imagers in my local astrosoc have recomended the Starlight Xpress Lodestar, they all use the on camera guider relays to issue guide commands, i've not heard of anyone using a lodestar & pulseguide.

I dont really see any reason why it wont work, but i would like to know for sure before i think of selling the Atik and getting a lodestar instead.

[MikeP]

If we ever get a clear night I'll let you know because I've had the same bulk / OAG issues with a DSI and decided to try a lodestar. In the past I've guided using ST-4 and a GPUSB but I thought it would be good to cut down on the cables.

I've had advice on settings from Daz who I believe uses a lodestar and pulse guides.

Mike

[BlueAstra]

I use a lodestar with an Orion OAG. However, I use it with PHD via the laptop, and the camera guide output plugs straight into the EQ6. I'm using EQMOD, and I've not really had a problem with PHD except very occasionally. Should I be looking at pulse guiding with EQMOD, is it better than PHD?

[Helen]

I've recently started guiding and have been using a SX guide head with a SXH9 and pulse guiding using Maxim and EQMod rather than using the ST4 connection. I've had no problems (except when I forget to connect Maxim to the scope - d'oh)

Helen

[MikeP]

Unless I misunderstand Blue, you'd still need to use PHD or some other guiding application.

I believe with your current configuration images go from the lodestar to the laptop (PHD) and the guiding adjustments from PHD go back to the lodestar and then on to the ST-4 port on the mount.

With EQASCOM (EQMOD) pulse guiding, the images would come from the lodestar to PHD but this time the guiding adjustments would be sent to EQASCOM and it would then send these on as pulse guide commands down the same cable that all its other mount commands are sent i.e. nothing is ever sent to the ST-4 port.

Alternatively, I might be talking rubbish, in which case I'm sue someone will correct me.

Mike

[BlueAstra]

No, I think its my lack of understanding of the guiding process.

The way I understand it is that the Lodestar sends images to the laptop via USB, PHD analyses them and sends control info back down the USB to the Lodestar. The Lodstar then passes the guiding info down the guide cable from the Lodestar to the mount guider input.

I'm not sure if this is 'pulse guiding' or not. If you use pulse guiding with Maxim does it just take the place of PHD and still send commands to the Lodestar and onto the mount? Or does it send the commands down EQMOD/EQDIR link direct to the mount and bypass the Lodestar guide output? The second option saves a guider cable from the Lodestar to the mount, but it wastes the capability of the Lodestar, and is it more accurate?

[SteveL]

PulseGuide is via ASCOM, and is sent via the serial connection to your mount. What you are descibing is ST4 guiding via the ST4 port on the mount.

If one system is working for you right now, there is no need to change. The die-hards will say that ST4 is vastly superior because there is less latency in that system, but I dont see that hapenning these days.

(Replace PHD with your guiding program of choice)

(ST4) Camera -> USB -> PHD -> USB -> Camera -> Mount

vs

(ASCOM) Camera -> USB -> PHD -> Serial/USB -> Mount

[chrisshillito]

PulseGuide is via ASCOM, and is sent via the serial connection to your mount. What you are descibing is ST4 guiding via the ST4 port on the mount.

If one system is working for you right now, there is no need to change. The die-hards will say that ST4 is vastly superior because there is less latency in that system, but I dont see that hapenning these days.

Yes, the term pulseguiding is missleading as both ST-4 and ASCOM methods results in pulses of tracking rate changes being implemented at the mount. Still its too late to change now so whenever you see the term pulseguide used - assume this is via ASCOM and not ST-4.

What the die-hards forget is that by far the most significant latency in an autoguided "closed loop" control system is the time taken in acquiring the guide exposure. Compared to this lag (which of course applies equally to both ST-4 and Pulseguide) any latency between a pulse being issued and being actioned (or inaccuracy of pulse duration) are quite insignificant.

Chris.

[BlueAstra]

OK, thanks for the replies. I think I now understand the guide setup better. One system is not inherently better than the other system so I think I will stay with my ST4 + Lodestar system since it works so well. Of course, I will have to try the other system, because its there!

[SteveP]

BlueAstra

I must be a die-hard! I do my guiding using the ST4 approach ie direct to the mount from my Lodestar. I've also used the so-called pulse guiding to guide my other EQ6. To be honest, I've not detected any difference in guiding performance between the two methods with the EQ6. I think it's a matter of preference and in my case, what I've got used to.

Of course with pulse guiding you can get rid of a cable! Perhaps more importantly, if using EQASCOM and you're also using some form of PEC then pulse guiding via EQASCOM is more stable and avoids conflict when PEC and EQASCOM are both sending pulses to the mount.

HTH

Steve

[daz]

Ryan

Yes, I use a lodestar and pulseguiding and have no issues at all.

Guiding is via Maxim (using Telescope control not Guide Relays).

Works a treat

[RyanParle]

Thanks Guys...

Daz you answered my question spot on!

I've always considered pulseguide to be a "neater" solution to guiding, firstly there is one less cable to worry about, also you have better control of the guiding pulses using software parameters.

I am also one of the seemingly few people who hate PHD... in my experience it is almost useless, sure it is simple to use in regards to calibration etc. but it is so effin unstable, i've tried it on 2 laptops and a desktop and all seem to crash for random unknown reasons, it seems daft to me to use somthing like PHD when i already use maxim for the image acquisition, one less application running is one less problem!