The sun today

[JR]

Not a great deal of sun spot activity but lots of prominences. This is processed as an inverse image, which adds a hint of 3 dimensions

Lunt 60Hα, f8.3/500, ZWO 178mm, best 50% of 500 frames at approx 30 per second, Autostakkert!3, imppg.

[Trev S]

Hi James,

That image shows an amazing amount of detail.  Is the background pale due to the inverse processing?

[JR]

Thanks very much Trevor.  I haven't had any luck posting the high res version.  

Yes the background is the negative of the usual black, and interestingly the variation is clear and shows the need to take flats in solar imaging.  For full disks with a background it's a clear plastic bag over the lens to produce sufficient blurring, and it's a bit hit and miss.  Or I haven't quite got the hang of it, (but it looks artistic).  Where the frame is all sun surface, substantial defocusing does it well and it's easy. 

James

Sent from my iPad

On 9 Aug 2022, at 17:27, Trev S <trevs...@gmail.com> wrote:



--
You received this message because you are subscribed to the Google Groups "croydonastro" group.
To unsubscribe from this group and stop receiving emails from it, send an email to croydonastro...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/croydonastro/3d8a34cf-860d-44f9-93f4-ec52749de6fan%40googlegroups.com.

[William Bottaci]

Hello James, looks like you saw the sun against a cloudy sky :). I wish that would work during cloudy nights.
I have to say, that yellow prominences against a white background ... doesn’t make them stand out much to me, but plenty of detail on the disk.
I'm not understanding the colours with your 'inverse image', does that mean that this is a negative image? If so, as Hα is red, the inverse of which is green...
Depending on your image processor, colours can be colourised, even Photoshop Elements can do this, so are you able to make the background blue?
Was it just the background you inverted?
Anyway, nice and sharp, plenty of detail; a shame that as always with the sun in Hα more can be seen of the prominences visually than can be captured - that's dynamic range for you.
Thanks for sharing.
William

On Tue, 9 Aug 2022 at 20:01, 'JR' via croydonastro <croydo...@googlegroups.com> wrote:
Thanks very much Trevor.  I haven't had any luck posting the high res version.  

Yes the background is the negative of the usual black, and interestingly the variation is clear and shows the need to take flats in solar imaging.  For full disks with a background it's a clear plastic bag over the lens to produce sufficient blurring, and it's a bit hit and miss.  Or I haven't quite got the hang of it, (but it looks artistic).  Where the frame is all sun surface, substantial defocusing does it well and it's easy.
James

On Tue, 9 Aug 2022 at 17:20, Trev S <trevs...@gmail.com> wrote:
Hi James,
That image shows an amazing amount of detail.  Is the background pale due to the inverse processing?

On Mon, 8 Aug 2022 at 18:39, 'JR' via croydonastro <croydo...@googlegroups.com> wrote:
Not a great deal of sun spot activity but lots of prominences.  This is processed as an inverse image, which adds a hint of 3 dimensions

Lunt 60Hα, f8.3/500, ZWO 178mm, best 50% of 500 frames at approx 30 per second, Autostakkert!3, imppg.

James

[JR]

Thanks very much for checking William. 

Inverse means what you get when you press the Invert command in an imaging package.  Colour as such isn't an issue with a monochrome image.  Black becomes white and vice versa, with at least 50 shades of grey swapping about in between.  Inverting enhances the contrast particularly in solar images, making details more visible.  The inverted background isn't uniform as it wasn't uniform black in the original.  Take flats.

James

--
You received this message because you are subscribed to the Google Groups "croydonastro" group.
To unsubscribe from this group and stop receiving emails from it, send an email to croydonastro...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/croydonastro/CAHfnR27CjdQQxwUM6vyuNHSwd_mv-Ts62R6Na%3DeVQwwsmkDPFQ%40mail.gmail.com.

Virus-free. www.avg.com