There's obviously still some room for improvement here.
This was shot on ASA 800 Kodak film, with a Pentax ME using a Photon Instruments 1147mm f/9 telescope with a 25mm eyepiece projection adapter, and 1/60th second exposure.
Monday, March 29, 2004
Sunday, March 28, 2004
Intelligent Design Arguments
A reader points me to a collection of links that purport to debunk the intelligent design arguments based on the supposed irreducible complexity of the flagellum. I have had a chance so far to look at one such paper, Kenneth R. Miller's "The Flagellum Unspun: The Collapse of 'Irreducible Complexity'," and it doesn't impress me.
The irreducible complexity argument is that a flagellum consists of about thirty discrete components, each of which is individually of no value to a cell, and therefore if it came about because of mutation, it would provide no advantage. Miller accurately portrays this argument in his paper:
Of course, one component caused by mutation might remain in the gene pool until another mutation took place that created another component, and then another component, and so on. But it doesn't do any good for the second component to show up in the gene pool unless it ends up in individuals that have the first component. Ditto for all the rest of the components required for a complete system--until the point is reached that some competitive advantage accrues to individual organisms from this collection of components coming together, these mutations are just random events, scattered across the gene pool for this species.
Consider what happens if the mutation for the first component happens. It will happen in one individual of the species. There is no advantage to this mutation, so its percentage of the gene pool doesn't change--it remains rare. If you have a billion individual proto-bacteria in an early ocean of Earth, and one of them gets this mutation, a million years later, that one mutation will have reproduced as fast as the other 999,999,999 non-mutants. To get that fully functional flagellum means that one of mutant bacteria has to get the mutation for component 2. One of its descendants must get the mutation for component 3, and so on, until you get the fully functional flagellum. Do the math: this is a serious problem.
Mutations are random; you should not get the exact same mutation (caused by a cosmic ray zapping an AT or CG pair in DNA, for example) in multiple individuals of a species. In several billion pairs along the double helix, what are the chances that a radiation source is going to cause the exact same positive mutation? Even if you admit the possibility that the same pair gets hit in two different individuals, remember that DNA contains a parity check that looks for and corrects coding errors. What are the chances that two different individuals, getting the same one in a billion mutation, are going to have their error checkers resolve base mismatches identically? (Note that radiation-induced cancers are a somewhat different situation. A cancer is a runaway process, while a positive mutation requires a much more precise change.)
Miller's argument is essentially that the irreducible complexity claim about the flagellum falls apart because of "type III secretory system (TTSS)":
An adequate refutation of irreducible complexity would require demonstrating that all, or nearly all of the ten or fifteen components exist in parallel forms as the author argues that TTSS is. It might indeed be the case that this can be done. The author's next statement seems to acknowledge the inadequacy of his claim:
A reader points me to a collection of links that purport to debunk the intelligent design arguments based on the supposed irreducible complexity of the flagellum. I have had a chance so far to look at one such paper, Kenneth R. Miller's "The Flagellum Unspun: The Collapse of 'Irreducible Complexity'," and it doesn't impress me.
The irreducible complexity argument is that a flagellum consists of about thirty discrete components, each of which is individually of no value to a cell, and therefore if it came about because of mutation, it would provide no advantage. Miller accurately portrays this argument in his paper:
In the case of the flagellum, the assertion of irreducible complexity means that a minimum number of protein components, perhaps 30, are required to produce a working biological function. By the logic of irreducible complexity, these individual components should have no function until all 30 are put into place, at which point the function of motility appears. What this means, of course, is that evolution could not have fashioned those components a few at a time, since they do not have functions that could be favored by natural selection. As Behe wrote: " . . . natural selection can only choose among systems that are already working" (Behe 2002), and an irreducibly complex system does not work unless all of its parts are in place. The flagellum is irreducibly complex, and therefore, it must have been designed. Case closed.Certainly, one component might show up in a population, and if it gave no competitive disadvantage, there is no reason for it to leave the gene pool--but neither would you expect its frequency to rise, either. (A point that neither Miller nor intelligent design advocates seem to have raised is that the mutation might be genetically linked to some other trait that is advantageous.)
