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Home Forums Observing and Imaging Group H-Alpha Images from 05/10/14

Viewing 15 posts - 1 through 15 (of 28 total)
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  • #8760
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Decided to put the day job to one side (oh, its the same as the hobby….bug***) and make the most of the Sun.

    Captured three decent images. Here is the first

     

    Ha Chrom 05-10-14 by astrograph ltd[/url], on Flickr

     

    and again as a negative which brings out the detail of the looping prominence

     

    Ha Chrom neg 05-10-14 by astrograph ltd[/url], on Flickr

     

    Equipment used

    APM 100/800 Refractor

    Daystar Quark Chromosphere

    Point Grey Blackfly (e2V c560 chip)

     

    I took images at different exposure levels and focus points with the intention of focus stacking and creating an HDR image. In the end one of the stacks (20% of 1000 frames used) was good enough to use on its own. A separate image was taken to capture the prominence.

    • This topic was modified 5 years, 2 months ago by Astrograph.
    #8762
    Sumitra
    Participant
    Topics: 21
    Replies: 233

    Wow, just wow! Amazing photos!
    So much detail can be see, it’s beautiful!

    #8764
    Brian Blake
    Participant
    Topics: 188
    Replies: 409

    Oh F*** yea, amazing.

    #8765
    Christina Chester
    Participant
    Topics: 19
    Replies: 196

    Seconded! Simply stunning detail!

    You’ve a great day job!

    #8766
    Mike Meynell
    Moderator
    Topics: 119
    Replies: 756

    Fabulous. Like the idea of using a negative image to bring out the detail in the prominences.

    Intrigued at the HDR idea… what were you trying to achieve with this?

    #8767
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Thanks for the kind words

    The HDR idea was really a carry over from daytime images. Digital cameras really are rubbish when it comes to dynamic range so I find I use bracketed exposures a lot and combine them in Photomatrix. It can create a bit of a surreal look sometimes but overall I like it.

    With solar, its often hard to find a compromise exposure setting because you have so many parts of the chromosphere which are really bright (like the flare area at the bottom) and also really dark. Therefore I have started to bracket images and then combine them. Its a learning curve at the moment. With this image I did complete an HDR but there was something about it not quite right mainly because I don’t think I got enough exposure range. I therefore used a single frame as normal. I am also trying focus stacking as at long focal lengths like this (3360mm), the limb can be in focus but detail further in can get soft. This image had focus on the prominence / filament and it managed to hold up right to the limb after sharpening.

    Of course all these extra frames might make for a better single image but on a mosaic it would be virtually impossible.

    #8772
    Mike Meynell
    Moderator
    Topics: 119
    Replies: 756

    The HDR idea was really a carry over from daytime images.

    I’ve never been a big fan of HDR photography. They always look slightly fake… too much contrast and saturation… but if it’s done well, then it can work. I’ve normally found that the default settings in most photo processing software make HDR images look artificial and really quite nasty to look at… you have to work at the image to give you something that looks believable.

    The only way I’ve found that makes HDR look OK is by ensuring that the base images are low contrast and low saturation. Only after combining the images would I use curves in Photoshop to bring back the contrast and saturation. It’s still difficult to avoid halos, along with noise in the shadow areas, and you have to be careful not to oversaturate the image.

    For astrophotography, I’ve heard that HDR has been used to good effect on images of the Orion Nebula and the Andromeda Galaxy, as you have similar problems to the Sun (bright areas and dark areas). It will be interesting to see if you can get this technique to work and produce “believable” images!

    #8799
    Tej
    Participant
    Topics: 39
    Replies: 597

    Great solar images, Rupert. Your day Job!?! j-e-a-l-o-u-s!!

    #8805
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Hi Tej,

    Well I sell Astronomy equipment don’t I, but unlike most I think I should know how to use it!

    I WISH this consisted of spending my time taking pictures ‘testing’ and ‘learning’ about equipment but in reality that’s just the excuse I give the wife to play when I am not working instead of my chores!

     

    #8810
    Brian Blake
    Participant
    Topics: 188
    Replies: 409

    Let’s hope she does not read this forum!

    #8824
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Playing with style. Any preferences??

    TriColour by astrograph ltd[/url], on Flickr

    #8825
    Mike Meynell
    Moderator
    Topics: 119
    Replies: 756

    The middle one gives a very strong 3-dimensional perspective to the image. I like that one, personally.

    #8827
    Andy Sawers
    Moderator
    Topics: 127
    Replies: 602

    I am also trying focus stacking as at long focal lengths like this (3360mm), the limb can be in focus but detail further in can get soft.

    Flippin’ ‘eck! The sun is 93 million miles away and you need to fine-tune the focus by less than its radius??? Wow!

    #8832
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Hi Andy

    But its got a radius of 700,000 km. That would be quite a depth of field!

    When you get round to staring at the Sun (or Moon) with your new scope you will soon see you have to refocus from the limb to the centre.

     

     

     

    #8837
    Tej
    Participant
    Topics: 39
    Replies: 597

    I personally prefer the left one as its more natural. I have processed my solar images as a negative too in the past because I have seen many others do this on the Astrobin imaging community but I found it very unnatural, although admittedly looks spectacular due to the 3D effect. ALso if you had sunspots on he surface they would look white and plages looking dark. I am not fond of the last one either because there is obvious layering and I prefer transparency in post processing.

    Those are my humble thoughts but more often than not I am aways in a minority with my opinions 🙂

    I didnt know the focus would be changed between limb and the middle though, I thought the sun is far enough away for the focus to be at infinity? On my little PST, I have to move it around to get the sweet spots…that’s not the same as focus is it? I thought those weet spots were the frequency ranges which I can adjust with the frequency knob.

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