Seanelly

Anything with mites in it I will avoid.

8 hours ago, michael8554 said:

Here's what the PHD2 developers said about your Guide Log:

"Guiding appears to be limited by the 13.6s period RA error component.  I think that the RA guiding could be improved by using shorter guide exposures, like 1s, or 1.5 s at most.

I'd also suggest upgrading to the latest version of PHD2 (or better, the latest dev version), and running the Guiding Assistant with 1s exposures to get recommendations for the RA and Dec min-move settings.

The ~765mm focal length of the imaging scope should be relatively forgiving and the above-mentioned RA guide error may not even be visible in the main camera subs."

 

So set exposure to 1 second or thereabouts BEFORE running GA, not after as an experiment as I suggested,  my bad.

Latest dev version at https://openphdguiding.org/phd2-2.6.6dev1-installer.exe

Just download and run it, don't uninstall the older one.

Without seeing your subs, thay too don't think there will be appreciable drift.

The largest component of your PE has a 13.6 second duration,  this can be seen in the PHD2 Log Viewer if you select a smoother section of the log graph and click on Statistics, that's why a faster exposure is suggested.

Michael 

More very helpful suggestions, Michael, and I hope in future to be able to take over analysis of my guiding/imaging, etc., with my newfound knowledge of the technical details we are delving into. You've been very supportive and I appreciate it immensely.

A quick summary of last night's tests: I  set up as usual, with one exception, allowing the scope to settle down for a few minutes after the slew to the third alignment star (again Vega), and no star drifting ensued or any trouble on that front, so I will continue to do this in future, though the times in past that the image drifted a good deal across the DSLR live-view while I was busy with PHD2 setup can't be attributed to the scope 'settling', in my opinion because the drift was so far and continuing so long after the scope was stationary. Hopefully, however, with the more patient approach I'll be taking it will be the last I will see (or you will read!) of this strange phenomena.

I set the parameters you suggested in PHD2 Brain (HFD: 1.5; untick Star-mass Detect), and used auto-star detect, but after several failed attempts where I got messages: HFD too low, I experimented with those two parameters and though I was able to eliminate the error messages by going back to the old parameters, I still could not get auto star detect to find a star that moved, so I selected a few of my own, but again, kept getting error 'star did not move enough'. So I abandoned M51 and sent the scope to M57, which by that time (app. 11 P.M.) was just above the tree line in the east and ready to image, though a little close to the horizon for my to attempt testing of sub quality.

I reset the Brain parameters (HFD; Sta-mass) you suggested, activated GA, then selected a star with what was probably too high an SNR at around 275, but at least PHD2 started calibration immediately, much to my relief. (Question: GA says select an unsaturated star with SNR >=8; Is 275 too high? I did't think the star I selected was saturated, but I'm not experienced enough to know.)

After GA routine I set the parameters it suggested, including the Drift-Limiting Exposure (which said 1.4), and started 3 minute exposures.

Seeing/imaging conditions were bad, with definite haze and considerable, what I believe is called ECMWF cloud, which is not so much cloud as the haze just mentioned.

Results were better than I expected, considering the challenging conditions, which probably dictated that I not attempt to compare or use the subs to change parameters in future, but I'm anxious to get this as right as possible before I wear out my welcome with you and didn't want to waste even these crappy conditions.

You asked previously after looking at the subs I passed on for your inspection what criteria I was using to grade them. I just magnify each sub and if I see 'egg' shapes then I consider them either iffy, if just noticeable; or bad, if there is a definite lengthening that would mar or blur the final image if too many were stacked with the 'good' subs. You said you didn't think my poor subs were all that bad, and that drove me again to inspect a good portion of each of the six nights of my 5m M81-82 subs taken a couple of months ago, and if I was pressed, I would reconsider somewhat my opinion that they are superior to the good subs I am capturing now. Good subs from last night and from earlier experiments through these troubles tells me that they are roughly the same as M81-82, though M81-82 are 5m exposures. The big difference is in the number of what I would consider poor subs these days, significantly higher than M81-82. Conditions may contribute to poor subs, but even some of the truly 'overcast-like' subs from last night are sharp with no hint of egginess, while on the other hand some of the poor subs came during the odd improvements in conditions. I am looking to the new PHD2 parameters and the PHD2 developers you contacted to hopefully correct these losses with yours and their analysis, and perhaps with better imaging conditions and the latest recommendations this will be solved.

Anyway, for what they're worth considering the lousy conditions, and after my struggle to begin imaging, I got 49 3m subs (800i), and found 18 in the poor class, as defined by me; 9 in the mediocre class that according to my criteria I would probably scrap; 9 in the so-so class that I would probably use, though with reservation; and 13 with no discernible faults whatsoever.