Of course, one component caused by mutation might remain in the gene pool until another mutation took place that created another component, and then another component, and so on. But it doesn't do any good for the second component to show up in the gene pool unless it ends up in individuals that have the first component. Ditto for all the rest of the components required for a complete system--until the point is reached that some competitive advantage accrues to individual organisms from this collection of components coming together, these mutations are just random events, scattered across the gene pool for this species.
Consider what happens if the mutation for the first component happens. It will happen in one individual of the species. There is no advantage to this mutation, so its percentage of the gene pool doesn't change--it remains rare. If you have a billion individual proto-bacteria in an early ocean of Earth, and one of them gets this mutation, a million years later, that one mutation will have reproduced as fast as the other 999,999,999 non-mutants. To get that fully functional flagellum means that one of mutant bacteria has to get the mutation for component 2. One of its descendants must get the mutation for component 3, and so on, until you get the fully functional flagellum. Do the math: this is a serious problem.
Mutations are random; you should not get the exact same mutation (caused by a cosmic ray zapping an AT or CG pair in DNA, for example) in multiple individuals of a species. In several billion pairs along the double helix, what are the chances that a radiation source is going to cause the exact same positive mutation? Even if you admit the possibility that the same pair gets hit in two different individuals, remember that DNA contains a parity check that looks for and corrects coding errors. What are the chances that two different individuals, getting the same one in a billion mutation, are going to have their error checkers resolve base mismatches identically? (Note that radiation-induced cancers are a somewhat different situation. A cancer is a runaway process, while a positive mutation requires a much more precise change.)
Miller's argument is essentially that the irreducible complexity claim about the flagellum falls apart because of "type III secretory system (TTSS)":
However, molecular studies of proteins in the TTSS have revealed a surprising fact - the proteins of the TTSS are directly homologous to the proteins in the basal portion of the bacterial flagellum.Miller's argument is that the TTSS is the basal portion of the bacterial flagellum, and here is an example of a basal portion of the bacterial flagellum performing some other useful function that might explain its existence, even before the other ten to fifteen parts come into existence. However, making the claim that the TTSS is homologous to the basal portion of the flagellum is not the same as saying that they are same. Homologous means "having the same evolutionary origin but serving different functions; 'the wing of a bat and the arm of a man are homologous'." The author is asserting that the TTSS and the basal portion of the bacterial flagellum have the same evolutionary origin. How does he know this? This is merely an assertion, a form of teleology.
...
According to the doctrine of irreducible complexity, however, this should not be possible. If the flagellum is indeed irreducibly complex, then removing just one part, let alone 10 or 15, should render what remains "by definition nonfunctional." Yet the TTSS is indeed fully-functional, even though it is missing most of the parts of the flagellum. The TTSS may be bad news for us, but for the bacteria that possess it, it is a truly valuable biochemical machine.
An adequate refutation of irreducible complexity would require demonstrating that all, or nearly all of the ten or fifteen components exist in parallel forms as the author argues that TTSS is. It might indeed be the case that this can be done. The author's next statement seems to acknowledge the inadequacy of his claim:
A second reaction, which I have heard directly after describing the relationship between the secretory apparatus and the flagellum, is the objection that the TTSS does not tell us how either it or the flagellum evolved. This is certainly true, although Aizawa has suggested that the TTSS may indeed be an evolutionary precursor of the flagellum (Aizawa 2001). Nonetheless, until we have produced a step-by-step account for the evolutionary derivation of the flagellum, one may indeed invoke the argument from ignorance for this and every other complex biochemical machine.Aizawa can suggest it all he wants; this doesn't make it necessarily true. What Miller calls the "argument from ignorance" is the claim that once we have all the information, and understood all the processes adequately, we will have enough knowledge to refute the claim of irreducible complexity with respect to the flagellum. Very true; once someone has all the data to show that all the thirty components that make up the flagellum exist in other forms, used for different mechanisms, and that these components provided a competitive advantage to the individual mutant bacterium in isolation, he will be right. But this requires biologists to do so, or at least demonstrate that many of these thirty individual components fit this pattern. One example--and TTSS, from Miller's description, isn't even clearly in that category--doesn't destroy the irreducible complexity argument. It only reduces the number of components that must be explained from thirty to twenty-nine.
