Astronomical Filters Archives

Zhumell SEE IT ALL Telescope Filter Set

The Zhumell SEE IT ALL Telescope Filter Set consists of four filters, a Sky-Glow filter, a UHC (Ultra High Contrast) filter, an O-III filter, and a

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Orion 1.25" Variable Polarizing Telescope Filter

The Orion Variable Polarizing Filter makes viewing the moon a more pleasurable experience. Unlike a neutral density filter that

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Baader Neodymium Moon and Skyglow Filter

Like it’s name suggests, this filter also helps the view of deep-sky objects in moonlight, something that other filters

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Zhummel See It All Filter Set

The first thing I looked at was Jupiter with my 2" 30 mm eye piece which provides 50X power. . First I looked at it with

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Astronomik LRGB Type IIc Filters

I have been using an Astronomik H-a filter for narrowband imaging in my Meade DSI-Pro cameras for over a year. I recently added

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Lab Test and First Light Report of 2" Zhumell Filter Set

My interest in astronomy started when I was 15 and saw Haley¡¯s comet through a pair of Bushnell binos. I had always wanted to buy a telescope but growing up in light and particulate polluted Bombay (now Mumbai), I gave up all notions of pursuing the hobby

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Filter Performance Comparisons

The following is a summary report of visual observations of emission nebulae comparing the performance of various filters intended for such objects.

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Orion's 2" OIII Filter

LPR, or Light Pollution Reduction filters block the most common wavelengths of the light glow we often call “light pollution”. Most of this offending light falls in the visible spectrum from 550 to 630 nanometers. LPR

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Mars Filter Comparison

The following is taken from a post in the beginners forum based on an observing report on the morning of 09-08-05

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Binoscope Company Narrow and Broadband Nebula Filters

I have been wanting an 2” 03 filter for sometime now but have not been able to afford one. When Joe Castoro came out with a 2” one for $135 I became interested.

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Baader Fringe Killer Filter

Santa sent me a new skywatcher 80/400 achromat refractor and as I knew it before Christmas, I took informations about it, and about the fact that it suffers from secondary color as it's not an APO. So I decided to go for a filter to reduce this secondary color.

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Sirius Optics Variable Filter System (VFS)

The Variable Filter System, or VFS, is a unique form of interference filter. The filter's glass has coatings deposited on one side of its surface and is unlike died colored glass absorption filters. This method of filtration rejects most incoming light while allowing a very high transmission of light through three thin bandwidths or peaks to come through the eyepiece. What makes it unique is that all three bandwidths are "variable" and move in unison.

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Astrocrumb Filter Slide

With a slide, using a filter becomes second-nature, as effortless as focusing.

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Orion V-Block Filter

Two of my current scopes are achromats. I purchased a 1.25" version of the Orion V-Block filter to try on them. The filter is advertised as a way to cut down chromatic aberration effects, such a colorful halo, and edge color, in an achromat.

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Sirius Optics NPC Neodymium Eyepiece Filter

Although color filters generally do have some limited applications for planetary viewing in bringing out certain detail, I have never a huge fan of them. I only have a light red filter for the dark markings of Mars and a pale blue one (Lumicon Deep-sky) for Jupiter and the Martian clouds and polar caps. Neither filter gets much use, and I have been somewhat skeptical that any filter could be produced which would be of much value to me for the planets. However, recently a new filter has come out which has dramatically changed my opinion of filtered viewing; the NPC Neodymium Eyepiece Filter from Sirius Optics.

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Zeiss Filters

I have been thinking for some time now to share my experiences with the selection of filters designed and manufactured by Zeiss. It has taken some years to acquire these filters, and while not a prolific filter user it is nice to get them out and give them some fresh air every now and then. They are all designed for the Zeiss

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Sirius Optics MV-20 Chromatic Aberration Suppression Filter

The MV-1 (minus-violet) eyepiece filter, developed by Al Misiuk of Sirius Optics, has been available for some time now and has gained significant popularity due to it's ability to remove the appearance of virtually all spurious color from achromatic refractors. Although the MV-1 achieves its purpose, it does impart a slight yellowish cast to objects that are viewed. It's not a perfect world. Or is it? Al has now produced a new generation minus-violet filter called the MV-20. It removes a significant amount of the annoying violet glow seen when viewing bright celestial objects through achromats, while still yielding a relatively natural color appearance to the objects with virtually no yellowish cast. Some time ago, I sent a refractor lens to Sirius Optics for MV-1 coating. After a few phone conversations with Al, he mentioned his new MV-20 filter. I acquired mine through him, but Sirius does not generally sell directly to the public. Several dealers, however, are listed on the Sirius website (www.siriusoptics.com). The MV-20 is still relatively new, and many of the dealers may not yet have it on their websites, so you may have to call and ask. Just to get a few things straight, this is still merely an

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Sirius Optics MV-20 Chromatic Aberration Suppression Filter

The MV-20 is still relatively new, and many of the dealers may not yet have it on their websites, so you may have to call and ask. Just to get a few things straight, this is still merely an eyepiece filter. It prevents certain wavelengths of light from passing through the eyepiece to your eye. It does not refocus light like a Chromacor lens does. The two principles are very different. The MV-20 will not turn an achromat into an apochromat. It will, however, reduce the visual appearance of 80-90% of chromatic aberration without unduly altering the natural appearance of planets and stars and without costing an arm and a leg.

