FILTERS
Last updated: 25 July 2012
Solar Skreen Adaption (11/08/06) Lumicon ND 25 Filter (09/27/05) Personal Solar Telescope (06/29/06) V Block filter (10/04/03) Coronado White Light Solar Filter (3/15/03) SolarMax 40 H-Alpha (04/30/02) Color Filter #21, Orange (12/23/00) Color Filter #56, Light Green (12/23/00) Light Pollution Reduction filter (06/22/05) Various filters (11/04/98) Orion Narrowband filter (09/23/08) Solar II Type 2 Plus solar filter (1/16/98) Narrowband Filter Color Filter #8, Light Yellow |
Top 10 Telescope Filters for Better Observing (07/25/12) Meade 908N Nebula filter (01/31/06) Baader Neodymium Moon, Skyglow Filter (09/13/05) Lumicon UHC Filter (10/24/03) Planetary Contrast Filter (8/15/03) Meade Variable Polarizer Filter (07/27/02) AstroSolar Safety Film (03/15/03) 6-Pocket Filter Case (12/23/00) Moon Filter (11/12/00) Orion Solar Filter (09/12/04) Lumicon OIII deep-sky filter (05/21/98) Solar View Type A Plus solar filter (12/29/97) ETX SOLAR SKREEN (01/25/00) Color Filter #82A, Light Blue |
Accessory | Manufacturer | Model | Price |
UHC Filter | Lumicon | N/A | $100 |
Craig M. Bobchin (ETX_Astro_Boy@sbcglobal.net) provided the following: "For my 40th Birthday last month I bought myself a Lumicon UHC filter
with some gift money I received. I'd been wanting a nebula filter since
I got my ETX-105 a couple of years ago. The only question was which
one? After quite a bit of research, I settled on the Lumicon UHC filter.
With the closing of Lumicon earlier this year I had dispaired ever
getting one of their filters. Luckily they were resurrected a few months
ago by Parks Optics.
The UHC filter allows only the two doubly-ionized oxygen lines (496 and 501nm lines) and H-beta line (486nm) emitted by planetary and most emission nebulae, while blocking, completely the rest of the overall spectrum of light. This allows for a very deep contrast between the nebula being viewed and the rest of the sky. I was anxious to try it out, so on the 1st semi clear night I set my 105 light mug in the backyard to cool down. After an hour or so I went fuzzy hunting. Now without the filter my 105 has bagged such objects as M8, M20, M57, M42, and via averted vision M1 not to mention a few others. With the exception of M42 none of these really wowed me. However I was undaunted, I decided to try for the Triffid (M 20) and Lagoon (M8) nebula right off before they sank to low. They were in the murk, but the filter cut through it and there was the Triffid showing some structure. It actually looked like a small black and white version of the pictures I've seen of this beautiful sight. The Lagoon was equally impressive. When I took the filter off neither object was visible. M57 without the filter showed a small smudge that looked like a smoke ring. With the filter it popped into view and could not be missed by anyone. With the bad light pollution where I live I decided to stop hunting fuzzies for the evening. Besides I know that the coming weekend would give me ample time to play with my $100.00 piece of glass. That weekend I was headed up to Palomar mountain for an outreach called "Explore the Stars". This promised to give me good dark skies away from any light pollution, and I would be able to observe as long as I could stay awake. Perfect conditions to stretch the abilities of my light mug. I knew there would be other scopes there, Most bigger, but some smaller or the same size as my 4 inch ETX. This would also give me a chance to see how the filter handled other scopes. On almost every object looked at, the filter made a huge difference. I was not the only one to see it. The Dumbbell (M27) was an oval shape with brightening at the lobes, and the unfiltered view showed a smudge. Ditto for M57, M8 and a host of others. I wasn't able to make out the Veil Nebula with or without the filter. I even tried an OIII filter but had no luck. A 4 in APO refractor showed it nicely however. I'm still going to try for it later. The Orion Nebula was amazing without the UHC, But, when I added the filter I saw structure in the nebula I had never seen before. I was even able to see M1 (the Crab Nebula) directly. No averted vision needed. I decided to try it on some planets as well. It really made the markings on Mars stand out, but there was a price to pay. It gave this weird 3d glasses effect. Almost like I was looking through a pair of those red and blue glasses used at 3-d movies. It was a bit disconcerting. Saturn too showed better detail, as did Jupiter. But all with the extra red/blue images. So bottom line, is the Lumicon UHC filter worth the $99.00 + tax I paid for it? Without a doubt. It really makes the nebulae stand out. It suppresses all the extra light such as stars, light pollution etc... It enhances contrast, and gives you views you never thought possible. If you are on the fence about spending the money for this, I say go for it. You will only kick yourself for not doing it sooner." |
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V Block filter | Orion | 05595 | $70 |