Why Has It Been So Quiet Here This Weekend?
The sky is blue (and black at night). It has been in the 60s and 70s during the day. I've been lured away from the computer by the beauty of a spring day. Sorry!
This evening I set up to do some astrophotography. (The last roll of film I had Wal-Mart develop was a bit disappointing--I thought I had ASA 100 speed film in the camera, not ASA 800, and everything came out severely overexposed.)
While setting up to do some Moon shots, I decided to see how stable the atmosphere was. As you know, I have been testing an Aries Chromacor and a Baader Planetarium Fringe Killer as solutions to the chromatic aberration problem on my Photon Instruments 127mm refractor. The results for the Chromacor have met my wildest expectations. This evening, the 4mm orthoscopic (287x) was still crisp on the Moon, so I put in a 9mm Orion orthoscopic with a 3x Televue Barlow (382x). Still crisp.
The next step up was a 7mm University Optics orthoscopic (just got it) with the Barlow (492x). The image was no longer crisp, but it wasn't bad, either. Some of the shadows that should be completely black were a very, very dark purple instead (the Chromacor is amazing in what it does, but it won't make an achromat into a true apochromat). The sensation of being less than 500 miles above the surface of the Moon was really quite overpowering.
The last step was the 6mm Celestron orthoscopic with the Barlow (573x). I wasn't seeing any more detail than I could see with the 7mm and Barlow, but I wasn't seeing any less--it was just a bit less pleasing of a image. Yes, I tried the 5mm University Optics orthoscopic with the Barlow (688x), and at this point, I had gone way off the deep end of too much power. I was definitely seeing less detail than the 6mm and Barlow.
Note: the Moon is one of those objects, perhaps because the contrast is so high, that seems to tolerate what amateurs call "crazy stupid" magnification. Jupiter reached the fuzz limit this evening at 229x--although it was still only about 50 degrees above the horizon (and thus impaired by too much atmosphere in the way), while the Moon was just about straight overhead.
UPDATE: Before you ask if I could see the flag (actually, flags, there were at least five Apollo missions that landed on the Moon), do the math, and you'll see why this isn't going to happen. To be perceived as a disc, an object must be about three minutes of arc. (Those of you with really sharp eyesight may see discs at two minutes of arc.) At 573x, it should be possible to perceive objects on the Moon as non-points if they are 600 meters in diameter or larger. To perceive the remaining equipment up there (which is much larger than the flags), you would need at least 16000x, and extraordinarily steady air here. Even then, you would not be perceiving detail, only blobs.
The sky is blue (and black at night). It has been in the 60s and 70s during the day. I've been lured away from the computer by the beauty of a spring day. Sorry!
This evening I set up to do some astrophotography. (The last roll of film I had Wal-Mart develop was a bit disappointing--I thought I had ASA 100 speed film in the camera, not ASA 800, and everything came out severely overexposed.)
While setting up to do some Moon shots, I decided to see how stable the atmosphere was. As you know, I have been testing an Aries Chromacor and a Baader Planetarium Fringe Killer as solutions to the chromatic aberration problem on my Photon Instruments 127mm refractor. The results for the Chromacor have met my wildest expectations. This evening, the 4mm orthoscopic (287x) was still crisp on the Moon, so I put in a 9mm Orion orthoscopic with a 3x Televue Barlow (382x). Still crisp.
The next step up was a 7mm University Optics orthoscopic (just got it) with the Barlow (492x). The image was no longer crisp, but it wasn't bad, either. Some of the shadows that should be completely black were a very, very dark purple instead (the Chromacor is amazing in what it does, but it won't make an achromat into a true apochromat). The sensation of being less than 500 miles above the surface of the Moon was really quite overpowering.
