SHO / RGB of North America / Pelican Nebulas

[metastable]

Captured last night with the “Goldman Array…”

(3) Nikon D800 full frame 36MP DSLR’s, (3) Star Adventurer 2i mounts, (3) Nikon 300mm f/4.5 lenses, (3) TC-301 2x Teleconverters for 600mm f/9, Astronomik 6nm Hydrogen, Sulphur & Oxygen Clip-In Filters, 10+ hrs of combined observation time in one night

[AstroBee]

Nice shot. Interesting setup you have there with three matching rigs. I would suggest for this target, leave the 2x teleconverter off with two benefits. Faster lens at 4.5 and wider fov to capture the entire NA and pelican nebulae. I see you have a couple of helpers there to make sure you are doing everything right.

[STEVE333]

Interesting approach to maximizing the amount of NB data you can collect. Instead of 3 nights with one mount and one filter each night you have chosen 1 night with three mounts each with a different filter. It must be hectic aligning all the mounts and collecting all the data simultaneously. Congratulations on getting it to work.

F/9 is difficult because of the much lower signal level. It can definitely make noise a problem.

However, you clearly captured both of the nebulae. Well done.

Steve

[metastable]

It went pretty well for the first try... I got RGB as well as narrowband Sulphur, Hydrogen and Oxygen data at 600mm f/9 with 3 cameras running concurrently in a single session. I was on site at about 7:45pm had all 3 narrowband cameras up and running by around 11:30p and let them run until 3am, so that’s over 9 hours of narrowband data in just those 3 hours. I set up one camera with no narrowband filter first to capture rgb, and once this was up and running I got the 2 other cameras capturing narrowband. Once those two were up and running I reconfigured the RGB camera for Hydrogen Alpha and as I mentioned from 11:30p til 3am all 3 cameras were capturing narrowband. I left the cameras running dark frames on the way home and continued to let the cameras capture more dark frames while I slept. The settings I chose were pretty extreme on the narrowband… 10 minutes per exposure at 6400iso for the hydrogen and oxygen filters and a full 20 minutes of open shutter per exposure on the sulphur filter. I used a bahtinov mask to focus every camera, and again after switching from RGB to Ha. The most troublesome thing that happened was I had very slow internet on my phone for plate solving to confirm aim. Also one of my USB batteries powering the mounts kept shutting off so I ended up running 2 mounts off a single USB battery pack (fortunately it had 2 output ports). Also next time I’ll remember to switch camera batteries when switching from RGB to Ha as the Ha session ended a little early from the camera battery running out of juice at some point.

I ended up with about 48x 60s RGB shots (2880s) @ 3200iso 600mm f/9, 19x 600s Ha shots (11400s) @ 6400iso, 28x 600s OIII shots (16800s) @ 6400iso and I think around 10x 1200s SII shots (12000s) @ 6400iso or about 12 hours of data total. I was physically there for about 7 hours and did about 4 hours of work in one chunk at the beginning of the session. I subsequently removed the stars from each of the SII, Ha, OIII images after blending with the RGB...



RGB:

Ha:

0III:

SII:

SHO-RGB Composite:

[STEVE333]

One suggestion - You might try reducing the star sizes on the SII image before combining with the Ha and OIII. It will reduce the halos on your final stars.

Cheers

[metastable]

I actually removed the stars with the dust and scratches photoshop filter on all the narrowband images so I think the blue halos are because the nikon 300mm f/4.5 lenses aren't apochromatic refractors. Probably the green band is most in focus and the red and blue bands are slightly out of focus...

[messier 111]

very nice shots , love the set up .thx .