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Equipment Discussions >> Classic Telescopes

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Jon Marinello
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Reged: 09/21/10

Loc: Santa Barbara, CA
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4663543 - 06/28/11 05:04 PM

Just checked the filter temperature again. It is just warm and not hot. I don't see how this will ever crack the filter. I will leave it up for a couple more hours.

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Jon Marinello
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Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4663691 - 06/28/11 06:39 PM Attachment (66 downloads)

At 3:35 PM I ended the current test. The filter didn't crack and was only warm. I decided to remove the current sun filter and switch to a standard Unitron solar filter. Let's see how that goes. But I expect it to work even better.

Edited by Jon Marinello (06/28/11 06:44 PM)


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Jon Marinello
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Reged: 09/21/10

Loc: Santa Barbara, CA
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4663703 - 06/28/11 06:45 PM Attachment (67 downloads)

With the filter on. It's staying very cool.

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BigC
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Reged: 09/29/10

Loc: SE Indiana
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4669813 - 07/02/11 10:38 AM

Jon,

I have to quibble with your choice of words.

The Herschel wedge should DIVERT,not dissipate most of the heat(and light).If it is the same 95% diversion as given for the Optica solar diagonal,then even with your 6" scope the little green filter is receiving roughly one-quarter of the sunlight(and heat) of the usual 60 to 76mm scope.That should be much less stress on the glass.Using the Herschel wedge diagonal in the classic(sized) 2 to 3 inch refractor ought to mean the green glass filter would hardly become warm since it would actually receive less sunlight than if were simply lying on a picnic table.


Seems a shame the solar diagonal are apparently noonger offered new.


Put a solar cell in the path of the diverted sunlight and charge your scope batteries or power a tracking motor.How about a self-powered sun scope that use a webcam ? A Sun AVI movie from dawn to dusk could be a project that would need a fortune in equipment.


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BigC
Carpal Tunnel
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Reged: 09/29/10

Loc: SE Indiana
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4669830 - 07/02/11 10:49 AM

Whoops!
I guess if the cover is kept closed the Herschel does dissipate the diverted heat.Bet that cover plate gets hot.Maybe it should have a heat sink attached.

And I did find an English firm offering new Herschel wedge diagonals,but only in the 2 inch size and priced over USD$200.


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Jon Marinello
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Reged: 09/21/10

Loc: Santa Barbara, CA
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4688725 - 07/12/11 02:00 PM

Here are the experiments I ran and the results.

Here are the results of the various test scenarios:

1. Star Diagonal [Solar filter mounted on star diagonal nose]
* 60mm (1: no crack, 2: no crack)
* 80mm (not completed due to weather)

2. Eyepiece [Solar filter mounted on eyepiece nose]
* 60mm (1: cracked, 2: no crack)
* 102mm (1: cracked)

3. Eyepiece/Herschel Wedge [Solar filter mounted on eyepiece nose combined with a Herschel Wedge]
* 152mm (1: no crack)

4. Unitron Filter/Herschel Wedge [Unitron Solar filter mounted on eyepiece top combined with a Herschel Wedge]
* 152mm (1: no crack)

Conclusions

Scenario 1
I was unable to get the filter to crack after to test runs with the 60mm scope. However, the filter did get hot. In my opinion there is a risk of a failure even with a small scope like this. The risks would increase with larger aperture scopes. The second test in this scenario wasn’t completed due to weather. Perhaps this line of the experimentation should be continued. Comments?

Scenario 2
I didn’t run all the originally planned tests in scenario 2 as I was able to get the standard sun filter to crack using the smallest scope i.e., 60mm. It is clear you should never ever use this setup or worse a larger aperture scope for looking at the sun!

Scenario 3
I started with my largest refractor in this test. Since there was no crack and very little heat generated at the filter I believe the other tests I could run in this scenario with smaller scopes are unnecessary. I believe this configuration is safe to use with scopes of this size or smaller. Larger scopes were not tested so their safety in this configuration is unknown.

Scenario 4
I started with my largest refractor in this test. Since there was no crack and hardly any heat generated at the filter I believe the other tests I could run in this scenario with smaller scopes are unnecessary. I believe this configuration is safe to use with scopes of this size or smaller. Larger scopes were not tested so their safety in this configuration is unknown.


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Jon Marinello
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Reged: 09/21/10

Loc: Santa Barbara, CA
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4694178 - 07/15/11 03:13 PM

Well things got quiet here so I will ping you all one last time on this topic.

