WILL IT BURN? - ..Filter Killer..

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
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WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 5:58 pm

Well the thread title says it all,

Here I will post various tests of some IR/UV cut filters and color filters coated with IR blocking to see if they burn stuff.

The test scope is a 120mm objective with 1000mm focal length.


It does not take a genius to realize if sunlight burns stuff, its going to kill your every expensive filters.

Going forward, I will be boldly honest here with my first test.

Beloptik KG3 IR/UV cut filter is effectively useless on its own for solar imaging.

This test was performed with a 2" beloptik IR/UV KG3 filter held within the focuser, as seen in the second image.

The burning is instantaneous. No further testing is needed with One filter, it will always burn and get incredibly hot at solar focus..


meade lable 120mm.jpg
meade lable 120mm.jpg (160.89 KiB) Viewed 1192 times
beloptic focuser 1.jpg
beloptic focuser 1.jpg (270.05 KiB) Viewed 1192 times
beloptic focuser 2.jpg
beloptic focuser 2.jpg (294.78 KiB) Viewed 1192 times
beloptic focuser 3.jpg
beloptic focuser 3.jpg (320.59 KiB) Viewed 1192 times
belooptik KG3 burning.gif
belooptik KG3 burning.gif (1.49 MiB) Viewed 1192 times
Last edited by TheSkyBurner on Mon May 28, 2018 6:21 pm, edited 1 time in total.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 6:20 pm

Okay, Now I have two beloptik IR.UV KG3 filters stacked in a train. One in the nose of the focuser, and one in the eyepiece holder.

Oh look, even two of these filters is not doing its job at protecting your expensive filters....

Burned instantaneously, double stacked still a fail.
beloptik 48mm double.jpg
beloptik 48mm double.jpg (178.55 KiB) Viewed 1190 times
beloptik 48mm double2.jpg
beloptik 48mm double2.jpg (144.55 KiB) Viewed 1190 times
beloptik BURNED.gif
beloptik BURNED.gif (1.51 MiB) Viewed 1190 times
Last edited by TheSkyBurner on Mon May 28, 2018 6:54 pm, edited 1 time in total.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 6:58 pm

Okay, Here I have Two beloptik IR.UV KG3 in a train, PLUS a B&W 486 IR/UV cut filter.

One belotik kg3 deep in the focuser, one kg3 on the nose of the barrel extension and the B&W 486 filter in the back of the barrel extension

BAD NEWS FOLKS.
EVEN TRIPLE STACKED IR/UV CUT FILTERS BURN INSTANTANEOUSLY.

beloptik plus bw 486.jpg
beloptik plus bw 486.jpg (266.93 KiB) Viewed 1185 times
beloptik plus bw 486 2.jpg
beloptik plus bw 486 2.jpg (178.99 KiB) Viewed 1185 times
triple stacked IRUV cut1.gif
triple stacked IRUV cut1.gif (2.27 MiB) Viewed 1185 times

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 7:18 pm

Okay well this final test sums it up for all combinations of just using IR/UV cut filters.

Here is double stacked beloptik IR.UV KG3
One B&W 486 IR/UV CUT
One B&W 415 UV SPEZIAL absorption filter


FAIL! Looks like no matter how many of these IR/UV blockers you place inside your focuser you are going to fry the first filter behind them.

I am going to be perfectly honest with you here now.

Do not believe anything daystar, beloptik or anyone else for that matter says about protecting your quark; any hydrogen alpha filter, any calcium filter and more important YOUR EYEBALLS with any of these products. The protection is clearly a myth.

triple stack iruv plus 514 uv spezial.jpg
triple stack iruv plus 514 uv spezial.jpg (211.01 KiB) Viewed 1183 times
bw UV spezial 415 filter.GIF
bw UV spezial 415 filter.GIF (7.78 MiB) Viewed 1183 times

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 8:02 pm

Okay now here is the most shocking truth of all. "FULL APERTURE PROTECTION IS THE ONLY WAY....."


Here is a 6" full aperture Tiffen infrared hot mirror (this thing retails for $800.00US). Mounted on the 120mm objective lens dew shield.

Behind it is the first Beloptik IR.UV KG3 in the nose of the focuser tube, the second Beloptik IR.UV KG3 threaded onto the nose of the 2" barrel extension, The B&W 486 IR/UV cut filter, the B&W 415 UV SPEZIAL Absorption filter All together in the barrel extension.

