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andrewluck

Cone & Fox Fur wide field

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This is the result of 16x 20 minute Ha frames taken over the two clear nights earlier this week with my FSQ85 / Moravian 16200 combination.

Processing in Pixinsight and resampled to 45% of the original size.

Andrew

Sh2_273_SGL.jpg

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That is an awesome result.... so much detail that it makes it look furry.

 

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Really excellent detail and contrast control.  One of the best I have seen of this target, which, by the way, I  prefer in mono.  What was the bandwidth of the Ha filter?

Chris

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Very nice!

Wow, you're pushing the envelope with a 16200 chip on the FSQ85.  A brave man to have bought that combination - it must be at the extreme edge of the FSQ85 imaging circle.  Your results speak for themselves though.

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Filter is the Baader 4.5nM Ha.

There's a thread here somewhere detailing some of the work I had to do getting acceptable (to me) results. I've ended up with some tape under one corner of the camera / filter wheel connection and, having focussed on a star in the centre of the field I then step out an additional 10 steps (about 50 micron). There's still some elongation top left, bottom right but I can live with that for the moment. Hint: machined adapters are never orthogonal and sometimes the tolerances will add up the wrong way and bite you!

After noise reduction in the linear phase (TGV & MMT) I used a histogram stretch rather than a masked stretch to preserve what contrast there was. Then there's 3 iterations of LocalHistogramEqualisation at scales of 64, 128 and 256 (decreasing amounts each time) to boost the contrast and then some S curves to finish. More noise reduction etc etc etc

 

Andrew

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3 hours ago, andrewluck said:

Filter is the Baader 4.5nM Ha.

There's a thread here somewhere detailing some of the work I had to do getting acceptable (to me) results. I've ended up with some tape under one corner of the camera / filter wheel connection and, having focussed on a star in the centre of the field I then step out an additional 10 steps (about 50 micron). There's still some elongation top left, bottom right but I can live with that for the moment. Hint: machined adapters are never orthogonal and sometimes the tolerances will add up the wrong way and bite you!

After noise reduction in the linear phase (TGV & MMT) I used a histogram stretch rather than a masked stretch to preserve what contrast there was. Then there's 3 iterations of LocalHistogramEqualisation at scales of 64, 128 and 256 (decreasing amounts each time) to boost the contrast and then some S curves to finish. More noise reduction etc etc etc

 

Andrew

Nope.  Didn’t get any of that?.  Seriously though, it’s an excellent mono image.  Superb detail.  Well done.

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On 20/02/2018 at 18:48, andrewluck said:

Filter is the Baader 4.5nM Ha.

There's a thread here somewhere detailing some of the work I had to do getting acceptable (to me) results. I've ended up with some tape under one corner of the camera / filter wheel connection and, having focussed on a star in the centre of the field I then step out an additional 10 steps (about 50 micron). There's still some elongation top left, bottom right but I can live with that for the moment. Hint: machined adapters are never orthogonal and sometimes the tolerances will add up the wrong way and bite you!

After noise reduction in the linear phase (TGV & MMT) I used a histogram stretch rather than a masked stretch to preserve what contrast there was. Then there's 3 iterations of LocalHistogramEqualisation at scales of 64, 128 and 256 (decreasing amounts each time) to boost the contrast and then some S curves to finish. More noise reduction etc etc etc

 

Andrew

Great image Andrew!

Do you (or does anyone else) use the new Tak EDP flattener for the FSQ-85?

https://www.takahashiuk.co.uk/Focal-Reducers/1399-/Takahashi-EDP-Flattener-for-FSQ85

What do you think of it?

Julian

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Hi Julian

I haven't got a flattener yet but I'll be pressing the buy button very soon. I'll also need a new adapter to connect it to the filter wheel.

<Edit> Button pressed. Also a set of M54 extenders </Edit>

Andrew

Edited by andrewluck
Updated information

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The flattener has now arrived and been installed. As I already had an adapter for the front of the filter wheel to connect to a CA-35 all I had to do was include some M54 extenders between the flattener and the adapter. The ones I used were these: https://www.aliexpress.com/store/product/A-set-of-M54-Extension-Tube-4-9MM/1371081_32819456658.html?spm=2114.12010612.8148356.4.73733ccaSiki3y

Originally, I intended ordering a new custom adapter once I'd determined the back focus requirement but I don't think this is essential.

The results are interesting. I was previously aware that these FSQ scopes are extremely sensitive to focus position and this hasn't changed with the flattener. Apparent tilt swings pretty wildly either side of focus and on my last trip to Namibia I was manually focusing an FSQ-106 by focusing for minimum tilt (completely ignoring the usual FWHM metric) and achieved good reults with this. Incidentally, using this method the direction of tilt indicates which way to turn the focuser which makes the process quicker.

With the Lakeside auto-focuser at home, I'm focusing on a star in the centre of the field and then offsetting 20 steps out. This has the effect of reducing the FWHM of the focus star from 6 to about 4 and reduces the indicated curvature from 30% to around 10%. Some further fine tuning is probably possible here and should yield a small improvement.

Capture.thumb.jpg.f81ea358b8cc0380d18c356906f95d11.jpg

As CCD Inspector doesn't distinguish between FWHM and eccentricity I also measured the image using Pixinsight with these results:

CCD_Image_164_eccentricity.jpg.14566728a28a6ba3cae68258f7f233b2.jpgCCD_Image_164_FWHM.jpg.629bdd20ee0a55587abf837f64f4da6b.jpg

The stars in the corners of the test image look like this:

CCD_Image_164_corners.jpg.c4954fd20d1df15634029ac06c0772d1.jpg

In summary, I'm very pleased and looking forward to the next clear night. If anyone is interested in the 3D plots either side of focus then ask and I'll post them.

Andrew

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