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Use of vintage eyepiece sun filters.

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#276 Terra Nova

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Posted 30 November 2017 - 10:15 AM

Yeah! :4

 

“You’ll shoot your eye out kid!” ;)


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#277 deSitter

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Posted 04 December 2017 - 08:07 AM

I still find it strange that the meticulous and careful Japanese could have sold these filters. There must have been evidence of failures. Also, it was probably intended only to be used with a Huygenian eyepiece having simple elements and with the focal plane rather far from the filter.

 

They make good dust caps :)

 

-drl


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#278 Joe Cepleur

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Posted 04 December 2017 - 05:57 PM

Why were these filters designed to fit at the eyepiece? Wouldn't it have been just as easy to fit them over the objective? Was it purely economic, a smaller filter being cheaper than a larger one?
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#279 nashvillebill

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Posted 04 July 2018 - 09:57 AM

Recently found in a vintage scope case (the filter, not the guitar pick, which I am using to point to the crack):IMG_0318.JPG IMG_0317.JPG IMG_0320.JPG

 

And yes, light passes through the crack. I've added a third picture with the filter on a flashlight.   Hopefully nobody was looking through this at the time.


Edited by nashvillebill, 04 July 2018 - 10:20 AM.

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#280 Kasmos

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Posted 04 July 2018 - 12:57 PM

I think it's strange how (for some cosmic reason), my last few telescope purchases have included the Sun filter but no Moon filter. The Moon filters must end up in Black Holes.

 

The latest one came without any eyepieces but there was that darn filter again! grin.gif 

 

Perhaps the explanation is, they don't get used so tend to stay in the box. 


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#281 deSitter

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Posted 06 July 2018 - 11:07 AM

I think it's strange how (for some cosmic reason), my last few telescope purchases have included the Sun filter but no Moon filter. The Moon filters must end up in Black Holes.

 

The latest one came without any eyepieces but there was that darn filter again! grin.gif

 

Perhaps the explanation is, they don't get used so tend to stay in the box. 

The Moon filter was not always included, particularly in earlier scopes. The only time I used mine was on Venus :)

 

-drl



#282 Kasmos

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Posted 06 July 2018 - 01:20 PM

I can't believe they sell these brand new from China.

Read the description for warnings.

 

Also available for 1.25" eyepieces!

 

https://www.ebay.com...3.c100754.m4842

 

 



#283 Terra Nova

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Posted 06 July 2018 - 02:48 PM

From the fine print at the bottom of their ad:

 

“Suitable for occasions: watch the rising sun, sunset (at noon, the sun is too strong, do not support the use, need to be equipped with other filter parts)”

“Usage: please turn the sunglasses into the lower part of the eyepiece after use, then connect the eyepiece to the zenith mirror. Reminder: please use it in the morning or evening, where the sun is not strong enough to cause an explosion and hurt your eyes. Where exceptionally high air quality is available, or buyers who need to see the sun for a long time, it is recommended to buy the Bard film! If you are Qinghai, Tibet, Yunnan and other air quality is particularly good, or plateau areas, it is recommended not to use this paragraph sunglasses, easy to hurt your eyes Oh! Note: do not watch for more than a minute, or it will burst easily, but it won't hurt eyes, because sunglasses are placed under the eyepiece.

 

:lol: It will explode but it won’t hurt your eyes because its under the eyepiece?! :foreheadslap:


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#284 rcwolpert

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Posted 06 July 2018 - 04:27 PM

I’m so glad to see that they provided detailed usage instructions! lol.gif  I feel so much safer.  They might have added, “Viewing sun much safer between sunset and sunrise”. 


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#285 Terra Nova

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Posted 06 July 2018 - 07:03 PM

^ :rofl: ^


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#286 Adam S

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Posted 21 July 2018 - 10:25 AM

I could lose my vision for only $2.50 plus shipping? What a bargain.


