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I am going to apply Permanent PEC correction to my AZ-EQ6 GT SkyWatcher mount in an attempt to eliminate most minor negative contributions to my so-and-so autoguide. I will do that by following instructions on the SynScan manual. Does anyone have some advice?
I also started using Guide Assistant of PHD2 and applying the calculated min-move and backlash changes suggested by the system. More, I tweaked the worm and gear bugs of the DEC axis to reduce the backlash, and after a few attempts I found the right position between screeching and jerky movements of the mount at one extreme, and shaky setup at the other. I hope getting some improvements to my awkward setup because I am afraid that the heavy (14-16 kg) and long (1600 mm focal length) Meade 7" refracting scope plus guide scope is close to this mount's limiting payload, and difficult to be correctly balanced. In addition to seeing, its length also makes it strongly sensitive to wind gusts making PHD2 log graphs look not so good. I cannot minimize these effects without changing my scope, which I don't want to do because of crisp images it yields under (rare) favourable conditions, so I started a search to minimize everything else that can be addressed.
Thank you for useful suggestions!
The struggles of a beginner learning how to use the equipment. :-)
Pointed mount North and Levelled EQ6 pro mount 8:30 pm Attached wireless release, 2" nose and UHC filter to Nikon DSLR Attached scope and camera, balanced scope for camera use Collimated the telescope -took 40 minutes of messing around Waited until dark. Took the dogs for a walk around the field to pass the time Polar aligned using the mobile app and sighting against Ursa major. Rebalanced DEC for eyepiece rather than camera 3 star alignment. 1st star was way off and took ages to get it in the eyepiece Restarted 3 star alignment. - Selected a star behind a house. Restarted 3 star alignment -complete. Checked collimation using a bright star - perfect (should bloody be after 40 minutes!) Tried to fine adjust polar alignment using a method discovered online (not drift- I don't think I have the patience.) Didn't work. Restarted 3 star alignment then used the polar alignment on SynScan Took a look at Jupiter was great to look at but not what I set out to do, I want DS images... Attached camera Used live view (LV) to try to focus stars Pointed the scope at M3 and took a 2 minute exposure Tried again with a 4 minute exposure SD card failed. Lost some family pics, grrr Now I have to explain to my partner that it wasn't because of Astronomy, these things just happen. Replaced SD card Took some cautious 1 minute exposures of M90 expecting the camera to explode Pictures were faint so moved to 4 minute with a little more confidence telling myself SD card failures can just happen. Noticed star trails Located a bright star Decided to give PEC training a try. Couldn't do it with an eyepiece. Tried with the camera in LV but noticed some gradual movement in the DEC axis. Hoped PEC training would sort this. Moved onto the Spiral Galaxy Took some 2 minute exposures of the whirlpool galaxy. Wireless timer worked flawlessly. Still a little faint so up'd the ISO and took some more. More detail but more noise. Took some darks with the same settings. Packed away while the camera did its thing. Viewed the pics briefly on laptop. There was star trails (DEC axis again and blurring) Went to bed 1:30 am
So what have I learned? Well DEC error was probably due to the balance of the scope being off. I never did re-balance for the camera. I've also learnt today that I should bias the balance slightly East so the gears engage better.
PEC training is a waste of time without an illuminated reticule which I don't have the desire to buy. I'd rather save for a guide scope and guide camera. I've learned I can refine the polar alignment after the 3 start alignment process.
I've also read on forums that perhaps I should manually move the scope to the first alignment start then continue with the usual process. I've also seen that two star may be the way forward for EQ6. So perhaps next time I'll start with a 2 star, polar align using the SynScan handset then back to 3 star with the first manual adjustment.
I should also purchase a few SD cards that are dedicated for Astrophotography and upload them ASAP after the session.
The Astronomik UHC Deep Sky Filter worked wonders with the images for where I live. I can now take longer exposures. Assuming I sort out DEC errors and invest in guiding rig.
I was just wondering if it is possible for me, to do PEC training using my Nikon DSLR and the cables that I got? I don't have a guiding setup yet, and I want to wait until the money is there and also getting more used to imaging. I tend to have a very good polar alignment, as the image doesn't drift through each frame, but rather there is a "jerk" or drift every other frame, when doing 2-3 minute subs. I guess that is periodic error, as it happens even on windless nights.