Ideally my goal of course is to see all my subs like these, but practically, I realize this can never be, considering all the variables that go into capturing subs. So my reasonable goal, like else's, is to limit my total losses and reduce the iffy class.

That's about it, unless you want examples from last night, though I doubt that will accomplish much considering the latest exchange between us and the terrible conditions, except to say that the GA recommendation to guide at 1.4s exposure was changed by me to 2s after checking the guide graph (not as good as a couple of nights ago, but as stated, conditions were very poor) some time into the imaging session, but with little difference that I could see, and so left it at 2s. From what you and the PHD2 techs have said, I suppose I couldn't really ask for better until I implement the changes suggested and give it another go, which looks good for Sunday night with much better conditions forecast.

I will download the link you've supplied (much thanks) to the latest version of PHD2 today and set the latest recommended parameters, including exposure setting to 1s before implementing GA.

In spite of all these troubles and my claim to going crazy over them, I find all this extremely interesting, and I'm looking at this as a very good lesson in guiding/imaging, and can see that much has been rectified up to this point, and the potential there to get fully back on track.

Big thanks, Sean

I love this little gem, and coincidentally am imaging it as I write this. I'm hoping for three hours to add to the two from a few days ago, which being my first crack at this lovely object surprised me in preliminary processing with it's strong colour and it's beautiful isolation. You've got both stars quite nicely and I hope I can do as well!

a fascinating subject, well done.

What a lovely, interesting sight.

A beautifully fitting way to end Ottawa, Ontario's Tulip Festival. If I can ever get my guiding like this example I could die happy.

A pleasing example of this massive cluster.

Exquisite, so much depth!

Wonderfully detailed, so much to see.

This is superb, much core detail, a very pleasing sight.

23 minutes ago, michael8554 said:

1)  To avoid locking on a hot pixel try setting the HFD to 1.5 in the Brain button/Guiding tab, and untick Star Mass Detection.

You say you are choosing good unsaturated stars, but you should allow PHD2 to select a star, it knows what's good for it ! Tools tab/auto select star

2)  In the left-hand pane of the GA results is Drift-Limiting Exposure, which was 0.8 seconds. But then it also always says to use 1 to 3 second exposures too in the right-hand of the display !

3) All I'm suggesting is to try a faster exposure, say 1.5 or 2 seconds, for 5 minutes without changing anything else, and see if it gives faster reactions to the excursions, and a smoother guiding graph as a result.

If the graph starts to yoyo then reduce the Aggression until it settles.

As I said, time to experiment a bit, but allow enough time for each new setting to stabilise.

 

Did you try balancing to take up the Dec backlash ?

 

Easing into my thoughts on your results, I didn't think your "poor" exposures were drifting that much, I'd be interested to see if others agree. 

What is your criteria? Is it the Score for each exposure in DSS ?

Try stacking all your subs and comparing with your best stack, if you're unhappy then ignore me !

Michael

 

Just on my way out the door as the weather is clear for the time being, but caught your response in time to write everything down. I will see to your suggestions and get back to you.

3 hours ago, Carbon Brush said:

Hi Sean. Comments from my observatory build.

1/ Make it bigger than you think now. Somehow extra scopes, mounts, accessories and the like need storing. Don't forget desk & chair space when a computer is involved.

2/ Make the roof open/close mechanism powered. Really nice not to have to tug and pull when cold and tired at the end of the night. Plan ahead in case shoulder joints are not so good in a few years.
I use a garage door opener on my roll off. Different roof configurations require different solutions.

3/ When I built my observatory in 2007 I did not know about SGL. There was very little build information on the web. So I made mistakes.
Spend time looking at others builds and use their good features. If possible have a look in person.

4/ If you use standard shed designs as a starter, think again. Put 150% to 200% the amount of 'shed' timber to keep things rigid. Whether putting timbers cloer together, or making them thicker.
Standard sheds rely on being a closed box for rigidity. Removing the roof means you lose strength. Also go overboard on roof strength. You need it to stay in shape when it moves.

Hope something in there is useful.

David.

1) Ya, I've been through the reflector start-up craze and spent more than I'd have liked in working my way up to a 10" Dob, so I'm not anxious to do it again by building this obs. too small to begin with, and 3 meters square seems to be where I'm headed. It is very secluded on the property, too, and if we build solid I may consider storing the reflector, etc., there, too.

2) Good suggestions on the roof. I'm into my sixties now and though with no physical handicaps yet, looking ahead makes sense. I live in Ottawa so snow and ice, etc., must be taken into account for roof mechanics. Definitely the most serious thing to consider, and I won't rush until I'm as sure as I can be. My contractor son is a whiz at this stuff, but he's used to spending other people's money with abandon, and though I wouldn't attempt this without him, I'm constantly bringing him back to reality in our discussions over this!

