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Solar filters: film or glass? Recommendations for a 6" refractor

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#26 foxwoodastronomy

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Posted 06 April 2023 - 06:00 PM

Based on all the information, I think that glass is the option I'll choose. 

I like the first image with the Seymour Solar glass filter, and they have in stock.

 

My refractor is 6 inches, but with the dew shield is 8 inches. I can remove the shield, but I'd rather to keep it. Is there any problem?

I can think of a few things to consider.

The larger diameter filter is going to cost you more and remember you have to buy a filter slightly larger that the outside diameter of the front of your optics.

One of the cons of glass is they weigh more so they change the balance of your scope and mounts.  The further out you have the glass filter the more mechanical advantage it is going to have tugging down on the front of your scope.

You need to be able to reach the filter easily to remove it at C2 and replace it at C3 without jarring your gear, and the further out it is the more leverage it will have on your mount as you touch it.

I don't have a real reason for this, but I just think it would be better closer to the optics, there sometimes is an issue with needing to slant your filter a couple of degrees to prevent ghosting of images from the partial phases.  But that depends on how long your dew shield is.  Mine is short.

It depends on whether or not your front objective has any protection at all with the dew filter off.  I need to leave the dew shield on my Takahashi because otherwise the front objective could be rubbed on easily.  There is no leading edge to the optical tube at all.

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#27 angelsp

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Posted 06 April 2023 - 09:05 PM

You are right, good point.

The dew shield is not large, the telescope is a Meade LXD75 AR6, but without the shield I think that I would have a similar problem than you with your Takahashi. I'll check that.



#28 foxwoodastronomy

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Posted 07 April 2023 - 05:40 AM

Discussion in response to what SteveInNZ wrote in his post above about using glass solar filters. I discuss this in-depth in my book and I have attached the three pages.  The bottom line is that you practice what you are going to do with your filters no matter what type you plan to use.  You need a routine; how and when you are going to take it off, where you are going to place it, and when and how you are going to replace it.  You need to be practicing your entire photography routine, under time pressure, in your living room.  Read these tips.  Gordon

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  • remove filter 1.jpg
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  • remove filter 3.jpg

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#29 marvyyk

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Posted 07 April 2023 - 06:10 AM

I use Thousand Oaks Solarlite films. I made two holders, one for my DSLR lenses and another one for my refractor... I bought a glue gun and some cardboard, so it cost me less than 5$...

 

Here what it looks on y refractor : https://flic.kr/p/2nHcWXj

 

I used this setup for our partial eclipse two years ago... 


Edited by marvyyk, 07 April 2023 - 09:58 AM.

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#30 foxwoodastronomy

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Posted 07 April 2023 - 09:54 AM

I use Thousand Oaks Solarlite films. I made two holders, one for my DSLR lenses and another one for my refractor... I bought a glue gun and some cardboard, so it cost me less than 5$...

 

Here what it looks on y refractor : https://www.flickr.c...4/in/datetaken/

 

I used this setup for our partial eclipse two years ago... 

Can you please post some pictures of your properly exposed partial eclipse phases through the SolarLite film?  I would be interested to see them.  Thanks.



#31 marvyyk

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Posted 07 April 2023 - 09:58 AM

Can you please post some pictures of your properly exposed partial eclipse phases through the SolarLite film?  I would be interested to see them.  Thanks.

Not sure about properly exposed... here's a picture inbetween clouds...

https://flic.kr/p/2m4L15N



#32 foxwoodastronomy

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Posted 07 April 2023 - 11:16 AM

Maersk,

A couple of things.  What I mean about a properly exposed solar disk is a reasonably bight center of the Sun, but preserving the natural darkening of the limb of the Sun. That is what you are trying to achieve with your partial-phase images of the eclipse. So it's hard to comment on your partial phase image because it is not a full disk, but looking at it I would say that it would be underexposed for a full disk.  But that is what I expect with SolarLite film.  It has a lower light transmission than glass, I estimate it to be about three stops slower than glass.

But that is not the worst problem.  The worst problem with SolarLite is the light bleed or haze that occurs around the partial phase images.  Your image confirmed my fears.  I modified your image with arrows to show you what I am talking about.  That haze doesn't happen with glass.  Even an overexposed full solar disk image has a clean cut-off at the edge of the Sun with no haze.  That is why I prefer glass for eclipse photography.  I have attached pages from my book for your review.  Gordon

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  • solalite haze from marvyyk copy.jpg
  • 4  page 59 full disk exposure 600.jpg
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#33 marvyyk

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Posted 07 April 2023 - 12:08 PM

Nevertheless, for the partial eclipse, it was cloudy, so i was not really able to make a lot of tests... it was capture in between clouds... So I'm happy with my image and with this filter generaly speaking...

 

Thanks for your advise. Good luck with the selling of your book.


Edited by marvyyk, 07 April 2023 - 12:37 PM.


#34 foxwoodastronomy

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Posted 07 April 2023 - 01:05 PM

Nevertheless, for the partial eclipse, it was cloudy, so i was not really able to make a lot of tests... it was capture in between clouds... So I'm happy with my image and with this filter generaly speaking...

 

Thanks for your advise. Good luck with the selling of your book.

Yes sir, I understand.  Thanks for commenting and discussing things. I hope I helped you for the future when you can test on the full solar disk without clouds, Gordon


Edited by foxwoodastronomy, 07 April 2023 - 02:16 PM.

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#35 Sebastian_Sajaroff

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Posted 15 April 2023 - 05:51 PM

I had Thousand Oaks film filter on a scope identical to yours. Excellent results, used it almost daily for about two years.
Baader also makes great solar filters.
Note that visual and photographical solar filters are not the same, buy the one appropriate for your purpose.
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#36 Nicole Sharp

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Posted 04 October 2023 - 07:58 PM

Hi,

Planning for the 2024 solar eclipse, I'd like to buy the filter to use with my 6" (1200mm, f/8) refractor. So asking the wise guys on this forum, what do they recommend without breaking the bank?

 

Thank you!

For a telescope, I recommend using Solar film instead of Solar glass.


Edited by Nicole Sharp, 04 October 2023 - 07:58 PM.




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