Stuart1971

Sometimes the recommended figures are not exact, the actual distance can vary from one set up to another, best to experiment with 0.5mm steps, back and fourth to see if you can better the stars, but the Image actually looks very good, I have bad tilt on my camera and am in the process of sorting out…it’s been a real pain the the behind TBH..😮

Those figures above show a bit of curvature, as the central figure is lower than the four corners…so a flattener may help, or if you have one fitted, then maybe adjust the spacing….you have an APC-s size sensor so with that scope, a flattener will help loads I would imagine…👍🏻 I dont think that is tilt at all….

Ordered the Baader UFC tilt adapter today so should be here on Wednesday, perfect as I use the baader UFS filter drawer system, and this fits straight to the back of that with just 9.75-10.5mm backspace, simple to adjust as the adjustment screws are in the edge and have in and out screws, couldn’t be simpler….so it’s perfect for me, as soon as it arrives the camera will be back in the tilt jig, and all sorted…hopefully Why didn’t QHY just make a tilt adapter built into the camera, would save so much trouble, there QC control is rubbish TBH to send out cameras with this issue….not happy at all https://www.baader-planetarium.com/en/baader-ufc-tilter.html

Does look like a good solid mount, and a good price too, and first reviews seem to be very promising too. I personally like the look of it, and I think it will give the Mesu’s a run for there money as it’s a much cheaper price, and still has a proper function to adjust Alt Az for PA, which the latest Mesu does not, you just have to mess about with spanner’s and such like which I think was a real backwards step… I am watching this mount and it’s new customer reviews with interest, it may well be my next big upgrade….👍🏻

Yes, spot on….excuse the pun… I too have just realised this, the AR window must also be a little out of true with the front face of the filter drawer I have fitted and that I am rotating the camera on, but not as much as the sensor, hence the two different size circles, also the more reflective surfaces you add puts more dots in the line, and as you said, the further from the sensor the surface is, the closer to the laser mount the dot falls, so with this logic, the bottom most dot is the correct one, so I had it right to start with… If I add the filter back it added a dot and I also added another surface under the camera and it added another even closer to the laser mount, so it seems to hold with what we have said, or more like what you said….😂 Also out of the filter, the AR window, and the cover slip, the cover slip has the most tilt….in relation to the front Face I am rotating on…😮😮, not good… Thanks for helping as I have gone on enough to you about this, I must be driving you mad…👍🏻

Interesting, as when the filter was fitted the three dots were in almost a straight line and directly in a line from where the laser is mounted, so the image below shows the three circles each dot made, the top dot is gone as the filter was removed after I plotted the circle, so maybe it is the bottom one, as it has some flaring and is furthest away from the laser, but does not explain why the circles are different diameters….the middle one is quite small and almost obscured by the dot….this one we think is the AR window…so does this mean the AR window has less tilt than the sensor, is that why the circle is smaller…..?/🤔🤔🤯🤯

Ah, ok In this video the top dot, I assume 🤔 is from the Cover glass, and the bottom is from the AR window…if so why does the AR dot move in a much wider circle, should they not move the same, or does this mean that the AR window is much more tilted than the sensor…😮 there is deffo a bit of flaring on the bottom dot, if you zoom in…so does this mean it is from the AR window…🤔🤔 The black dots are from me plotting the movement, as at the time I thought the bottom one was the one I should be watching, but since changed my mind…but I could still be wrong…😂 EEEA7727-29A8-4F92-8945-AFAE61F4922E.MOV

Thanks for that My scope is f5.3 TakFSQ85, camera is QHY268c same as the ASI2600mc well I can’t see any pixel reflections near the AR window reflection at all, (just a few around the laser base about 6” away) so I can’t use that…I have just two dots as shown above, one from the AR window and one from the cover window, and don’t know which is which as they are the same brightness, one moves in a circle about 2-3mm across and the other one 4mm across… so I have not had the luck you had in sorting it out….

This guy says you should ignore the window reflections and use the pixel array reflection to set the tilt….🤔🤔 https://www.macobservatory.com/blog/2021/11/28/how-to-remove-sensor-tilt-from-your-astrophotography-camera-while-indoors

In which case I have very little tilt, probably about a 2-3mm circle, would this make much of a difference to the stars…I guess it would, just wondering really how much tilt is acceptable and will not really affect the stars on one side of the image….🤔🤔 I get it’s best to have none, but is there a point where it will not manifest in the images….

Would you agree that the centre dot here is much more pronounced and round and more symmetrical then the other two which have a bit of flare, the top one turned out to be from the filter…so that left the other two, which I think I chose the wrong one…. I am assuming that the reflection from the slip cover, should be a more perfect dot due to it coming from the closest to the sensor itself…correct…? Just not sure why the AR window dot should move in a bigger circle, then the cover slip dot, as it closer to the base…🤔

Yes I have just come to the same conclusion, they seem pretty much the same brightness, also why are there no pixel array dots near to these two…🤔 they only seem to show further away towards where the laser is situated, wonder if I have to steep angle on the laser beam, and it should be more upright… I think it is the other dot, as the one I thought has a slight red flare around it, which would make more sense it’s from the AR window…🤔 do you think…?

