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ASTRO: The Spider Sorry no Fly as yet
IC 417 aka SH2-234 and LBN 804 is sometimes known as The Spider with
nearby NGC 1931 being the Fly. The wavy "silk thread" on the left points to where the fly is located. This was taken last fall and lost on the hard drive along with a few other Sharpless objects. All have nasty gradients. In this case it was due to horrid reflections from the K star (actually 2 5th magnitude K stars about 20" apart). It totally ruined the green and blue frames. Casting overlapping donuts all over the image. Why red was not bothered I can't fathom. No sign of the reflections in that color. Apparently it passed rather than reflected all light from the orange star. I hope I only removed gradient and not real nebulosity nor left gradient that should have been removed. It got a bit dicey in the nebula telling one from the other. I don't know if the blue color in the core of the globules is real or gradient. If gradient it suddenly got stronger at the globules so think I'm correct though I don't find this color in the web images I found of it. Most were low resolution images capturing the near by "fly" as well. I couldn't find much of a distance estimate on this other than a rather general 10,000 light years. 14" LX200R @ f/10, L=4x10'+3x30'Ha, R=2x10x3+50%Ha, B&G=2x10x3+20%Ha, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
#2
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ASTRO: The Spider Sorry no Fly as yet
Interesting object, don't recall seeing it before. Nice job Rick!
Rick Johnson wrote: IC 417 aka SH2-234 and LBN 804 is sometimes known as The Spider with nearby NGC 1931 being the Fly. The wavy "silk thread" on the left points to where the fly is located. This was taken last fall and lost on the hard drive along with a few other Sharpless objects. All have nasty gradients. In this case it was due to horrid reflections from the K star (actually 2 5th magnitude K stars about 20" apart). It totally ruined the green and blue frames. Casting overlapping donuts all over the image. Why red was not bothered I can't fathom. No sign of the reflections in that color. Apparently it passed rather than reflected all light from the orange star. I hope I only removed gradient and not real nebulosity nor left gradient that should have been removed. It got a bit dicey in the nebula telling one from the other. I don't know if the blue color in the core of the globules is real or gradient. If gradient it suddenly got stronger at the globules so think I'm correct though I don't find this color in the web images I found of it. Most were low resolution images capturing the near by "fly" as well. I couldn't find much of a distance estimate on this other than a rather general 10,000 light years. 14" LX200R @ f/10, L=4x10'+3x30'Ha, R=2x10x3+50%Ha, B&G=2x10x3+20%Ha, STL-11000XM, Paramount ME Rick ------------------------------------------------------------------------ -- John N. Gretchen III http://www.tisd.net/~jng3 |
#3
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ASTRO: The Spider Sorry no Fly as yet
that's pretty cool Rick
It reminds me that I need to return to that area I shot it with the 18" back in 2006 when I got me another Dream Machine http://www.narrowbandimaging.com/ic4..._csha_page.htm http://www.narrowbandimaging.com/ima...a_12x20min.jpg I may have forgotten to fix the mirror image issue with the DM that I have... "Rick Johnson" wrote in message . com... IC 417 aka SH2-234 and LBN 804 is sometimes known as The Spider with nearby NGC 1931 being the Fly. The wavy "silk thread" on the left points to where the fly is located. This was taken last fall and lost on the hard drive along with a few other Sharpless objects. All have nasty gradients. In this case it was due to horrid reflections from the K star (actually 2 5th magnitude K stars about 20" apart). It totally ruined the green and blue frames. Casting overlapping donuts all over the image. Why red was not bothered I can't fathom. No sign of the reflections in that color. Apparently it passed rather than reflected all light from the orange star. I hope I only removed gradient and not real nebulosity nor left gradient that should have been removed. It got a bit dicey in the nebula telling one from the other. I don't know if the blue color in the core of the globules is real or gradient. If gradient it suddenly got stronger at the globules so think I'm correct though I don't find this color in the web images I found of it. Most were low resolution images capturing the near by "fly" as well. I couldn't find much of a distance estimate on this other than a rather general 10,000 light years. 14" LX200R @ f/10, L=4x10'+3x30'Ha, R=2x10x3+50%Ha, B&G=2x10x3+20%Ha, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
#4
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ASTRO: The Spider Sorry no Fly as yet
I hadn't thought about it. Guess a back lit CCD would give a mirror
image! Rick Richard Crisp wrote: that's pretty cool Rick It reminds me that I need to return to that area I shot it with the 18" back in 2006 when I got me another Dream Machine http://www.narrowbandimaging.com/ic4..._csha_page.htm http://www.narrowbandimaging.com/ima...a_12x20min.jpg I may have forgotten to fix the mirror image issue with the DM that I have... "Rick Johnson" wrote in message . com... IC 417 aka SH2-234 and LBN 804 is sometimes known as The Spider with nearby NGC 1931 being the Fly. The wavy "silk thread" on the left points to where the fly is located. This was taken last fall and lost on the hard drive along with a few other Sharpless objects. All have nasty gradients. In this case it was due to horrid reflections from the K star (actually 2 5th magnitude K stars about 20" apart). It totally ruined the green and blue frames. Casting overlapping donuts all over the image. Why red was not bothered I can't fathom. No sign of the reflections in that color. Apparently it passed rather than reflected all light from the orange star. I hope I only removed gradient and not real nebulosity nor left gradient that should have been removed. It got a bit dicey in the nebula telling one from the other. I don't know if the blue color in the core of the globules is real or gradient. If gradient it suddenly got stronger at the globules so think I'm correct though I don't find this color in the web images I found of it. Most were low resolution images capturing the near by "fly" as well. I couldn't find much of a distance estimate on this other than a rather general 10,000 light years. 14" LX200R @ f/10, L=4x10'+3x30'Ha, R=2x10x3+50%Ha, B&G=2x10x3+20%Ha, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
#5
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ASTRO: The Spider Sorry no Fly as yet
That's a good one. Makes me wonder why I haven't imaged this object myself.
