Jump to content

NLCbanner2024.jpg.2478be509670e60c2d6efd04834b8b47.jpg

Maxim guiding problems - again!!

daz

Recommended Posts

daz

daz

Posted
Posted

OK, so its been sometime since I did any guiding, but I'm sure I've not forgotten anything!!

Maxim just would not guide last night at all. Set the calibration time to 40 seconds (!), agressiveness to 8 and started the routine.

Expose for 2 seconds, no problem.

Calibrate, no problem

Track - problem!! The x-axis would report an ever decreasing error, eventually getting to over 4 pixels in error.

When I stop the tracking and re-expose - nothing has moved!

Everythin is as it was before - i.e. I have not changed scope, alignment was spot on, balance was OK, drivers were not changed, etc....

Any suggestions, Maxim Gurus??

Link to comment
Share on other sites
moocher

moocher

Posted
Posted

Not sure if its any consolation but i had exactly the same problem last night. I`m trying to use a 135mm lens to guide with. Hows ya PA? Mine is a little off. Next job when i get some clear stuff. Have you tried Align master? Its REALLY good and quick!!!!!!

Alan

Link to comment
Share on other sites
barkis

barkis

Posted
Posted
Thanks for those links Ron!

I'm going to balance everything again, check the PA, etc, etc....

And then beat Maxim into submission!! :)

HehHeh!. MartinB is the Maxim man Daz. I'm sure if your club doesn't work, Martin's has it under control:D.

Ron.:eek:

Link to comment
Share on other sites
roundycat

roundycat

Posted
Posted

In short, no. The guide rate should be set to x1 or x0.5 and not changed, ie, the same for cal and actual guiding. The 40s cal time is way too long but it will only serve to give you a slightly better cal at the expense of waiting forever for it to finish. You can have problems like this from time to time, I just hit the cal button again and try again. Make sure you are not trying to guide on a hot pixel.

Dennis

Link to comment
Share on other sites
NickH

NickH

Posted
Posted

If it's any consolation, I had the first issues ever with PHD tonight...calibrated fine, but trailing stars...scopes were not balanced on all axis in the SBS setup..sorted that and now it's spot on again.. lost 50 mins of subs though...

Link to comment
Share on other sites
Ibbo!

Ibbo!

Posted
Posted

I watch the calibration sequence like a hawk just make sure it does not pick the wrong star at any time

I use 20 secs cali time and 2 to 3 secs exp

Having said that it even with a seemingly good cali routine it has been way off and has taken a full shut down and restart of the PC

By the nature of what we do we are generally in a hurry to get set up(esp after the weather we get here) and the time we do it we are probably K********d so I forgot things and swear blind (and verbally at odd times of the night)I did it the same way as last time it worked(I am talking about me ) my usal trick is not to switch the NJP over to tracking rate instead of slew and the 1st calibration move is about 15 degs

I think the club is still a good idea (a very large club) :):evil6:

hope you sort it out

Steve

Link to comment
Share on other sites
steppenwolf

steppenwolf

Posted
Posted

I find MaximDL to be great for guiding but some nights I have to select several stars to find one that will calibrate successfully so that I end up with a nice right angled 'L' shaped trace. Other nights it all works automatically and selects the 'right' star itself. Once it has calibrated correctly I never have a problem for the rest of that session and I use 15 second calibration timings (2 second exposure - although that is irrelevant in this context!) with my 400mm guide 'scope.

I much prefer throwing the whole lot down the garden to using a club ....

Link to comment
Share on other sites
MartinB

MartinB

Posted
Posted
HehHeh!. MartinB is the Maxim man Daz. I'm sure if your club doesn't work, Martin's has it under control:D.

Ron.:D

:) Not sure about that Ron but I'll have a go! Just to check we are talking about the same things: -

Calibration time - the time the scope moves each axis so total time for 40 secs = (40x4) + (4x2). I aim for a minimum movement of 10 pixels in each axis. If I have a bit of backlash in dec I increase the time a little which reduces the proportion of the movement effected by backlash. As Dennis says, it isn't necessary to keep repeating the calibration provided you enter the dec of the star used for calibration and tick the pier flip box if you are imaging with the mount flipped compared with when calibrated.

Guide rate - the amount the scope is speeded up or slowed down relative to sidereal tracking rate (should never be more than 1 for RA)

Expsosure time - determines your guide cycle rate. 2seconds in your case so a guide cycle of fractionally more than this.

I'm not sure what your tracking graph was like Daz, was it oscillating or just progressively moving away from the target? If it's just moving away and not oscillating there are 2 things I can think of, you could have inadvertenly disabled tracking in one axis or the guide cable is faulty. However, you said when you re exposed that the guide star was in exactly the same position, I presume you mean exactly the same pixel co-ordinates. Are you 100% confident that you haven't done an exposue under the expose tab and your new guide exposure is tucked under the old image. I've done this a few times, it's quite easy to do! Obviously if you do this everything looks the same!

If the track is oscillating these are the possible causes that I can think of :-

1) as Ibbo says, Maxim easily gets confused if there are stars around of similar brightness to the one chosen. It loves hot pixels as well. Check that the calibration track is a good right angle and that the star is returning to its starting point. It is best to calibrate with a nice bright star, say mag 4 which is very much brighter than anything else around.

2) using a saturated guide star. If the guide star is saturated it isn't possible for maxim to calculate an accurate centroid and it will weave around.

3) over aggressive guiding in poor seeing. An aggression of 8 is pretty high if the seeing is bad, the guiding starts to chase the seeing and the oscillations start to go off scale.

4) make sure you haven't inadvertently switched backlash compensation on under the settings tab!

Don't know if there is anything in there that would fit the bill

Link to comment
Share on other sites
daz

daz

Posted
  • Author
Posted

Thanks for all the input guys :D

I shall go "back to basics" at next clear sky and double check EVERYTHING!!

Interesting you mention cables Martin, as I had issues with the FW cable as well last time, so I might well replace everything with as high quality cables...

I'll keep you all posted and again, thanks for all the input...

P.S. Is there a recommended spec for the club?? :)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.