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wesdon1

how safe is Solar Observing through foil like filters ?

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+1 for having a process. One time I put my scope out and was rushing because it was intermittent cloud and I wanted a ‘quick look’ in between the clouds. Focused on getting set up quickly I nearly looked through at the sun without putting the filter on. Luckily I spotted it the missing filter otherwise it could have ended in disaster. That was a lesson learned - don’t rush - have a process to avoid silly errors. Now I go through a stringent mental checklist much like Mark outlines above. It sounds silly that i could forget the filter and if I read about someone else doing it I’d probably think that it was an impossible mistake to make because it’s so obvious, but distractions happen to us all when setting up kit. this one could have had serious consequences. I share so that others may learn. Be careful out there and be safe when solar observing have a checklist, it could save your vision  and your embarrassment.

Steve

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That's very good advice Steve. The risks are entirely avoidable as long as you are methodical and think about what you are doing. It is when changing things over that I find I have to be more careful than setting up just for solar; changing my refractor over from night time mode to solar is the most important as forgetting to put the wedge in could be disastrous.

Never get complacent and never rush, I guess that's the key to staying safe. I think we all do a good job on here of keeping that front of mind for solar observers.

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9 hours ago, Adam J said:

I think its more to do with if I owned it myself I would know its condition and that it had been well looked after. :)

One of the beauties of a herschel wedge is that if it is damaged, the only thing that happens is the views get worse as less light is directed towards your eye.

Pretty unlikely anyway as any astronomer or observer I know is very careful with there kit and looks after it well.

As John has illustrated, solar observing can be completely safe so long as good sense and care is used, much like many other things in life. If I'm not careful driving my car......... you get the picture.

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I mostly use a 66mm refractor for white light with a Lunt Herschel Wedge. 

I connect everything to the scope and double check several times that the wedge has the red "hot" warning spot on the back before I attach to the mount and look through it. 

As Steve and Stu have said a checklist is certainly the way to go and don't rush. Check and double check and only start observing when you're sure everything is OK. 

I opted for a Herschel Wedge for the reasons that Stu has stated above. I tried the film a few times and really enjoyed the views but had concerns as you have and so I did some research and opted for a wedge and have never looked back. 

 

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Posted (edited)
On 25/05/2019 at 20:48, John said:

I feel that the Herschel Wedge is a pretty safe approach. Even if, in the most extreme circumstances, the wedge falls out of the scope, all the light and heat goes straight out of the back of the scope and not towards the eye at all.

 

 

Unless your eye is still over the EP tube, which would be highly unlikely because the wedge wouldn't be able to fall out with your eye in the way. 

On a more serious note.....

The film filter is extremely safe once you keep it in good condition. If you think its damaged, chuck it out. They are cheap enough to replace. A Hershel wedge is a much better alternative for WL observing but are not exactly cheap. They become even more expensive when you add the cost of a polarizing filter and a continuum filter. Practically doubles the cost.

Most HW come with the ND filter insitu, mine didn't. I had to buy one. 

ALWAYS check if the ND filter comes with the HW.

Edited by LukeSkywatcher
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I make a new filter every new season. I ask for a new Baader solar film every xmas, throw away my old filter regardless. I check the filter religiously through out the year. But for the sake of £18 its worth replacing yearly. 

I also converted an old 6x30 finder into a solar finder. Removed the optics, put a dust cap at the front with a pin hole and a transparent dust cap at the rear. That projects a white dot onto the rear cap and makes lining up the sun a breeze. 

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You should have put some of the film on the finder. Makes a great solar finder particularily if you use a 9x50 finder and you can buy filter cells to fit the 9x50 finder as well.

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On 25/05/2019 at 19:03, ollypenrice said:

The Baader film might actually be safer because it is a double sided filter. Once it's delivered it should be fitted into a permananent ring the size of the scope's aperture so that it undergoes no further crumpling and it should be cared for properly, stored in a box etc. When fitted to the scope it should have permanent ties holding it in place against wind or knocks. It can be easily checked for pinholes and these can be blacked out. They won't show for the same reasons that a secondary mirror doesn't show.

Remember to block finderscopes, Telrads, etc., or you can get a nasty burn at the focal point!

If you really are worried you could try the projection method. Google solar projection and you'll find many ways of doing it.

Olly

 

On 25/05/2019 at 19:30, Philip R said:

As long as you check the filter for defects, i.e. pinholes, rips, securely attached to your OTA or 35mm/DSLR lens, etc., before each and every use, solar safety films are perfectly safe. Also worth mentioning that you should make a solar filter for your finderscope and/or RDF - better still, remove either or both before viewing and use the shadow for alignment. 

+1 from me on the above... solar observing is no joke and setup always needs triple checking.

