(See my American Nebula)
I started guiding at the beginning of 2010 and had no problems with guiding until the last few images.
I decided to watch it last night to see what was actually happening and every so often it would lose the star, and then latch onto it again. I had it set to 0.5 last night.
Any ideas any-one?
I guess I should have watched the histogram, I haven't remembered to do that yet.
Carole
What did you have set to 0.5 ?
In what way did PhD lose the star?
Did the star "jump" outside the search rectangle?
Or did the star's SNR drop too far?
QuoteWhat did you have set to 0.5 ?
The littledrop box centre bottom, I think this is the exposure.
QuoteDid the star "jump" outside the search rectangle?
Or did the star's SNR drop too far?
It did jump outside the rectangle at one point near the beginning but I had the drop box set at 0.02 (it had defaulted to this), so I stopped and repositioned PHD and re-set drop box at 0.5.
I think the rest of the time the SNR dropped too far and the green box round the star changed to orange until it latched onto it again.
Should I set it to 1.0?
Carole
0.5s is low andcould lead to too many guide corrections especially in bad seeing which could contribute to you loosing your guide star. I generally use 3-5 second exposures at home to average seeing but I can use much shorter guide exposures at DSC because of the more stable conditions.
Robert
Thanks Robert, I will use longer exposure in PHD. It might well be I had a longer setting at one time and some-how it got changed and I didn't remember what the best setting should have been.
One day I'll actually do an image with everything right!!! Focus, guiding.
At least I got the focus right on the NA Nebula as I got it really accurate in Bahtinov grabber.
Two steps forward and 1 1/2 steps back every time!!!!
Carole
Quote from: Carole
One day I'll actually do an image with everything right!!! Focus, guiding.
At least I got the focus right on the NA Nebula as I got it really accurate in Bahtinov grabber.
Two steps forward and 1 1/2 steps back every time!!!!
Carole,
Part of the reason for this is that you are trying to learn everything at once and so there are lots of things unfamiliar to you in your imaging setup, any one of which might go wrong. You have jumped straight into the full complexity of guided imaging whereas most people take a more step by step approach. In my own case I was regularly imaging for 15 months before I began to use a laptop PC or even attempt guiding. But I gained confidence in using my camera on my scope and during that time I produced many images I am still very proud of.
If I'm honest, I think your approach is more likely to lead to frustration because with so many things to go wrong, one of them will go wrong and the chance of getting a successful image on a particular evening is much smaller. It was the continuing pleasure of producing good images that drove me forwards to improve my technique and to add useful extra bits of equipment as required.
Having said that, I think you are almost there now and you will be producing fine images like the rest of us. But I don't envy the path you have taken.
Mark
I am surprised to hear that Mark, as I thought I was being very slow at getting to grips with everything.
I am enjoying the challenge though despite its frustrations, just sorry I have to keep asking questions but I don't have enough technical understanding to know when and why things go wrong.
Carole
I agree with Mark, starting off can be very daunting, especially if you start off near the deep end.
As you're now starting to find out that everything is critical it might be worthwhile putting together a checklist while you're still learning the in's and out's... just a thought.
Robert
Quoteit might be worthwhile putting together a checklist
I have got a file of information, and also have a set up "routine".
But as I have occasionally forgotten something it might be a good idea (like forgetting to put the splitters on so I could use my dew heaters), but as it is all set up in the Observatory it's only really when I go to DSC that the routine goes awry.
I do need to make a list of things like default and normal settings though.
Carole
Quoteit's only really when I go to DSC that the routine goes awry
Carole, you imaged NA in the observatory and forgot the Bias Frames.
This was not me taking the P, but how hard is to make a list and use it until it becomes second nature ? Stick one in the car and one in the observatory - sorted
Unfortunately I've actually got to do something so I can make a list of what I did
Clouds?
QuoteClouds?
You could order this as a starter.
http://www.transair.co.uk/product4.asp?SID=2&Product_ID=1070 (http://www.transair.co.uk/product4.asp?SID=2&Product_ID=1070) :cheesy:
I agree with Robert.
