Celestron is offering these white light solar filters: https://www.celestron.com/collection...-solar-filters
They claim compliance with ISO standards - which only apply to naked eye "sunglasses" type filters!
here's no mention of transmission curves or surface accuracy of these filters.
The filter material is manufactured by American Paper Optics who ONLY manufacture eclipse glasses.....and don't have any available data on their material - only that it meets ISO.
Nothing like the info available from Baader.
I'd be interested in feedback from any users of these filters.
I'm concerned that the quality will be nowhere near the minimum 1/4 wave.
Let me know.
Ken
Ok, I managed to get one of these filters for the C8.
Tried it out today….
Very poor results!
I need to double check the collimation of the C8 just to make sure it’s not contributing to the issue.( I’ll probably temporarily mount the filter on the SW120mm which I know, with the Baader wedge gives excellent results)
Visually, it didn’t want to come to focus and the image was soft and lacked significant detail. Not impressed!
The filter seems to be made from two (??) layers - a shiny heavy reflective front layer and a dark rear layer which results in an orange solar image.
The President of the supplier of the filter material American Paper Optics says his business is 3D and Eclipse glasses and that he doesn’t know about the suitability of his filters to telescopes!!!!
I’ve sent emails to Celestron to ask for further technical details of this filter - transmission curves and surface quality- 1/10 or 1/4 wave or what?
In fairness I will retest this filter with the SW120.
Stay tuned.
For comparison I temporarily mounted the 8"sct Eclipsmart filter on my SW120/1000 refractor.
I then changed over to an 80mm clear Baader Solar film filter.
Then finally added my Baader Cool Herschel wedge.
All SER videos taken within minutes of each other, all processed the same way in AS3!
Final file sizes reduced to 1000 pixel width and JPG.
I think it is pretty obvious which solar white light filter is the best and which is the worst.
I'd appreciate your comments.
I’ve got one of the eclipsmart filters for my c8. I don’t have any other white light filters to provide a comparison though. One thing I did notice was that the views always got worse after a short time and I assumed this was due to thermal issues in the scope. But I have very much enjoyed those initial views and reasonably sharp to my inexperienced eye.
Thanks yes I see them now. That is quite a stark difference. I think I’ve only had one or 2 goes solar imaging and none for years… so I can only compare to what I’ve seen through the eyepiece. With the c8 it was certainly sharper than the first one but perhaps not as good as the wedge…from memory.
Thanks for sharing this
For comparison I temporarily mounted the 8"sct Eclipsmart filter on my SW120/1000 refractor.
I then changed over to an 80mm clear Baader Solar film filter.
Then finally added my Baader Cool Herschel wedge.
All SER videos taken within minutes of each other, all processed the same way in AS3!
Final file sizes reduced to 1000 pixel width and JPG.
I think it is pretty obvious which solar white light filter is the best and which is the worst.
I'd appreciate your comments.
This is really interesting to me, thanks for posting, I only just noticed this thread. A while ago when I was first starting out I bought one of these Eclipsmart filters for my 6" SCT. I tried it out on the Sun looking for spots, but it was at a time when the sun was at its minimum and no spots were visible. I found it difficult to see anything (other than a big white circle ), focusing was difficult and I have left it in the cupboard until now.
I plan on trying to image the eclipse from Melbourne (so I'll see a small bit missing at best) and post the results here on IIS. I've also more recently purchased a sheet of Baader 5.0 Solar film which I had planned to mount on something, but have never got around to it. Maybe I can cut the American Paper Optics film out of the Eclipsmart holder and use it to install the Baader film on my 6"...
So I just had a go this morning with my 6" SCT, Eclipsmart filter and Canon 700D.
I banged off 50 jpgs in quick succession with the camera in "Sports" mode, accidentally had the resolution at "S1" (2600x1768 pixels), stacked the best 75% in AS!3, sharpened in Registax using one of my "Moon" settings, and here is the result.
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,481
Hi Ken,
Your image taken with the Baader Astrosolar film looks like a very badly mounted filter. Baader Astrosolar needs to be mounted stress free. It doesn't matter if the filter isn't tight, in fact they specifically say not to stretch it tight. Yours also seems to have a lot of light leakage causing all that flare. This is not my experience using the Astrosolar film. The Herschell Wedge may well be a superior product to the film, but I don't think the difference is nearly as stark nor big as you have illustrated.
Joe,
The Baader filter was only a 80mm aperture which I Gaffa taped to the 120mm refractor for test purposes.
The Baader film had been mounted correctly.
A nice comparison Ken, but I agree with Joe in the the Baader film sample looks way worse than what's prossible with that product at that aperture. Baader film is closer in image quality to a Herschel wedge than the sample image suggests and is an absolute no-brainer for anyone wanting to do white-light solar on a budget, provided they already own an optic.
Edit - Here's a crop from a single shot taken through a homemade Baader film filter from my recent trip to WA. This with a fullframe camera, 370mm FL and 60mm aperture, operating at just 50% of the resolution the scope is actually capable of. The filter was first used in Cairns more than 10 years ago and has seen some mileage since. The Herschel wedge would not have produced an image that much better, plus it's the wrong tool to use in a total solar eclipse. I reckon that's pretty useable for a decade-old piece of mylar worth $2.50
Mirko,
I agree 100%!
I honestly don't know what Celestron were thinking when they offered this "EclipseSmart" filter for sale.
I've yet to find any successful images taken with this filter.
A bit of research.....
The original Celestron Solar filters (Item #94128) were based on Baader Solar Film. (These are still available through Alibaba etc)
The current "EclipSmart" (Item #94244) doesn't use the Baader film but uses the American Paper Optics film.
I have not heard from Celestron regards my concerns.......
Mirko,
I agree 100%!
I honestly don't know what Celestron were thinking when they offered this "EclipseSmart" filter for sale.
Well to be fair, they were thinking that you could capture a solar eclipse with it. And you can (as I showed).
Quote:
Originally Posted by Merlin66
A bit of research.....
The original Celestron Solar filters (Item #94128) were based on Baader Solar Film. (These are still available through Alibaba etc)
The current "EclipSmart" (Item #94244) doesn't use the Baader film but uses the American Paper Optics film.
My Eclipsmart is part# 94243, and it uses APO film. I didn't realise they used to use the Baader film, it certainly would have been better with it. Maybe they like the orange appearance from the APO film?
Given the terrible reviews it gets, I was actually quite surprised with the quality of the images I achieved on the sun spots (images above), given a 6" SCT with marginal collimation and only 50 frames from a DSLR...
), focusing was difficult and I have left it in the cupboard until now.