Tim Haller (electra188@comcast.net) reports: "I have and use the V Block filter from Orion. The filter does work as advertised by controlling the fringing effect around bright objects like Mars, the moon and bright stars (1st magnitude or better). But the effect is very subtle. The filter certainly helps with chromatic aberration, but don't expect $4000 apochromatic refractor performance from the V Block with the ETX-70. I extract a lot of performance from my ETX-70 and can notice (and enjoy) the difference the V Block filter makes during my observations. If you observe just a few times a year, I don't think that the V Block will be of much use to you. Save the dough and buy a quality eyepiece that you can use with the 70 and any other scope that you might upgrade to in the future. Good luck - from a satisfied ETX-70 owner." | |||
Planetary Contrast Filter | Coronado Sirius Optics | N/A | $75 |
Kian Jek (kianjin@well.com) reports: "At a recent Star Party I was handed a Sirius Optics Planetary Contrast filter to try out. The view of Mars thru my ETX-125 at 211x was so good that I went ahead and bought one the very next day! The PC filter is unlike any other dyed or colored filter. I've always found colored filters, e.g. the yellow or light red ones for Mars somewhat "unnatural". But as many users here have pointed out, the current views of Mars are so bright that it is sometimes hard to make out fine details without resorting to one of these filters. The PC filter however, is designed to allow light to pass through in 3 narrow wavelengths, corresponding to the red, green and blue portions of the visual spectrum. The result is a subtle contrast enhancement and somehow images appear slightly sharper because of the selective filtering I guess. The image of Mars is slightly tinted yellowish in my opinion, but details are more discernable and most important, the view is closer to 'reality'. You can check out www.siriusoptics.com to find out more about the PC filter, and try googling around to find some reviews of it. The filter also improves views of Jupiter and Saturn, so I think it's something that all planetary enthusiasts should have in their accessory box." | |||
White Light Solar Filter | Coronado Technology Group | W90 | $249 |
Coronado Technology Group sent me their new "Better White Light Filter" for the ETX-90. This high-end filter presents a natural yellow view of the Sun unlike the orange or blue look with other solar filters. This, combined with the screw-on style, makes for a quality solar filter for the serious white light solar observer. I like the safety that a screw-on solar filter provides. Once, while observing through another amateur's telescope, his solar filter blew off in the wind. Fortunately I jumped away from the eyepiece in time to avoid any eye damage. But this demonstrates how important it is to properly secure a solar filter; since the Coronado filter screws into the threads on the correcting lens of the ETX-90 this a very safe filter. As with any solar filter, you still need to cover the finderscope.
![]() ![]() ![]() ![]() ![]() Mike here: I took some photos of a naked eye sunspot; you can see them on my Astrophotography Gallery - Sun page. |
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SolarMax 40 H-alpha Solar Filter | Coronado Technology Group | N/A | $800 (approx) |
On Saturday, 6 January 2001, I and many others had a sneak preview of a new, low-cost Hydrogen-alpha solar filter from Coronado Manufacturing. David Lunt came to Oceanside Photo & Telescope to show off their new amateur solar filter. Unlike other solar filters which just reduce the Sun's light and harmful radiation passing through your telescope letting you view sunspots and some other "white-light" details, H-alpha filters let you see our Sun in all its glory, including prominences visible on the limb (which would normally require a total solar eclipse to be seen). H-alpha filters work by passing a very narrow and specific frequency band and blocking out everything else. The Sun comes alive for you when viewing through one of these filters. In the past, these filters have been very expensive (at least 2-3 times the cost of an ETX-125EC) but this new model, expected to cost about $800, brings H-alpha viewing to a much wider amateur astronomy audience. The filter actually consists of two filters: a 40mm filter that covers the aperture of your telescope (using an adapter plate) and an eyepiece filter (attaches to the eyepiece like other eyepiece filters). During this sneak preview there was a very large prominence (a "rainbox-shaped arc" one) that was easily visible at all magnifications. The view of details on the Sun's disk was very sharp. The filter was attached to a small refractor, which actually made for a fine solar instrument. According to David Lunt, the ETX-60AT and ETX-70AT will perform really well with the new filter. The ETX-90EC and ETX-125EC models can also be used but since both are longer focal length telescopes than the -60/-70 models, stopping them down to the 40mm aperture of the filter will make the solar image dimmer. For the -90/-125 models, the filter will be offset to avoid the blockage of the secondary mirror. Coronado will have adapter plates for nearly every popular telescope model and the new filter is expected to be available in April 2001. Take a look at the solar images on Coronado's web site (http://coronadofilters.com/) to see examples of what you can expect to see with the new filter. If you are as intrigued by this as I am, Oceanside Photo & Telescope is accepting pre-orders; contact Mike Fowler at 800-483-6287, 760-722-3343, or opt@optcorp.com to get on their list. I hope to have a more extensive actual usage review online as soon as I can get one of the new filters. Thanks to Oceanside Photo & Telescope for setting up this sneak preview.