The last step was the 6mm Celestron orthoscopic with the Barlow (573x). I wasn't seeing any more detail than I could see with the 7mm and Barlow, but I wasn't seeing any less--it was just a bit less pleasing of a image. Yes, I tried the 5mm University Optics orthoscopic with the Barlow (688x), and at this point, I had gone way off the deep end of too much power. I was definitely seeing less detail than the 6mm and Barlow.
Note: the Moon is one of those objects, perhaps because the contrast is so high, that seems to tolerate what amateurs call "crazy stupid" magnification. Jupiter reached the fuzz limit this evening at 229x--although it was still only about 50 degrees above the horizon (and thus impaired by too much atmosphere in the way), while the Moon was just about straight overhead.
UPDATE: Before you ask if I could see the flag (actually, flags, there were at least five Apollo missions that landed on the Moon), do the math, and you'll see why this isn't going to happen. To be perceived as a disc, an object must be about three minutes of arc. (Those of you with really sharp eyesight may see discs at two minutes of arc.) At 573x, it should be possible to perceive objects on the Moon as non-points if they are 600 meters in diameter or larger. To perceive the remaining equipment up there (which is much larger than the flags), you would need at least 16000x, and extraordinarily steady air here. Even then, you would not be perceiving detail, only blobs.
Saturday, March 20, 2004
Awesome Chromacor
I'll still be gushing for a while about the combination of the Chromacor and my 5" refractor. Seeing conditions were better last night; I was able to go up to 286x on Saturn--and the image was just beginning to soften, largely because of turbulence. I could see one brownish cloud band about 30 degrees from the equator--and what I think are some of the fainter satellites nearer the planet.
Jupiter did better at 190x, and here there was more detail visible than I could ever hope to draw. The cloud bands across the planet (at least four dark bands) were not even stripes, but tremendously irregular and complex, with swirls at the edges that I could not quite resolve, but that I could tell were present. There was only the faintest hint of chromatic abberation--so little that I was not always sure that I was seeing it.
And all this from my backyard, which is suburban, light polluted, and suffering the turbulence of cooling concrete! If the sky clears, I'll go to the Boise Astronomical Star Party tonight, where I have a decently dark sky, twenty miles east of Boise.
I'll still be gushing for a while about the combination of the Chromacor and my 5" refractor. Seeing conditions were better last night; I was able to go up to 286x on Saturn--and the image was just beginning to soften, largely because of turbulence. I could see one brownish cloud band about 30 degrees from the equator--and what I think are some of the fainter satellites nearer the planet.
Jupiter did better at 190x, and here there was more detail visible than I could ever hope to draw. The cloud bands across the planet (at least four dark bands) were not even stripes, but tremendously irregular and complex, with swirls at the edges that I could not quite resolve, but that I could tell were present. There was only the faintest hint of chromatic abberation--so little that I was not always sure that I was seeing it.
And all this from my backyard, which is suburban, light polluted, and suffering the turbulence of cooling concrete! If the sky clears, I'll go to the Boise Astronomical Star Party tonight, where I have a decently dark sky, twenty miles east of Boise.
Thursday, March 18, 2004
The Apochromat Owners Are Going To Turn Purple (Not Green) With Envy
I received a threaded diagonal today, screwed in the Chromacor, set up the telescope, and aimed at Jupiter. Seeing wasn't great, largely because the moisture in the air was beginning to turn to fog, but the violet and green fringes on opposite limbs of the planet that I saw a few nights ago (signs of inadequate collimation of the Chromacor)--completely gone. Jupiter is as color-free at 286x as it would be in an apochromat. I can see (I think) more detail at 190x than I could a few nights ago with the Chromacor--and definitely more than with the uncorrected scope.
I plan to take it to the Boise Astronomical Society star party Saturday night, where we have much darker skies--and then I should see what this scope can do! I have spent about $1000 so far--about a fifth of what an apochromat of equivalent aperture would cost. I do not doubt that my scope is still inferior in mechanical quality, and perhaps even in optical quality--but from what I have seen under comparable skies, the difference in image quality is not dramatic.