Stefan "Rick Johnson" schrieb im Newsbeitrag . com... IC 417 aka SH2-234 and LBN 804 is sometimes known as The Spider with nearby NGC 1931 being the Fly. The wavy "silk thread" on the left points to where the fly is located. This was taken last fall and lost on the hard drive along with a few other Sharpless objects. All have nasty gradients. In this case it was due to horrid reflections from the K star (actually 2 5th magnitude K stars about 20" apart). It totally ruined the green and blue frames. Casting overlapping donuts all over the image. Why red was not bothered I can't fathom. No sign of the reflections in that color. Apparently it passed rather than reflected all light from the orange star. I hope I only removed gradient and not real nebulosity nor left gradient that should have been removed. It got a bit dicey in the nebula telling one from the other. I don't know if the blue color in the core of the globules is real or gradient. If gradient it suddenly got stronger at the globules so think I'm correct though I don't find this color in the web images I found of it. Most were low resolution images capturing the near by "fly" as well. I couldn't find much of a distance estimate on this other than a rather general 10,000 light years. 14" LX200R @ f/10, L=4x10'+3x30'Ha, R=2x10x3+50%Ha, B&G=2x10x3+20%Ha, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
#6
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ASTRO: The Spider Sorry no Fly as yet
no that's not it at all Rick
the issue is that there are quadrant amplifiers: four total on the chip there are several different ways to read it out: you can use any one of the four amplifiers to read the whole chip or you can use two and split it into half or you can use four amplifiers and get it done in quadrants splitting the chip in half means you can read it out twice as fast at the same pixel rate per amplifier: so you can get it 2x faster with the same noise ditto on using four amps: you can get it dumped in 1/4 of the time with the same pixel rate per amp/ a-d converter FLI only uses one of the four amplifiers. The chips come with a datasheet giving the noise specs for each amplifier and often times one or more amplifer is either non-functional or is noisy. So the physical position of the amplifier used in a DM may vary from camera to camera: any one of four orientations is possible as I understand it. because of the way the chips are clocked, you may end up getting the image mirror imaged, upside down or correctly oriented Maxim DL includes a "global reorientation" that will do the same thing to all images downloaded, such as flip vertical and rotate 180 degrees, so the orientation correction can be made transparent and that is great if you always use the same camera. For me I use different cameras and most don't give me the reversed image that but this particular DM does, so it is always a matter of remembering to flip; depending on the camera and settings in Maxim: there's just no escape for me :-) "Rick Johnson" wrote in message . com... I hadn't thought about it. Guess a back lit CCD would give a mirror image! Rick Richard Crisp wrote: that's pretty cool Rick It reminds me that I need to return to that area I shot it with the 18" back in 2006 when I got me another Dream Machine http://www.narrowbandimaging.com/ic4..._csha_page.htm http://www.narrowbandimaging.com/ima...a_12x20min.jpg I may have forgotten to fix the mirror image issue with the DM that I have... "Rick Johnson" wrote in message . com... IC 417 aka SH2-234 and LBN 804 is sometimes known as The Spider with nearby NGC 1931 being the Fly. The wavy "silk thread" on the left points to where the fly is located. This was taken last fall and lost on the hard drive along with a few other Sharpless objects. All have nasty gradients. In this case it was due to horrid reflections from the K star (actually 2 5th magnitude K stars about 20" apart). It totally ruined the green and blue frames. Casting overlapping donuts all over the image. Why red was not bothered I can't fathom. No sign of the reflections in that color. Apparently it passed rather than reflected all light from the orange star. I hope I only removed gradient and not real nebulosity nor left gradient that should have been removed. It got a bit dicey in the nebula telling one from the other. I don't know if the blue color in the core of the globules is real or gradient. If gradient it suddenly got stronger at the globules so think I'm correct though I don't find this color in the web images I found of it. Most were low resolution images capturing the near by "fly" as well. I couldn't find much of a distance estimate on this other than a rather general 10,000 light years. 14" LX200R @ f/10, L=4x10'+3x30'Ha, R=2x10x3+50%Ha, B&G=2x10x3+20%Ha, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
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