Astro 9 - Fall '07 Dark Sky Trip to Bonny Doon

Oct 13, 2007

Our class meet on the evening of Saturday, Oct 13 at the Santa Cruz Astronomy Club's twice monthly starparty at Bonny Doon Airfield. Skies were clear, but damp from yesterday's rain. Chris Angelos and I tried to find Comet F1 LONEOS but it was already too low by the time the sky was dark enough to see well. I brought along the 8" f/4 and ST2000XCM for optimal imaging, and also the LXD75 mount + oak board for helping students get some guided pictures.

Alerted by Sharahm, I did a doublecheck on Comet F1 LONEOS and found it would be 6 degrees up in the northwest when the sun was -12; perhaps barely above the redwoods in a barely dark enough sky to grab some sort of photo? So I quickly air popped some popcorn, grabbed my bottle of almonds, and headed up; if I hurried I could get set up by 7:30pm. Kevin arrived right after sunset, even before I did. Ridell and Sakaya arrived next. Chris Angelos and about a half dozen of the other SCAC members were already setting up when I arrived. Chris A. and I tried valiantly to find the comet, but it was just too low into the trees by the time it was dark enough to find in binoc's. We never did see it. My plan for digital photography was to take charge of that myself, and allow each of the students to help execute the photographs so that each student who participated could claim some joint ownership and have fun digitally polishing their prize one their own later. I was very concerned with efficiency because we did not have AC power and because I expected heavy dew. Our little 12v dew gun was going to zap our batteries quickly. If we could keep it up till midnight before flameout I'd declare victory and cut/and/run. Below, I'm posting my own versions of the 3 deep sky wonders photographed with the 8" f/4 + GM8 + ST2000xcm. I'm 'watermarking' each for now, to distinguish from later student-generated versions. I quickly got set up on the Lagoon Nebula, which was in the darkest part of the sky but would not remain up for long. Then, the North America Nebula's "mexico" area, and then Chris arrived and requested a nebula or galaxy subject; I settled on the Plieades.

We were humming along getting target after target, both on the LXD platform and with the ST2000xcm, and students with individual tripod opportunities. But dew indeed settled in on us, and at one point I plugged our dew gun through the fused connector powering the LXD 75 mount - and fried the fuse. I keep my fuses with the 10" LX200 case. Doh! No more guided wide-angle shots. Still, students followed suggestions in getting creative with foreground opportunities / background stars using tripod alone. By midnight, my computer battery and backup were all pooped out, and I was only able to finish the last 5 minute frame on the Plieades by AC inverter powering the computer - an extremely inefficient solution, and the gel battery quickly complained about low battery draw every time I had to use the dew gun on this same battery. Yet, in total, we prevailed - and the night was a big success.

As inspiration for the Astro 9er's to dig in and massage the raw photos to their own vision of perfection, I'm including my own efforts below. Each took about 10-15 minutes of work, and I think they are quite fine, thank you! Each uses CCDOPS5, dark subtracted but no flat field, sRGB+gamma single-shot color processed, then stacked in Registax 3, and fine tuned in Photoshop CS2 with help from Astronomy Tools Photoshop actions ver 1.4 (in quotes).

The Lagoon Nebula. 5x5min = 25 minute stack The nebula was low in the southwest, only 15 degrees up, and color separation due to refraction is evident on the brighter stars. Photoshop CS2: levels, saturation, smart sharpen (gaussian). AstroTools: 4x 'make stars smaller', 'deep space noise reduction', 'space noise reduction', re-leveled. Compare this fine photo with one I took using the 80mm f/6 Megrez refractor, under perfect high Sierra conditions. The bigger, faster Meade 8" f/4 here is the easy winner, plus more experience with Photoshop.

The North America Nebula, "Mexico" Region. 9x5min stack = 45 minutes. Photoshop CS2: levels, smart sharpen (gaussian), Astro Tools: 2x 'make stars smaller', 2x 'space noise reduction', levels, saturation.

The Plieades. 7x5min stack, composed by Chris, of the Plieades showing both the blue dust reflections and also the red H-alpha cloud near Merope. South is up and right. I made generous use of Photoshop CS2 (levels, saturation, unsharp mask + Astronomy Tools actions: 3x 'make stars smaller', 'space noise reduction', 'deep space noise reduction'

Eventually the student versions will be posted here, so check back towards the end of the semester.