AVX Sidereal rate question

[TheButcher]

Hey all,

It looks like I may finally get a chance to go out tomorrow night with my new eyes, the Doc gave me full clearance .

Now this is probably a stupid question, but what does the rate mean on the AVX Mount compared to other terms like 0.7x or 0.9x sidereal. When I go to my AVX with Nextstar+ it offers Sidereal rate in percentages in the Dec. and Ra. It is currently at 50% now for both (as I have not touched it yet).

I was reading Jay-Tee's tips on PHD2 for better guiding and he said th use a sidereal rate of 0.9x now how would I do that with my AVX mount, do I change bot RA and DEC to 90%? Or am I looking in the wrong place.

Thanks all.

[JayTee]

For visual use, that sidereal rate does not come into play. It is the rate that is commanded by PHD2 when it is making a guiding correction. Since you aren't guiding, that setting with those numbers won't be used. So don't worry about it.

Cheers,
JT

[yobbo89]

As Jay tee said. It's a pulse guide setting, ie if it's set at 0.5x it will pulse 2 x longer then it being at 1.0x,the variance is to adjust the mounts guiding to improve smoothness and aggressiveness for guide commands while tracking a star with phd or other software . It's only activated with pulse commands, need no apply for regular mount tracking.

[Micke187]

I have it set on 0.5x and I havnt had any issues with my guiding.

[TheButcher]

Thanks guys. I am guiding with an Orion 50mm Deluxe with Helical and a ZWO 290mm with PHD2 through Sequence Generator Pro. So basically the rate will just adjust the performance if I am having any issues, so a .9x would be to set it at 90% it would be tracking faster (More aggressive?) and PHD2 would be more involved in sending pulses therefore possibly making it more acurate? And 50% would equal .5x and that is the standard and should be fine on most occassion? I hope I got this right lol

Thanks all

[yobbo89]

it's like a gearbox,that only gets activated when phd ask for a pulse command to correct onto a star when the star moves,every telescope runs different , it's up to the user to find out what works best, you may find your recommended setting online for your mount from other users . typically 0.5x would be a starting point.

having a setting to high might give you quick jolty spikes ie strong but short guide pulses , and having a setting to low would give you light but long pulse guides,

Think of it as slew rate on your telescope and the time of the slew is the pulse length, most telescopes have 3-5 different slew speeds.

typical behaviour of phd guiding for example is something like ,star drifts out of guide box so mount sends a 200ms pulse east

let's say we did a test,that the star drifted the same amount on all the test,

the test would be what kind of commands would we see with the different guide speed settings.

let's say the 200ms pulse was with 1.0x guide speed

if we change the guide speed to 0.5x the pulse length would be 400 ms, thus it will be a more smoother correction , a softer but longer pulse,if you think of it in terms as a gear box you should understand.

[yobbo89]

copy pasted from the phd manual below.it doesn't say much , typically i start at 0.5x test it, then go to 0.6x test that then go to 0.4 x and test, it will get worse or better, pick the one that just works .


5. Mount connection pane: mount guide speed. This is another area that seems to cause confusion. The guidespeed isa parameter
set in the mount or in the mount driver, it's not something controlled by PHD2. PHD2 never sets the mount guidespeed, it only reads it.
It is usually expressed as a multiple of the sidereal rate and is typically in the range of 0.5x - 1x sidereal. Despite what you may read
elsewhere, it's generally best to use guidespeeds in this range rather than much lower speeds. Higher guidespeedscan help to clear
backlash more quickly and may help to overcome stiction problems. If you say 'yes' to the connection option prompt, PHD2 will attempt to
read the current guidespeed from the mount. If This fails for some reason, you'll need to enter the guidespeed manually. PHD2 uses this
value to automatically set the calibration step-size and to aid in checking calibration results; but the guidespeed information is not important
for the actual guiding. If you're using different guidespeeds on the RAand Decaxes,enter the larger value. If you really can't determine
what the guidespeed settings are on the mount, leave the setting at the default value of 0.5X.

edit: had to correct some copy paste errors.

[TheButcher]

Thanks Yobbo,

That explains alot about it