The following clarifications have been received from Coronado: Sent: Thursday, January 11, 2001 18:57:45 "Coronado Instruments Ltd. has developed a 40mm H alpha filter for Solar observing. This filter will be on the market late April and the company is attempting to retail the filter at below $1,000.00. At a recent demo of the filter at OPT , Gerry Hogan, speaking for Coronado announced that they are seraching for a name for this new filter and that they will take suggestions at a sun@coronadofilters.com. If they select and use a name submitted by a member of the public, they will reward that person with one of the filters. The name will become the sole property of Coronado Instruments Ltd." Mike here: I'm still trying to get one but in the meantime here is a short report from Vincent (vincent_ysc1@yahoo.com): "First try of SolarMax 40 with ETX90EC,40mm eyepiece+X2 barlow. looking through from this filter have a exciting feeling, and also addicting." ![]() |
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Baader Planetarium AstroSolar Safety Film | Astro-Physics, Inc. | N/A | $30 |
Glenn Smollinger (gsmollin@snip.net) tells us: "Sky and Telescope magazine did a review of the Baader Planetarium AstroSolar Safety Film, where they called it "the new standard". With the Dec. 25, 2000 solar eclipse loomimg, I bought it from the sole US distributor, Astro-Physics, Inc. The film is available in two sizes, A4, for $30, and a roll 1m X 500mm. I bought the former. It is also available in density 5 visual, and density 3.8 for photographic use. I bought the density five. You can cut the A4 size in half, and make a filter for the objective of the ETX90EC, and one for the 30mm finder scope. The included instructions show two different cells; use the instructions from Astro-Physics to make the objective filter. Its a better design, uses less filter material, and gives a nearly flat filter surface. Use the simpler Baader Planetarium design to make the filter cell for the finderscope. It will give a wrinkled surface, but who cares for a finderscope.
When pointing the telescope DO NOT LOOK AT THE SUN! Instead, examine the shadow of the telscope on a wall or screen, or even the ground. When the shadow of the OTA has been carefully minimized, look in the finderscope, and you will see the sun. I found that the 40 mm eyepiece was the best for viewing the eclipse. The atmospheric turbulence has pretty bad by 12:45 PM. The image was a neutral white, with sunspots clearly visible, including the penumbral brushes. I could use the 25 mm eyepiece as well, but found I was at the magnification limit with the 25 mm + 2X barlow due to turbulence. The most exciting moment was when I thought I could see sunlight streaming through a mountain valley on the moon right at the terminator of the eclipse. S&T reported seeing solar faculae on the suns surface, but I could not confirm this. Perhaps the turbulence was too great.
I can recommend this product. For $30 you can assemble two filters for ETX90 telescopes, including the finderscopes. With the half square meter size, a club can assemble filters for even less."
![]() Michael Teige (mteige@yahoo.com) writes: "Today the Sun finally came out up here in Seattle! First try of my BAADER AstroSolar film mounted in my homemade filter cell with my ETX90 EC. ![]() ![]() |
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6-Pocket Filter Case | Orion Telescopes & Binoculars | #15092 | $9 |
![]() ![]() ![]() ![]() I decided to add some velcro to the belt loop so that I could attach the case to the velcro on my tripod. The photos on the right show the case closed and open. This works very well and puts all my filters within easy reach. |
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Color Filter #21, Orange | Orion Telescopes & Binoculars | #5534 | $10 |
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#56 Light Green | Orion Telescopes & Binoculars | #5574 | $10 |
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Moon Filter | Scopetronix | N/A | $13 |
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Light Pollution Reduction | Celestron | N/A | $69 |
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Solar Filter | Orion | #7733 | $60 |
Eric Gregoire (jazzn2day@home.com) notes: "I only have had a chance to pull it out a few times (The Mercury transit was
a bust here... too cloudy on the horizon!) but so far I have only good
things to say about it.