3) I have all summer to get this right, so if I don't, I have nobody to blame but myself.

4) Again, I rely on the genius of my son for a solid build. He's erected many decks, sheds, docks, garages, etc., many of his own design, and the fact that he's continually sought after for these things is a testament to his capabilities. 

Thanks for the input. Sean

19 hours ago, cotak said:

Raptors better not disappoint this year, but then again the Leafs did it for decades and still sell out their games. I still remember when people switch from lets go Raptors to lets go Pizza once they realize we were going to lose and just wanted the free pizza next day with your ticket if they go above 100.

The head's fine. Heads bleed a lot even with minor scratch, but what I did took some doing to fix. The glue the ER doc used took something like 6 weeks to come out and was itchy. 

The size is 6 foot by 6 foot exterior. I only image so the scale of it was not really a concern when I started, and the wife didn't want something that big cause she was concerned I'd use up all the yard space. In hindsight a bit more negotiation or taking the apologize after the fact track, and getting a bigger building might have been a good idea. As now I realize future OTA size is now going to be observatory limited. And this is also one of the reasons why I ended up with a CEM60EC instead of a CEM120EC, at some point while drooling over the 120EC I realize that I wasn't going to be able to really load it up. The other side of this is that the slide I used are rated for 400lb per pair. While I suspect a 8x8 size roof would still be within spec it doesn't leave much room and I'd question performance under snow loads with roof closed.

The estimated limit to OTA length + imaging train now is about 1 to 1.2 meters depending on balance point. If the building was north oriented I could get a much bigger length so if that's possible for you it might be a good way to minimize the scale of the building while still being able to fit larger kit. Another thing to consider is your own scale, I am not a slim guy even though I am Chinese, but I am not fat either. So I can move around the setup without too many issues, but someone bigger around the middle might find it much more challenging.

In all though if I do it again I'd aim for single section roof to ease automation and likely do a 8x8 instead to gain that extra space for flexibility.

 

This summer's addition would be to finish painting it/trimming, add the automation and potentially solar power the whole lot so I don't have to extension cord it everytime I want to image. The lack of AC power was to reduce the costs and disturbance as I don't think the whole yard dug up to fit AC power was something my wife would have been too happy with. However, again it would be nice to be able to have power on all the time.

 

Surely the Raptors cannot be said to have disappointed their fans this year no matter how their season ends now? I suppose if you absolutely must see a championship from this year then nothing will do but victory, but as a fairweather fan I see nothing but good now no matter what the final outcome. That said, Toronto would be a madhouse with a championship trophy! As a dedicated Ottawa Rough Rider fan since the first Grey Cup I recall seeing in 1966, I certainly know how to grin and bear mediocre seasons, and seeing the newly minted Ottawa Redblacks win the Grey Cup in 2016 was the sporting highlight of my life, even above the great Clements to Gabriel win in '76 and the Canada/Russia Summit Series in '72, because with age I appreciate these things so much more!

I don't know if this will make you feel good or bad or neutral, but I remember watching the Leafs win their last Stanley Cup in '67, or perhaps you are old enough to have seen it yourself. If not, it may be some consolation that I was cheering for the Habs and I cried when Toronto scored the empty net goal to ice the last game!

I've heard that glue is sometimes used for a cut, though never had it done. At least it wasn't staples.

I do have in the back of my mind the possibility of upsizing to the 120 APO from the 100, and though my midsection is not really an issue (yet), I'm leaning toward 9'x9' because though it's more cost, I don't want to get into the same situation I found myself in jumping from a 4.5" reflector to a 6" to finally being satisfied with a 10" dob. Go big or go home, my son said last night, but he's not paying for it. But I'm not paying him, either, so there are savings right there. We will have to consider how to roof this thing.

The issue of power has come up, my son wanting to trench in a fixed supply, but I vetoed this. I don't mind continuing with an extension cord for the time being, and we can always do it later if it comes to that. Biggest issue is COST. I keep telling my wife that I'm done with the expenditures in this hobby, and it was so while I was observing, but imaging is a whole nuther story.

1) Four calibrations: For some reason lately the first few stars I choose for calibration do not move and eventually I get a fail message 'star did not move enough'. I'm choosing good unsaturated stars with 8>SNR but it is like I am choosing bad pixels or something even though I've tried stars with 100> SNR with the same results. So now I can tell within ten seconds or so that the star is not moving and I try another and after a few times I get one that starts to move right away. I have no idea why this is, but it never happened before this recent trouble began except for a couple of times when I was just starting out with PHD2 and I chose bad pixels. Is it possible to select bad pixels with high SNR? (BTW, you mentioned in your previous response, quote: "GA once only at the start of each night, Calibrate near each new object." Is the calibration we are speaking of above what you are talking about? (it had me somewhat confused as I thought it might mean a different calibration elsewhere, but I believe now that it is one and the same, meaning I use GA to start the night, and when I switch to a new object I simply go through the calibration routine again.)