Make yourself a
complete check list.
Starting from
Erect Tripod
Point North
Level Tripod
Mount telescopes
Add camera ect, ect,
Check level again
Polar align
ect, ect
Main camera in usb1
guide in usb2
ect, ect.
You might think is silly to put things down line point north, or level tripod,
but after you have set everything up, its a bugger to try and remember did i do that or not.
and if you are not north, level and polar aligned, then this is just going to add to your problems
as you will believe these have been done and its the guiding thats against you.
Ask Fay, I believe she has polar aligned on the wrong star, as have I. And that really does make you scratch your head.
Mac.
QuoteClouds?
I am 99% sure the clouds came later Chris, unless maybe there was a thin layer I wasn't aware of, but this has been a problem the last 2 or 3 times I have imaged, so it has to be more than clouds.
QuoteCarole, you imaged NA in the observatory and forgot the Bias Frames.
I don't do BIAS frames every time Mick as I am building up a library of them same as I am with darks. They just happened to be on a different PC when I did the processing and thought I'd get them later and in my enthusiasm forgot. Also to be honest I hadn't realised how critical they were until now. Also I read this
QuoteYou don't need to take new Bias frames very often, just once or twice a year, because the read noise doesn't change much over the life of a DSLR.
QuoteMain camera in usb1 guide in usb2
If these were not plugged in the same USB port, could that cause guide problems, the laptop recognised them when they were plugged in with a little beep and all cameras and mount were recognised?
Carole
Sounds like cables to me?
QuoteSounds like cables to me?
Starting to think that Chris.
I have had an even worse problem tonight as it wouldn't even calibrate. It first of all said there was a
Dec calibration failure, and then it said there was an
RA calibration failure because the star did not move enough.So...........for the purpose of exclusion I tried my other laptop. After trying a number of ports it could not find the GPUSB, so I removed the USB extension lead and used it directly from the shorter GPUSB cable and it recognised it that time. This time it calibrated but then started to have the same problems as last night - kept losing the star.
So I think that's eliminated the software and the laptop.
I will try my other mount next time I am out and if it happens with that too it can't co-incidentally be both mounts, it must be the cables.
The joys of imaging. Yes Fay I know "you warn me".
I only bought these cables less than a year ago which is annoying but cheaper than a duff mount.
Carole
Carole,
I've occasionally had a similar problem with PhD. In my case, closing PhD and then restarting it always does the trick.
Also, you need to check if the star actually does move during calibration. Watch the calibration take place becuase it helps diagnose what may be happening - does the star move? - does the GPUSB LED flicker? In my case the star didn't move and that's why the calibration failed. After restarting PhD it worked just fine.
Mark
QuoteIn my case, closing PhD and then restarting it always does the trick.
No, I tried that, and the calibration is only a new part of the problem.
Also I have tried two different laptops.
The star definitley moved when it calibrated on the 2nd laptop (XP) as I watched that (at one point it said it was sorting something out on backlash so don't know if that's clue but still managed to calibrate.
I can't be sure about the calibration on the 1st laptop (Vista) which I did last night. However it still lost the guide star consistently on both laptops and on the Vista it wouldn't calibrate tonight but it did last night.
Quotedoes the GPUSB LED flicker?
Yes I checked that on the 2nd laptop (XP) and it was flickering.
I always try restarting things if they don't work but it made no difference.
Thanks anyway, I think it's a process of elimination.
Carole
Calculating backlash is a normal part of the calibration procedure - if you watch the calibration in progress you will see it come up every time. You really must watch the calibration take place because then you can begin to gain experience of what a successful calibration process looks like and then what is different about a failed one.
If you keep losing your guidestar then find a brighter guidestar by adjusting the guidescope rings. Or increase the exposure time (on the dropdown box) - you can increase it to a few seconds but note that this will also slow down the calibration process significantly. Losing the guidestar (low SNR) is another reason for failure to calibrate. When you click on a star, its SNR appears in the status bar - I would choose a star with a SNR of at least 5. Increasing the exposure time will increase the SNR of the stars.
