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Looking at the sun with an 8SE?

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#1 dml33

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Posted 08 April 2021 - 01:09 PM

I have an 8SE and I hate how it just sits all day long pretty much useless when it so beautiful outside. 

 

How can I look at the sun with this scope during the day? What equipment do I need to go along with it? I want to look at sun spots and flares.



#2 carolinaskies

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Posted 08 April 2021 - 01:26 PM

I have an 8SE and I hate how it just sits all day long pretty much useless when it so beautiful outside. 

 

How can I look at the sun with this scope during the day? What equipment do I need to go along with it? I want to look at sun spots and flares.

You can get either a full aperture solar filter or a sub-aperture solar filter.  I personally prefer full aperture solid filters vs the film filters. Both need to be stored correctly to not damage their surfaces.  

A sub-aperture filter uses a smaller filter on full aperture cap. 

Only choose visual solar filters if you ever plan to look at the sun, photographic versions let in more light and can damage your eyes.  

https://www.google.c...chrome&ie=UTF-8


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#3 B 26354

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Posted 08 April 2021 - 01:38 PM

Either of these "white-light" filters will allow you to view sunspots:

 

https://www.highpoin...elescopes-94244

 

https://astrozap.com...t=8278567813164

 

grin.gif



#4 Oort Cloud

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Posted 08 April 2021 - 02:01 PM

If you want to view prominences (what I assume you mean by flares), that requires special equipment (usually a solar telescope). The aperture filters mentioned by others will only allow you to see sunspots. I have one for my 6se, it's pretty underwhelming tbh, especially since there aren't always even sunspots to view. The last time I used it, it was just a big white dot with no detail whatsoever.
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#5 alphatripleplus

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Posted 09 April 2021 - 07:51 AM

I have a full aperture visual filter that works pretty well for viewing sunspots, transits and partial eclipses.


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#6 carolinaskies

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Posted 09 April 2021 - 11:43 AM

The following image was taken in 2003 with a 35mm film camera through my 8" LX200 Classic F/6.3 using a glass full white light solar filter by Thousand Oaks. 

Sunspots06102003 015 (2).jpg


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#7 Napp

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Posted 09 April 2021 - 11:59 AM

White light filters really can only show sunspots and sometimes when seeing is really good some granulation if used with a Baader Solar Continuum Filter.  It's true the sun is around solar minimum right now but should become more active in the next few years.  If you don't want to spend a lot just get a sheet of Baader Solar Safety Film for visual and make your own.  You can make a full aperture filter or a sub-aperture filter.  A sub-aperture will do fine as seeing will almost never support 8 inches of aperture.  The nice bonus of this approach is that Baader film provides a better quality view than the other films or glass filters.  If you don't want to make one you can buy a premade filter using Baader film.  Here's a site with instructions on how to make a solar filter holder.

 

https://astrosolar.c...rmation/how-to/

 

You can do hydrogen alpha observing with an SCT but it is expensive.  DayStar makes Quarks for SCT's, however, an energy rejection filter must be installed over the Corrector.

 

http://www.daystarfi...OMBOQuark.shtml



#8 bobhen

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Posted 09 April 2021 - 04:49 PM

For white light observing of sunspots your least expensive option is to purchase Baader solar film and make a front-mounted solar filter. You could, of course, purchase a front mounted filter using film that is already made. Baader solar film is better than the inexpensive glass filters.

 

To see prominences and disk details in the light of hydrogen alpha you might want to consider purchasing a separate solar telescope like a LUNT 40mm at around $600 to $800 or the LUNT 50mm for around $900.

 

With the above you could mount the solar telescope on top of or side-by-side with the C8 and observe in both white light and the light of hydrogen alpha.

 

Solar astronomy is fun and has some observing advantages (like it's usually warm out, no bugs, no late nights, etc.) and when the sun is active you can observe feature changes in real-time. Solar imaging is also challenging. 

 

HERE is a link to the LUNT solar telescopes page.

 

Bob


Edited by bobhen, 10 April 2021 - 05:25 AM.

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#9 deepwoods1

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Posted 09 April 2021 - 08:29 PM

Sol is quiet now, give it a couple of years and we should have Sunspots, Prominences and power outages from CME’s. 



#10 WadeH237

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Posted 09 April 2021 - 08:46 PM

As has been mentioned, sunspots are easy (when the sun is actually active) with a white light solar filter.

 

To see prominences, you would need an Ha filter specifically designed for solar work.  I have seen such a filter for a C8, but it would cost many times more than your entire C8SE.

 

Also, just to get it out there:  DO NOT look at the sun through any telescope unless it is specifically equipped for solar observing, and you are very familiar with how to use the gear correctly.  A mistake with a solar filter can instantly cause permanent blindness!


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#11 dhkaiser

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Posted 10 April 2021 - 07:13 AM

Never use a night time Ha filter to view the sun!  Not the same as a solar Ha filter.  Be safe!


