autoguiding EQ6-help!

[seeker372011]

I am used to 20 minute subs with my CG5 and was looking to be able to do the same or better with my brand new EQ6 ,...yet after trying for the last 6 hours autoguiding has failed completely

I was trying to autoguide with PHD guiding, using the GPUSB interface;
PHD calibrates fine, starts guiding but issimply unable to hold the guide star at the cross hairs and result is long star trails, even with just 5 minute subs.

PHD log shows progressively greater error in RA, even though it does seem to pull it back eventually. Sub pixel corrections in Dec, looks fine generally

I have tried eveything I could think off..RA agressiveness-both increasing to 120% and reducing to 85%;

RA backlash various settings from 00 10 00 (default supposedly but it did not come that way from the factory) and higher and lower settings

I have also tried changing auto guide rate from 0.5 sidereal to 0.75 and even 1

nothing works

Its possibly autoguiding..just not accurately enough

my polar alignment was perfect and it was balanced so that the motors were pulling just slightly against the counterweight

I just cant think of what else to try

grateful for any suggestion. This is extremely frustrating. :(:(:(

Thanks
narayan

[seeker372011]

The attached is typical of what is happening..process out of control in RA..

any suggestions, anyone?

thanks

[DeanoNZL]

Narayan,
Have you tried to alter the "autoguide rate" that is set in the handset?
It maybe set to 0.5x. Try 1.0x to see if it makes any change.
Also, how many steps does PHD take to calibrate?

[seeker372011]

Adrian:

yes I did try-I tried 0.75 and also 1.0..no luck

It seems to take around 24 steps in the West direction when the RA backlash is set to 0 00 00, longer if I set the backlash to any positive number;about 18 to 20 in North
regards

Narayan

[DeanoNZL]

In the advanced setup (brain), what have you for calibration step?
With a smaller guide scope, I use 750-1000.
Also, you could try a barlow in the guide scope to increase magnification.
Let me know.

[seeker372011]

Adrian,

do you consider 24 steps to be too much? I used to get around the same with my CG% and that always guided perfectly.

Having siad that, the calibration step does not-as far as I understand -have much to do with guiding. Its purely to aid in calibration-I think the idea is to use (say) 1000ms if one is calibrating using a star near the pole and 500ms when far away from the pole

It seems to be calibrating Ok though, just for some reason not keeping up-actually in some way reinforcing the error in RA

I just hope I don't have a dodgy EQ6 which require surgery on its innards

I am going to try the court of last resort-uninstalling PHD guiding and reinstalling a fresh version..dont know why that should or would help but when you are ut of ideas and dealing with software...

[davewaldo]

This may be very a silly thing to suggest, but sometimes my HEQ5 will stop tracking in RA. I think it is a bug with 3.21 version of the software. Is it possible that your new mount is ceasing to track and the guiding is trying to do both but failing? When mine stops (very rarely) I need to go into setup -> Tracking -> then turn RA tracking back on.

Just thought I'd mention this in case it helps, but I'm sure you would have noticed.

Dave.

[seeker372011]

Well thanks for that suggestion, I will double check to make sure, its not a silly suggestion at all, esp if RA tracking has failed you for no reason at all.

[Terry B]

Have you tried any other programme for guideing like guidemaster?
Another option is to take the hand controller out of the equation and use EQMOD.

[seeker372011]

I thought of trying guidemaster but it doesnt seem to list my guide camera-an Orion Deep Space Imager- as a supported camera. Guidedog has not been migrated to Vista-(to add to my headaches I am now on Vista)

I will try EQMOD..but I suppose I need some special cable for that again from shoestring?

[mrsnipey]

Narayan, My eq6 stopped autoguiding the other day as well after months of it working perfectly.
It took me until tonight to realise that my settings in PHD Guiding had changed. For some reason my Dec Guiding was turned off.
I set the eq6 to Sidereal + Pec for tracking mode, set PHD Dec guiding to Auto and it worked beautifully tonight.
I definitely didn't change any of my settings in PHD Guiding as everything was working perfectly. Anyway, I thought it might help.
D

[seeker372011]

I have had my Dec tracking turn off in PHD in the past. This happens when in 60 attempts PHD is unable to get the guide star to move the required distance (number of pixels) for calibration. This can happen when your mount gets stuck in some wierd backlash loop.