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#287 dhferguson

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Posted 23 September 2018 - 11:20 PM

Cheers,

 

Indeed, the best advice is simply never to use the eyepiece-based "Sun" filters ... never! That quick look is not worth the crack, the blinding flash, and then the permanent eye damage. I liked one poster's conception of the "Sun marshall," too. Indeed, an aperture solar screen can be blown/hit/fall/etc. off. I use Velcro to be sure. Also, when others are around, you must watch them like hawks! I've had youngsters try to remove the cap on the finder!

 

Here's another problem with solar viewing some of you may not have thought of. In lieu of a full aperture filter (i.e., Tuthill, Thousand Oaks, etc.), some of us have projected the Sun through an eyepiece. If you do this, make sure the eyepiece is uncoated and not cemented. Otherwise, the heat will damage the coatings and/or cement, and ruin that potentially expensive eyepiece. The best choices for a projection eyepiece are uncoated two-element designs, such as Huygens, Ramsden, or symmetrical types. They are surprisingly hard to find these days.

 

Happy observing always,

 

Don


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#288 Uranotopia

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Posted 28 October 2018 - 04:00 PM

Hello together,

I can remenber the older times, when there were many telescopes sold with 0.965 inch equipment, especially with those very dangerous sun filters! Of course it was told to reduce the the telescope's aperture down to 2 inches - but who followed this advice?

Nevertheless I cannot remember any report about hurt blinded eyes, but probably there were many amateur astronomers with eye damages...

But by now there are some interesting shops, who sell 0.965" star diagnonals (mirrors) and colour filters (green, blue,yellow and red) - of course produced in China. But I think, the brand "Datyson" shouldn't be so bad...

So, I ordered a star diagonal and three colour filters for my two vintage telescopes, optimized only for 0.965 inch equipment. The new equipment will be delivered until mid of November. When it will arrive, I'll write a little report about these additional equpitment for my scopes here.

 

Hoping for clear skies!

Carsten


Edited by Uranotopia, 28 October 2018 - 04:01 PM.

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#289 AstroKerr

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Posted 31 December 2018 - 11:59 PM

I still find it strange that the meticulous and careful Japanese could have sold these filters. 

If they assumed others would be careful and meticulous in their use of said filters, perhaps not so surprising. They may well have thought that it would be rather obvious to anyone that using those filters in the eyepiece of a telescope in other than the prescribed manner could or would have extremely deleterious effects upon the eye. 

 

or not... 


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#290 Uranotopia

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Posted 04 January 2019 - 06:43 PM

Yeah!
And don't forget, that the tekescope's tube will become warm or hot!
There's similar recommend as if you use the solar projection method: only safe with achromatic doublet refractors and without plastic or clued eyepieces!
Some years ago I'd ruined a cheap 'plastic style' star diagonal and simple eyepiece with solar projection with 80/400 doublet achromatic.
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#291 photoracer18

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Posted 20 February 2019 - 04:48 PM

Now, how safe are the solar filters criterion sold that looked like barlow's? I've seen on of them on here a while ago.

Also how do you use a hershel wedge on a newt?


You don't as they are not designed for Newts. They are really designed for refractors and maybe for Cats but I never liked the idea of the full aperture of the Cat falling on the smaller secondary either. Best thing for a Cat or Newt is a solar filter on the front of the tube. If a truss Dob don't do it without a light shield around the truss. I personally prefer a wedge on a refractor over a solar filter over the objective as I think the view is sharper. I have used a Herschel wedge since the late 60's when I bought my first one from Optica b/c. Still have it but also have a Lunt now, too.
My SV102ABV OK4 doublet is my current designated solar scope with both wedges and front filters plus a 40mm Coronado with adapter on the front and a BF10 diagonal at the back for Ha.
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#292 Terry Atwood 1

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Posted 25 June 2019 - 05:13 PM

I have always understood that the screw-on solar filters for the 0.965 eyepieces were for use with the 60mm scope with which they came, and you put on the objective dust cap then removed the smaller plastic cap on the dust cover which opened up a smaller 40mm or so mask opening to use when viewing the sun thus further reducing the aperture of the 60mm scope to about 40mm.