2) GA suggestions: You mentioned taking care to follow these recommendations and that is what I did, and I swear that I saw GA recommending exposures 'between 1 and 3 seconds', and since I was exposing at 2.5 already, I left it that way. The weather may be clear enough tonight to set up at least for a while and I will scour GA recommendations to see where I missed this absolute (0.8 or whatever it says tonight) number. My guide camera will take faster exposures, I believe down to 0.1 seconds or maybe it is 0.01 seconds, but at any rate I've tried exposures occasionally at .5 second to see the how guiding reacted, so I know it will do this at least.

3) Unfortunately I can't answer that because I left the exposures at 2.5 seconds because of what I saw (what I swear I saw!) GA recommend, between 1-3 seconds. If fortune favours me with a few hours of clear weather tonight I will find the correct GA exposure recommendation you refer to and perhaps experiment with it around that recommendation to see if I can tweak it better.

From what you've said and asked I feel much better about nailing this down, and believe that you are right that a little fine tuning will see this overwith for good. Fingers crossed. Sean

That was quite the slide show, nicely documented. I hope your head healed up, no Frankenstein scar? Would your drive to the hospital be considered distracted driving? (Okay, enough, I'm sure it was nothing to laugh at at the time. Once I was helping a buddy move a bed/couch (I forget what they're called exactly) and the cheap cord we were using to tie it closed snapped and the thing sprung open and caught several of my fingers so bad that I was afraid I'd severed one or all because while we were carefully folding it to get my hand out the blood was pouring out of the glove. Fortunately it was more fright than serious, though I do have a couple of nasty scars.)

I will definitely be installing a pier, as much for rigidity as for ground clearance inside; I've kicked my tripod legs one time too many! Sinking it won't be too much of a problem, as my son has installed a number of pilings for decks, etc. Even a flagpole one time! It looks about 2 meters square? After a year plus, are you finding it at all cramped? I was thinking 3x3 but that may be overdoing it, especially as I will only be in there for setup, not observing, and extra width is extra cost.

That is an interesting roof design, something I'll keep in mind as I go forward. I'm not very concerned with how it will finish out, as it will be fairly well hidden from view from the house (my wife's concern), and almost entirely from neighbors (my concern), though knowing my son, I'll have to keep a rein on his enthusiasm for aesthetics. As long as it is solid, functional and weather-proofed to a reasonable degree I'll be happy. I think my dog might wonder why his house is so much smaller, though, haha. Thanks a bunch for the ideas.

(Just watched the Raptors game. I'm not much into basketball, but that was exciting.)

Hi, folks. I'd like to set up a permanent location about 20 meters off the side of the house to hold my imaging scope. I am quite handy and my son is an experienced contractor so we are confident of handling what needs to be done, but this is something neither of us wishes to jump into without some tech advice. Can anyone provide suggestions or details or preferably schematics for a reasonably priced observatory to enclose an F9 100mm APO that will be mounted on a pier, especially a simple roof design that can be manipulated by one person. Any help would be greatly appreciated.

Hello, Michael. If you could indulge me once more (a figure of speech, perhaps I mean once or twice more), I have the results from Tuesday night's imaging session, and results are mixed.

I was very conscious of my setup routine, tension, balance, cable placement, etc., but while centering the third star (Vega) of alignment in the DSLR 10x live-view box for B-mask focusing, I noticed it was drifting briefly uncommanded, not out of the box, so the drift was not much, but some drift nonetheless, and I had to recenter a couple of times before it settled down. Then after focusing and re-placing the star in the unmagnified center of the DSLR where it was originally after 3-star align, I selected M51 and after framing this galaxy with a couple of 30s exposures I turned my attention to activating GA, and when I returned to the DSLR (2 minutes?) to check positioning of M51 with another 30s exposure, M51 had drifted up the DSLR live-view screen exactly as it had done before! Not all the way out, but a significant drift considering that the DSLR live-view was unmagnified, and far enough that I had no choice but to re-center it, which I did with a couple of short exposures, and then moved it around a few times to see if it would drift again but it seemed stable this time, so I went back to PHD2 to reset.

Here is the last short (30s) exposure taken to frame M51 in the DSLR live-view. Magnified, you can see that the image shows star trails (significantly, in the same direction as all the bad subs in the earlier sessions that started all this trouble) over the 30 second exposure, which I only discovered later when studying the exposures:

IMG_5248.CR2

And here is the 30s exposure after activating GA where I discovered that the image had drifted in the DSLR live-view along the lines of the star trails in the image above:

IMG_5251.CR2

All that aside, once GA gave me the go-ahead and I set the recommendations it provided, I started 3 minute exposures. I could not find calibration setting in GA and only discovered last night that it lies in the 'brain' section of PHD2. This I will rectify next session, but it remained as-is for the two objects I imaged Tuesday night.