So this train has FOUR reflective IR cut filters and one UV Absoption filter. FIVE total filters stacked to filter out infrared and ultraviolet.

Guess what? FAIL.

Even the full aperture IR cut test in front of FOUR other "safety" filters burns instantaneously.
There is nothing protective about these filters at all.
Attachments
full aperture IR cut burn.GIF
full aperture IR cut burn.GIF (7.33 MiB) Viewed 1178 times
Full apertture IR cut.jpg
Full apertture IR cut.jpg (182 KiB) Viewed 1178 times
Full apertture IR cut 1.jpg
Full apertture IR cut 1.jpg (123.93 KiB) Viewed 1178 times

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 9:07 pm

Now onto the first color filter.

This is a Baader planetarium G-ccd filter, paired with the Beloptik IR.UV KG3 filter.

ANNNNNND FAIL! So much for "IR BLOCKING"

So this pretty much settles it. Do I even need to test the B-CCD filter for you at this point?

The secretive Apollo Lasky IR rejective telenegative compound doublet is looking like a mighty fine solar product right about now, I will test that in the very end.
G-ccd filter beloptik kg3 FAIL.GIF
G-ccd filter beloptik kg3 FAIL.GIF (6.51 MiB) Viewed 1173 times
1.25 baader planetarium g-ccd3.jpg
1.25 baader planetarium g-ccd3.jpg (224.83 KiB) Viewed 1173 times
1.25 baader planetarium g-ccd 2.jpg
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1.25 baader planetarium g-ccd.jpg
1.25 baader planetarium g-ccd.jpg (182.53 KiB) Viewed 1173 times

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Re: WILL IT BURN? - ..Filter Killer..

Post by mdwmark » Mon May 28, 2018 9:37 pm

Yep, I know. Over the years repairing filters, I have come across many that where damage using to fast of scopes. Like your burning ants analogy. 100mm F/15 with no ERF will melt a .54" spot in the delrin of the front plate and take out the blocker over time.
The point of the front mounted ERF was to keep the heat out of the scope and also lessen the thermal load on the filter.
The yellow ERF does very little , the old surplus red glass drops some of the heat. I tested how much, with my 3" F/30 scope. The temperature at focus was around 54C. The RG610 dropped in down to the high 40's. and the RG630 mid 40's.
The Baader D-ERF ( the day I checked) just read the air temperature. These where all at F/30. I didn't check them at F/8 or faster.
The internal ERF, like the Baader 35nm would be the next best approach with dealing with the heat. This filter is hard coated so it can handle the heat. Just keep it up in the beam so the energy density is spread out.

The front blocker of a Quark is rated at a maximum temperature of 70C(according to Andover's catalog).

I think you made your point.
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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Mon May 28, 2018 10:29 pm

mdwmark wrote:
Mon May 28, 2018 9:37 pm
The front blocker of a Quark is rated at a maximum temperature of 70C(according to Andover's catalog).

I think you made your point.
Mark W.

Im starting to wonder if a circular polarizer placed over the objective is the right approach, then the erf. Then clock the intensity on the first polarization turn of the first filter element


How quickly will Valery's 295mm scope hit 70c? That would be a crazy fun test :)

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Re: WILL IT BURN? - ..Filter Killer..

Post by mdwmark » Mon May 28, 2018 11:45 pm

I was thinking, The front of the telecentric is not at prime focus. So it will be hot but not as bad as prime focus. If your using an F/5 then I don't think it would make much difference.
I'm not sure the distance for the Quark but I would guest about 45mm in front of prime focus would be a good place to try. See what type of temperatures you would be talking about at that point. That is a more realistic test.
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Re: WILL IT BURN? - ..Filter Killer..

Post by mdwmark » Tue May 29, 2018 3:37 am

BUT , when you move in and out to focus, you will run into that problem of high heat.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Tue May 29, 2018 6:09 pm

Got my b-ccd filters today but i am thinking about just returning them. I already know its gonna burn stuff, even faster than the g-ccd. More intensity in the blue wavelengths.
baader planetarium bccd .jpg
baader planetarium bccd .jpg (252.31 KiB) Viewed 1103 times
Last edited by TheSkyBurner on Tue May 29, 2018 7:16 pm, edited 1 time in total.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Tue May 29, 2018 9:10 pm

I just forwarded this thread to a filter design team and Requested they develop A solution to this problem, ill keep you updated.

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Re: WILL IT BURN? - ..Filter Killer..