 

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On 26/05/2019 at 14:51, Trikeflyer said:

+1 for having a process. One time I put my scope out and was rushing because it was intermittent cloud and I wanted a ‘quick look’ in between the clouds. Focused on getting set up quickly I nearly looked through at the sun without putting the filter on. Luckily I spotted it the missing filter otherwise it could have ended in disaster. That was a lesson learned - don’t rush - have a process to avoid silly errors. Now I go through a stringent mental checklist much like Mark outlines above. It sounds silly that i could forget the filter and if I read about someone else doing it I’d probably think that it was an impossible mistake to make because it’s so obvious, but distractions happen to us all when setting up kit. this one could have had serious consequences. I share so that others may learn. Be careful out there and be safe when solar observing have a checklist, it could save your vision  and your embarrassment.

Steve

That is scaringly close to disaster.... lucky that you spotted the missing filter.

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2 hours ago, johninderby said:

You should have put some of the film on the finder. Makes a great solar finder particularily if you use a 9x50 finder and you can buy filter cells to fit the 9x50 finder as well.

That sounds like a great idea. I will keep an eye out for a cheap 9x50. Or check Astroboot.

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Posted (edited)
On 25/05/2019 at 10:30, Philip R said:

As long as you check the filter for defects, i.e. pinholes, rips, securely attached to your OTA or 35mm/DSLR lens, etc., before each and every use, solar safety films are perfectly safe. Also worth mentioning that you should make a solar filter for your finderscope and/or RDF - better still, remove either or both before viewing and use the shadow for alignment. 

Oop's! ...I forgot to add binoculars, spotting scopes, compact cameras, etc.

FWIW - during the 1999 solar eclipse, I got a burn on my forehead/temple from my RDF, because I forgot to remove it form my OTA.

Play and stay safe peoples. :icon_salut:  

Edited by Philip R
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28 minutes ago, johninderby said:

Wow that looks just the job. And a proper cell for the filter. Looks like the old Orion USA solar filters. Just need a 50mm finder.

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On 25/05/2019 at 13:41, Mark at Beaufort said:

@wesdon1you have received some positive and good advice. As Alien 13 stated above if you are using a reflector it is not suitable for solar projection.

Anyway this is my procedure when undertaking white light solar observing.

  1. I remove all items from the OTA - finders etc
  2. I inspect my solar filter each time - firstly by looking at a very bright LED light in my kitchen
  3. I then hand hold the filter looking at the Sun
  4. The filter is then secured to the OTA 
  5. I then find the Sun using a device like this - https://www.ebay.co.uk/itm/SVBONY-Solar-Finder-Scope-Fully-Metal-Mount-Dovetail-Slots-Mount-Dovetail-Slots/323318485106?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
  6. I usually look into the eyepiece tube (no eyepiece fitted) to see if I can see any pin holes. If there are any pin holes you can cover them as Olly stated above

I have used Baader film, Glass filters (Orion and Thousand Oaks) and a Herschel Wedge and I happy to say no problems to date. You may decide to make your own - here is a video produced by Pete Lawrence for the Sky at Night - https://www.bbc.co.uk/programmes/p014hpkh

Finally, always check each time and don't rush. Have a procedure that you know works for you and stay with it.

Hi and so sorry for such late reply, i've been away on holiday and couldn't access internet on phone without huge roaming charges. My goodness thanks so much for going to all that trouble writing all that procedure/information for me regarding my fears over Solar Observing. I'm very very grateful. I will follow your brilliant advice and i'm excited now as you have given me the confidence that i can Solar Observe safely if i do it properly and never cut corners, so to speak. Thanks again Mark. 

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A massive Thank You to all members who took the trouble to give me brilliant advice on Solar Observing safely. I'm new to Astronomy and i'm so happy and learning all the time. I can't over-state how helpful it is when more experienced members/astronomers help people like myself who are new to the Hobby and trying to make sense of the vast amounts of information that one needs to observe the night sky and daylight solar observing etc. So Thank You to all you good people, i'm very grateful for all the help. 

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No one has mentioned it but you can make a very safe dedicated solarscope by removing the silvering/aluminium from the primary and secondary mirrors of a "small" Newtonian scope, you would need an ND filter and perhaps a IR cut filter too for observing but should be fine without for imaging.

Alan

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1 hour ago, wesdon1 said:

A massive Thank You to all members who took the trouble to give me brilliant advice on Solar Observing safely. I'm new to Astronomy and i'm so happy and learning all the time. I can't over-state how helpful it is when more experienced members/astronomers help people like myself who are new to the Hobby and trying to make sense of the vast amounts of information that one needs to observe the night sky and daylight solar observing etc. So Thank You to all you good people, i'm very grateful for all the help. 

We're all here to learn, share the knowledge and most importantly.... enjoy the hobby.

 

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On 07/06/2019 at 13:06, Alien 13 said:

No one has mentioned it but you can make a very safe dedicated solarscope by removing the silvering/aluminium from the primary and secondary mirrors of a "small" Newtonian scope, you would need an ND filter and perhaps a IR cut filter too for observing but should be fine without for imaging.