I received a threaded diagonal today, screwed in the Chromacor, set up the telescope, and aimed at Jupiter. Seeing wasn't great, largely because the moisture in the air was beginning to turn to fog, but the violet and green fringes on opposite limbs of the planet that I saw a few nights ago (signs of inadequate collimation of the Chromacor)--completely gone. Jupiter is as color-free at 286x as it would be in an apochromat. I can see (I think) more detail at 190x than I could a few nights ago with the Chromacor--and definitely more than with the uncorrected scope.
I plan to take it to the Boise Astronomical Society star party Saturday night, where we have much darker skies--and then I should see what this scope can do! I have spent about $1000 so far--about a fifth of what an apochromat of equivalent aperture would cost. I do not doubt that my scope is still inferior in mechanical quality, and perhaps even in optical quality--but from what I have seen under comparable skies, the difference in image quality is not dramatic.
The "Hate Crime" That Wasn't
David Bernstein blogs about a convenient "hate crime" at Claremont-McKenna College, where the new president is trying to drag a relatively middle of the road college (yes, there a few left) to the left:
This isn't the first time, of course, that an anti-homosexual "hate crime" has turned out to be lies:
One of the reasons for these false reports is obvious: it provides political advantage to homosexuals to claim that they are the victims of such crimes. Indeed, a "hate crime" against lesbian Regan Wolf was successful in getting South Carolina to pass a "hate crimes" law--and then it turned out that she faked it:
David Bernstein blogs about a convenient "hate crime" at Claremont-McKenna College, where the new president is trying to drag a relatively middle of the road college (yes, there a few left) to the left:
It seemed an outstanding stroke of luck for the administration when, in the midst of a push for greater "tolerance" and "diversity," a visiting left-wing faculty member's car was vandalized. Windows were smashed, tires slashed, and racist and anti-homosexual slogans spray painted on the professor's car.Except: two witnesses saw the "victim" doing the vandalism.
This isn't the first time, of course, that an anti-homosexual "hate crime" has turned out to be lies:
MORGAN HILL -- The alleged abduction and sexual assault of a gay man left bound and gagged along Highway 101 in Morgan Hill last week was a hoax, Santa Clara County sheriff's officials said yesterday.And this example:
The alleged victim was trying to cover up for a night away from home and his partner, according to investigators. The matter, which was being investigated as a hate crime, is now being forwarded to the Santa Clara County District Attorney's office, which will determine whether to file charges against him for filing a false police report.
In 2001, a gay student at the College of New Jersey confessed to sending death threats to himself and a gay student group. He was suspended from campus during the investigation and charged with a felony on suspicion of filing false police reports and harassment.While I can't find it online, there was at least one lesbian pastor in San Francisco in the late 1990s who reported being attacked, vile things written on her face, etc.--and then, as the evidence that she had done it herself mounted, she finally recanted, and left town.
One of the reasons for these false reports is obvious: it provides political advantage to homosexuals to claim that they are the victims of such crimes. Indeed, a "hate crime" against lesbian Regan Wolf was successful in getting South Carolina to pass a "hate crimes" law--and then it turned out that she faked it:
Regan Wolf, a South Carolina woman who told police in 1998 that she had been tied up and whipped because she is a lesbian, has been fined $125 for filing a false report.There are certainly hate crimes being committed against homosexuals. But how many? As this testimony from a Congressional committee points out, there are economic motivations as well, and there are reasons to suspect that the number charged as false reports is way too low:
One reason the arrest and conviction numbers may be suppressed is that both law enforcement and insurance companies generally are hesitant to press cases of fake hate crimes unless the evidence is overwhelming. To falsely accuse a real victim of hate would be the gravest injustice, compounding the hurt and damage already suffered. And no insurance company wants to be on the wrong side of a civil trial decision accusing it of dealing in bad faith with a hate crime victim.UPDATE: Here's a link to a much more detailed account of the sequence of events, including the name of the "victim."
