EQ6 Pro Tripod-Crash & Strange camera behaviour...

[Alveprinsen]

Mount: NEQ6 Pro.

Camera: Nikon D3100 DSLR

I prepared my scope and camera for a 6 hour shooting session which started 21:00pm last night. The target: M31.

Now, I couldnt remember which time the camera and tripod would crash. I could swear it was 03:10am, but... a gnawing feeling in the back of my head told me it might be 02:10am... but then again, it couldnt possibly be 02:10am could it? Because I watched it almost crash only a few weeks ago, and I could swear that was 03:10am, since I recall it was pretty late.

Anyhow, thinking it was 03:10am, I went to bed... with a slightly troubled mind.... convincing myself that it had to be 03:10am, since 02:10am would simply be way too early for it to crash...

So, at 02:30am I get up, and I walk down to the observatory. The sky is absolutely magnificent... I rejoice... 6 hours of continous footage.. This is overkill, and will surely land me some nice results.

My rejoice suddenly stops to a halt though, as I approach the observatory, and hear a rather heart-shattering klicking sound. I had been wrong... The camera has allready crashed. I quickly stop the mount from tracking, while PHD Guiding is pinging and flashing red like hell....

Looking at the last pictures on the camera - counting them backwards - it seems the mount has been doing this for about 40 minutes... 02:10am indeed........

Anyhow, I slew it back to parking position, no nasty noises... I slew it to different targets, and it appears to slew just fine.. no apparent choppyness, or nasty klicking sounds.

HOWEVER... it does miss every target by a mile.. So I slew it to Jupiter, and slew manually while looking through the camera seeker. Indeed, it is quite off.

Now,

Question #1: What is the likelyhood that I have actually caused any severe damage to my mount? Should I be experiencing noise and chopping when slewing if there was damage? Or will this possibly manifest at a later time when tracking a target?

Question #2: Is it cogs and wheels that turn about in the NEQ6 Pro, or belts? If belts - I suspect there might be miniscule or no damage. Cogs and wheels on the other hand... chipped teeth? Not good.

Question #3: Is there any good way of checking for damage without opening it up? Is there any slewing procedure I can do to check for problems?

Question #4: The mount alignment is now way off. Even after restarting mount and everything. I suspect it is because in the mounts mind, it was still moving, when in fact not. I forgot to check whether or not it landed exactly in its home position on its two axis. I will do that in 2 hours when I go back to fetch my dark frames. However, if its alignment IS off, even though its axis are parked to a perfect 0 on the clocks - will a simple realignment of the whole thing be sufficient to get it back on track?

And now, to my camera related question:

Looking through my light-frames in the camera, I notice that in the middle of the 36 10 minute exposure frames, some frames are completely dark... Like, I have 7-8 light frames that are 100%, then suddenly one that seems to be of extremely low exposure, followed by 2-3 frames that are completely black, then following another really low-exposure - and then the normally exposed light frames again. I hypothesize that perhaps the interval between the frames (7 secs) is too short when doing so many exposurs. The camera has therefore been unable to properly save pictures before the shutter release has been activated. This has nothing to do with the tripod crash either, since these dim and black pictures occured well before the crash.

When getting ready to activate the dark-frame sequence - I noticed that the camera would nolonger respond to the remote shutter release controler. Not until I pulled the power on the camera, and pulled the batteries from the shutter release controler that is.

Question #1b: Does anyone have similar experience with a DSLR turning out low to non exposure pictures in the middle of a series?

All input in both these matters will be greatly appreciated!

PS: Yes, I should have activated limits... I've been doing M42 exclusively recently which doesnt require it. M31 however is at one point straight up in the sky, and with a twist....

Sincerely, Alveprinsen.

[vince 66]

I did not realise that a mount could crash. My mount suddenly stopped working last week while it was slew ing to Neptune there was a bit of a clunk noise and it stopped dead in its tracks. When I slewed back to the park position it was a mile off. The next evening I re set every thing from scratch and every thing worked fine after that.

[rob0971]

I expect its just the clutch that has slipped & realigning will sort it. Can't help with the camera problem though.

[ronin]

A few answers, but not all.

THe drive is by cogs, so you do have the possibility that one or more have become damaged. If that is the case then check to what extent. http://rowanastronomy.com/products.htm have a bekt drive update in development for your mount, just no idea what stage of development it is in at present.

The covers will have to come off to look at the state of the mechanism.

Rather then cog damage I would have expected a pin to have sheered or given up. Based on the sensible engineering idea that a pin is easier and cheaper to replace then a cog or motor.

Concerning (4) I am not sure, would have expected that with all power removed the mount reverted to a default atate where it has no idea about anything and needs all new data and realignment. If you tried alignment after the crash without a power off and possibly reset then the mount probably have little idea where it is pointing. It will certainly have lost it's initial setup.

Camera: I think they need a rest between exposures. Recall that it was recommended the rest = exposure time. Think that heat builds up so that could be the reason for the lost exposures. Not 100% sure but there is a recollection of this. Suspect 100% wait is extreme but a simple thing to remember. 50%-70% may be OK.