Results from 26x3m M51subs were varied. 9 were very good, 10 showed very slight star trails under heavy cropping but adequate for wide-field look, and 7 showed significant trails, not as bad as they were in the previous sessions where all the trouble started, but pretty much useless nonetheless. Following are an example of each.

Good 3m M51 sub:

IMG_5269.CR2

Mediocre sub:

IMG_5275.CR2

Bad sub:

IMG_5289.CR2

Keep in mind that even the bad subs show star trails significantly shorter than the trails that first brought all this to mine and your attention a couple of weeks ago, which were perhaps 3 times longer, and I'm wondering if it's possible that the 7/26 bad M51 subs from Tuesday might be attributed to the scope orientation, which was nearly vertical during the 90 or so minutes of exposing?

I wonder this because after M51 I switched to M57 and my percentage of bad subs dropped from 7/26 for M51, to 14/69 for M57, though a loss that is still far more than I was getting before all this trouble started.

I imaged 69 3m exposures of M57. 42 were good, 13 mediocre, and the 14 bad ones just mentioned. Following are examples of each.

Good 3m M57 sub:

IMG_5297.CR2

Mediocre sub:

IMG_5305.CR2

Bad sub:

IMG_5309.CR2

Again keep in mind that these short star trails are nowhere near as bad as the ones that brought all this to our attention in the first place, so something has changed for the better. That said, I remind you that my sub losses before all this were minimal, perhaps 2-3% at most. I thought that maybe all this scrutiny of my subs was making me too critical of their appearance, but I checked a bunch of my subs from six sessions a couple of months ago comprising 17 hours total of 5 minute exposures on M81-M82, and they are near perfect, an example of which follows.

Typical 5m sub of M81-M82:

IMG_2775.CR2

I'm at a loss as to why even the best subs from Tuesday night can't match the typical M81-M82 sub. They are okay, but looking at my M81-M82's thoroughly shows me they are crisper without a doubt. This is driving me crazy.

Finally, I attach the guide log from Tuesday night.

PHD2_GuideLog_2019-05-21_215054.txt

What on earth, or should I say Heaven, is going on? (A rhetorical question for the most part, but at this stage I'll try any suggestions you might have!)

Yours in agony, Sean

1 hour ago, michael8554 said:

GA once only at the start of each night, Calibrate near each new object.

Michael 

10/4, thanks.

Is/has anyone out there using/used this type of scope, be it the 80, 100 or 120mm aperture? I can't find anything in search. I'd like to see some SGL critiques and images, preferably but not necessarily with a DSLR. Online search brings up many 100ED images, but very few more definitive, and besides, the comments associated with the images (in Flickr, etc.) are almost exclusively plain dry facts. I bought the 100 in November of last year after many hours and days of reading reviews and general info on scope manufacturers, focal length, cost, etc., and I must say that so far I have zero regrets where quality, price, and performance are concerned.

I read more often than not that buying a shorter focal length scope was the best way for a beginner to get into imaging, as it was more forgiving, but I'm glad I went with my gut on the 900mm, mainly because I have a preference for globs and galaxies rather than nebulae, and from what I gathered I was fairly certain that with experience I could handle any problems a longer focal length scope might bring.

I bought the scope as a package deal which included the HEQ5 mount (another relatively quality piece for the price for this cash-starved newby) and Orion guidescope/guide camera, focal reducer-in short, everything I thought I needed (turns out not quite, but that's a whole nuther story) except my Canon T6i, which I picked up for a song (I won it in a karaoke contest, haha, just kidding, sorry if you've heard that one before) from an Ottawa University student who had used it for a semester. She said she took maybe only a few hundred photos before dropping the course, and the camera picture count was 1750/10,000 when I checked, considerably more than she said, but still nearly new, unless she lied and had rolled over the count, but the camera and screen were spotless, and even if so, 11,750 shutter releases was peanuts. My T2i has been used almost every day for five years taking hundreds of daytime photos and is still going strong, though I've worn out a couple of lenses. (My techie brother modded the T6i for $100 (I insisted he get something for his trouble) and it has performed flawlessly, and another welcome bit of savings.)

Anyway, plug for Canon out of the way, does anyone have anything to show or say concerning this scope, keeping in mind the relatively low price, etc.? I want the good with the bad, if it comes to that, as if there are any potential problems with it I'd like to have a heads-up.

Sean

I will be using the GA for each new object at least for the immediate future, and will see to the backlash setting.

I just broke away a few minutes to check the handset backlash settings for the mount and both Dec and Alt are set at 0 value, which is the disable mode (manual).