Mark
Carole,
Whenever I've had the ' not enough movement' message its always been cables. I'm discounting Meade specific issues to do with the hand controller.
Duncan
QuoteOr increase the exposure time (on the dropdown box) - you can increase it to a few seconds but note that this will also slow down the calibration process significantly.
Did that too and noticed the calibration time increased.
QuoteWhenever I've had the ' not enough movement' message its always been cables. I'm discounting Meade specific issues to do with the hand controller.
Hmmm does the handcontroller have something to do with guiding? I wouldn't have thought of that as once you've slewed to your object you don't need to touch it any more, but that it worth thinking about if it does as I had some problems with this hand controller cutting out once before and decided it was loss of power, and now seems to be OK.
Well I guess I'll get to the bottom of it eventually, it's useful having two mounts now as at least I can interchange things and eliminate the culprit, but I don't have two sets of cables. Does any-one have a set I could borrow if need be (are they the same for all mounts?) I use a GPUSB and an RJ12 cable.
Carole
I'm still working my way through eliminating things to do with guiding but having a night with stars on a night when I am at home is holding me up.
So far I think I have eliminated the cables as I tried the manual NSEW pad within PHD and watched the LED light in the GPUSB and it definitely flickered red and green. I then listened to the sounds of the mount change as I did it which was quite difficult as it is so faint. The East and West I could definitely hear a change in sound, but not so clear on NS. However at this stage my handset cut out and (this is the second time this has happened). So I changed to the handset on my spare mount and I again could definitely hear the East and West sound changes on the mount and I am fairly certain I heard them on North and South although it was VERY faint.
So it looks like the signals are getting through OK.
So what else is there to eliminate:
Having tried two different laptops when all this happened I think discounts the laptops and the PHD software as I got the same problem on both.
Some-one has suggested to me that it could be the network on the laptop that is causing a conflict and causing the signal to drop. I have both 02 (for a dongle) and the Observatory network set up on the laptops. Although the O2 is not being used at the time, is there any possibility that this might be causing some sort of a conflict ? Even if I am not actually using them at the time. My problems seem to have started around the time of putting these networks on.
Also this handset that has cut out twice. Would a handset have anything to do with guiding problems?
I am thinking to uninstall the networks just to see whether it makes any difference.
Carole
You are not testing laptops, software, or cables - you are testing laptops with all sorts of poop plugged in including a problematic handset.
Unplug everything, including the possibly duff handset and test everything with ONLY a laptop and a handset you know works.
Otherwise you'll be stuck knowing the problem could be either -
Laptop
Cables
Software
Dongle
Network
Handset
If it works with everything unplugged, plug things in one at a time and test again - When it stops working, unplug the last thing and test again, if it works don't plug the offending item in again.
Guiding won't work unless most of those things are plugged in, that's why I am trying to eliminate things one at a time.
I am just asking whether a network (switched on or not) can cause a conflict? I don't want to have to uninstall unless really necessary.
I can easily eliminate the dodgy handset.
As I said
QuoteSome-one has suggested to me that it could be the network on the laptop that is causing a conflict and causing the signal to drop.
, but this is some-one who knows about PCs but has never done guiding.
Carole
I meant don't plug in things you don't need
Network - no
Dongle - no
Suspect handset - no
having a network plugged in wont make the blindest bit of difference to your guiding.
Although if you notice your router moving across the table i;d suspect something is defiantly wrong.
As i've said before, plug every piece of your equipment one by one into every usb port, and install the drivers each time.
When that is finished, reboot your pc and then plug in the equipment you need,
Which should be guide camera and mount cable.
I would do the following.
Start the software you use to image with, and check you are getting an image. If yes, then your camera and cable is ok.
Close the software down
Start the software you use to controll the mount, connect to the mount and use the software to move the mount.
If this works then the software and the cables and the mount are working ok.
close this down.
you know now that the cables, mount and camera are all ok.
start your guiding software and go through the motions.
if it dosent work, then either the software is corrupt, (unlightly, but not impossible) or some of the settings are incorrect.
As said before, start with the exposure of the star, make it longer and then see what happens.
