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Cool telescope at WSP

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#1 kfrederick

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Posted 11 February 2013 - 08:12 AM

Had my best views ever in a fast 32inch at WSP I was very impressed .

#2 polaraligned

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Posted 11 February 2013 - 08:21 AM

That is good...more details?? How fast? Kennedy mirror? Wood or aluminum structure?

#3 Mirzam

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Posted 11 February 2013 - 08:31 AM

And how did your chief perform?

JimC

#4 kfrederick

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Posted 11 February 2013 - 09:21 AM

I liked the views in my CHief Had some astig but nice contrast I thought .the mount needs work .They had very heavy dew but only my eyepiece dew up .I used no heat. Some big boys got to look .Howie G has some ideas for my side supports for my primary . But the views in that 32 was unreal good . Very impressed .Did not think a telescope that fast could work that good . The sky was very steady The Orion Neb had detail so vivid I have not seen in pic it was worth the trip .Glad Mike ask me to look .

#5 Pinbout

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Posted 11 February 2013 - 09:58 AM

who made the scope and who made the mirror?

#6 Dave O

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Posted 11 February 2013 - 10:09 AM

Could you see color in the Orion Nebula? I've heard many can see 'green', and in the larger scopes even blues and a bit of red ... just curious ... :)

#7 kfrederick

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Posted 11 February 2013 - 10:56 AM

Blood red and patterns in the dust clouds unlike I have seen even in pic very steady air. I think the mirror was a f3.7 Lockwood

#8 bremms

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Posted 11 February 2013 - 01:36 PM

Good collimation and a coma corrector?

#9 Mike Lockwood

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Posted 11 February 2013 - 02:12 PM

Blood red and patterns in the dust clouds unlike I have seen even in pic very steady air. I think the mirror was a f3.7 Lockwood

Close, it is f/3.6. Good to meet you, Kevin. Keep working on the mechanical aspects of your scope.

Good collimation and a coma corrector?

Yes, and a SIPS (which is a Paracorr II).

Jupiter at ~700x was my favorite view of the event. Many other objects were too detailed to describe. Sirius' companion, the Pup, was trivial to see. Color in M42 and M43 was easy to see in the 32" and smaller scopes, and there were 10 stars in the Trapezium.

We had more clear skies this year than last, but the seeing was a little better last year when we were viewing Mars at ~900x with the same scope, and the Eskimo Nebula at 2000x+.

#10 Darren Drake

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Posted 11 February 2013 - 05:57 PM

Mike,
Will we see some more details about your trip on your website?

#11 kfrederick

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Posted 12 February 2013 - 08:36 AM

Seeing the trapezium looked like a open cluster . Titan disk was big . Great planet views . Size does matter and great sky . I could see no coma and the edge was great .

#12 mark cowan

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Posted 12 February 2013 - 03:47 PM

Kevin, are you thinking of joining the ranks of the unwashed? :poke:

Best,
Mark

#13 kfrederick

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Posted 12 February 2013 - 04:32 PM

I was impressed and glad to use it . With Al very cool . Worth the trip . Much more than a 25 .

#14 mark cowan

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Posted 12 February 2013 - 06:40 PM

That is kind of the general rule for resolution. Bigger aperture with a CO under excellent skies beats smaller unobstructed. :shrug:

How well did your Chief acquit itself, then? What were comments like?

Best,
Mark

#15 kfrederick

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Posted 13 February 2013 - 06:42 AM

The Chief did good I thought The back ground sky was black and was noted by one person . Also The high contrast was noted by some . I was showing astig in the defocused images but in focus it worked good . Al said to finish it and take it to Stelafane .I just wonted to have the pros look . And that happened . I am glad I came . And glad I got a look in that 32 inch .

#16 Mike I. Jones

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Posted 13 February 2013 - 09:21 AM

Your Chief is by definition an off-axis system, so even with all perfect optics (which yours come very close to), there will be astigmatism as you roll through focus. There is even astigmatism at best focus, but it's so slight it gets lost in the diffraction patterns. There is a very shallow focusing range either side of best focus before you visually see the astigmatism. I'll post up through-focus spots of your Chief later today.

That being said, is there any chance your support system is very very slightly warping Carl's mirror? Even though it's a strong hyperboloid, you could still star test it and look for through-focus astigmatism without the correctors in the path. Just a thought.

Mike

#17 kfrederick

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Posted 13 February 2013 - 11:47 AM

Thanks Mike My edge supports for the primary was hanging up Howie Glatter is making me a new support . I set it up in the day but didnot work on it at night. The image was the best on my last night. I am planing a new box so I can have the lens out of the way when the laser is used as it is altered some .Or use your idea of the laser mounted at the center of the incomeing light . My setup was off some .But I liked the views and very proud of the work You and Dave did for me .On Eds Chief.design. :jump: :jump: :jump:

#18 careysub

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Posted 16 February 2013 - 06:48 PM

Could you see color in the Orion Nebula? I've heard many can see 'green', and in the larger scopes even blues and a bit of red ... just curious ... :)


On another thread (and forum) someone was just saying that the surface brightness of an extended object is always the same at equal exit pupil (limited of course by your eye's entrance pupil). That would mean that in viewing a nebula in a large scope you are seeing it at higher magnification, but the same surface brightness.