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#12 Jon Isaacs

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Posted 10 April 2021 - 08:21 AM

I have a full aperture visual filter that works pretty well for viewing sunspots, transits and partial eclipses.

 

waytogo.gif

 

Here's a few photos of some transits, eclipses and incidental sunspots. I find sunspots viewed in a white light filter very special. I have 40 mm PST h-alpha solar that shows granulations, fine surface details and prominences but there's magic in the white light views.  These were all taken with a hand held camera.

 

- Mercury transit. Celestron C-5, Nikon Coolpix 4500.  It's the small circular dot in the lower left. 

 

4624525-transit of mercury.jpg

 

- Venus transit. I'd seen two Mercury transits and was expecting something similar. We were camping at about 9000 feet in the Bighorn mountains and the clouds parted to reveal spectacular and very rare transit of Venus.  

 
5789855-Venus transit Cloudy Nights 1.jpg
 
A partial solar eclipse taken with a C-5 and the Coolpix 4500. Nice sunspots.
 
4163164-eclipse C-5.jpg
 
Another partial solar eclipse.
 
Partial Solar Eclipse Nexus 5.jpg

 

Lots of fun.

 

Jon

 


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#13 Bill Barlow

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Posted 12 April 2021 - 11:17 AM

Very nice pictures, Jon.  I have Baader white solar filters for all my telescopes I now own.  Very interesting to view sunspots when they are visible and watch them change over time.  The 3” Tak is super sharp as is the C5.  The 8” Meade shows more resolution but seeing conditions sometime shows turbulent effects of the atmosphere.

 

Bill



#14 Achernar

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Posted 13 April 2021 - 04:41 PM

An over the aperture solar filter is what you need to do this safely for both your eyes and your telescope. DO NOT project the Sun through an SCT, ever. It will destroy the optics.

 

Taras

Attached Thumbnails

  • sun_12_27_2020_10_35_10_174MM_MONO_LUMINANCE_default wavelets_1000_2.jpg


#15 WadeH237

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Posted 13 April 2021 - 05:25 PM

Personally, I would never use a filter that mounts at the back of the telescope.  The objective will direct a huge amount of energy there, and it's not unheard of them to crack.  I also agree that you should always filter the sun at the front of the scope for an SCT, or other reflector.

 

The exception to this is that, if you have a refractor, you can get a Herschel wedge that replaces the diagonal.  A Herschel wedge is not a filter.  It uses a prism to direct a small amount of light to the eyepiece and directs the rest of the energy to a heat sync to dissipate it.  You can pair a Herscel wedge with a variable polarizing filter (between the wedge and the eyepiece) to adjust the final brightness of the sun.  I have a setup like this, and it's by far my favorite way to view sunspots.  But again, a Hershel wedge is only safe to use with a refractor.  Other types of scopes are too susceptible to damage from shining the unfiltered sun through the scope.


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#16 gnowellsct

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Posted 14 April 2021 - 12:41 PM

Seeing solar flares is roughly a $1k to $2k proposition...on three and four inch refractors, assuming you already own the refractor.  I have the quark combo.

 

Seeing solar flares in a c8 is a $5,000 proposition   

 

H-alpha is the key, and it is expensive.  There are 40 and 50mm h-alpha scopes some people love 'em but they never appealed to me.  They keep costs below $1k.

 

White light observing is cheap.  I like the Kendrick solar filters for white light.  They cost a bit more but are sturdy and worth it.  But I never solar observe in white light any more.

 

 

Geoffrey solar in CFF.jpg

 


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#17 gnowellsct

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Posted 14 April 2021 - 12:46 PM

Personally, I would never use a filter that mounts at the back of the telescope.  The objective will direct a huge amount of energy there, and it's not unheard of them to crack.  I also agree that you should always filter the sun at the front of the scope for an SCT, or other reflector.

 

The exception to this is that, if you have a refractor, you can get a Herschel wedge that replaces the diagonal.  A Herschel wedge is not a filter.  It uses a prism to direct a small amount of light to the eyepiece and directs the rest of the energy to a heat sync to dissipate it.  You can pair a Herscel wedge with a variable polarizing filter (between the wedge and the eyepiece) to adjust the final brightness of the sun.  I have a setup like this, and it's by far my favorite way to view sunspots.  But again, a Hershel wedge is only safe to use with a refractor.  Other types of scopes are too susceptible to damage from shining the unfiltered sun through the scope.

 

The daystar h-alpha set up uses an ERF on the entrance to the diagonal on a refractor.  Nothing goes over the front.  

 

With a dielectric mirror you don't even really need the ERF, but I'm a nervous individual and prefer to use one.  But the dielectric is protective if you forget to put it on, which has happened to me.  (Even if the heat were passed through, which it isn't, it would have to melt its way through the etalon).

