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Sun In White Light 19-05-2013. 10:00

Steve Ward

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Having resisted the urge to spend / waste £170.00 on Continuum and UV/IR Block filters at the I.A.S. yesterday ( thank you 'Starman' for the sound advice)

I had a little play with what I've got lying around instead . . . :smiley:

Shot 3 sets with (i) ST120 + UHC (ii) ED80 + OIII (iii) ED80 + #56 Green.

Need to do a proper comparison with the OIII and #56 as the OIII set was cut short , but I'm definitely switching back to the ED80 and probably going for a 2" #56 Green very soon. I had to rest the 1 1/4" #56 I have inside he Barlow today as the T-connector has welded itself together . . . :rolleyes:

ST120 + UHC.


ED80 + OIII.


ED80 + #56 Green.


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Interesting comparison, and some great shots. The ED80 does have much better chromatic correction, but I am left to wonder what the result would be like with O-III and ST120. Using a single narrow band must be much better than using a collection of narrow bands that the UHC filter passes. Baader solar continuum might be better still. It also needs more exposure time, but the transmission in the band pass is good. You probably get more light than with O-III, and probably a sufficiently narrow band-pass to control CA.

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Just out of interest Steve, what exposure time / ISO did you use with the ED 80 / #56 combination. With my 80mm and 2x barlow I find I need to go to ISO 400 to get an exposure time of less than 1/1000th second (which is desirable to "freeze" the seeing as best I can).

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Hi David ,

Just had to rummage through the 'recycle bin' to find the details .... :grin:

The ED80 - #56 Green were at 1/1000s @ ISO 200.

ED80 - OIII were at 1/800 @ ISO 200.

ST120 - UHC were at 1/1600s @ ISO 100.

Bear in mind ( excuse the pun ) that I'm using the ND3.8 imaging film not the ND5.0 Visual precisely for this reason .

Just waiting for a predicted slot in the cloud for another go , I'm probably going to stick with the ED80 - OIII Combo as I know this gives great results , it's the set-up I used last year and only stopped using it to free up the ED80 for the Dark side.

@ Michael .... I tried the ST120 - OIII when I first switched the kit , but it didn't give the same level of detail as the UHC-S/L combo , that was however just to my eyes . . . :p

I was very close to getting the Continuum but after numerous conversations at IAS and realising that I'd want the UV/IR block as well I decided that it was too much to spend on the offchance of improvement , had I had the opportunity to compare views I may have been persuaded , and the discounts on offer were not particularly impressive , nothing better than on-line prices from the two people that had them . . . :mad:

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