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Wide Integrated Flux around M81 and M82.


ollypenrice

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Project with Peter Woods and Paul Kummer.

Didn't the IFN use to be faint?  My first attempt had over 20 hours, using a Tak 106 and Atik 11000 CCD. This new version is demonstrably deeper, demonstrably cleaner,  about 4x wider, and took 3.4 hours in a piddling little camera lens!

Times change. Samyang 135 at F2, Avalon M Uno, TS 2600 OSC CMOS camera. Ha in the Cigar comes from an old telescopic image, not that it makes much difference. For some reason the poor stars in one corner of the lens have gone away. On this run they were very good.

M8182IFNFINAL2web.thumb.jpg.1b847d60f19658a2f22f9a333f685205.jpg

Olly

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8 minutes ago, ollypenrice said:

No, the image I posted is a single panel from a Samyang camera lens, 135mm.

Olly

Ah. explains all :)  Amazing image and spent about 1 hour aligning with mine to see if I had gotten a true IF or processed induced (made up) IFN :)

 

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1 hour ago, Catanonia said:

Ah. explains all :)  Amazing image and spent about 1 hour aligning with mine to see if I had gotten a true IF or processed induced (made up) IFN :)

 

I think we all do that with the IFN - and quite rightly. I overlaid this on my earlier version and was relieved to find good agreement.

Olly

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41 minutes ago, gorann said:

A lot of IFN around there indeed! I It reminded me of this image by Kees Scherer:

https://www.astrobin.com/389783/

132 hours and 15 panels with an Esprit 100. So you really saved some time with the SY135.

wow, that image was some dedication :)  Sometimes I wonder whether to buy a camera lens for wide field rather than doing mosaics. 

The only real benefit I see to mosaics is if you want to do large prints with them, otherwise it only serves the pixel peeker / zoomers out there ;)

 

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4 hours ago, gorann said:

A lot of IFN around there indeed! I It reminded me of this image by Kees Scherer:

https://www.astrobin.com/389783/

132 hours and 15 panels with an Esprit 100. So you really saved some time with the SY135.

It's an interesting comparison. The main structures agree, which is good. In some places I have more contrast, in some places he does, but the shapes are very comparable. Since it isn't an image inviting 'zoomability,' and since star size can now be controlled, I have to say that I'd rather take this picture in 3.4 hours, but a real IFN buff would, rightly, go for his. It's beautifully put together.

Olly

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4 hours ago, Catanonia said:

wow, that image was some dedication :)  Sometimes I wonder whether to buy a camera lens for wide field rather than doing mosaics. 

The only real benefit I see to mosaics is if you want to do large prints with them, otherwise it only serves the pixel peeker / zoomers out there ;)

 

It does depend on the target. In the IFN image, here, there is nothing much to resolve apart from M81 and M82 and, if you want to see those in detail, just take a telescopic image. Now that star size can be controlled, the big lens disadvantage of large stars is rectified. However, if the frame contains lots of finely detailed objects, you will see a lack of resolution in those regions when using a lens, even unzoomed at PC screen size. This is where it becomes advantageous to do composite images in which regions of interest have a boost in resolution from higher res data where it will make a difference. Since the high res data will be downsized to fit, it does not need a high S/N ratio. Our plan is to try, say, 4 hours in the Samyang plus an hour per region of interest in the Rasa and blend those. The blending is simplified because the starless high res can be blended with the starless widefield and then the widefield stars re-applied for the lot. This will provide visual continuity and make the overlays seamless.

Olly

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