Author Topic: White Light  (Read 933 times)

linghetade

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White Light
« on: December 26, 2017, 09:47:03 AM »
Recently got curious about solar viewing and obtained a glass solar filter that matches both my 80mm refractor and 90mm cassegrain telescopes.  Saw the consumer review on Baader ASTF style filters and have ordered one for my own 102mm Cassegrain.I'm begining to worry about pixel size and wonder whether there'sa size limitation beyond the Sun's picture would be too smart to safely view.



Tsar Daniels

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Re: White Light
« Reply #1 on: December 28, 2017, 01:54:59 AM »
As long as you have an intact white light filter that covers the aperture securely there should be no problem.

acoplochop

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Re: White Light
« Reply #2 on: January 01, 2018, 07:27:08 AM »
Also, I've seen white light filtersfor larger scopes that are off axis filters. They have a filter smaller than the aperture of the scope off to the side (away from the secondary mirror). For example, a white light solar filter for a 12" scope might have a 4" filter off to one side. For example:

http://www.telescope...s?keyword=solar

Full disclosure: it looks like Orion sells full aperture solar filters for apertures up to 11".

Nick Nisianakis

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Re: White Light
« Reply #3 on: January 08, 2018, 05:32:40 AM »
Quote
Recently got interested in solar viewing and got a glass solar filter that fits both my 80mm refractor and 90mm cassegrain telescopes. Saw the user review on Baader ASTF style filters and have ordered one for my 102mm Cassegrain.I'm begining to worry about aperture size and wonder if there'sa size limit beyond which the Sun's image would be too bright to safely view.


You will be fine. Baader Astro Solar Film (BASF) is an excellent product. If you find the solar image a little to bright for your liking, simple additional filtration will take care of that issue. Depending upon your budget, you have a couple of options. Starting with the less expensive filtration, you can approach solar observing with basic color filters used in conjunction with your full aperture BASF. Red (W#25) or orange (W#23A) filters work very well in isolating and enhancing sunspot umbrae. Further, a green (W#56 or W#58) filter works well at bring out solar granulation and faculae. There are also various neutral density filters (0.9/2.0) for example, that will aid in reducing any unwanted brightness of the solar disk. Variable polarizing filters are excellent in that you can "tune in" the degree of interference to suit your personal needs. A violet filter (W#47) is good for white light flare searches. If you have the funds, I would strongly recommend investing in a Baader Solar Continuum Filter. The continuum filter provides excellent contrasting relief of solar granulation and faculae. The solar disk will be presented in a light green cast. But I would only invest in this filter if you find you are gaining an interest in solar observing. They are a rather pricey. It is important to remember that no filter is a magic bullet. Use of additional filtration coupled with some experience, will help tease out solar detail with some applied effort. Ensure that the BASF objective filter is tightly attached to the telescope and follow the manufacturer instructions to the letter. From that point on, enjoy the show! Clear skies.

Bill

Michael Ritchie

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Re: White Light
« Reply #4 on: January 12, 2018, 06:50:46 AM »
Quote
Quote

Recently got interested in solar viewing and got a glass solar filter that fits both my 80mm refractor and 90mm cassegrain telescopes. Saw the user review on Baader ASTF style filters and have ordered one for my 102mm Cassegrain.I'm begining to worry about aperture size and wonder if there'sa size limit beyond which the Sun's image would be too bright to safely view.


You will be fine. Baader Astro Solar Film (BASF) is an excellent product. If you find the solar image a little to bright for your liking, simple additional filtration will take care of that issue. Depending upon your budget, you have a couple of options. Starting with the less expensive filtration, you can approach solar observing with basic color filters used in conjunction with your full aperture BASF. Red (W#25) or orange (W#23A) filters work very well in isolating and enhancing sunspot umbrae. Further, a green (W#56 or W#58) filter works well at bring out solar granulation and faculae. There are also various neutral density filters (0.9/2.0) for example, that will aid in reducing any unwanted brightness of the solar disk. Variable polarizing filters are excellent in that you can "tune in" the degree of interference to suit your personal needs. A violet filter (W#47) is good for white light flare searches. If you have the funds, I would strongly recommend investing in a Baader Solar Continuum Filter. The continuum filter provides excellent contrasting relief of solar granulation and faculae. The solar disk will be presented in a light green cast. But I would only invest in this filter if you find you are gaining an interest in solar observing. They are a rather pricey. It is important to remember that no filter is a magic bullet. Use of additional filtration coupled with some experience, will help tease out solar detail with some applied effort. Ensure that the BASF objective filter is tightly attached to the telescope and follow the manufacturer instructions to the letter. From that point on, enjoy the show! Clear skies.

