I did a full new callibration run the other night. I adjusted the PA just the small amount it said to. I ran another large model this time 330 points. It took about 3 hours to do (perhaps my 10 second exposure length at 3x3 binning is too long).
I would say you can significantly reduce this time. Personally i use 9x9 binning (STL11000) with about 2 sec exposure for about 240 odd points an hr. You could easily do this with you gear Greg with bigger aperture and a more sensitive camera. maybe you need to tweek your image link parameters.
Quote:
Originally Posted by gregbradley
But then when I did my normal PEC autoguided image there was a noticeable improvement in the roundness of the already quite good stars. Everything was tighter and the final image will show better resolution and sharpness because of it.
Do you find you can do a 5 minute sub with sharp round stars with just ProTrack?
Well it seams Protrack, autoguiding and PEC are working well together for you Greg. With protrack on and i thing PEC was on, ive done 15 min unguided at 2.5m FL with round stars. This was after using a 550 - 600 point model, not a re-calibrated model. the original models have given me more success than recalibration runs in terms of Protrack unguided tracking. Pointing is spot on.
Quote:
Originally Posted by gregbradley
As far as adding to an existing model when you try to do an automated callibration tpoint run it gives you several options. Can't you just use the sync function or short mapping run if something has been adjusted manually to bring the model back to reflect the current state of the mount after physical adjustments?
When you start up one night and you find the mount points, say, 1/2 to 1 FOV away from where it says its pointing, then you can sync back into the existing model by image linking the photograph then synching the mount to it. that's fine. This wont work if you make ANY adjustments to the mount weather it be PA or loosening or changing the scope / dovetail position on the mount. In this case you need to choose the recalibrate for portable telescope and recalibration permanently mounted telescope respectively. You select the appropriate option then do your 20 or so point recalibration run as described in the manual and this thread. It doesn't need to be super modeled.
Josh
PS, I havent yet read Peters reply to you Greg, so sorry Peter if ive repeated what you have said.
The only way out of this situation would be to do a full T-Point run starting from scratch every time you make physical adjustment to the mount because this would allow one to make direct comparisons between each run as to PA accuracy.
I'm sure if I've got this wrong somebody will jump in. I'm actually hoping there is a different answer! And I hope I have not confused this even more!! It reflects my current understanding of this.
As far as my understanding of Tpoint goes Peter, I think you understand it well. I will say that after you have donr the 200 point tpoint run, this should give you an excelent representation of your PA and from there, any adjustments made to the PA should be made in confidence. Apart from that, as you say above, if you make an adjustment to your PA, then do a full 50 point polar alignment tpoint run to verify before and after PA reports with supermodel. 50 points is all you need realy. DOnt read off the recalibration PA report.
In reallity, we have seen that there is no perfect PA position and that aiming directly at the refracted pole may not be the best option. So in practice, when the PA report says its excelent an no further adjustments are needed, then you OK.
Do you think your Dec drift was because of the loose pier mounting bolts? Have hou tried another guiding run with the tight bolts?
Do you think your Dec drift was because of the loose pier mounting bolts? Have hou tried another guiding run with the tight bolts?
Josh
Josh[/QUOTE]
I sure hope so! Especially given that my original PA report was evidently in error given the loose bolts. But, I've yet had no opportunity to test properly. I'm also hopeful that some of the unexplained spikes might have been due to wind impacting on the mount. I think I will make one more move of the mount and hopefully be done with PA for a while.
I sure hope so! Especially given that my original PA report was evidently in error given the loose bolts. But, I've yet had no opportunity to test properly. I'm also hopeful that some of the unexplained spikes might have been due to wind impacting on the mount. I think I will make one more move of the mount and hopefully be done with PA for a while.
Thanks for all,
Peter
Wind definitely causes PE spikes. You can watch the guiding, hear the gusts and see the errors spike up straight afterwards. Also depends on the type of scope. A closed tube CDK would be like a sailboat. It would have no hope in the wind. Even mild winds will affect those large closed tubes. Not ideal as a design but probably easy to build.