  • Does anyone have any more comments on this?
  • Should I continue with more tests of Scenario 1? (I am willing to)
  • Do others agree with my summary and position?
  • Are there additional scenarios that should be tested?
  • Should we get this thread added to the top of this forum permanently as Preston suggested? (I think we should)


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Jim Curry
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Reged: 10/29/07

Loc: STL
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4694775 - 07/15/11 11:00 PM

>Should we get this thread added to the top of this forum permanently as Preston suggested? <

Yes but change the title to: "Use of vintage ep sun filters...NOT"

And the one and only post should be: Don't even think about it!

Jim


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Rich (RLTYS)Moderator
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Reged: 12/18/04

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Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jim Curry]
      #4695153 - 07/16/11 08:15 AM

Quote:

>Should we get this thread added to the top of this forum permanently as Preston suggested? <

Yes but change the title to: "Use of vintage ep sun filters...NOT"


And the one and only post should be: Don't even think about it!

Jim




Would like to but we are limited to three tacked threads.

Rich (RLTYS)


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Joe Cepleur
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Reged: 03/18/10

Loc: Dark North Woods
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Rich (RLTYS)]
      #4695171 - 07/16/11 08:46 AM

This was a neat experiment. Thanks, Jon, for being the one to test the evidence.

The tests show that these old sun filters are unreliable, so no one should use them. Anyone who thinks it will be okay to use one at the diagonal (further from the point of focus) with a small aperture scope misinterprets the simple fact that they were not precision manufactured to begin with, and are too old to be trusted now. Several postings illustrate that guaranteed instant blindness upon failure is a myth, but instant, permanent damage to the eyes is not.

Testing with the Herschel wedge was admirably thorough, but somewhat beside the point. One would not expect cracks with 95% of the heat removed.

The ability to tack only three threads is a limitation that perhaps the pending upgrade to the site's software will change. It speaks to the need for Cloudy Nights to become not just a constantly changing conversation, but a better site for creating a vast, searchable trove of knowledge. Certainly anyone who visits should learn not to use these old filters.


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clintwhitman
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Reged: 01/01/07

Loc: CALI SoEasyACavemanCanSlewIt
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Jon Marinello]
      #4695574 - 07/16/11 01:55 PM

Quote:

Hi All.
Without a Hershel Wedge in conjunction with a solar filer it is not "safe" to view the sun with any size refractor telescope. Other than that you can use a solar rejection mask that installs over the objective, but I find a Hershel wedge and a Zeiss ND filter to be the best setup for high magnification viewing of Sun spots with any size refractor. Also the optical flats that Unitron used in there solar wedges are very good and seem to work as well as Optima BC or Bader wedges.
As to taking readings of the heat generated at the focal plane of a telescope pointed at the sun. I can tell you the exact reading. Really Hot!!!
(aveman




Jon I posted my thoughts on this in the first part of the thread.
There are many way to observe the sun and over the years allot of junk has been made by companies for this purpose. I was taught by Pons and other old timers the dos and donuts. The first thing they said was this. Only use Zeiss or Baader designed ND filters that are designed to reject IR and other solar radiation. Also only use time tested and well made solar wedges like Unitron, Optima BC or other high quality device should be the only ones used. As for using Unitron Slip over filters and the other cheap ones supplied with telescopes kits I would not suggest this for long term viewing even with a good solar wedge. Get good filters made by experts if you dont want lumpy corneas!!


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clintwhitman
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Reged: 01/01/07

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Re: Use of vintage eyepiece sun filters... Why not? new [Re: Rich (RLTYS)]
      #4695584 - 07/16/11 02:01 PM

Quote:

Quote:

>Should we get this thread added to the top of this forum permanently as Preston suggested? <

Yes but change the title to: "Use of vintage ep sun filters...NOT"


And the one and only post should be: Don't even think about it!

Jim




Would like to but we are limited to three tacked threads.

Rich (RLTYS)




RICH,
Would it be a good idea to add this to the (Useful Classic Scopes Links)?? And add a header saying DO NOT LOOK AT THE SUN! or USE SOLAR FILTERS.......Also put a side note not to look down the barrel of a gun with the bolt closed. (same thought)
(aveman

Edited by clintwhitman (07/16/11 02:05 PM)


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Jon Marinello
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Loc: Santa Barbara, CA
Re: Use of vintage eyepiece sun filters... Why not? new [Re: clintwhitman]
      #4695823 - 07/16/11 04:33 PM

Hey Clint,

Are Zeiss ND filters still available new? If so can you point me at them with a link?

jon


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Jon Marinello
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Reged: 09/21/10

Loc: Santa Barbara, CA
Re: Use of vintage eyepiece sun filters... Why not? new [Re: clintwhitman]
      #4695825 - 07/16/11 04:34 PM

That sounds like a great idea Clint. How about that Rich?