Bill
Thanks for responding to my concerns. I am new to solar and just a little afraid of it. The information you have provided is exactly what I was looking for. I have two of the color filters you mentioned, but never thought to use them in conjunction with my solar filter. It's a whole new path to follow.

John Edwards

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Re: White Light
« Reply #5 on: January 12, 2018, 06:32:37 PM »
Sounds like you're walking that path the right way, with appropriate care and caution.

A small matter that is often not mentioned: if you have an optical finder mounted to the telescope, cap the objective lens. I burned a hole in a coat sleeve, once upon a time, forgetting to do this. Better yet, take the finder scope off. I use one of these to get the sun in view:

http://www.dynapod.com/dyna-hp1.html

Max Sandell

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Re: White Light
« Reply #6 on: January 13, 2018, 02:56:15 AM »
Quote
Quote

Quote

Recently got interested in solar viewing and got a glass solar filter that fits both my 80mm refractor and 90mm cassegrain telescopes. Saw the user review on Baader ASTF style filters and have ordered one for my 102mm Cassegrain.I'm begining to worry about aperture size and wonder if there'sa size limit beyond which the Sun's image would be too bright to safely view.


You will be fine. Baader Astro Solar Film (BASF) is an excellent product. If you find the solar image a little to bright for your liking, simple additional filtration will take care of that issue. Depending upon your budget, you have a couple of options. Starting with the less expensive filtration, you can approach solar observing with basic color filters used in conjunction with your full aperture BASF. Red (W#25) or orange (W#23A) filters work very well in isolating and enhancing sunspot umbrae. Further, a green (W#56 or W#58) filter works well at bring out solar granulation and faculae. There are also various neutral density filters (0.9/2.0) for example, that will aid in reducing any unwanted brightness of the solar disk. Variable polarizing filters are excellent in that you can "tune in" the degree of interference to suit your personal needs. A violet filter (W#47) is good for white light flare searches. If you have the funds, I would strongly recommend investing in a Baader Solar Continuum Filter. The continuum filter provides excellent contrasting relief of solar granulation and faculae. The solar disk will be presented in a light green cast. But I would only invest in this filter if you find you are gaining an interest in solar observing. They are a rather pricey. It is important to remember that no filter is a magic bullet. Use of additional filtration coupled with some experience, will help tease out solar detail with some applied effort. Ensure that the BASF objective filter is tightly attached to the telescope and follow the manufacturer instructions to the letter. From that point on, enjoy the show! Clear skies.

Bill
Thanks for responding to my concerns. I am new to solar and just a little afraid of it. The information you have provided is exactly what I was looking for. I have two of the color filters you mentioned, but never thought to use them in conjunction with my solar filter. It's a whole new path to follow.

You're very welcome. Solar observing is a wonderful pastime. Good luck!

subhymerlo

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Re: White Light
« Reply #7 on: January 16, 2018, 12:44:41 AM »
Quote
Sounds like you're walking that path the right way, with appropriate care and caution.

A small matter that is often not mentioned: if you have an optical finder mounted to the telescope, cap the objective lens. I burned a hole in a coat sleeve, once upon a time, forgetting to do this. Better yet, take the finder scope off. I use one of these to get the sun in view:

http://www.dynapod.com/dyna-hp1.html

Excellent point Tom.

Santosh Wolf

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Re: White Light
« Reply #8 on: January 17, 2018, 01:13:01 AM »
That piece of advice about findersis important! Just remove all finders while solar viewing except shadow finders. You can look at the shadow of your scope on the ground and when its size is minimal, usually a circle, you are aimed at the sun.

I once saw an observer who had neglected to remove his finder stand up from his eyepiece sniffing the air cautiously and curiously while his bangs smoldered!