What is your opinion of belt drive conversion for the HEQ5? I've read here only positive results, that it can reduce backlash, etc., and though I'm in no hurry to explain another astro-related purchase to my wife, it surely can't be that expensive, and I'm confident I could do it myself, as I deal with relatively similar stuff-albeit usually on a larger scale-on a daily basis. If it can help improve my images, I would seriously consider it.

Sorry to leave you hanging again for the last ten minutes (haha), I just tried to recover the lost files as you suggested and also went deeper for online strategy but they are nowhere to be found. I might be persuaded to believe in a mislabeling issue and they are hanging around somewhere if I were not sure that I did not because of their relevance to my situation, also because mislabeling two files at the same time is a boner I just can't believe I'd make, besides, the date search has revealed nothing. Quite frankly I now feel that if they are so intent on hiding from me they can bloody well stay there, I will know soon enough how my imaging is faring without them. (That said, my preliminary curious look at a couple of the subs of M57 (no star trails!) before the folder mishap were fascinating (great colour!), and I can't wait to get in a solid night imaging this ring nebula.)

As for the guidescope issue: I see that the dovetail (I called it a wedge earlier) foot of the guidescope bracket can be viewed as quite inflexible in the main scope base, especially as in my case there is no extra shoe or adapter added that might increase the possibility of unwanted movement, but the guidescope tube in its bracket is less so, as the three alignment screws (you mentioned two) are not steel as I said in error earlier, but nylon. If I were having these drifting issues constantly I might be inclined to see this setup as more of a culprit, but at any rate I will keep an eye on things in this area.

I hope you can bear with me a little further come Wednesday (weather permitting, which looks good for Tuesday night) and hopefully celebrate a little on helping a fellow skywatcher get back on track-actually get onto a better track.

Cheers, Sean.

16 hours ago, michael8554 said:

A lot to digest there Sean, but here goes:

I don't have an explanation for the short period of drift after releasing any of the slew buttons - unless you have Backlash Compensation enabled on the mount, as mentioned before ?

Trailing in Dec on your images when PA is good could be due to Dec Backlash, which can be minimised with one-direction PHD2 Dec guiding.

Guiding Assistant gives a confirmation of your PA, and gives recommendations for PHD2 settings based on the Seeing for that session. In your Friday run it shows Dec heading off south due to your 8.1arcmin PA, that your RA PE has peaks of about 20arcsecs. Dec Backlash is 5,839 milliseconds, so the recommendation is Dec guiding in one direction. Also suggests a 1 second exposure, you used 3 seconds.

As you gain confidence you will use GA less frequently.

Guiding in one direction entails:
Setting PA to be no better than about 4 arcmins, so that the mount gently drifts in one direction.
Balance the scope to be slightly heavy in the opposite direction, which takes up the backlash.
PHD2 will correct the gentle PA drift, and if the scope balance is right, it should not go out of balance in the opposite direction, which could take 5.839 seconds to correct !

Friday night, no drift after releasing slew buttons - let's hope you are now good to go for future sessions 😆

You deleted the M3 and M57 images and emptied the Recycle Bin ? I've used my Huawei phone to hack a North Korean nuke missile test, it's heading your way.......

Your M51 image, composed of your good subs, is as good as I get in terms of star shape, but a jpeg of one of your 10% of poorer 3 minute subs, stretched if necessary, would have been more informative. 

Now to your guiding.
There are many Dec excusions of up to +/- 5 arcsecs, which will give you Dec drift on some of your 3 minute subs. Try Dec guiding in one direction only ?
I notice you are ST4 guiding. PHD2 can compensate for the different guide corrections needed for high and low Dec targets, if you have cabled to give RA and Dec positions to PHD2. 
You haven't, so in your case PHD2 recommends you do a Calibration for every different target, so that PHD2 can give correctly sized guide corrections for each target Dec.
I can only see one Calibration, despite targeting three different objects at 47 Dec, 28 Dec, and 33 Dec ?

Now a word about your guidescope.
Your imaging scale is about 1 arcsec/pixel I would guess, and your guide image scale is 6.62 arcsecs/pixel, according to your PHD2 settings.
That means if your guidecam shifted only 1 pixel (5.2um) due to a less than optimum mount, your images would move nearly 2 pixels on your T6i.                                                                                                                                                                       Is your guidescope mounted rigidly enough not to move small fraction of the thickness of a hair under gravity as the mount tracks to different positions ? When you have experienced unwanted moves in you imaging, it's worth removing a possible
source.  Hence the concerns of some of us !

Michael

The recent Friday session I finally managed to fit in that showed no drift after releasing the directional buttons I think tells me that previously either something was not battened down or my balance was off, but the fact it happened four times in a row while getting progressively worse and now it seems fine, even with the extra caution Friday given to the setup, just has me baffled. If I never see it again I'll be happy, but it will bug me for a long time to come.