Wednesday, March 17, 2004
An Amazing Artifact Is For Sale
You know who Clyde Tombaugh was? The discoverer of Pluto, back in 1930? Offered for sale:
You know who Clyde Tombaugh was? The discoverer of Pluto, back in 1930? Offered for sale:
This 16-inch telescope was Clyde Tombaugh's biggest effort. Although the mirror was completed around 1944, heavy work on the metal superstructure did not begin in earnest until about 1957 and the telescope finally saw first light in Las Cruces around 1960. Its primary system is a 16-inch f/10 mirror hand-ground, figured, and completed by the discoverer of Pluto himself. The mirror is outstanding; during the early 1980s, Tombaugh and David Levy used an 8mm eyepiece (which gives a magnification of 524) to observe the spokes in Saturn's rings with it.What makes this sale especially poignant is who is offering it:
Patsy Tombaugh c/o David Levy
Tuesday, March 16, 2004
Goodbye to An Old Friend
I have a buyer for my Televue Ranger (the ivory tube model, not the green one), and I will be shipping it off tomorrow or Thursday (depending on when the payment hits my PayPal account). I took it out to the backyard for one final observing session with it. If you don't understand how you can get sentimental over a piece of glass, let me give you analogy you might understand: it's like saying goodbye to my cat, when I moved away to college, and couldn't take my cat, Amboy II, with me. (Amboy? The II? The mother was named after Amboy Crater, a cinder cone in the Mojave Desert we were visiting the day she was born.)
The Ranger doesn't do anything as well as my 5" refractor (except show a little blacker sky around planets), but it is so incredibly sleek and elegant. While it won't show quite as much detail on Saturn or Jupiter, it is still absolutely amazing, considering how small and light it is. It is by far the smallest and lightest real astronomical telescope that I have ever used. I suspect that I will break down one of these days, and buy a larger Televue scope--if only they weren't so expensive!
The Ranger isn't an apochromat, but it is very, very good on color correction. Only on Venus, the Moon, and Jupiter, do you see any color at all, and only on Venus could it be considered a substantial obstacle to seeing detail--if there were any detail to see in Venus's clouds. As an experiment, I used the Baader Fringe Killer filter that I just bought with my 4mm eyepiece in the Ranger. Venus still had a violet haze, but so little that it was not a nuisance. On Jupiter, the Fringe Killer completely wiped out what little violet haze there was.
I have a buyer for my Televue Ranger (the ivory tube model, not the green one), and I will be shipping it off tomorrow or Thursday (depending on when the payment hits my PayPal account). I took it out to the backyard for one final observing session with it. If you don't understand how you can get sentimental over a piece of glass, let me give you analogy you might understand: it's like saying goodbye to my cat, when I moved away to college, and couldn't take my cat, Amboy II, with me. (Amboy? The II? The mother was named after Amboy Crater, a cinder cone in the Mojave Desert we were visiting the day she was born.)
The Ranger doesn't do anything as well as my 5" refractor (except show a little blacker sky around planets), but it is so incredibly sleek and elegant. While it won't show quite as much detail on Saturn or Jupiter, it is still absolutely amazing, considering how small and light it is. It is by far the smallest and lightest real astronomical telescope that I have ever used. I suspect that I will break down one of these days, and buy a larger Televue scope--if only they weren't so expensive!
The Ranger isn't an apochromat, but it is very, very good on color correction. Only on Venus, the Moon, and Jupiter, do you see any color at all, and only on Venus could it be considered a substantial obstacle to seeing detail--if there were any detail to see in Venus's clouds. As an experiment, I used the Baader Fringe Killer filter that I just bought with my 4mm eyepiece in the Ranger. Venus still had a violet haze, but so little that it was not a nuisance. On Jupiter, the Fringe Killer completely wiped out what little violet haze there was.
