just got a flattener. improvement but not perfect. left side blurry? Tilt?

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realflow100 United States of America
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just got a flattener. improvement but not perfect. left side blurry? Tilt?

#1

Post by realflow100 »


rotated the objective lens assembly to see if it changes but it doesnt. its still on the left side. I shimmed the focuser to try to make it not wobble as much side to side. still has a significant amount of blurryness on the left maybe 25% of the image
rest of image middle top bottom and right are great and as good as can really get.
I think I somehow have some focuser tilt that I can't seem to get rid of. think my focuser isn't attached on perfectly straight. im not sure how to fix it.

am I just splitting hairs at this point and should I just crop the left part of the image out?
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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Re: just got a flattener. improvement but not perfect. left side blurry? Tilt?

#2

Post by realflow100 »


I decided to fiddle with the objective again and slightly loosened the 3 screws holding it onto the tube. VERY slightly tilted it towards the left. BOOM hugely reduced blurry edges! So much better in fact!
left and right sides are about equal now in sharpness.

I went and shimmed the lens cell on the tube with a small rectangle of 2 layers of duct tape to give it a slight bit of "lift" so when I tighten the screws it stays this way.
I think the distance is off by like 0.5mm for the flattener and sensor spacing. but I may be just splitting hairs at this point. Point sources look good. almost perfect. Not quite. but very close.
Terrestrial objects show a tiny bit of a "ghostly" tail to them. but overall mostly sharp at the edges.
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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realflow100 United States of America
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Re: just got a flattener. improvement but not perfect. left side blurry? Tilt?

#3

Post by realflow100 »


increasing the spacing for the flattener and sensor makes it worse. (Even the tiniest increase makes it significantly worse. like 0.5 of a millimeter causes it to be a lot worse)
I can't go in the other direction unless I got some kind of slim/compact T2 m42 thread ring adapter. or m48 thread
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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realflow100 United States of America
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Re: just got a flattener. improvement but not perfect. left side blurry? Tilt?

#4

Post by realflow100 »


ok nevermind about the lens cell/objective tilt... is it possible it might be some other form of tilt then? the chromatic aberrations in the middle of the frame show a very slight "shift" to the right. although the central core of stars looks fine
at the corners and sides theres STILL some coma/blurryness. which shouldn't happen if my flattener is properly spaced? right?
Could my sensor be showing tilt?? (is it possible it only shows up at wide apertures and long focal lengths. whereas its not noticable with normal camera lenses?)

Also the top of the frame shows a huge dark vignetting when taking photos at high shutter speeds in the daytime. but ONLY when I use my camera with my telescope! Not with any of my camera lenses. and even does not show up with no lens. I'm very confused by it. its totally fine at slower shutter speeds (under 1/500 or something not sure. maybe 1/800)
Could the long focal length and wide aperture of the telescope be causing a slightly slow shutter to be showing visible problems that dont show up at shorter and slower focal lengths?
50mm F1.8 doesnt show any problem at 1/4000
and even 200mm F6.3 doesnt show any problems either. Im super confused

My cameras shutter actuations is about 35k total (21k pics taken 13k live view) is that in the danger zone?
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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realflow100 United States of America
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Re: just got a flattener. improvement but not perfect. left side blurry? Tilt?

#5

Post by realflow100 »


it seems like its a combination of VERY slight focuser tilt + very slightly off field flattener distance. I tried slightly adjusting the focuser by like 0.1mm and it helps. left and right are almost equal. but still slightly blurry. is there anything I could do to easily tweak the flattener distance or something? Pieces of scotch tape layers or something??
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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realflow100 United States of America
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Re: just got a flattener. improvement but not perfect. left side blurry? Tilt?

#6

Post by realflow100 »


I tried increasing the spacing a LOT. a millimeter at a time.
it didnt really change the edges hardly at all until about 4mm. where it looked slightly improved.
but I'm not able to reach infinity focus anymore! I just can't win can i??
The edges look "glowy" like a ghostly very slight double image effect on the edges of objects. and objects look slightly soft and fuzzy. Not crisp.
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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