Upon first opening it, the filter appears very similar in looks to its
competition (more expensive competition) feels solid and shows high quality
manufacture. A small envelope of "stick-ons" are included for a continued
snug fit. The directions are clear and simple (how much can you say about a
solar filter?) and cover any on the spot repairs you might need to make over
years of use. If only someone were to think of putting a 10 cent lens cover
for the finderscope... but I digress. First off, I'd like to say that
finding something that big and obvious isn't as immediately simple as you
might think. No finderscope and nothing visible in the EP until you're on
target... The entire solar disc was a natural orange/yellow color and spots
were visible in the standard 26mm Plossl. The addition of the 2x Barlow
provided some nice clarity and I can say I look forward to further observing
when I acquire some new eyepieces. As usual Orion provides a quality product
with an affordable price tag. A worthwhile addition to the standard
equipment especially in this busy Solar year. How often we forget about
viewing our neighboring star..."
Matt Raffel (mattr@microobjects.com) adds: "I didn't see any information concerning the Meade ETX125 using a solar filter from orion telescopes (maybe I missed it). I have discovered that the Orion Solar Filter (part #7727) 5.70" will work just fine with the ETX. It fit very snuggly. I did not need to add any extra tape liner." |
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Various filters | Various | N/A | Varies |
Ken Saggese (jk.saggese@prodigy.net) writes: "I have used several of the filters offered by Meade and wanted to share my experiences with fellow users. Specifically, I have tried the #12 yellow, #23A light red, #58 green, and #80A medium blue (these four are Meade's filter set no. 1); separately, I have also purchased #21 orange, #8 light yellow, #82A light blue, #ND96 (neutral moon filter), and #908B (broadband nebula filter). I have used these primarily on Jupiter and Saturn. First of all, I immediately discovered that #58 green and #23A light red are simply too dense for use with the ETX, which is slightly light-challenged as it is due to its 90mm aperture. #21 orange may be usable, but I was not convinced that it rendered any significant improvement in contrast (I'm not sure orange is a good color for Jupiter anyway). I would not reccommend any of these three filters for use with the ETX. #ND96 is somewhat useful for looking at a bright gibbous moon (if you want to), and also reduces the roiling glare from Venus somewhat. I have found it to be limited in its usefulness but not a bad purchase. The four filters that I have enjoyed are #80A and #82A (medium and light blue, respectively), and #8 and #12 (light yellow and yellow, respectively). The yellows seem to clarify Saturn's rings (#12 in good seeing especially), while the blues enhance Jupiter's banding. #80A is perhaps a tiny shade too dark, and I only use it under very good seeing. Most commonly I use #82A on Jupiter and Saturn for surface markings, and switch to the yellows only for trying to pry out the Cassini division. #82A and #8 are the two most useful filters, in my opinion. They also seem to enhance the visibility of moon features as well, although they do not render visible anything that wasn't already, instead simply making them more apparent. The nebula filter seems to work decently on the Orion nebula, but--as advertised--doesn't significantly improve the view of the Andromeda Galaxy. If you are really into nebula rather than planets (I'm not), the #908B filter does help, but it costs about eighty bucks. All others are about eighteen each." | |||
UltraBlock Narrowband Light-Pollution filter Oxygen III deep-sky filter |
Orion Lumicon |
5654 N/A |
$100 $100 |
David Fischer (AstroFrk69@aol.com) compares two popular deep-sky filters: "In today's market, there are many filters out there. From color filters, to deep-sky filters, each has its own and unique purpose. I have used and experimented with Orion's deep-sky filter and Lumicon's Oxygen III (Olll) filter for sometime now and I have compared and contrasted the two. After several observations of faint and relatively bright nebula using the etx, I found the filter which would fulfill my needs. One night I observed m42 with both filters. I immediately saw a difference in the brightness of the nebula with both. However, more subtle details were noticeable in the nebula using the Olll. One drawback I will admit is that the Olll dimmed the trapezium stars greatly, while Orion's wasn't as strong. But I feel that the Olll had the edge of making the nebula brighter. Both filters did a remarkable job on this object. This next object put these filters to the test. I drove to a remote dark observing sight and observed m76, the Butterfly Nebula (also known as little dumbbell). This has a magnitude of about 12 and was a very difficult object to find because of its low brightness. Using a tel-rad mounted on my etx, (mounted by bungee cords and some imagination), I got the etx within the area of where this object was. (I have been observing for about 3 years now and my eye has become more sensitive to light.....so finding this object was slightly easier.) I first used Orion's filter. The nebula became more noticeable, but I wasn't impressed. I then used the Olll and I could see the difference. The Olll made this object much brighter compared to Orion's. In my amateur opinion, I feel that Lumicon's Olll filter is one of the best deep-sky filters out there. It can be bought almost anywhere with the average price of $99.95. There is only a slight difference between the Olll and Orion's, and for beginners either will do just fine. But for the more serious astronomer, the Olll has the edge. Equipment used: Meade ETX, 22mm Panoptic eyepiece, 15mm Panoptic eyepiece, 9mm Nagler eyepiece"