Chromacor
The seeing last night, while not spectacular, was good enough for me to start to test the Chromacor that I recently bought from Astrobuffet for my 5" refractor. I've been fiddling with the Chromacor for most of a week now, using a diagonal loaned to me by a co-worker. (The diagonal that came with the Photon Instruments refractor isn't threaded for 48mm filters.) There is a bit of tinkering required, and I know that I am not quite done yet--but even at perhaps 85% of what it is capable of, I was able to see some impressive results.
Venus was surrounded by a violet haze in my uncorrected scope; with the Chromacor installed, Venus was essentially color-free. I could see a slight, but not objectionable violet fringe on one limb, and a very slight green fringe on the other (indicating that the Chromacor isn't perfectly collimated in the diagonal).
Jupiter had a violet halo at 190x; with the Chromacor, there was a barely perceptible violet fringe on one limb, with green on the opposite. Again, this is a collimation issue.
If all the Chromacor did was reduce the color, it wouldn't be worth the almost $600 I spent on it (and the remainng $70 I am spending on a threaded diagonal). It definitely provides a more contrasty image, with more detail visible--and even under less than wonderful seeing, I found that the Chromacor would let me go up to 286x, while uncorrected, the scope was limited to about 190x.
Saturn seems not get much of a benefit from the Chromacor, being relatively faint and with a smaller pallette of colors, it doesn't seem to get as much benefit from the Chromacor's color correction.
The seeing last night, while not spectacular, was good enough for me to start to test the Chromacor that I recently bought from Astrobuffet for my 5" refractor. I've been fiddling with the Chromacor for most of a week now, using a diagonal loaned to me by a co-worker. (The diagonal that came with the Photon Instruments refractor isn't threaded for 48mm filters.) There is a bit of tinkering required, and I know that I am not quite done yet--but even at perhaps 85% of what it is capable of, I was able to see some impressive results.
Venus was surrounded by a violet haze in my uncorrected scope; with the Chromacor installed, Venus was essentially color-free. I could see a slight, but not objectionable violet fringe on one limb, and a very slight green fringe on the other (indicating that the Chromacor isn't perfectly collimated in the diagonal).
Jupiter had a violet halo at 190x; with the Chromacor, there was a barely perceptible violet fringe on one limb, with green on the opposite. Again, this is a collimation issue.
If all the Chromacor did was reduce the color, it wouldn't be worth the almost $600 I spent on it (and the remainng $70 I am spending on a threaded diagonal). It definitely provides a more contrasty image, with more detail visible--and even under less than wonderful seeing, I found that the Chromacor would let me go up to 286x, while uncorrected, the scope was limited to about 190x.
Saturn seems not get much of a benefit from the Chromacor, being relatively faint and with a smaller pallette of colors, it doesn't seem to get as much benefit from the Chromacor's color correction.
Wednesday, March 10, 2004
Needed: 2" Threaded Diagonal For A Few Days
Okay, the Chromacor for the 5" refractor arrived yesterday, and I started preparation to install it--and then I discovered that the 2" diagonal that came with the refractor isn't threaded. (There is something on the inside of the barrel that looks like threading, but according to Photon Instruments, this just prevents internal reflections.)
Okay, I could buy a 2" diagonal that is threaded for filters, but I only need this for a few days to make sure that the Chromacor justifies its expense in improved image. If not, back it goes. So if you hve a 2" diagonal threaded for 48mm filters lying around, and you could let me borrow it for a few days, I would be happy to pay the shipping costs both ways.
Okay, the Chromacor for the 5" refractor arrived yesterday, and I started preparation to install it--and then I discovered that the 2" diagonal that came with the refractor isn't threaded. (There is something on the inside of the barrel that looks like threading, but according to Photon Instruments, this just prevents internal reflections.)
Okay, I could buy a 2" diagonal that is threaded for filters, but I only need this for a few days to make sure that the Chromacor justifies its expense in improved image. If not, back it goes. So if you hve a 2" diagonal threaded for 48mm filters lying around, and you could let me borrow it for a few days, I would be happy to pay the shipping costs both ways.
Subscribe to:
Posts (Atom)