I will have to check on the settings for backlash hopefully Tuesday night with a bit of lucky clear weather. All these settings (backlash,etc.) are new to me, as well as the Guide Assistant recommendations, which I never noticed after it finished it's routine. I just assumed it would take care of those by itself (pretty sure you knew who you were dealing with here from the start but this is more proof how new I am at to this).

As to that silly business of deleting M3 and M57 subs, I never emptied the recycle bin, did not even send the subs there, I just looked there for them but they were not to be found, nor anywhere else. I can't even recall how I lost them. I thought I had separated everything into folders but after checking each sub of M51 I moved on to check M3 and M57 but the folders had vanished. Maybe I should have been a magician!

As to that nuke crack, why are you using Chinese Huawei technology after all the [removed word] they've stirred up, both the country and the company?  And you can't fool me, any N. Korean missile fired in this direction, if it ever got off the launch pad, would no doubt land closer to Japan than Canada.

Re guiding: My experience with noticeably improved guiding Friday night after using Guide Assist was an eye opener. I did not know how necessary it was in my case, and I will use it for each new target in future.

Guidescope: You will have noticed the SW scope I am using for imaging. I don't know if you've seen it, but the metal wedge mount for the guidescope is dovetailed to fit the metal Orion guidescope base and secured by a single, strong screw. I went over it thoroughly on Friday during setup and it is very solid. I can't vouch for materials or design used in these two areas in the past which may possibly be the source of the questionable reputation, but I work as an industrial millwright, and while the technical side is not my strong suit (you will have noticed, haha), I really do know a strong, mechanical connection when I see one, so while I don't rule it out entirely as as contributing to my problem, it is the least of my worries. If my drifting had occurred on just one night, or on a couple of separate nights, I might perhaps suspect that the dew heater I use on the guidescope had caught up on something and pulled on the guidscope, but four sessions in a row blows that up.

Tuesday night (hopefully) I will follow all the Guide Assist recommendations and briefly test-image several more widely separated objects, and pass on any bad sub examples and the log. I hate to say it for your sake but I hope all my troubles over those four nights were an anomaly that I'll never see again and I've just wasted your time. If that is the case, hopefully the compensation on your part will be that I know a fair bit more about what I'm doing than I did before all this happened, which will no doubt improve my images, and you've shown yourself to be very selfless with your time.

But first things first.

20 hours ago, michael8554 said:

Look forward to seeing the before and after images.

So after centering the third alignment star, it continues drifting across the dslr screen.

Is that in dec or ra, is it always in that direction, how long does it drift for ?

Are the stars in your images drifting in the same direction, or is it different in each image ?

Michael 

So, if you've got time, I've got answers and I've got questions.

I can't provide images of the star drift during those four imaging sessions in question because while checking over each sub to potentially go into DSS I deleted all the bad ones. I didn't realize that I might need to reference them, and though I have plenty of room on my portable drives for storage, I didn't see any use in holding onto junk subs. I do have the good subs of M3 that I subsequently stacked, processed and posted in my album, 3+ hours out of about twelve imaged.

After centering the third alignment star, then exchanging the eyepiece/diagonal for the DSLR and positioning the star in the DSLR 10x box for focusing, the star continued to drift for a short period of time in the direction it came from after I took my finger off the handset directional control. This was under 10x, don't forget, so the drift was not much, but it was there nonetheless, and on the last disastrous night of the four sessions, after the star drifted and I re-centered it in the DSLR 10x and achieved focus and then slewed to M3 and framed the object, I turned my attention to setting up PHD2, and when I turned back to the DSLR  live-view screen a few minutes later, M3 had drifted halfway up the (unmagnified now, so a significant drift) screen of the DSLR. Seeing as how the image had already stopped moving and was still placed as such that my cropping would make it unnecessary to centre the image anyway, I left it that way and started imaging. I lost all subs on that last night.

The star trails were not long, but these subs were only two minutes duration, and I've gotten much better results just guiding off the mount alone. All trails are in the same direction, what I believe to be declination, as I was imaging toward the east and the trails were running to the top right of the subs (I hope that is not misleading).

Friday night I got my first chance to set up and test since that last disastrous session. I checked over all the gear, making sure everything was as it should be, and took great care in balance and locking everything down securely, etc. There was no drift of the third alignment star in the DSLR 10x live-view screen, so that was already an improvement, and after the mount slewed to M51, I framed it and then went through the Guiding Assistant routine.

I asked this question earlier in the thread but got no answer, and I've yet to get into the PHD2 analysis link provided: Is it recommended to use Guide Assist every time you set up, or perhaps only every time you want to image a new object, or just randomly on occasion? This is more relevant to me now because my guiding last night was better than I've ever seen it. There were occasional blips, but generally speaking it was exceptional.