If its still not working reset the guiding software to the default settings and start again.
Mac.
now, start the guiding program.
I often have times when the calibration fails because of the star not moving enough. I have to go to another part of the sky, well away from north, & find another one, then go back to where I want to image & it then it guides ok on whatever star I select, even though I have calibrated in a different part of the sky.
Mac I have already done what you suggested but have not found any problems except that guiding is not working properly when I try to guide on a star which is why I am searching for a less likely cause.
Fay that is worth thinking about as the last time I was trying to guide I was doing M81/M82 and of course that is close to the North pole. However the problems started when I was doing NGC7000 which isn't.
Carole
OK, now I understand what the difficulties are.
My first attempt at the G word was not good -
Forgot to turn EQAscom on
Forgot to focus guide scope
Forgot to carry out alignment
Forgot to turn PHD Guiding on/start
Forgot that when you change orientation of camera, need to refocus
I'll reassemble everything indoors and Make a List
Running before walking springs to mind :oops:
A little bird is reminding me that you never ;) read instructions.....................
Amongst other difficulties last night, I had one of those weird guiding problems.
Guiding quite happily and then for no obvious reason the guidestar drifted off.
Reselected guidestar but it drifted off again immediately.
Restarted PHD but GPUSB was unable to find the mount.
Aha! That must have ben the cause.
Pulled out the GPUSB USB cable (N.B. it wasn't loose) to reset GPUSB electronics and plugged it back in.
Restarted PHD,GPUSB found the mount, I recalibrated, then all was fine.
QuoteA little bird is reminding me that you never read instructions.....................
Shuddup :P
:lol:
Right well I have checked everything now methodically and can't eliminate anything, and guiding STILL will not work on either of 2 Mounts, or 2 laptops.
I have come to the conclusion that it might be the guide camera as I could not seem to get sharp focus on a star last night no matter how much I tried, calibration failed every time, so am wondering whether it has got some moisture inside the camera from leaving it in the Observatory despite having a dehumidifier in there. YES I had the dew heaters on and the scope was not misted up.
This is the same camera that I had problems with last year which would not work on LX and so it got relegated to a Guide camera. Up until now it has worked OK, but just as the damp weather is starting suddenly things start going wrong. I would quite happily buy a new camera if I knew for certain this was the problem or at least keep ithis one indoors in future if drying it out works.
Mark has kindly offered to help me as apart from keeping the camera indoors over the next week to see if that makes any difference I have run out of ideas now.
Carole
Stick the camera in the airing cupboard, even my scope goes in there if its got really dewy.
Yep I think I'll give this a try.
Carole
I love my QSI QHYCCD and AstroArt, I just don't have these problems......
Can't get focus on a star? That would certainly cause problems with guiding.
What do you mean by it? Do you mean that there is not enough movement on the focuser to bring the star into focus. Or is it that the star does not appear very sharp even at the point of best focus?
Try it in daylight (focus on a distant tree for example) before you dry the equipment out. If again it is "blurry" at the point of best focus then build up of condensation somewhere in the imaging train does sound like a likely cause. But this ought to be pretty obvious just by examining the CCD itself and by looking through the guidescope.
Is it still the Nikon lens you are using? I'm still using mine. But they do need to be stored in the dry to stop fungal growth inside.
Mark
Quoteapart from keeping the camera indoors over the next week to see if that makes any difference I have run out of ideas now.
Stick it in one of those zippy food bags with a desicant pack inside.
you know the ones.
(http://lakeland.scene7.com/is/image/Lakeland/10432?$normal2$)
This one -
Quotethe star does not appear very sharp even at the point of best focus?
QuoteTry it in daylight (focus on a distant tree for example) before you dry the equipment out.
Oh dear, already started drying it out.
Will try a tree today.
Carole
You'll have a job trying to dry a tree in this weather.
Not been able to get any further due to cloud, but tonight I got outside after having had the guide camera in the airing cupboard for 1 1/2 weeks and thought I'd try guiding on a bright star and picked Aldebaran. Calibrated in W & E, but failed in N and it automatically switched the Dec guiding off, this happened several times, but when I clicked OK to the "Dec guiding closing down box", it went into guiding happily in RA only. then after about 5 minutes lost the star which wandered away from the crosshairs and eventually PHD gave up.