Thanks… I just wish I could tell which dot is the correct one, as one moves in a much bigger circle than the other, does that tell me anything…as if it’s the dot that is not moving much at all, then the tilt is very minimal, they seem the same brightness too, I thought the one that did not move as much may have been one of the set of dots from the pixel array, as it seemed to move about the same amount as all the others further back, but this would mean that there was no reflection from the AR window….🤔🤔🤯

Well, after a bit of messing about I think I managed to see how much tilt I have in my QHY268c camera First of all I left the filter in and the laser produced 3 dots, as per (first picture below), and I tracked the wrong dot as then I removed the filter as I realised it was an UV/IR block filter, and then dot i was tracking disappeared, and left me two, (second image below), so had to start again, so I tracked both and plotted with dots, i only have an AR window on my camera so if you have a UV/IR window you will probably see three dots. so then I rotated the camera and one of the two dots moved in a very small circle, the other, which I am assuming is the cover slip reflection and the one I need to concentrate on, moved in roughly a 4mm diameter circle, (see pictures and video below) not sure how much tilt that relates too, but a single piece of A4 paper under the edge was about right to move the dot to the centre of the 4mm circle, as this would mean the tilt should be eliminated, I don’t have my tilt adapter yet, so can’t sort it permanently ☹️☹️ Am I correct in assuming I have chosen the correct dot to concentrate on, or does it not really matter…as when tilt is corrected both dots will remain static…? 6A630EBE-3811-47B4-8DCA-46CF873F1354.MOV

Yes, you are perfectly correct, I was over thinking it all, and making it harder in my head than it needed to be, thanks for explaining….and thanks for the jig idea, the thought of adjusting under the night sky in live imaging conditions, brought me out in a hot sweat….😂😂

I have no idea why not, as I am still trying to get my head around the idea, I just assumed, probably wrongly, that the centre would not be good, as again I wrongly assumed that the centre would not move, just spin on the spot during rotation, and not show the error, and if tilt was from one side to another the centre would stay pretty much in the same spot, but I am probably looking at all this totally wrong…🤯🤯

Thanks very much, just a couple of things that I can’t get my head around, I have the QHY268c with the IMX571 sensor, surely if I aim the laser certain parts of this, when I rotate the camera, the beam could go off the edge of the sensor and then come back on..? so does that mean ideally it needs to be aimed near the centre…? I am trying to visualise the sensor being tilted, say long edge to long edge, but if the beam was pointed bang in the middle, then would the dot not then move when rotated as the centre would be pretty much still….or am I missing something….?? I have taken the laser out of a Baader collimator I had, as I don’t use it, it’s a 1mw but it’s a class 2 red beam, I assume this will be fine as otherwise Baader would not have sold it for this purpose…? sorry to be dim…

Just built my own tilt test jig, based on Olly’s idea, so questions, where at the sensor to point the laser for best results…as I assume if pointed at the centre it won’t show much in the way if movement…? Or am I missing something… and where can I get a suitable laser pointer to do the job, as my Baader 1mw collimating laser is not powerful enough and is a bit big and bulky… And re the laser reflection dots, is it the cover slip reflection or one of the pixel reflections I am looking to work on, as I have read conflicting ideas on this…?

Yes, I am not sure what he means with regards to critical backspacing when no flattener or reducer is fitted….makes no sense to me, but then I am not the most clued up on this sort of thing….🤔🤔

Yes it’s a quadruplet..👍🏻 but any refractor triplet or doublet with no flattener fitted does not have any backspace issues, and not critical as you just rack focuser to where ever it’s in focus, you have no choice where this focus point is…and that’s it it’s only with flatteners and reducers fitted where you need the correct back focus from said reducer or flattener…to get correct star shapes…

Just been in the garage for an hour and knocked this up as per the @ollypenrice idea for a tilt jig, I liked the idea of the camera at the top method for a couple of reasons, it will eliminate any other tilt other than sensor tilt, like sag, and no need to worry about how to support the camera while rotating, just need to find a suitable laser and then fasten that.. The tilter I am ordering is the Baader UFC version to fit on my filter slide, which has push pull screws on the sides so will be simple to adjust…similar to the Geurd Newman version. Also where at the sensor should I point the laser, obviously not at the centre, so am guessing about 2/3rds the way across so the beam does not leave the chip surface when rotating…??

Also how can I change back focus if I don’t have a flattener, there is nothing to change backfocus from surely, the focus point is the focus point….🤔🤔

No backfocus issue as I don’t have the flattener yet….🤔 just bd corner stars due to needing one 👍🏻

Can anybody tell me how you can determine the difference between sensor tilt and the need for a flattener…? I have ordered the flattener for my scope as it’s now needed after getting my QHY268c,Tak FSQ85 scopes does not work well with modern small pixel sensors, as these scopes were designed for large pixel CCD cameras, because of this Takahashi have bought out a new separate flattener to address this issue, which I have ordered, it causes really bad star shapes in the edges of the frame, but according to ASTAP it’s also got bad tilt, and not sure how much of the issue is the need for the flattener, and how much is tilt…🤔🤔 Just wondered if there was a way to tell the difference….

So, I have decided to do some testing on my set up for tilt using ASTAP, and I do have some, but it does seem too bad, so here comes, what maybe a stupid question, will field curvature, due to not having my flattener fitted with the images I was using to test, screw up the tilt results, as the results clearly show some tilt and curvature…and wondered how much of the tilt result would be affected by the field curvature… I have only just got the flattener, so it’s not been used yet… Thanks for looking Stuart