PHD assumes you have no Dec motors and just tries to guide in RA.

This used to happen all the time with my CG5 so I have checked frequently that this was not happening with the EQ6. Usually this happens if the last movement of the hand controller in the Cg5 is not an up and right. Dont think this applies to an Eq6 though.

Its interesting you have set to PEC +sidereal because I have it set to Sidereal. I have NOt done PEC training though so it probably wont work for me will it?

[batema]

Hi narayan,
I have just bought an EQ6 mount and hope I do not have the same frustration as I am having with our schools HEQ5. We also use PHD and the same thing happens. If you go to Equipment Techniques and softwear a person called Matty P posted "Not happy with PHD guiding". It is currently on page 1 of this section. It may help however most of it is above my head. We usually get maybe 2 X 4 min subs before the dreaded DONG DONG sound and we are lost. I will try some suggestions above but the positive thing is that if we are both having this problem hopefully its not a defective mount. Good luck If you find the solution please post it. Thanks Mark B

[seeker372011]

I am not sure if I am quite ready to declare victory but I did get the mount to autoguide.
A guy over at CN suggested that I need to set the slew rate to 1 x. This makes absolutely no sense But since I was trying every suggestion , I tried this last night.
To my surprise the mount actually autoguided.

I am unable to repeat the experiment tonight as the weather conditions are ordinary, but it certainly worked yesterday

I still have big problems with the amplitude of the delta(variations from the mean) in RA ..but at least the process is being brought back under control

so its certainly worth a try if you are having the same problems as I am

also I did completely uninstall and reinstall PHD and GPUSB drivers butthe guiding didnt work till I followed this suggsetion

Yes it makes no sense.
But on a sample size of one-it worked!

here's the log from PHD..not inspiring in RA but as I said at least its guiding..Next challenge-try and reduce the amplitude of the RA error

[seeker372011]

oh and that was over two hours

[seeker372011]

PS as advised over at the yahoo EQ6 group I reduced the backlash settings to zero. This is how it came from the factory anyway even though the manual says the default is 10' 0"

[mrsnipey]

I only set it to PEC + siderial because I was trying everything to get it to start autoguiding again. This was the first combination that started working so I kept it.

To be honest, I don't even know what PEC + Sidereal means. I know what each of the individual terms means, but together... :shrug:

[seeker372011]

I have a bit of an update tonight..I autoguided for a while on a random target in Scorpius and think-have yet to check the log-that it was reasonabily ok..but PHD crashed-the first time this has ever happened to me. Restarted and ran for 30 to 40 minutes and it looked OK (will check the log tomorrow).

I then tried on a random target in the SMC-I wasnt imaging you understand , just testing autoguiding-and it failed again!


This is not making any sense :(
:shrug:

Narayan

[Phil]

I no with my G11 the balance has to be set right. It may sound stupid but play around with the weights. It may help a little.
Phil

[Astrod00d]

That's right, with my EQ6 the balance has to be slightly heavy to the east so that the RA mechanism has a small preload.

Cheers,

Rob

[seeker372011]

Yes, I made absolutely sure that the mount was east heavy. Phil I had the same thought as you did and did play around with the weights to make it even more east heavy , but no joy

(i also went the other way with the weights-making it slightly less east heavy)

[g__day]

Is it over shooting on RA - causing an oscillation?

I ponder are your min pixel movement before a guide command is issued to sensitive. It defaults to 0.20 of a pixel (and can see down to 0.01 Craig told me). However I generally set mine to 0.8 - 1.2 depending on seeing, focal length of guide scope and pixel size of guide camera. The key factor is are your arc/seconds per pixel on your guide scope too sensitive for your viewing conditions. If a pixel is only seeing 0.5 arc seconds and seeing isn't really better than 2-3 well you are going to be over correcting everywhere - and your chart looked like that to me.

