monochromatic photography of jupiter and saturn
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Photographs of the parish lantern, which I made several years ago by way of ultra-violet light, revealed the presence of an extensive dark area en se promenant sur rounding the crater Aristarchus, which would not appear on dishes made by ways of yellow mild, and could not be diagnosed visually. Control experiments, manufactured in the lab, made it appear probable that the deposit consisted of sulphur or perhaps sulphur bearing rock. That appeared to me personally probable that even more interesting results can be obtained in the case of the planets, especially Roter planet (umgangssprachlich), and initial experiments had been carried on during the past summer at my East Hamp ton Lab with a horizontally telescope of 56 foot focal size and 18 inches béance, figured by Mellish, and nickel finished by the approach described inside the Astrophysical Journal for August. A deposit of nickel is necessary for the reason that silver reflects just 4% from the light around the range utilized, which will lies among wave-lengths 3 thousands and 3300.
This looking glass was utilized for conjunction using a large Gaertner coelostat, which has been placed at my disposal by Naval Observatory. The reflect of this device was substituted by a 16-inch flat, as well nickel finished, and photographs were created of the moon and Jupiter by way of infrared, discolored, violet and ultra-violet lumination. Notwithstanding the fact that a moving plate holder, provided with eyepieces for appropriate following, was used, it was identified difficult to secure sufficiently sharp definition, because of the rather rapid regular drift of the image that was very difficult to follow. The finding more above was not very good, and on the few nights because it was reasonable the mosquitoes were awful. Much useful experience was gained yet, in the use of the monochromatic ray filtration. In the earlier experiments on the celestial satellite, I employed, for the ultra-violet beam filter, a rather thick pay in of material silver on uviol cup. This was abandoned in the present operate, owing to it is great opacity even for the ultra-violet region transmitted, and a rectangular glass cell. closed with plates of uviol a glass, and filled up with dense bromine vapor, found in its place. Such a cell, when ever used with a regular (i. elizabeth., not isochroma tic) dish, gives a photo taking image shaped by wave-lengths below 3500 exclusively. By combining this with a slim layer of the very thin down solution of chromate of potash, the transmission is usually practicall the same as with the silver film, even though the time of publicity is only about one-tenth as long. In August, through the courtesy of Dr . G. E. Blooming, Director in the Mt. Wilson Observatory, the 60 inches reflector was placed inside my dis posal for several nights, and by working continually from sunset to daybreak
I was in a position to secure an extremely complete set of pictures of the parish lantern in yel low and ultra-violet light and some forty negatives of Jupiter and Saturn in infra-red, yellow-colored, violet and ultra-violet mild. The telescope was used on the eighty ft . focus and since the magnifying mirrors were silvered, the region of the spectrum utilized for the ultraviolet photography was slightly significantly less refrangible than in the earlier job. Preliminary experi ments was made within the spectrum of sunlight following three reflections from silver precious metal and tranny through the bromine cell. Complete data lso are garding these kinds of matters will probably be published shortly in the Astro physical Log. Extremely interesting results were received in the case of Saturn. The infra-red picture, taken by wave plans above 7200, showed the ball around the planet almost devoid of surface markings, the tiniest trace from the faint slim belts showing. The photographs created using the yellow-colored screen revealed the belts distinctly, offering about the same internet marketing pression while visual findings. On the china made with the violet ray-filter (transmission 4000-4500), a very extensive dark belt surrounded the planet’s collar, occupying the location of the planet which was brightest in yellow mild. In addition to this dark equatorial belt a darker polar limit of significant size made an appearance in the photographs. So dif ferent were the two images that, were it not to get the band, it would be hard to believe that that they represented the same object. In ultra violet lumination the appearance was much the same, however the dark seatbelt was not quite so wide, the bright area between the polar cap as well as the belt getting distinctly broader. Photographs constructed with the several monochromatic filtration are reproduced.
Two ideas suggested themselves in justification of the dark belt. We may be dealing with a fine mist or dust particles which forms an extension with the crepe diamond ring down to the ball of the planet. This hypothesis appears to be favored by the situation that for the negatives created by ultra violet light (and to a less degree by violet) the atmosphere between the ball of the planet and the ring is distinctly denser than the location just outside. This would show that the region inside of the ring was filled with some materials which reflected the short wave-lengths into a slight level. No trace of this darkening appears in any of the discs made with the yellow display screen, even on one that was many times overexposed, which seems to show the phenomenon can be real. This kind of peculiarity was, however , certainly not detected until the work was finished, and i also should choose to verify this, or have this verified, ahead of setting it down since an established truth. The luminosity is much as well feeble showing in the styles. Dr . Blooming will have the density scored with the Hartman photometer the moment some vehicle repairs are completed. I do certainly not, however , believe the darker belt is in reality as a result of absorption of the dust engagement ring, for assess ments made by Mr. Ellerman showed the belt extended higher up on the ball of the planet than the line of area of the airplane of the bands. Moreover it seems highly likely that the seatbelt and the darker polar cap are to be discussed in the same way. The other hypothesis takes on the existence in the globe’s atmosphere of some substance capable of absorbing violet and ultraviolet light. This material might be a fine mist or dust, or any gas capable of gripping, riveting the more re frangible area of the spectrum. Such a gas would be of your pale yellow color, and sulphur water vapor and chlorine naturally occur to us. I use, however examined the ingestion
spectrum of both of these smells in quartz bulbs, together with the result which the absorption appears to be much stronger in the ultra-violet as compared to the purple, which is in dis- arrangement with the scenario that the strap appears larger in violet than in ultraviolet light. Right up until spectrograms can be obtained showing the complete spectra in the different areas of the planet it really is useless to take a position as to the nature of the materials which causes the absorption. Within the infra-red picture the ball of the planet is significantly brighter incomparison to the brightest area of the ring than on the purple and uv pictures. This kind of again suggests a misting or dust in the globe’s atmos- world which scatters the shorter wave-lengths. My infra-red picture graphs of landscapes have got clearly indicated that we can get clear photographs through a green haze by using the variety region previously mentioned 7200. Tn these photos it will be recalled that the green sky comes out grayscale the grass and plants snow white.
(See my Physical Optics, page 626, second edition. ) Interesting results were obtained as well in the case of Jupiter. In infra-red light the belts had been scarcely obvious, while the purple and especi ally the ultra-violet pictures showed darker belts, of which no find could be observed in pictures made with the yellow screen, or perhaps by attention observations around the planet. In view of the interesting results obtained with the two mentioned here planets I hope that related observations will probably be made of Mars on the occasion of their next around approach to the planet earth. I manufactured one image of the planet in October with ultra-violet light, but the dvd was as well small to present much of interest. T have been completely aided through this work with a grant from your Gould Fund of the Nationwide Academy of Sciences.