Whence does the ability to start seeing colors in the nebula come then?

#19 Mike I. Jones

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Posted 16 February 2013 - 07:53 PM

Google "Purkinje effect" (it's pronounced Pur-Kine). It's all there, explained better than I can.
Mike

#20 careysub

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Posted 17 February 2013 - 02:11 PM

Google "Purkinje effect" (it's pronounced Pur-Kine). It's all there, explained better than I can.
Mike


Doesn't seem to address the issue. It discusses the process of extinction of color vision as light levels drop to "night-time" levels.

The question is the apparent contradiction between the claim that extended objects have the same surface brightness regardless of aperture (with the same exit pupil); and the claim that large aperture telescopes allow seeing color in extended objects that are absent in smaller scopes.

One possibility is that there are brighter regions within the Orion Nebula that become magnified in a large scope to the point that they become visible and can thus generate color perception.

#21 MKV

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Posted 17 February 2013 - 02:40 PM

Google "Purkinje effect" (it's pronounced Pur-Kine). It's all there, explained better than I can.
Mike

Actually, the name is Czech, spelled Purkyne and is pronounced poor-kinye. The e at the end is a yat, which looks like an e with a small chevron on top of it, and is pronounced ye. The spelling Purkinje is probably a German rendition of the Czech spelling.

#22 Starman1

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Posted 18 February 2013 - 12:48 PM

Google "Purkinje effect" (it's pronounced Pur-Kine). It's all there, explained better than I can.
Mike


Doesn't seem to address the issue. It discusses the process of extinction of color vision as light levels drop to "night-time" levels.

The question is the apparent contradiction between the claim that extended objects have the same surface brightness regardless of aperture (with the same exit pupil); and the claim that large aperture telescopes allow seeing color in extended objects that are absent in smaller scopes.

One possibility is that there are brighter regions within the Orion Nebula that become magnified in a large scope to the point that they become visible and can thus generate color perception.


It does seem that the larger scope, at the same exit pupil, pours a lot more light into the eye from the much-larger object image.
If more color is visible in larger scopes (and I can verify that this is true), then it will be because the cones in the eye start turning on when the image on the retina is brighter overall or brighter per cone, as in viewing brighter stars.

Here's what I mean:
Double the width of the image (4X the area on the retina), but keep the exit pupil the same (i.e. by doubling the aperture), which doubles the magnification. The brightness per square millimeter on the focal plane of the scope is the same in both cases, but in the case of equal exit pupils, 4X the overall light is concentrated in exactly the same exit pupil in the larger scope. The image of the object is larger, so the brain notices it and sees details in it a lot easier. The surface brightness of the object is the same as in the smaller scope but the size is 4X as great by area, so the overall light from the object has increased 4X in the exit pupil of the eyepiece and the retina of the eye.

At least, that's how I read the increased visibility of fainter objects in bigger scopes even though calculations of surface brightness show that the objects per unit brightness has not gone up. The total number of photons from the object has gone up, but the photons per unit area has not. 4X the overall brightness spread over 4X the area = the same brightness per unit area.

The Purkinje Effect relates to the change in visual response to color as the eye becomes scotopic. The most notable aspect is the maximum sensitivity of the eye changes from 550nm in daylight (green) to around 500nm at night (blue-green), making reds even less visible than they were during the day.

"Cold hearted Orb, that rules the night;
Steals the colors from our sight.
Red is gray and yellow, white......"

Were it not for the fact that viewing the Orion Nebula through a scope can damage one's night vision, I would be skeptical we saw actual colors. At the faint limits of our eye, we see brighter grey as green and dimmer grey as red, and it leads us to see color in nebulae that we really can't see. It is an illusion. We all see it, so it is a human eye-related illusion, but an illusion nonetheless.

But, in the Orion Nebula, and in scopes a lot smaller than 32", colors other than red and green can be seen. I see blues, beige-yellow areas, purplish mauve, and greens and reds--in different areas of the nebula, and matching color photographs in terms of colors per area. Those colors are real and seen as real.

But we also have the example of M27, where the eye sees colors reversed from the photographs because of that false color illusion. So we have to be careful in attributing true colors to objects seen.

"But we decide what is right, and what is illusion."

#23 Mark Harry

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Posted 18 February 2013 - 02:44 PM

14" Fast (relatively) scope- in order of detection
******
indigo, dark red, yellowish-green, and GREEN.(faint-bright)

******
Does that confirm your post???
M.

#24 Starman1

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Posted 18 February 2013 - 02:47 PM

Mark,
Try looking for the beige-yellow nebula color on one side of the Regio Centralis. The other side is a red-violet and forms a good contrast, color-wise.
Don

#25 Atl

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Posted 18 February 2013 - 05:30 PM

I think the bigger the scope the more color can be seen. I also think this varies person to person. The concept that color vision drops off with dark adaption is not a black and white given. When observing one never reaches full dark adaptation because one is exposing the eye to light. Through my 12.5" dob M42 is bright enough to cause after images when I look away.In my experience I see light pink in M42, and some blue green in M78 consistently if transparency is high and the eyepiece focal length is long. I can imagine through a 32" the sky would be awash with color.






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