Donnell Keown

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Re: White Light
« Reply #9 on: January 18, 2018, 08:40:29 AM »
Quote
That piece of advice about findersis important! Just remove all finders while solar viewing except shadow finders. You can look at the shadow of your scope on the ground and when its size is minimal, usually a circle, you are aimed at the sun.

I once saw an observer who had neglected to remove his finder stand up from his eyepiece sniffing the air cautiously and curiously while his bangs smoldered!

I was in my mid teens, out looking at the sun on a bright winter morning. I smelled smoke, and saw wispsof white vapor curling up from my forearm. Fortunately it had been a snowy Illinois winter, and a nearby pile of snow, left from shoveling the driveway, was my salvation. At least, it was until I tried to explain to the folks how I'd ruined one sleeve of my coat!

Robert Spencer

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Re: White Light
« Reply #10 on: January 23, 2018, 04:54:51 AM »
Something I didn't see mentioned here is that there's a practical limit to solar aperture size, around 4-5 inches from what I've read. Seeing tends to be pretty horrid when the sun's out, and larger apertures tend to make that more pronounced. At 102 mm, a tad under 4", you shouldn't have too much trouble unless you set up in a parking lot.

A few weeks ago I made an off-axis filter with the Baader film for my 12" Dob. It works pretty well, although the seeing was spotty the one day I've had a chance to use it. The aperture is somewhere between 4 and 5 inches ... it is a tad bright, but not uncomfortably so. The ND filter I have on the way, or perhaps various color filters, ought to help with that.

quetafulra

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Re: White Light
« Reply #11 on: January 23, 2018, 05:23:39 AM »
+1 on an off-axis Baader film filter plus color filters for solar viewing.

For my 10" dob the off axis hole is 3", but even with the denser Baader film filter it is a bit bright for my eyes to bring out the most detail. Color filters in addition sharpen things up for me. I've also tried a moon filter but see more detail with the color filters.

Sean Meyer

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Re: White Light
« Reply #12 on: January 31, 2018, 07:29:24 AM »
I have found solar viewing to be very rewarding so far... and since I work evenings (14:00 to 23:00), sometimes that is all the viewing I get to do. Sadly, I don't get much time for solar viewing lately due to all the overtime I am required for.

I too, was a bit concerned about solar viewing at first. But after using my homemade solar filter for a few sessions, I am less nervous about it. I check the filter for pinholes/leakage prior to using it and have had no issues. Following is a picture of my rig:



^^^^ "The Beast", ready for solar viewing... Following is a pic I took with my iPhone 6 through the eyepiece...
^^^^ there were a couple of sunspots in the upper left quadrant, but the iPhone couldn't resolve them.

I have since used the green W # 58 filter that Reptilicus recommended and it does indeed help with detail.

All in all, I have been very pleased with this aspect of the hobby. The cost? About $15 for the Thousand Oaks solar film from Amazon and the green filter came in a set of 4 for about $29.

Clear skies guys!

CB

Mike Meckler

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Re: White Light
« Reply #13 on: January 31, 2018, 10:48:27 AM »
CB,

Glad to hear white solar observing is working out for you.  As long as it is secured tightly to the dew shield and you inspect it before each session for serviceability, your good to go. Be especially careful on windy days. Clear skies...

Bill

Antonio Stanton

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Re: White Light
« Reply #14 on: February 02, 2018, 03:14:15 PM »
Quote
CB,

Glad to hear white solar observing is working out for you.  As long as it is secured tightly to the dew shield and you inspect it before each session for serviceability, your good to go. Be especially careful on windy days. Clear skies...

Bill


You know, I wasn't sure it would appeal to me, but since I could get into it economically enough, I felt it was worth a try. Now, I am captivated with it. Even though it has been a weak cycle, I have enjoyed seeing the sunspot activity that has been there. I am also looking forward to the transit this May.

I have rubber tips on the securing screws for my filter and they grip VERY tenaciously. I check it for pinholes before I mount it and then check it once it is mounted to be sure it is gripping like it should. We have a lot of wind here in Texas, and it was a primary concern when I built it. So far so good!

Thanks for the encouragement, Bill!

Clear skies!

CB