I suggest:

Turn backlash to 0 on RA and DEC - definitely let PHD manage this.

Try and adjust pulse length so it takes 15 - 30 pulses to move the star sufficiently to calibrate.

I set RA aggressiveness to about 85% and Hysteresis to about 10%. Purists suggest more aggressiveness (95% - 100%) and less hysteresis (5% - 0%) when calibrating and about my levels when guiding.

Experiment with minimum pixel movement before guide pulse is issued from 0.2 up in 0.1 increments to see where your sweet spot is (seeing based). Definitely use the PHD chart function and look at the Osc(illation) index - you want that as small as can be.

[Babalyon 5]

To use EQMOD, update your hand controller on an older PC with a genuine Serial port(and XP not Vista, wouldnt use Vista at all[my opinion only-don't wanna start a war]) to version 3.23. once you have done then you can use PC Direct mode to control the mount through EQMOD. You also need the latest ASCOM platform. Follow these instructions to use EQMOD when your ready.

1. Open SN (Starry Night 6.23) Or your choice of program with scope control
2. Open Telescope control window of SN
3. Connect supplied cable to hand controller and PC. I have a
docking
station with serial I/O port. (If you have one connect GPS
to PC)
5. Switch on EQ6, select start from Home (parked) position.
6.Enter latitude, longitude,date and time.Continue.
Choose "No" to question "Do you want to start alignment?"
7.In HC choose Utility mode and choose Direct PC.
8.In SN Telescope panel press "Connect" button.
9. This is maybe just my PC but I have to Press Ctrl-key to
activate
the mouse again so I can continue.
10. Select "Setup" from EQMOD pop-up panel.
11. As I use a GPS-receiver I press GPSbutton on EQMOD panel.
Then press "Retrieve co-ordinate and time" button (baud rate
etc
must be set correctly)and finally Accept Data button. Of course
the
co-ordinates can be entered manually and time taken from your PC.
12. Disconnect GPS (just unplug the USB connector)
13. Select alignment (1 Star or N star)
14. I now connect the game pad (rumble pad)and press Initialize
button on EQMOD panel to be sure it connects.
15.Choose alignment star on the SN screen and "Slew to" that star
by right clicking it.
16. Align the star on the telescope haircross using the game pad
and press accept (I do it on the game pad but can be done on the
small pop-up EQMOD alignment window button as well.
17. If needed (N Star) repeat 15. and 16. as many times as you
wish and when ready click "End" button on EQMOD alignment panel.
18. Enjoy sperprecise Gotos if you used N star with enough
alignment stars.
19. To quit press "Park to Home position" on EQMOD main panel.
Wait until scope has parked,. Press disconnect button on SN Telescope
panel. Switch off EQ6 power.

I dont use the game pad yet, but I think I will.

I think pec+sidereal means sidereal rate tracking which incorporates PE corrections.
You could also try to join the EQMOD yahoo user group for support.:hi:

[seeker372011]

:( my laptop runs Vista

[seeker372011]

here's the latest graph..improvement from my last time out but still going over +-3 pixels from time to time in RA...does anyone else have a PHD log they would care to share, so I can compare my mount with others? If you can email me your log please do so at n_mukkavilli-at-yahoo.com.au (i am happy to graph it)
also would anyone have a suggestion as to how to further tame these RA wild swings?

I achieved this improvement BTW by weighting the mount rather more than I am used to in the East--and it brought the RA swings from 8 pixels down to plus or minus 3 .The Dec looks good,course I dont know what the Losmandy brigade would say but its heaps better than my CG5

[seeker372011]

I have set my backlash to zero;aggressiveness-I cant get it to guide unless I go to 110%. My hysteresis is at 10 %-maybe I can experiment with 5%

minimum pixel movement is at default -0.15 from memory-but gee, it does a fine job in Dec..will experiment with this setting too, its one I haven't tinkered with.

gotta ask what's the OSC-I dont seem to have it in my version of PHD?