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Useful Filters for Viewing Deep-Sky Objects

The broad-band "Light-pollution Reduction (LPR) filters are designed to improve the visibility of a variety of Deep-Sky objects by blocking out the common Mercury vapor, Sodium, and some other emission lines from man-made or natural sources which contribute to light pollution, while letting through a broad range of other more useful wavelengths. Since the eye is mainly a "contrast detector", this selective screening out of some of the background skyglow increases the contrast and helps Deep-sky objects stand out more noticably.

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Sirius Optics Minus Violet Filter

Over the past year there has been some serious debate within the achromatic refractor community as to how to deal with false color. One company has proposed an apochromatic lens system to completely correct an achromatic telescope. Al Misiuk at Sirius Optics on the other hand decided to create a simple filter to remove excess violet from the image produced by a conventional achromatic refractor.

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Lumicon Multiple Filter Selector

For those of us who have more than one filter in our equipment arsenal, it is frequently a hastle (and even a hazard) to keep screwing, unscrewing, or even handling small 1.25" eyepiece filters, especially in the dark. Enter the Lumicon Multiple Filter Selector, a filter holder and selector for up to 5 Lumicon filters (or other low-profile filters with similar threads) at once for instant access at the eyepiece while viewing. In this way, the right filter for any object can be moved into place without looking away from the eyepiece, or fumbling in the dark for each filter. While this is potentially a great convenience for the observer, it comes at a price, both financial and logistical.

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Baader Planeterium Moon & Skyglow Filter

Markus just sent me a rather interesting item on the basis of, "test it, and if you like it, keep it and send me a check. If you don't like it, send it back to me." The sheet that accompanied the small box says this is a "BAADER PLANETARIUM MOON & SKYGLOW FILTER." The literature says that it is a 1.25" filter designed to thread into a standard 1.25" eyepiece and "not a simple colored filter" but a "selective contrast filter" intended to block "in the visual spectral ranges" light from sky and street lighting. It is also said to increase contrast on lunar and planetary observing but preserve "bright-dark contrast." Markus said that, unlike most color filters, this filter is optical glass, not simple colored glass, and has "flat-parallel polished surfaces."

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Baader Planeterium Moon & Skyglow Filter

Markus just sent me a rather interesting item on the basis of, "test it, and if you like it, keep it and send me a check. If you don't like it, send it back to me." The sheet that accompanied the small box says this is a "BAADER PLANETARIUM MOON & SKYGLOW FILTER." The literature says that it is a 1.25" filter designed to thread into a standard 1.25" eyepiece and "not a simple colored filter" but a "selective contrast filter" intended to block "in the visual spectral ranges" light from sky and street lighting. It is also said to increase contrast on lunar and planetary observing but preserve "bright-dark contrast." Markus said that, unlike most color filters, this filter is optical glass, not simple colored glass, and has "flat-parallel polished surfaces."

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Sirius Optics Variable Filter System (VFS)

This is one nice little piece of equipment. It has a simple and elegant design. It is anodized aluminum with a flat black finish. This housing has 1.25" in-out barrels and can only be used with 1.25" eyepieces. It feels like it weighs about half a pound. There is also a really nice red engraved plate. Fortunately, it is a lot easier to use than it is to describe. As you can see in the photo, a portion of the filter protrudes from the housing. The filter's diameter is about 3". The wheel's edge that protrudes from the housing is numbered for use as a reference. The filter spins around using your finger at this location. Just rotate the wheel and watch the filter vary the renditions on a given object seen at the eyepiece. I simply rotated the filter wheel without regard to the numerical scale, as I was interested in all the possibilities that the VFS has. Since the wheel rotates so smoothly, it was easily to go back and forth while observing.

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Baader Planeterium Moon & Skyglow Filter

Markus just sent me a rather interesting item on the basis of, "test it, and if you like it, keep it and send me a check. If you don't like it, send it back to me." The sheet that accompanied the small box says this is a "BAADER PLANETARIUM MOON & SKYGLOW FILTER." The literature says that it is a 1.25" filter designed to thread into a standard 1.25" eyepiece and "not a simple colored filter" but a "selective contrast filter" intended to block "in the visual spectral ranges" light from sky and street lighting. It is also said to increase contrast on lunar and planetary observing but preserve "bright-dark contrast." Markus said that, unlike most color filters, this filter is optical glass, not simple colored glass, and has "flat-parallel polished surfaces."

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