Scratching my head I rang Mark who is down with a cold and unable to come over as planned, and he said he could offer no explanation. I'm now completely foxed.
Anyway, went back to scope and thought I'd do some unguided imaging instead, and by this time the Guide scope was no longer pointing at a bright star, and I clicked on guiding for the hell of it, and hey presto, it's now working.
So it looks as though it must have been moisture in the Guide camera. But not sure why it wouldn't calibrate on Aldebaran.
Been a nightmare to sort out.
So busily imaging at the moment - Yippi :lol:
Carole
Hi Carole,
Try picking dimmer stars. I calibrated PHD while pointed at Cappella, but I didn't use that, I used a nearby star that was just visible on my QHY5 using a 2 second exposure. Bright stars are too big (that's what I've been lead to believe), small stars are more pointy sources that PHD can more easily work out the centre of when doing it's calculations.
Happy guiding.
Duncan
QuoteBright stars are too big
Yes I hope that was the reason.
QuoteQHY5
I'm seriously thinking about buying one of these now as this camera has given me nothing but grief ever since I bought it (do you remember it was the one that wouldn't do LX and in the end I gave up and bought a DSLR and decided to use it as a guide camera.
Carole
Hi Carole,
The QHY5 was a good purchase. It just works, nice wide fov (big chip) so plenty of stars to choose from. Also with your mount you could use an autoguider cable and have fewer things connected to your laptop which must be a good thing.
Duncan
Quoteyou could use an autoguider cable
Is that different to what I have now?
I have a GPUSB cable attached to an RJ12 which is one USB plugged into laptop.
Thanks
Carole
With the QHY, there is 1 x USB to the laptop and 1 x RJ11 direct from the QHY to the mount - PHD guides the mount directly from the camera
Quote from: mickw
With the QHY, there is 1 x USB to the laptop and 1 x RJ11 direct from the QHY to the mount - PHD guides the mount directly from the camera
Really? I didn't realise that - I'm still using my Shoestring GPUSB to connect to the mount and just using the USB lead from the QHY5 to the laptop.
Mark
Yes I was a bit flumoxed (? spelling) by that and knew Mark had the same set up as me (Mount and guiding kit) and was going to ask him whether he went straight to Mount from camera. Well so long as it works with my existing cables I don't mind.
Carole
If the mount is controlled from your computer then there is no point in using yet another cable from Guider to the autoguider port on the mount. Believe me it makes no difference other than to add another cable, in fact you then get into the issues of whether the guider output is compatible with the mount autoguider input. I needed an adaptor for my Takahashi and in the end I decided that there was no advantage (using either PHD or MaximDL) as the guiding is as good either way.
With autoguider control cable:
1) PC reads autoguider via usb
2) PC sends correction to autoguider via usb
3) Autoguider sets relays/optoisolators for required period via RJ11 cable.
4) Mount moves to correct
Without autoguider cable:
1) PC reads autoguider via USB
2) PC sends correction to mount via USB
3) Mount moves to correct
Hope that helps
Robert
Thanks for that Robert.
I did think there would be "issues" with both ASCOM and QHY/PHD trying to control the mount but figured the "manufacturers know best".
Although at least there are options to control the mount with or without ASCOM or whatever.
Going back to this, fingers crossed I think I've finally cracked it. Or at least fingers crossed I have.
Having spent the best part of the last few months tearing my hair out and swapping various bits of equipment etc etc. I suddenly had a thought that I had Restored my Mount to Factory settings a few months ago (due to it going a bit crazy) and it just occured to me which hemisphere it had put the mount in. (I've never set up a mount from new, so it did not cross my mind that this might have been re-set).
I checked and found it was not set to either hemisphere it was set to NONE. I've re-set it to Northern hemisphere and so far it seems to be working fine again now. So fingers crossed I hope this has now finally fixed it. It's a wonder it was working at all.
Carole