Is the camera set as a default to take it's own darks? Many are set such that if an exposure is greater then 1 sec then the camera will take it's own dark, that is the default setting on mine. The dark it takes is the same exposure time as the normal exposure. If your camera is the same then it in effect the expoure time doubles and this is done by the camera independant of the release timer. Found this out on my camera and release timer. The remote shutter release controller may not have accounted for this and could have upset the On/Off settings.

Your remote shutter release not doing anything may simply be the camera went into an error state to protect itself. If it was heat and an exposure problem then not taking an exposure would seem a safe error state. Basically the camera decided to not take any further esposures until looked at, looked at beiong a poweroff/on from the owner, then it would recheck a temperature sensor for the chip.

I would remove all power for a few hours and then redo all data and alignment required for the mount. Although sensibly something should have given up as a failsafe to have minimised damage. Sounds like the mount needs a torque sensor.

[Zakalwe]

There'll be almost certainly no damage to the mount. The clicking that you heard is the stepper motors. They will make that noise when the torque exceeds a level.

I've crashed my mount a couple of times and it sounds horrendous, but it'll be fine. The mount will have lost it's alignment....just power off and redo the GOTO/EQMOD alignment

[Alveprinsen]

Concerning (4) I am not sure, would have expected that with all power removed the mount reverted to a default atate where it has no idea about anything and needs all new data and realignment. If you tried alignment after the crash without a power off and possibly reset then the mount probably have little idea where it is pointing. It will certainly have lost it's initial setup.

Camera: I think they need a rest between exposures. Recall that it was recommended the rest = exposure time. Think that heat builds up so that could be the reason for the lost exposures. Not 100% sure but there is a recollection of this. Suspect 100% wait is extreme but a simple thing to remember. 50%-70% may be OK.

I would remove all power for a few hours and then redo all data and alignment required for the mount. Although sensibly something should have given up as a failsafe to have minimised damage. Sounds like the mount needs a torque sensor.

Hello, and thank you for the extensive feedback.

I suspect a realignment of the mount will do the trick. Will have to get out early tonight before its dark enough to start takign pictures. Dont want to waste those precious dark-hours.

50% wait between pictures? Like 10 minute exposure, 5 minute wait? That to me, sounds insane... I can do secounds... or perhaps even 1 minute, but 5? No way. As for overheating - the camera was exposed to -1 degrees below zero(celcius) most of not the entire time. I doubt it overheated.

I've previously done like 18 - 20 consecutive frames with 10 min exposure, 7 sec. delay between exposures, and it hasnt blacked out on me like this. I suspect I was pushing the limits setting it to 36 frames with the same delay. I will up the wait to like... 15 sec. It should be more than enough. I dont think heat is a problem.

[Alveprinsen]

There'll be almost certainly no damage to the mount. The clicking that you heard is the stepper motors. They will make that noise when the torque exceeds a level.

I've crashed my mount a couple of times and it sounds horrendous, but it'll be fine. The mount will have lost it's alignment....just power off and redo the GOTO/EQMOD alignment

Good to hear. Gonna do my 12 star alignment all over again...

[Alveprinsen]

I did not realise that a mount could crash. My mount suddenly stopped working last week while it was slew ing to Neptune there was a bit of a clunk noise and it stopped dead in its tracks. When I slewed back to the park position it was a mile off. The next evening I re set every thing from scratch and every thing worked fine after that.

Music to my ears... Looking forward to doing this tonight and hopefully getting everything back to the way it was..

[Tinker1947]

It could be the drive gear is missing the worm drive and just needs adjustment to bring them back together......after i re greased my mount it start clunking in one place when slewed manually for the 360 degrees just needed adjusting to fix it..... 

[Zakalwe]

Good to hear. Gonna do my 12 star alignment all over again...

I presume that you are using EQMOD?

I bet that when you parked the mount it missed it's "Home" position by a mile? Thats because the NEQ6 has no encoders, so it only "knows" its position from the stepper motor impulses (AFAIK).  So it is "blind" to where the scope is actually pointing. When the scope is physically blocked, the mount keeps sending pulses to the stepper motors and it has no way of knowing that the scope is not moving. Hence the alignment goes out the window.

[Alveprinsen]

I presume that you are using EQMOD?

I bet that when you parked the mount it missed it's "Home" position by a mile? Thats because the NEQ6 has no encoders, so it only "knows" its position from the stepper motor impulses (AFAIK).  So it is "blind" to where the scope is actually pointing. When the scope is physically blocked, the mount keeps sending pulses to the stepper motors and it has no way of knowing that the scope is not moving. Hence the alignment goes out the window.

I forgot to check the clocks this morning to see if the axis hit their respective home positions. I will check again tonight when I go down there to correct my mess. Your hypothesis appears sound though.. This is what I suspected as well... that the tripod thinks its moving, when its actually not... Thus scewing the actual position.

And yes... EQMOD...

[Alveprinsen]

Oh, and this is how light subs of M31 looks like when the mount pushes the camera over one of the tripod legs:

The other ones look like multiple EKG readings of someone dying horribly....

Sincerely, Alveprinsen.