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mikey cee
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Reged: 01/18/07

Loc: bellevue ne.
Re: Use of vintage eyepiece sun filters... Why not? new [Re: clintwhitman]
      #4695836 - 07/16/11 04:42 PM

Quote:

Quote:

Quote:

>Should we get this thread added to the top of this forum permanently as Preston suggested? <

Yes but change the title to: "Use of vintage ep sun filters...NOT"


And the one and only post should be: Don't even think about it!

Jim




Would like to but we are limited to three tacked threads.

Rich (RLTYS)




RICH,
Would it be a good idea to add this to the (Useful Classic Scopes Links)?? And add a header saying DO NOT LOOK AT THE SUN! or USE SOLAR FILTERS.......Also put a side note not to look down the barrel of a gun with the bolt closed. (same thought)
(aveman


And never nail up a wanted "dead or alive" poster with the pistol grip! Mike

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Datapanic
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Reged: 10/17/09

Loc: Tucson, Arizona
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Rich (RLTYS)]
      #4695928 - 07/16/11 05:45 PM

Quote:

Quote:

>Should we get this thread added to the top of this forum permanently as Preston suggested? <

Yes but change the title to: "Use of vintage ep sun filters...NOT"


And the one and only post should be: Don't even think about it!

Jim




Would like to but we are limited to three tacked threads.

Rich (RLTYS)




Well, that's no fair! Some of the other forums have more stickies that 3! For example, Mounts has 4 and Reflectors has 5!

I think Clint's suggestion to add a link in the Useful Classic Scopes Links sticky would be good.


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John Carruthers
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Reged: 02/02/07

Loc: Kent, UK
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Datapanic]
      #4696621 - 07/17/11 04:45 AM

a bit late but my 2p, I was taught when solar viewing to pass a hand over the eyepiece before putting your eye near it, only takes a second, might save an eye?
Hands are sensitive to IR, eyes are not.

I demonstrate toasting marshmallows with my scope to drive home the idea.


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Rich (RLTYS)Moderator
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Reged: 12/18/04

Loc: New York (Long Island)
Re: Use of vintage eyepiece sun filters... Why not? new [Re: Datapanic]
      #4696752 - 07/17/11 08:12 AM

Quote:

Quote:

Quote:

>Should we get this thread added to the top of this forum permanently as Preston suggested? <

Yes but change the title to: "Use of vintage ep sun filters...NOT"


And the one and only post should be: Don't even think about it!

Jim




Would like to but we are limited to three tacked threads.

Rich (RLTYS)




Well, that's no fair! Some of the other forums have more stickies that 3! For example, Mounts has 4 and Reflectors has 5!

I think Clint's suggestion to add a link in the Useful Classic Scopes Links sticky would be good.




Your right I checked and some forums do have more stickeys. I'll make this thread a stickey and see what happens.

Rich (RLTYS)


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Stellarfire
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Reged: 07/10/11

Loc: Switzerland
Re: Use of vintage eyepiece sun filters. new [Re: Jon Marinello]
      #4780743 - 08/31/11 06:52 PM Attachment (59 downloads)

During the 1970's, in my youth, I used such a eyepiece solar filter when observing the sun with my Tasco 9TE-5 60/700mm refractor. Absolutely nobody told me how dangerous such a filter could be.... I used it more than four years, no accident so far. I remember very well to the filtered green image of the sun and enjoyed the observations of sun spots. Very interesting experience for a joungster. But I would not use again this type of filters. There are better solutions today.

Picture shows the full set of Tasco 9TE-5 accessories including the srew-in solar filter. Pure 1960's/1970's nostalgia.

Stephan


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Jason H.
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Reged: 11/23/07

Loc: Central Florida
Re: Use of vintage eyepiece sun filters. [Re: Stellarfire]
      #4863358 - 10/15/11 11:27 PM Attachment (67 downloads)

Quote:

During the 1970's, in my youth, I used such a eyepiece solar filter when observing the sun with my Tasco 9TE-5 60/700mm refractor. Absolutely nobody told me how dangerous such a filter could be.... I used it more than four years, no accident so far. I remember very well to the filtered green image of the sun and enjoyed the observations of sun spots. Very interesting experience for a joungster. But I would not use again this type of filters. There are better solutions today.

Picture shows the full set of Tasco 9TE-5 accessories including the srew-in solar filter. Pure 1960's/1970's nostalgia.

Stephan




I also remember viewing the Sun through my first telescope (a Traq scope with the dreaded Sun filter), when I was a kid. I remember feeling slightly blinded in daylight, and the Sunspot views were burned into my mind too.

This image added just to hint at the referred to green filter view of sunspots, DO NOT DO THIS! This is from this year via a Tasco green Sun filter (it didn't crack, but DON'T DO THIS!) but via a $14.95 50mm Vivitar MASKED DOWN TO 35MM. DON'T DO THIS!

Jason H.


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