Hopefully its simply loose bolts. Kind of humorous in a way. Searching for obscure software/firmware glitches and hitech explanations to do with T-point models, backlash settings and its just loose bolts!
Kind of matches my experience though. Often problems are simple ones and often in your face type obvious ones rather than abstruse hidden in software issues.
Wind definitely causes PE spikes. You can watch the guiding, hear the gusts and see the errors spike up straight afterwards. Also depends on the type of scope. A closed tube CDK would be like a sailboat. It would have no hope in the wind. Even mild winds will affect those large closed tubes. Not ideal as a design but probably easy to build.
Hopefully its simply loose bolts. Kind of humorous in a way. Searching for obscure software/firmware glitches and hitech explanations to do with T-point models, backlash settings and its just loose bolts!
Kind of matches my experience though. Often problems are simple ones and often in your face type obvious ones rather than abstruse hidden in software issues.
Greg.
No kidding!! I kind of feel like an idiot. Tonight looks to be clear so the verdict awaits!
Imagine those poor Bisque boys sweating beads in frustration trying to figure this one (mount problem? software problem?) and it turns out to be wind gusts? Oops.
Imagine those poor Bisque boys sweating beads in frustration trying to figure this one (mount problem? software problem?) and it turns out to be wind gusts? Oops.
Yes, it must be frustrating. I agree!
Unfortunately, though, tightenting down the mount, and running brand new T-Point models, have produced strange unguided results which I simply do not understand.
The resuls shown below were taken after midnight in good seeing at dec=+3, HA=0, close to the meridian with X=RA. Analysis of the 15+ min tracking log (this was with PEC on and Protrack off but unguided tracking) shows corrected PEC of .7 arcsec. But the graph looks pretty terrible! Almost immediately there is a large rise of nearly 6 arcsec (I imaged at 1.56 arcsec/pix) followed by several bumps. Only around 850 sec-1,000 sec does the tracking drift down to the X axis. And there is steady drift in Y as well. More than I believe should be seen at HA=0 where any declination drift should be quite minimal. To me it looks like both axis are drifting. But how could that be if polar alignment is supposedly so good? My T-Point PA report (based on nearly 200 points) is -23 arcsec azi and -15 in ME from refracted pole.
I asked the question at SB as to whether not seeing the whole sky could cause an error in PA using T-Point. I only see from overhead to the West and not very low to South and North. The answer I received was that it ought not to make a difference, but that T-Point is a statistical model and more points are better. I guess that leaves the door open.
Please turn ProTrack off, pretend you've never even heard of Tpoint and ignore its polar alignment suggestions, spend some time drift aligning your mount, then repeat your test a few more times. Any difference?
Please turn ProTrack off, pretend you've never even heard of Tpoint and ignore its polar alignment suggestions, spend some time drift aligning your mount, then repeat your test a few more times. Any difference?
That will certainly be my next step! I was thinking about using Pempro to do this which I believe is a drift align using a camera. I've never done one before so I'm sure I will mess it up before I get it!
BTW, Protrack was off for the guiding graph posted above. Does it look right to you?
Ill second the suggestion for a ccd drift align polar alignment check. The results will be interesting to see.
Josh,
I've been thinking that I might try one thing first that shouldn't take too long. If the problem is that my pointing samples are skewed so much to the West, I wonder what result I would get if I confined my samples so there was no bias in any direction?
You can see my horizon line compared to what I propose. It wouldn't take too long to run this and then compare the polar reports for the two models. If they are the same or very close then I will drift align, but if not hopefully the new model would be better.
I appreciate what your saying, but i think samples low on the horizon are a significant contributor to the accuracy of the model. Maybe a question for Patrick W...?
Having said that, I would be interested in the results.
I appreciate what your saying, but i think samples low on the horizon are a significant contributor to the accuracy of the model. Maybe a question for Patrick W...?
Having said that, I would be interested in the results.