I have another question that might be solved from the guide log provided below, but as stated, I have not yet looked at the analysis link so I do not know. While my guiding was very good according to the graph, I noticed that my polar alignment error in the Guide Assist routine ended up at around 8.0, whereas the first log I provided for the bad sessions earlier proved my PA alignment error at only 0.5. If I'm reading and understanding all this correctly and the discrepancy is truly an indication of bad PA, then it may be because while the handset provided Polaris position at 1:30, I just may have set the mount to 1:20 instead. It was just one of those things where after everything is done and you have started imaging, you run over the routine in your head to try and find any flaws, and this PA 1:20/1:30 stuck in my head all evening. There was no way I was going to start all over again, and I figured if PA was bad, it would still be possible to image while taking that into account, and so my question is, if all this be so, would guiding still be as good as it was last night?

And now for the results, good, bad, and just plain embarrassing. I imaged about ninety minutes each of M51, M3 and finally 2 hours M57 as a late-night addition, three different locations in the sky for a good overall test, and even got up before dawn to grab darks, flats and bias. But stupidly, in my routine to organize the folders before stacking, I somehow deleted the subs for M3 and M57 (I need to get more sleep, haha). Go ahead, hit me now and get it over with-tell you what, I'll do it myself right now. Ouch. What gets me in all that is I'm usually so careful anyway in my setup, and yet here I was at the most important of imaging sessions fretting over possibly clumsy PA and then dumping valuable images not even in the recycle bin where I could retrieve them and save the day. Anyway, I still had M51.

I lost about 10% of the subs to star trails or 'globbing', if I can use that word, but the types of losses were nothing like the consistent one-track trails of the bad M3 subs in question, and I'm hoping that this high loss can be attributed to the fact that while the mount RA was nearly parallel to the ground and so my balance there would have been spot on, the scope itself was nearly vertical for the roughly 90 minutes of imaging, and while my balance there was as good as I could make it, I'm wondering if this vertical attitude had anything to do with the high rate of loss.

Sorry for the long-winded explanations. I post here the 1h 4m M51 image, composed of 3m subs and about 50 each of the three other calibration frames in DSS and tweaked in PS, and also the guide log.

If the problem has cleared up, which won't really be known until the next session, fine and dandy, but it would still leave me wondering what caused it in the first place for all four of the imaging sessions of a new object.

PHD2_GuideLog_2019-05-17_215239.txt

Twenty easy and simple years owning a visual dob spoiled me into thinking that doing the research, getting input from various sources, and springing for a basic imaging rig was as far as the cost would go, but I underestimated by a good deal the cost of all the 'extras' necessary to get another step closer to better photos, or simply to acquire necessary gear that was overlooked in the original research. SGL was a great source of information and encouragement as I sourced my rig, but nobody ever pointed out that once you think you've reached the end of the road and can now order all your stuff and away you go, there is always another, smaller road that continues the journey, and the cost. I don't say this in blame, I am, after all, responsible for everything I do, and of course everyone here wants to support a budding fellow amateur astronomer just as I encourage people following behind me, I just wish I could believe that the next time I tell my wife that this purchase will finally complete my setup, it will actually be true.

5 hours ago, michael8554 said:

To sum up:

Your PA is good, and your guiding is good enough that stars shouldn't be drifting.

I'm having trouble understanding what your problem looks like on images.

Perhaps you could post a before and an after jpeg, same durations, from sessions before and after your problem arose ?

Michael

Thanks, I'm glad to see that you confirm my PA/guiding is not the problem.

As I write this the scope/mount is undergoing it's first imaging session since the problem in question arose about ten days ago, crappy weather hogging the entire interval, and irregardless of the full moon, as it makes no difference for test purposes.  I double-checked all connections, mounts, screws, etc., paid close attention to PA and balance and focus, etc., and used PHD2 Guide Assistant before starting on a selection of shortish exposures. I saw no hint of image creep on the third star, so that was an improvement already. I won't have all the data until tomorrow.

 In a nutshell, for four straight imaging sessions, all on M3 for my first crack at this glob, I was seeing the last stars of the three-star alignments, while I was in the process of centering them in the DSLR 10x live-view screen for focusing, continue moving across the DSLR live-view screen even after I released the directional button, not far the first couple of times, though I lost more than half my subs to short star trails, but by the fourth session M3, after I got my focus and re-centered the image, continued to drift halfway across the unmagnified DSLR live-view screen while I was in the process of getting PHD2 running, and all my subs were lost to short star trails, something I haven't had to deal with since my first days getting things up and running. These four sessions were each set up separately, as I'd been doing successfully leading up to that point.

I'll have more to go on tomorrow, but the suspense is killing me.

This galaxy is one of my favorites, and you've done it proud.