So, I have both my Nikon DSLR and my mount hooked up to my pc (the mount through port in the Celestron Advanced VX Controller), from which I can send slew commands. I have the periodic error correction tool too, but as of right now it seems that I have to monitor and correct any PE myself, which I honestly don't want to do as doing that 8 minutes straight with precision doesn't sound easy. So can I hook up the DSLR through say PHD2 and let it correct for me, and do the PEC training, or do I need the actual cable that goes into the Guider port of the mount? Any thoughts on if this is possible would be well received! And if not, I guess I'll either just need to get used to shorter subs (or throwing 1/2 of them away), or trying to do the training manually with the zoomed image of Backyard Nikon..
If you are using an auto-guiding scope and ccd with PHD, do you need to worry about drift alignment and/or periodic error correction of the mount?
I decided that after modding my 40D, in the last few years taking a few long exposure images successfully with the modded DSLR even up to 45min (30 mins usually) subs at 2000mm with all subs usable unless clouds ruined the exposure.
Lately I thought I'd tackle a new challenge, that challenge being PEC training on the CGEM to see if I can improve the tracking quality (RMS in PHD) and in turn tighten the star bloat a bit and improve the detail, particularly imaging at F10.
Currently my attempts failed miserably. Initially I learned the hard way that you can not train PE on the CGEM using the GPUSB autoguider port, can't even have the cable plugged it since the CGEM starts to make a tapping noise and the whole alignment gets confused or theres is a conflict between the autoguider and the handcontroller, the mount becomes unusable until it is power cycled.
The second attempt was to connect the NexRemote via COM8 (on my laptop) and generate a Virtual COM32 for PHD to connect to the NexRemote. PECTools connected to NexRemote directly, so had all three bits of software talking to each other.
I have installed ASCOM version 6 and the Celestron ASCOM drivers. I connected PHD using ASCOM via these drivers.
I aligned the scope via nothing but NexRemote on the laptop, the NexRemote read the GPS and aligned successfully.
I located a guide star, calibrated PHD and commenced guiding, which it was guiding with no problems.
Till this point everything was smooth and as expected but here's where the problem started... I had PECTools connected and seemingly everything was OK, it found the index, which came up with a dialog box warning that the scope will move up to 2 degrees, which it did when I hit "OK", returning the guide star to nearly the same spot, which I thought was quite good for such a small FOV since I was using the IS21au618 CCD as a guide camera with a 1/4" CCD.
I resumed guiding in PHD, hit "Train PEC" to start the training procedure and nothing... where the sine curve is, there is meant to be a yellow line showing the start point and a grey line moving as the scope goes through its 479 second worm cycle. I waited for more than 10 minutes than left it for a half hour to see what will happen and nothing. When I hit stop training nothing changed on the graph. Same thing was with batch training, I left it for 90 minutes and still nothing, no files generated nor was there any difference in the software after I stopped training.
I decided to do a PEC training procedure using the hand controller (after starting from the beginning, aligning the scope using the hand controller) on the scope, which it seemed to be OK, PHD was guiding and the mount was recording, after 8 odd minutes it stopped. When I initiated playback, it seemed to improve the guiding scale a bit, but not so much as to be worth while.. but a improvement nonetheless.
I tried running everything with administrator privileges with no change.
I'm under the impression that the CGEM has a 3 cycle worm period before truly being periodic, so the way to get the best result is to average over 6, 9 or 12 cycles and upload the result.
Has anyone tried this and had a similar outcome, or does anyone have any advise... the laptop I'm using is a Sony VAIO running Windows Vista Basic... but all of the controls are working so I'm reluctant to think that the OS is incompatible with the software.
The second thing I tried was using "PERecorder" which worked OK with the calibration and verification until I hit "Record" to record the PE... all it did was display a error message, a crossed out rectangle was all that was shown where the PE graph was supposed to be generated and the tracking was stopped of course losing the guide star. When checking the hand control Tracking setup, it changed from EQ-South to "Zone-5"... Normally there is no "Zone-5" option, just OFF, EQ-North and EQ-South.
Sorry for the novel but currently I'm out of ideas, if anyone has any ideas, help would be appreciated.