Josh
Well, now that you ask.... I did ask him in the thread at SB. He did say to collect points very low down to the West. So I've done that in my current model considerably more than I ever have before. I have a terrific pointing model but I think my PA is further off than ever before no matter what the PA report indicates. My guess is that there are no "compensating" points low in the East and something is going off. I specifically asked Patrick if my particular horizon could be a problem. He didn't think so but did say more points are better statistically. I think there is a possibility that T-Point is not working properly when there is 50% of a horizon missing. Anyway I'm going to run the experient as soon as the weather breaks. I'm really curious.
That will certainly be my next step! I was thinking about using Pempro to do this which I believe is a drift align using a camera. I've never done one before so I'm sure I will mess it up before I get it!
BTW, Protrack was off for the guiding graph posted above. Does it look right to you?
Thanks,
Peter
I was going to recommend Pempro! My last PA was using Pempro just once. I then did a ~ 180 point TPoint and got a RMS (on my MX) of 4.3as. I eventually messed it all up by removing the mount for maintenance but plan to do it again tonight, the moon's not conducive even for NB, being just where I don't want it!
I was going to recommend Pempro! My last PA was using Pempro just once. I then did a ~ 180 point TPoint and got a RMS (on my MX) of 4.3as. I eventually messed it all up by removing the mount for maintenance but plan to do it again tonight, the moon's not conducive even for NB, being just where I don't want it!
Charles
So, Charles, you used Pempro to align the MX and your T-Point was just for pointing? Or, did you further adjust the mount based on T-Point's PA report? I guess I'm curious as to how close T-Point said you were after running Pempro first. Of course you probably are not so restricted in viewing as I am!
I recently purchased Pempro on the basis from a few threads here that it gives superior results. There was a long thread recently about PEC in Sky X and PMX mount being out of whack.
My PEC on both PME and PMX improve the stars in my images. But I am looking for that extra tweak as per Ron Wodaski's talk at AAIC about software being the cheapest component of your system. And to tweak your existing system to get the biggest gain for buck compared to constantly upgrading gear.
For the record I recently did a 330 poin t-point model and turned Protrack on. I noticed sharper stars and tighter guiding with Protrack and PEC on with my PME.
I recently purchased Pempro on the basis from a few threads here that it gives superior results. There was a long thread recently about PEC in Sky X and PMX mount being out of whack.
My PEC on both PME and PMX improve the stars in my images. But I am looking for that extra tweak as per Ron Wodaski's talk at AAIC about software being the cheapest component of your system. And to tweak your existing system to get the biggest gain for buck compared to constantly upgrading gear.
For the record I recently did a 330 poin t-point model and turned Protrack on. I noticed sharper stars and tighter guiding with Protrack and PEC on with my PME.
Greg.
Yes, and wouldn't you guess that I started that thread on PEC at SB. Maybe I should get a prize for "longest threads or something" since I obviously cannot do any imaging!!! You know there was a PEC bug in TSX just in the Southern Hemisphere that is now fixed, but it took ages for SB to recognise what so many users here were reporting. Anyway, I'm still using the model for PEC I got using Pempro. I'm sure that T-Point normally works fine for most people in terms of Polar Alignment. I think my horizon is messing with the logic of that program because I now believe I have never been properly aligned no matter what T-Point has said. It has caused me a lot of grief for too long, but when a person is just getting started with imaging it takes a bit of time before one has the confidence to say "I don't think this is my fault."
So, Charles, you used Pempro to align the MX and your T-Point was just for pointing? Or, did you further adjust the mount based on T-Point's PA report? I guess I'm curious as to how close T-Point said you were after running Pempro first. Of course you probably are not so restricted in viewing as I am!
Peter
After the alignment with Pempro, I ran the 180 ish image TPoint and the RMS was 4.3. The Model said 'excellent' for both axis and therefore I didn't touch anything. I'm currently re-doing the exercise as I recently removed the mount from the pier for maintenance and would have lost the fine adjustment.