[09/23/08] Steve Hollar (sjhollar@dslextreme.com) adds: "I splurged and bought myself an Orion UltraBlock Narrowband filter. In a word, I must say, WOW! Up front, it is not designed for astrophotography. It is for visual observing. What it does is block the light waves emitted by most artificial light sources, the kinds that give us our cursed light pollution while letting hydrogen-beta and ionized oxygen wavelengths pass through. It is for nebulas and not for stars, planets, or clusters. Visually it noticeably darkens the background and gives stars, which are also dimmed, a greenish tinge. My first target was the Lagoon Nebula M8. Although it was fairly low in the sky, I was blown away by the clarity of the gas clouds. The dark band separating the two clouds was very apparent. And, the surrounding sky was very black. To check the difference, I pulled the eyepiece and removed the filter. Now the nebula was just visible as a gray smudge. I could not distinguish the dark band, and, the rest of the sky had more of a very dark gray cast. Looking at the Dumbbell Nebula M27 and Ring Nebula M57 were even more impressive as they were much higher in the sky, almost overhead. They really stood out against a black sky. If a person is going to spend some money on one filter, I can highly recommend this filter. Naturally there are other brands, which I don't have so can not make a comparison, but, reviews I've read rate this one right up there at the top." |
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Solar II Type 2 Plus solar filter | Thousand Oaks | N/A | $79 |
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Solar View Type A Plus solar filter | Thousand Oaks | N/A | $65 |
![]() Dave (AstroFrk69@aol.com) reports: "I just want to inform you that I just received my thousand oaks type A+ solar filter for my etx. When I got it I was thrilled. I opened it up, read the instructions, and couldn't wait to try it out. I brought everything outside (my scope, eyepieces, etc...) to cool down. It was about 9 in the morning and I had everything set up for my first view of the Sun. I placed the filter on the scope, (you have to keep checking it because it can slide off even with the extra felt inside of it), I then covered the finderscope. this is very important. You can accidentally look through it and blind yourself, not only ruining your eye sight, but the finderscope as well. I placed a little cover thingy on the front of the finderscope which "turned it off." Using a 22mm panoptic eyepiece (yes it fits in the etx), I started "searching" for the Sun. You have to scan the sky for the sun because you have no guide. Out of no where, there she was. Wow. That is the only word I can say to my reaction of first seeing it. The sunspots were easily visible. I put in my 9mm nagler with a barlow and got a closer look at the sunspots. The etx held up beautifully. The images were crisp and perfectly clear, and there was no fuzz. This scope and filter are amazing. If you're getting an etx, or already have one, definitely get a solar filter. It is astounding." |
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Narrowband Filter | Meade | 908N | $90 |
Adolfo Viana (aviana@impsat.net.co) provided the following comments: "I recently got a Meade Narrowband filter, since here in Bogota we have a well poluted area, one of my first targets was M57, that night we were using the ETX and a LX50 8", with the use of the filter the image was very clear through the ETX, the big difference with the LX50 was in the apparent size, both observations were with the Meade 26mm SP." | |||
ETX SOLAR SKREEN | Tuthill, Inc. | N/A | $48 |
Don (TheDBarbee@aol.com) notes the following about the ETX SOLAR SKREEN from Roger Tuthill (800-223-1063 or 908-232-1786). "Wow this is a GREAT product. The views of the Son are just mindboggling. Worth every penny. The Solar Screen is $48.00; there is shipping."
Douglas E. Cann (cann@axionet.com) adds "Just wanted to share my latest accessory that I received for my vintage ETX (July 1996) which is still performing flawlessly. I bought one of Roger Tuthill's Solar Skeens for viewing the sun. This will now double the use of my ETX. The sun is getting pretty active right now and I wanted to get the filter before there is a rush on them. The 90 mm ETX is the perfect size for solar observation and my first test run on the weekend confirmed this. It is a mylar filter and although I was torn between this and one of the glass filters, I decided on the mylar one for weight and after hearing various reports and reading the write up in Sky and Telescope last summer. The light blue image of the sun is no problem and although I experimented by adding different colored filters to my eyepieces, the solar filter on its own gave the best details. A light green filter 'may' improve the contrast. I will have to wait for another sunny day. Anyway, I am very pleased with its perfomance and would reccomend this filter to all ETX owners." |
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Photo-Visual Color Filter #8, Light Yellow | Meade | 07512 | $18 |
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Photo-Visual Color Filter #82A, Light Blue | Meade | 07521 | $18 |
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