Post by bart1805 » Tue May 29, 2018 9:49 pm

I am sorry, but don't fully understand what you are trying to prove. You say for example that "Beloptik KG3 IR/UV cut filter is effectively useless on its own for solar imaging". Ok, but is that news? Where does Beloptik say that this filter can be used "on its own for solar imaging". As far as I understand Beloptik says that these filters should be used in conjunction with an Erf in front of the telescope. So if you want to test if what a manufacturer says is right you should test it the way it is advised to be used.
Even a Baader D-Erf in front of a 150 mm F8 achromat lets through quite a lot of heat. If you combine it with a Baader 35nm filter this is solved.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Tue May 29, 2018 10:42 pm

bart1805: Sorry man, but thats not how this works out. Lunt Calcium K line filters are exposed to the full heat, and the ls152 calcium module is placed behind a herschel wedge because of the issue.

If a filter is described as od5 for blocking heat, there should be none coming out of the back end. If a filter is advertised as being totally blocked, then it should be totally blocked. If 1 person finds a flaw in this system, the whole system is wrong.

Baader planetarium advertise their filters as IR blocked. It does not describe the level of blocking, yet at the same time displays the solar fraunhofer lines on the box indicating that somewhere "solar light" was applied to them. If you look closely at the solar spectrum on the baader planetarium boxes both calcium K-line , calcium H-line are advertised.

This is how it works, if I pay for something that is IR blocked for my calcium spectrum it better be blocked. We should not have to buy 7 filters to accomplish the blocking.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Tue May 29, 2018 10:50 pm

One last note, look at the picture of the lunt calcium module. You see that red tag on the back? It says "caution: HOT!" The LS152 is 30mm larger than my test scope, and 2 focal ratios faster. Its putting out alot more fire onto one filter system, thus the warning lable.

Image

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Tue May 29, 2018 11:09 pm

IF the baader planetarium D-ERF filter can start a fire then I also have a problem with that setup, and the only way to prove that the 35nm filter puts out the fire is to get a 200mm telescope and perform the test and post the results. But as I see it right now, if you are putting the first component of a $2000 optical system behind a "fire laser" then you are a quite literally playing with fire.

The only true protection is applied by a deep negative focal plane.

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Re: WILL IT BURN? - ..Filter Killer..

Post by bart1805 » Tue May 29, 2018 11:17 pm

Baader UV/IR blocking filters open at 1100 nm.
https://www.baader-planetarium.com/en/d ... filter.pdf
Did you prove that they open up before 1100 nm?

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Wed May 30, 2018 12:16 am

bart1805 wrote:
Tue May 29, 2018 11:17 pm
Baader UV/IR blocking filters open at 1100 nm.
https://www.baader-planetarium.com/en/d ... filter.pdf
Did you prove that they open up before 1100 nm?
I could... but the problem is it blocks the calcium k-line and calcium h line, and does not block 1200-1500mm. upto 1500nm is what causes some of the burning; and these are not blocked there.
baader planetarium iruvcut.jpg
baader planetarium iruvcut.jpg (48 KiB) Viewed 1066 times
Also again; the level of blocking is not posted so this is not offering any protection estimation either . It just says "comprehensive 44 layer coating". Well most all modern ir/uv cut filters have a 44 layer coating...

The baader planetarium IR/UV cut filter will burn things just like all the rest of them when pointed at the sun using my test scope, I promise you this without even having to test it.

I do have the neodymium filter which has the IR/UV cut built into it, so i will test it the next sunny day i get.
baader planetarium neodymium.jpg
baader planetarium neodymium.jpg (231.62 KiB) Viewed 1066 times

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Wed May 30, 2018 12:20 am

Baader planetariums OWN filtergram, showing "uv/ir cut" in a stack to be used as an h-alpha filter pass.

Look at 1200nm... So this just confirms everything, they already know their system passes a ton of heat.
baader planetarium iruvcut HA pass.jpg
baader planetarium iruvcut HA pass.jpg (65.24 KiB) Viewed 1065 times
information pulled right from the .pdf you posted from baader-planetarium.com
https://www.baader-planetarium.com/en/d ... filter.pdf

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Re: WILL IT BURN? - ..Filter Killer..

Post by Spectral Joe » Wed May 30, 2018 3:27 am

I've had this discussion before, it rarely sinks in but I'll try again.