Alan

Hi Alan, thanks for your comments. I must say ( as a very inexperienced newbie, i hasten to add! ) your idea sounds a little scary ? What if one didn't do the job properly and some dangerous Sun light leaked through to ones retina and caused awful permanent damage ? The thought terrifies me mate! Al;though i can see the ingenuity of the idea! If done properly, by a competent experienced amateur astronomer, it sounds like a brilliant way to Solar gaze! Thanks, Wes.

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7 minutes ago, wesdon1 said:

Hi Alan, thanks for your comments. I must say ( as a very inexperienced newbie, i hasten to add! ) your idea sounds a little scary ? What if one didn't do the job properly and some dangerous Sun light leaked through to ones retina and caused awful permanent damage ? The thought terrifies me mate! Al;though i can see the ingenuity of the idea! If done properly, by a competent experienced amateur astronomer, it sounds like a brilliant way to Solar gaze! Thanks, Wes.

The Newt idea is not for the inexperienced but works in a similar way to the Herchel wedge, as mentioned before the projection methods are the safest form of Solar observing.

Alan

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6 minutes ago, Alien 13 said:

The Newt idea is not for the inexperienced but works in a similar way to the Herchel wedge, as mentioned before the projection methods are the safest form of Solar observing.

Alan

Oh yes, forgive me, i forgot about Solar Projection method! lol. I feel silly also because I've never even heard of a Herchel wedge? lol ( Google time i think! lol ) Thanks Alan, i'm always super grateful for the excellent advice more experienced members like yourself take the time to give to still learning newbies like myself.

 

Wes.

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Posted (edited)
On ‎25‎/‎05‎/‎2019 at 13:41, Mark at Beaufort said:

 

  1. I then find the Sun using a device like this - https://www.ebay.co.uk/itm/SVBONY-Solar-Finder-Scope-Fully-Metal-Mount-Dovetail-Slots-Mount-Dovetail-Slots/323318485106?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
  2. I usually look into the eyepiece tube (no eyepiece fitted) to see if I can see any pin holes. If there are any pin holes you can cover them as Olly stated above

I have used Baader film, Glass filters (Orion and Thousand Oaks) and a Herschel Wedge and I happy to say no problems to date. You may decide to make your own - here is a video produced by Pete Lawrence for the Sky at Night - https://www.bbc.co.uk/programmes/p014hpkh

Finally, always check each time and don't rush. Have a procedure that you know works for you and stay with it.

Another great way of locating the sun, which I also use for finding Mercury and Venus in daylight, is via a sidereal clock and setting circles (if your telescope has them).  In fact you don't need a sideal clock as such anymore, as there is an app which you can download onto an iphone.

John

 

Edited by johnturley

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Posted (edited)

A lot of people DO make DIY (cardboard + Solar Film!) Solar filters...
Which, if you use common sense... have experience, are perfectly OK.

If you fancy something a bit more Solid... "Ready made". I like these:
https://www.baader-planetarium.com/en/asbf-astrosolar-binocular-filter-od-5.0-(50mm---100mm).html
They are quite expensive... a PITA if you poke a finger at/through it! 😬 
(As others have noted you should not use a damaged solar film ***)

But if you do damage one, I found that by undoing the small screws
the Filter Film is only *Baader Film* (super?) *glued* to a plastic ring. 
Tear out old/damaged film and carefully replace it with some new... 🙂

As ever, we have to make sensible judgements re. our own abilities? 

P.S. A caveat (from my own personal follies): Do not try to CLEAN a
Solar Film. However "careful" you are, I noted it removes the surface
Aluminium coating and reduces the (required ND5+) filter density! 😖

</wibble>

Edited by Macavity

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P.P.S. In the interest of TOTAL frankness, I see that Baader now use
"Tamper Proof" screws on their Filters! (Perhaps that is WISER? lol)
Don't poke filters with your Finger! lol. Note too visual film is ND5.0
and "Imaging" (ND3.8) film is insufficient protection for eyes etc. 🙂

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On 25/05/2019 at 11:57, Stu said:

 

I have actually, unwittingly, viewed through a filter with some pinhole in it. The result? I'm not blind and didn't suffer any permanent affects. I just had little squiggles before my eyes for a while, much like after looked at a light bulb (although much much smaller) or other bright light source. I'm not recommending it obviously, but with sensible precautions the foil is very safe.

 

I had a similar experience when I was a boy with my 60mm refractor and the dreaded "solar filter" that was something like a bit of welders mask screwed in the back of the eyepiece (yeah, I know, I know.. :( )

I'm not sure how the injury came about, the filter didn't fail nor did it have any defects, but the "dazzled" sensation in my right eye only improved slightly over the next few days and since then I've had a blind spot in the center of vision. My brain has long since learned to ignore it and  fill in with my left eye. But that wasn't always the case, begin right eye dominant.

The damage is very minimal physically and only one optometrist has noticed it during routine eye exams while examining my retinas. 

Never since have I aligned my eyes with a sun/telescope combination. I don't doubt that there are a number of absolutely safe methods but I'll look at the excellent images here on SGL if I want to know what's happening on the Sun! 

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