This auction is for a 1984 Celestron (Carton or Hoya of Japan) .965-inch LPR Model 3 broadband filter. It will come with its original plexiglass storage disc.
The Model 3 is exceptionally rare to come across as they were marketed poorly and were not a common size to catch the eye of advanced visual observers seeking a nebular-class ocular filter. And so I would bet very few of you here probably have ever seen one.
The very first Light Pollution Reduction filters, like this one, became available in the catalogs as far back as 1978. They were void of any company logo on the body. Their cases usually did not feature the mpn codes, but always the model's name. Also, at this time no "Celestron" branding was used.
For now, the mpn, which is not listed in even the big master catalogs, is soon to be under 93570, which we will see come 1985 and just a few years before it disappears.
It is (1) of (7) available models to choose from; the model number indicating its direct application to either the telescope, eyepiece, or diagonal. For example: the LPR #1 works on the C8, C5, and C90 with the LAR; the LPR #2 only fits the C11 and C14 (also the Meade 12 and 16 cassegrains of later years). A LPR #4 fits any 1.25-inch eyepiece with threads.
In this, the filter you see here would be sold under "Light Pollution Reduction Filters Model #3".
From 1978 until late winter of 1988, the (7) models were:
* Model 1 Threads into rear cell of C8, onto the LAR, or in reducer plate of C11/C14
* Model 2 Threads directly onto rear cell of C11/C14
* Model 3 Threads into any .96" ocular
* Model 4 Threads into any 1.25" ocular
* Model 5 Threads into any 2" ocular
* Model 6 Fits the 11x80 and 20x80 binoculars (get 2 filters)
* Model 7 Threads onto back of Off-Axis Guider
By 1989, the LPRs are reduced to just (3) models. And instead of being advertised as "# Model", they are now advertised with alphabets; "LPR Filters-Model A (for 1.25-inch eyepieces)" would be an example.
As you guess it, the .965-inch LPR filter never makes it to 1989 and will never again surface with Celestron. Over the years beyond this point, some of the LPR models will disappear and reappear, and the alphabet system will be ousted, but only the 1.25-inch and Rear Cell models will carry on beyond 2000, which, by this era, are now made in Korea.
Model: LPR Model #3
Threads to: .965-inch eyepieces
Design: mercury and sodium vapor wavelength elimination filtration;
enhanced incoming hydrogen alpha/hydrogen beta wavelength transmission
Optics: multiple layer interference filters in glass
Clear aperture: 15.7mm
Materials: anodized aluminum and glass
Weight: 0.2 ounces
Unlike the bigger LPR filters, Model 3 will not experience any generation changes. It will always appear in its all-black anodized milled aluminum, volcano-shaped, knurled, bevel-faceted look. It will never feature any etchings or painted characters to source brand affiliation, and it will have always ONLY come from Japan.
The LPR Filter Model #3 will thread to virtually ANY .965-inch eyepiece made in Japan or Taiwan and most (but not all) from China. I have used it the Meade Series II Orthoscopics, Orion Explorer Series Kellners (and Orthoscopics), Takahashi Hi-Orthos, the mid-1990s Pentax SMC orthos, Celestron/Vixen kellners, Celestron Halloweens and SMAs, and even the very old classics, like the Towa Or. 6mm, Optica b/c HM18mm, and later era Unitron kellners.
The LPR or Light Pollution Reduction filter is very much like the Lumicon Deep-Sky Filter, Orion SkyGlow Broadband, and Meade Nebular Broadband in the sense that it reduces certain bandwidths of light; particularly those emitted by sodium vapor and mercury vapor lights. When this "pressure" or "noise" in the sky is reduced, the object of interest becomes enhanced via contrast; a bright light source immediately surrounded by blackness or very little-to-zero haze. It can be a stark difference between seeing regions of detail in M51, M31 or even the Fish's Mouth of M42 and not seeing any intricate detail at all.
Now a primary misconception, definitely a signature of an intermediate observer, is that these LPR filters will magically allow you to see all these wondrous, knotted, molted, glowing details in nebulae and galaxies that was entirely invisible without the filter. On the contrary, there is nothing magical about what the LPR filter does; it is filtering out very specific wavelengths of light so that your brain doesn't have to stress trying to separate images you are not interested in seeing. In fact, this filter will darken everything, not make it brighter. ONLY an increase in APERTURE can increase your brightness (unless we argue about the legendary Collins I-3). But what it will do is allow you to see finer, subtle details in the object.
Generally, I would say these filters are intended for telescopes in the 6-inch and larger class, especially since apertures in the 2.4-inch to 4.5-inch are already light-starved and have enough of a time getting the Messier list on their own. But there are (2) reasons why this .965-inch LPR Model 3 will more than work for you:
1) You may have a vintage set of very high quality kellners, orthoscopics, plossls, or huygens mittenzweys in .965-inch size that you want to use in your 8-inch Cave Student A or perhaps your Astro-Physics Starfire 6 f/9. I do this ALL the time. Some of my very best ever eyepieces were .965-inch (Pentax SMC orthos and the Orion-Vixen original Sirius Plossls) and I use reducer bushings in the larger telescope focusers so I can use vintage eyepieces in large aperture reflectors and refractors.
2) If you are in the heart of urbanization; like Los Angeles, NYC, Chicago, Miami....then yes, even your 60mm to 90mm refractor CAN BENIFIT from this little LPR filter.
Quite rare and virtually unknown, the Celestron LPR Model 3 is here to serve you and your vintage Japanese eyepieces for combat against the glow of the city residing near your stargazing field.
This auction ad was completely, organically written by Veradale Mobile Observatory, not an A.I. software device; an actual honest-to-goodness, real human with over 20 years experience with now over 1000 telescopes made from today and all the way back to 1948.