#293 CharlieB

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Posted 25 June 2019 - 06:11 PM

They came with all different apertures.  I have one that came with my Swift 831 (76mm).  Just pack them away and forget about them.  They are too dangerous to use.



#294 havasman

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Posted 25 June 2019 - 06:50 PM

Ah, the strategy that never seems to go away and die. My old buddy David often referred to the concept of chlorine for the gene pool when discussing such matters and proposed that determined adherents to such bad concepts should be allowed to execute their ideas and sometimes by doing so execute themselves too. He declared them BRILLIANT, as in -   https://www.youtube....?v=3DPKf7y1F-Q 



#295 Joe Cepleur

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Posted 05 July 2019 - 03:10 PM

Used properly, eyepiece mounted Sun filters are less likely to break. No one doubts that. Never used, they are certain never to break. The statistics no longer matter, if the injured eye is yours. It's safer to never use them, especially with the easy availability of solar films to cover the aperture. 



#296 Terra Nova

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Posted 05 July 2019 - 06:05 PM

You don't as they are not designed for Newts. They are really designed for refractors and maybe for Cats but I never liked the idea of the full aperture of the Cat falling on the smaller secondary either. Best thing for a Cat or Newt is a solar filter on the front of the tube. If a truss Dob don't do it without a light shield around the truss. I personally prefer a wedge on a refractor over a solar filter over the objective as I think the view is sharper. I have used a Herschel wedge since the late 60's when I bought my first one from Optica b/c. Still have it but also have a Lunt now, too.
My SV102ABV OK4 doublet is my current designated solar scope with both wedges and front filters plus a 40mm Coronado with adapter on the front and a BF10 diagonal at the back for Ha.

Actually that’s not true. A Herschel wedge can be used in place of the secondary mirror in a solar Newtonian. In fact you can design a Newtonian exclusively used for solar observation and not have the primary aluminized and use a Herschel wedge in place of the secondary. Alternatively, you can swap out the secondary for a wedge in a double-duty Newtonian. Keep in mind that the Herschel wedge by itself will filter out about 95% of the direct sunlight, so you will still need the additional filtration provided by an ND3.0 solar filter between the wedge and the eyepiece to make it safe and even additional filtration like a green, yellow, or polarizing filter to bring it down to comfortable levels. If an unaluminized primary is used in conjunction with a wedge, somewhat lesser tertiary filtration is required.


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#297 Terra Nova

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Posted 05 July 2019 - 06:09 PM

PS- Some of us will remember Herschel wedges for Newtonians being sold by Edmund Scientific back in the day, and IIRC, instructions for the construction of solar Newtonians were given in Thompson’s Making Your Own Telescope, Sam Brown’s Telescopes You Can Build, and Ingals’ Amateur Telescope Making.


Edited by terraclarke, 05 July 2019 - 06:10 PM.

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#298 photoracer18

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Posted 13 August 2019 - 03:38 PM

This is probably a silly question but will the SUN filter let enough light through to project an image on the solar projection screen?

Robert

Not from my memory it won't. In the early days when I had a 60mm Unitron (124) I tried projection, did not try any of those sun filters and ended up with an Optica b/c Herschel diagonal. I used it off and on for 50+ years until recently I sold it to someone looking for that model and replaced it with a Lunt Herschel diagonal. I still use mylar and glass objective filters and also have a 40mm Daystar setup on one of my refractors. They are all good when the Sun is busy. Just don't take chances.



#299 photoracer18

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Posted 13 August 2019 - 03:42 PM

Why were these filters designed to fit at the eyepiece? Wouldn't it have been just as easy to fit them over the objective? Was it purely economic, a smaller filter being cheaper than a larger one?

I don't remember many of those .965" diagonals having threads on them. Besides those filters were really small so on the diagonal they would severely stop down the light throughput, whereas on the eyepiece the light cone was already fairly small.




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