Astro Session - October 17, 2017

Color version of M81 (Bode's Galaxy) in the constellation Ursa Major (Big Dipper). From another set of subs I shot at 4am--this time with the color QHY CMOS camera, QHY5III178. Info: 21 x 300 sec. with 20 dark frames, QHY5III178 color CMOS, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control. 

Posted October 17, 2017

Astro Session - October 13, 2017

IC 405--"Flaming Star Nebula" in the constellation Auriga, centered on the mag. +6 star AE Aurigae. It's relatively close to us, at about 1,500 light-years. This set of subframes covers the center of the fairly large nebula, which measures 37 x 19 arcminutes. (6 x 1200 second subs in Ha, O3, S2, taken with my current main setup: Atik414Ex mono CCD, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control). 

Posted October 13, 2017

Astro Session - October 12, 2017

NGC 281 (IC 11, Sh2-184) "Pacman Nebula" in the constellation Cassiopeia. More narrowband imaging, although the moon is waning, and didn't even make into the sky until the early morning hours. I completed the subs for NGC 281 by 1am, and scheduled some narrowband exposures of IC 405, Flaming Star Nebula. (subframe info: 6 x 1200 second exposures in Ha, 5 x 1200 sec OIII & SII with 16 dark frames, Atik414Ex mono CCD, Astronomik 6nm Ha, OIII, SII, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control).

Posted October 12, 2017

Astro Session - October 12, 2017

M81 (Bode's Galaxy) and M82 (Cigar Galaxy) in the constellation Ursa Major (Big Dipper). I was up at 4am, and there's the big dipper swinging around and climbing into the sky. Bode's and the cigar galaxy were just waiting to be captured. Info: 15 x 120 sec. with 10 dark frames, Atik414Ex mono CCD, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control.

Posted October 12, 2017

Astro Session - October 5, 2017

NGC 6888 - Crescent Nebula in Ha (4 x 1200 second subs + 15 dark frames stacked in DSS). I continued my hydrogen alpha campaign tonight, with a couple more targets, including the Crescent. My goal over the next month or two is to continue capturing these nebulae in O3 and S2, and use those results with these Ha shots to produce color images. I may also test out some Ha+RGB image processing on a couple of the brighter ones like IC 1369a, the Elephant Trunk Nebula. 

Posted October 5, 2017

Astro Session - October 5, 2017

I finally made some time to process one of the image sets I shot on October 2, and here's one result: narrowband of the central region of the emission nebula IC 1805, the Heart Nebula, which is only 7500 lightyears away in the constellation Cassiopeia. (It's almost in our backyard!) I used the "Hubble Palette", mapping the separate hydrogen alpha, oxygen, and sulfur image channels to RGB channels (SII = Red, Ha = Green, OIII = Blue) in the final. (subframe info: 4 x 1200 second Ha, 4 x 600 sec OIII & SII with 2x2 binning, Atik414Ex mono CCD, William Optics GT-81). I'm not entirely happy with this one, but good enough to post. 

Posted October 5, 2017

Astro Session - October 4, 2017

Astrophotography with a full moon! I switched to narrowband imaging a few days ago, which has the advantage of limiting the light to a very narrow range, and not really being affected by the light of the sun reflected off the big smiling face of our moon. The requirements are far stricter than color or LRGB imaging in terms of exposure times (10 - 30 minute exposures are typical), which in turn require far tighter alignment for the mount and guiding system. I have three narrowband filters--Ha (hydrogen alpha) OIII (oxygen) and SII (sulfur), all with 6nm bandpass. For these images below I'm only imaging with the Ha filter and the Atik 414EX monochrome CCD camera. Image info: top-left: IC 1848 Soul Nebula (the center portion), bottom-left: IC 1369a Elephant Trunk Nebula, right: NGC 281 Pacman Nebula. 4 x 20 minute (1200 second) subs stacked in DSS.

 

Posted October 4, 2017

Astro Session - October 2, 2017

I love this early autumn weather! Here's a 20 minute hydrogen alpha exposure/sub of IC 1805, the Heart Nebula, a diffuse nebula in Cassiopeia. FoV: 1.05 × 0.79° (William Optics GT-81, Atik 414Ex CCD, ZWO ASI120MM guide camera with WO 50mm guide scope, Astronomik Ha 6nm filter).

I will post my actual setup for this one soon--mainly because I want to lock down my portable gear for reference when setting up in the field. What amazed me tonight was the ability to get pretty clean 20-minute subframes with the new iOptron CEM25P mount, leveled, pointed toward the NCP, and a quick polar align. And all of this on the back deck, which isn't the most stable platform around. (There is some star elongation at the top right and bottom left corners, which I'm attributing to the image train and focuser sag. It's slight, but it's there. My next large-ish purchase for the GT-81 is a Moonlite focuser, which will significantly improve the rigidity of the system). 

I have to say I am really impressed by the CEM25P mount (the latest iteration of the ZEQ25 from iOptron), and I was expecting quite a bit of precision given that the company pretty much guarantees a low periodic error (< ± 10 arc seconds). But to have this come through without even trying...well, that makes me happy.

 

Posted October 2, 2017