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Shootout at the One Yard Corral...


ollypenrice

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I may be a certifiable refractor nut but I know when I'm on thin ice and at about a metre of focal length there is that darned MN190 out there which can rattle an apo's lens cell and no mistake. With forum members aiming some very good glass at M81 and M82 at the moment I thought it would be interesting to do some real comparing. I really doubt that the TEC140 can actually beat the MN. It is almost twice as slow, to boot. It may not even match it, despite the prodigious cost. OK, it is smaller and doesn't need collimating or upgrading (Feathertouch is standard) but it is very expensive. These are crops from an image embracing the two galaxies. 8 Hrs in Luminance, Atik 4000 mono. I didn't need 8 hours for these bits but I'm also struggling to get a bit of Integrated FLux. Not that I'm sure there is any left after Peter's AO12 drank it all!!

These were processed from the same data stack but with a shorter stretch layer masked in for the cores.

Olly

1209784388_rtTLf-X3.jpg

1209784461_74gKs-X3.jpg

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I have 4 hours 40 minutes of M81/M82 from last night in the 190MN to process today, I would be more than happy to let you have the data in a day or two if you want to compare (OK, its with a OSC M25C, but still might be useful if you want it)

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I have 4 hours 40 minutes of M81/M82 from last night in the 190MN to process today, I would be more than happy to let you have the data in a day or two if you want to compare (OK, its with a OSC M25C, but still might be useful if you want it)

Cheers Steve. In fact just comparing them at the same scale would be worth it. I'm still a way off with another night of Lum for the flux, a colour night and an Ha night.

Olly

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Nice, Olly. I did a very similar test image a couple of years back with my AP130 (1040mm at f/8) and a very sensitive SBIG NABG CCD, and got similar results - the look of your image immediately brought mine back to mind.

The effects of seeing are interesting though, as I shot mine in very good conditions (the double bottom-centre of M81 was almost cleanly split) so I wonder if the refractor might still have an edge if the seeing can support it. Otherwise (as another refractor nut) I agree about the MN190 :)

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Nice, Olly. I did a very similar test image a couple of years back with my AP130 (1040mm at f/8) and a very sensitive SBIG NABG CCD, and got similar results - the look of your image immediately brought mine back to mind.

The effects of seeing are interesting though, as I shot mine in very good conditions (the double bottom-centre of M81 was almost cleanly split) so I wonder if the refractor might still have an edge if the seeing can support it. Otherwise (as another refractor nut) I agree about the MN190 :)

Boy, you did well to split that double in a full stretch. I have been looking at a few big hitters like Gendler with a 20 inch etc and they don't get a clean split. I guess the atmosphere limits it. I had a look at the linear data and it is split on mine but will only stand a couple of short stretches before the components make contact...

Olly

post-15040-13387754222_thumb.jpg

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