Rather than just burn stuff why not just think for a minute about what radiation actually reaches the Earth from the Sun. How many people here have ever seen a solar radiation plot and thought about what it means? The great assumption is that "heat" is only the result of infrared radiation, and that filtering out the IR will eliminate the heat. Wrong. Most of the energy that reaches the Earth's surface from the Sun is visible light, which peaks in intensity at around 500nm. Even if all of the IR is eliminated heat will be generated when the remaining visible light is absorbed. Here's an exercise to try: get a spreadsheet program, any one will do. Search for a solar radiation file (just search "solar spectrum", the ASTM G173 Direct file is a good one), integrate the whole spectrum and then integrate what's left after you multiply various filter transmissions by the spectral curve. Then you can feel like an actual scientist, doing quantitative work. You will be surprised at how much energy is left when the extreme ends of the spectrum are cut out.
Observing the Sun with complex optical systems since 1966, and still haven't burned, melted or damaged anything.
Not blind yet, either!
Light pollution? I only observe the Sun, magnitude -26.74. Pollute that!

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Wed May 30, 2018 3:37 am

Spectral Joe wrote:
Wed May 30, 2018 3:27 am
I've had this discussion before, it rarely sinks in but I'll try again.

Then you can feel like an actual scientist, doing quantitative work. You will be surprised at how much energy is left when the extreme ends of the spectrum are cut out.
You know I could do what you said with the spread sheet and kill off time, but its a [hot place] of alot more fun to use a 1 watt red, green, or blue focused laser pointer to make the same point; Right?

I understand that combined solar energy is able to start a fire, and that separating the wavelengths down to narrow band still will not eliminate the intense "spallative ablation ray". Thus my extended tests with the green and blue filters still causing a fire, and my notion that calcium system requires an objective mounted polarizer, so that the actual intensity of rays can be clocked on the first filter element and then reoriented at the camera .

But then again, most hydrogen alpha systems by default is in a deep negative focal beam. Which i also state is the only "safe" way to protect your filters. So logically, we need a negative element that is corrected for calcium systems.

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Wed May 30, 2018 4:02 am

so now the question comes to mind, what transmission level brings the thermal load down to 37c(body temperature) at all wavelengths.

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Re: WILL IT BURN? - ..Filter Killer..

Post by bart1805 » Wed May 30, 2018 7:06 am

TheSkyBurner wrote:
Wed May 30, 2018 12:20 am
Look at 1200nm... So this just confirms everything, they already know their system passes a ton of heat.
Yep, that is my point. What you "discovered" you can find easily on their website. Combined with what spectraljoe wrote the question for me is did you really believe that a UV/IR blocking filter, stacked or not, could prevent you from burning something?
And where exactly do manufacturers like Beloptik or Baader say that their filters are capable of preventing just that?

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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Wed May 30, 2018 2:33 pm

bart1805 wrote:
Wed May 30, 2018 7:06 am
TheSkyBurner wrote:
Wed May 30, 2018 12:20 am
Look at 1200nm... So this just confirms everything, they already know their system passes a ton of heat.
Yep, that is my point. What you "discovered" you can find easily on their website. Combined with what spectraljoe wrote the question for me is did you really believe that a UV/IR blocking filter, stacked or not, could prevent you from burning something?
And where exactly do manufacturers like Beloptik or Baader say that their filters are capable of preventing just that?
They are all advertised as "reducing the thermal load on your filters" , and it just isnt true especially if we take into the curve-ball point that spectral joe threw out.

I would like the filters to be labeled properly with the actual amount of blocking they provide, like the baader planetarium filter is advertised as fully blocked.

We need to know just how much infrared/uv is being blocked. Even with the b-ccd and g-ccd filters, are they still letting any other light through? I already know that I can stack the b-ccd with the g-ccd and get a sliver of O3 transmission out of it.

I have some very expensive filters and if they get damaged i would be pretty upset knowing It was because of missing or misleading data.
U filter is advertised as fully blocked, but not past 1150nm because its not intended for solar use.
venus filter.jpg
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Re: WILL IT BURN? - ..Filter Killer..

Post by TheSkyBurner » Wed May 30, 2018 2:39 pm

So i keep running into this problem with baader planetarium products. They advertise as one thing then display another thing. Here is another graph for the U filter. You will see that there are blips around 700nm - 900nm but zero from 1000-1500nm

So what is true?
baader u filter .jpg
baader u filter .jpg (110.3 KiB) Viewed 1003 times
baader U filter 2.jpg
baader U filter 2.jpg (68.19 KiB) Viewed 1003 times
information pulled from baader-planetarium.com
https://www.baader-planetarium.com/de/d ... filter.pdf

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