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Seeing celestial objects in white
- Calibos
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- Red Giant
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16 years 11 months ago #59342
by Calibos
Keith D.
16" Meade Lightbridge Truss Dobsonian with Servocat Tracking/GOTO
Ethos 3.7sx,6,8,10,13,17,21mm
Nagler 31mm
Replied by Calibos on topic Re: Seeing celestial objects in white
Well, I'm just back in from what turned out to be a short session. Bloody mist rolled in just after I had everything set up.
Colour Perception the same in both eyes. Which is lucky because boy did it feel wrong looking through the scope with my left eye.
Even tried the glasses that I never wear anyway. No difference.
Seeing wasn't good enough to use the 5mm and with the 8mm 187x I could barely make out any detail. Same contrast issue but at this size I just couldn't nail down the shape of the darker patches enough to bother checking with Mars Previewer.
Someone on another forum suggested that Hyperions while great for DSO's aren't as suited for planets. He suggested some TV PLossls which he said were warmer than the Hyp's and had less glass. The closest I had was my Orion Sirius Plossl so I gave that a try. I had the Hyps from day one so I never used the sirius for anything other than alignment stars. (Small FOV, easier to centre star)
Anyway. Guess what. Mars lost the colder white and took on a slightly orangey hue. I'd still call it white but definately a warmer white.
Maybe not alone do I need to get a look in other scopes to compare but I need to borrow some different EP's for a few minutes at the next meet too.
Defocussing didn't bring out anymore colour. When I had defocussed fully I couldn't see any tube currents around the rim but there were uniform cells crossing the defocussed mars, and when I put my fingers at the edge of the FOV. OMG!! The convection currents!! never noticed that before. Just goes to show how important seeing is when you think about it. Nothing we can do about atmospheric seeing but it is so important not to view objects over houses, to minimise tube currents and boundary layer. I can see why people go to so much trouble to minimise these. I know my hand is an extreme example but still.
Colour Perception the same in both eyes. Which is lucky because boy did it feel wrong looking through the scope with my left eye.
Even tried the glasses that I never wear anyway. No difference.
Seeing wasn't good enough to use the 5mm and with the 8mm 187x I could barely make out any detail. Same contrast issue but at this size I just couldn't nail down the shape of the darker patches enough to bother checking with Mars Previewer.
Someone on another forum suggested that Hyperions while great for DSO's aren't as suited for planets. He suggested some TV PLossls which he said were warmer than the Hyp's and had less glass. The closest I had was my Orion Sirius Plossl so I gave that a try. I had the Hyps from day one so I never used the sirius for anything other than alignment stars. (Small FOV, easier to centre star)
Anyway. Guess what. Mars lost the colder white and took on a slightly orangey hue. I'd still call it white but definately a warmer white.
Maybe not alone do I need to get a look in other scopes to compare but I need to borrow some different EP's for a few minutes at the next meet too.
Defocussing didn't bring out anymore colour. When I had defocussed fully I couldn't see any tube currents around the rim but there were uniform cells crossing the defocussed mars, and when I put my fingers at the edge of the FOV. OMG!! The convection currents!! never noticed that before. Just goes to show how important seeing is when you think about it. Nothing we can do about atmospheric seeing but it is so important not to view objects over houses, to minimise tube currents and boundary layer. I can see why people go to so much trouble to minimise these. I know my hand is an extreme example but still.
Keith D.
16" Meade Lightbridge Truss Dobsonian with Servocat Tracking/GOTO
Ethos 3.7sx,6,8,10,13,17,21mm
Nagler 31mm
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- pj30something
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- Super Giant
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16 years 11 months ago #59343
by pj30something
Paul C
My next scope is going to be a Vixen VMC200L Catadioptric OTA
Replied by pj30something on topic Re: Seeing celestial objects in white
Defocussing didn't bring out anymore colour.
I dont know much but that amazes me. Mars tonight was WHITE/BLUE.....but to me (not so far from Bray) when i defocused showed a lovley rusty colour.
I just went out to scope Saturn.......and its complete cloud cover.
I dont know much but that amazes me. Mars tonight was WHITE/BLUE.....but to me (not so far from Bray) when i defocused showed a lovley rusty colour.
I just went out to scope Saturn.......and its complete cloud cover.
Paul C
My next scope is going to be a Vixen VMC200L Catadioptric OTA
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- dave_lillis
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- Super Giant
16 years 11 months ago #59361
by dave_lillis
Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.
+ 12"LX200, MK67, Meade2045, 4"refractor
Replied by dave_lillis on topic Re: Seeing celestial objects in white
Well lads,
I'm glad the defocused images are showing colour and you see how important thermals in scopes are.
It's very interesting that the hyperions seems to lack red transmission, I've never used one of these eyepieces so you learn something new everyday on these boards.
I'm glad the defocused images are showing colour and you see how important thermals in scopes are.
It's very interesting that the hyperions seems to lack red transmission, I've never used one of these eyepieces so you learn something new everyday on these boards.
Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.
+ 12"LX200, MK67, Meade2045, 4"refractor
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