Finally got some clear skies to do some shooting, drove an hour to a reservoir outside Salt Lake City to get out of the horrible air pollution and fog that's been developing at night. It was COLD, when I finally threw in the towel it was -9 degrees Fahrenheit and pretty much everything was frozen solid, definitely the coldest I've ever shot in. I wanted to test out my Tamron 150-600mm lens with my now full-spectrum modified Nikon D7000 with some guiding on my Star Adventurer tracking mount. I was going to do a mosaic of the Flame and Horsehead Nebula over to the Running Man and Orion Nebula, did 2 hours of the Flame and Horsehead and then moved the lens fov over to the Orion/Running Man and started having tons of problems with the guiding. By that time Orion was up near the meridian and that was causing havoc with the large lens on the modest Star Adventurer. I ended up flipping over to Andromeda and getting some shots of that, I'll try to post that later. Acquisition Details: Nikon D7000 (full spectrum with a UV/IR Cut filter added) + Tamron 150-600mm lens at 300mm Sky Watcher Star Adventurer tracking mount guided by Orion 50mm mini guide scope and ToupTek Guidecam via PHD2 30 x 4 minute exposures at f6.3 and ISO 1600 120 Bias frames and 40 Flat frames applied Calibrated, Debayered, Registered and Stacked in PixInsight Geometry crop followed by LinearFit to red channel, Dynamic Background Extraction, SCNR on green channel, screen transfer function to take out of linear state, and contrast/saturation curves. Exported as 16-bit Tiff to Photoshop. In Photoshop I did a bit more curves enhancement and a minor star size reduction and sharpening. Kind of disappointed in this lens, the flair on the brighter stars with the coma at f6.3 has me shaking my head, I hadn't noticed that problem before and it's a bit...ugly. Considering selling this lens and just picking up a high quality 80mm refractor with better optics.
Here's the second image I put together from last night, this one of Andromeda, same setup as before with my Nikon D7000 and Tamron 150-600mm lens at 300mm. This time I did 17 exposures at 4 minutes, ISO 1600, and f6.3. Pretty much the same stacking and editing process as the Horsehead and Flame Nebula shot with calibration and stacking in PixInsight, Dynamic Background Extraction (x2 for this shot since I was shooting into the light pollution of the SLC metro area and had some tough gradients), color calibration, masked stretch, then export to Photoshop for curves and saturation plus star size reduction. I missed the focus by just a little bit so the image is soft, plus there are the same stupid flares around the bright stars because of this lens.
Tonight's image is the Witchhead Nebula. Details: Astrotech AT65EDQ Nikon D7000 Sirius EQ-G guided with Orion 50mm mini guide scope and ToupTek Guide Cam 6 x 10 minute exposures at ISO 400 80 x bias frames 30 x flat frames Calibrated, corrected, debayered, stacked in PixInsight. Edits in PI are Dynamic Background Extraction, SCNR to remove green, masked stretch, curves adjustment to boost shadows. Exported to Photoshop, edits in Photoshop were Dust and Scatches with screen layer to increase brightness, followed by overlay layer with high pass filter to increase contrast, then some curves modification for slight contrast adjustments. Followed that with color blotch reduction, smart sharpen, and slight star size reduction. Final edits done in Lightroom (mostly noise reduction and some saturation). I need to restack this with different stacking perameters, my pixel rejection wasn't strong enough I guess and there are some geosynch satellite trails passing right through the top of the nebula. Only had 2 hours to shoot and ended up tossing away half my frames for one reason or another, forgot to take the bahtinov mask off, forgot to set the NikonHacker black point hack for 3 of the exposures, battery ran out half way through one exposure, focus was off for one exposure. More learning experiences with this scope and mount, I guess. Oh and it was even colder tonight at Rockport, around 5 degrees when I left, I'm really getting tired of shooting in such cold temps, looking forward to spring.