 

The interesting thing about these setups is that they don't get hot at all.  You can observe with an ERF over the diagonal, nothing over the 4 or 5" refractor objective, for 8 hours or 80 and the scope will remain cool to the touch: at ambient, in any case.

 

Greg N


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#18 gnowellsct

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Posted 14 April 2021 - 01:00 PM

Here's the same pic with some explanations.  Note that the etalon requires power for a heater to get to operational temperature!  The solar heat has passed back out the front of the scope, and ambient temperatures are not sufficient for good performance.  You need a "telecentric" barlow (power mate) to get to the right focal ratio and have the view work.  Ordinary barlows don't do the trick. 

 

The ERF (energy rejection filter) that goes over the diagonal is transparent.  If you hold it up to the sun and look through, it hurts. (so don't do it)  But it is efficient at what it does.

 

--Greg N

Attached Thumbnails

  • Geoffrey solar in CFF - EXPLANATIONS.jpg

Edited by gnowellsct, 14 April 2021 - 01:01 PM.


#19 WadeH237

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Posted 14 April 2021 - 01:12 PM

The daystar h-alpha set up uses an ERF on the entrance to the diagonal on a refractor.  Nothing goes over the front. 

Thanks for the clarification.

 

I was mainly referring to white light filters.  Solar Ha filter systems for "regular" telescopes are very different from white light filters and (at least as far as I know) mostly have multiple components to separate energy rejection from actual filtering of the desired wavelength.


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#20 StarmanDan

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Posted 14 April 2021 - 01:28 PM

You can do white light viewing using a full aperture solar filter made to fit the front of the telescope.  Here are a couple of my scopes fitted with solar filters during the 2017 solar eclipse.  Note these will only allow you to see sunspots and not flares and proms.  For those you need a dedicated solar telescope.

Attached Thumbnails

  • wfabCuX - Imgur.jpg
  • SCT images - Imgur.jpg
  • SCT images - Imgur(1).jpg
  • Eclipse 2017 - Imgur.jpg


#21 dcaponeii

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Posted 15 April 2021 - 07:46 AM

Personally, I would never use a filter that mounts at the back of the telescope.  The objective will direct a huge amount of energy there, and it's not unheard of them to crack.  I also agree that you should always filter the sun at the front of the scope for an SCT, or other reflector.

 

The exception to this is that, if you have a refractor, you can get a Herschel wedge that replaces the diagonal.  A Herschel wedge is not a filter.  It uses a prism to direct a small amount of light to the eyepiece and directs the rest of the energy to a heat sync to dissipate it.  You can pair a Herscel wedge with a variable polarizing filter (between the wedge and the eyepiece) to adjust the final brightness of the sun.  I have a setup like this, and it's by far my favorite way to view sunspots.  But again, a Hershel wedge is only safe to use with a refractor.  Other types of scopes are too susceptible to damage from shining the unfiltered sun through the scope.

The damaged spot on my retina from the failure of a 0.925mm refractor eyepiece solar filter from when I was in junior high can attest to this.  Full aperture filter is the way to go with an SCT.  Projection is ok with a refractor or even a Newtonian but not with an SCT.


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#22 th3r3ds0x

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Posted 16 April 2021 - 09:01 AM

I have an 8SE and I hate how it just sits all day long pretty much useless when it so beautiful outside.

How can I look at the sun with this scope during the day? What equipment do I need to go along with it? I want to look at sun spots and flares.


I used mine to view and photograph the solar eclipse in 2017. I did have to mount the ota on my CGEM, the camera wouldn’t clear the stock alt/az mount on a mid-day sun.

As for filter, Celestron makes a great one that attaches like the lens cap. Works wonderfully!

#23 Cliff Halliwell

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Posted 19 April 2021 - 11:38 AM

Another little note on solar observing. An observing friend once pointed his SCT at the sun with, of course his white-light solar filter on.  He forgot to cover his finder scope front element. The rear cap was on and he quickly noticed that it was melting.  Next would have been his shoulder. 


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#24 Nippon

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Posted 19 April 2021 - 01:29 PM

What I read years ago is it was a bad idea to do solar projection with an SCT because it could cause the adhesive that holds the secondary to fail. Back when I read this a Newtonian secondary was typically held with mirror clips. Most Newtonians I see made today are also held with adhesives so I would not use those for solar projection either. 



#25 Achernar

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Posted Yesterday, 08:55 PM

What I read years ago is it was a bad idea to do solar projection with an SCT because it could cause the adhesive that holds the secondary to fail. Back when I read this a Newtonian secondary was typically held with mirror clips. Most Newtonians I see made today are also held with adhesives so I would not use those for solar projection either. 

Even with a small Newtonian, using the full aperture can be risky to the optics. But a large Newtonian/Dobsonian can catch fire if pointed directly at the Sun.

 

Taras




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