Saturday, August 25, 2012

wide field sky from the city (Toronto)

8:19 PM, 24 Aug 2012. I uncovered the 'scope. Moved the battery outside, the GFCI power bar, the eyepieces.

Checked the weather from EC. Toronto. Current Conditions. Mainly Sunny. 24°C. Observed at Toronto Pearson Int'l Airport on 8:00 PM EDT Friday 24 August 2012. Condition: Mainly Sunny. Pressure: 102.0 kPa. Tendency: rising. Visibility: 24 km. Temperature: 24.1°C. Dewpoint: 16.3°C. Humidity: 62 %. Wind: SE 13 km/h. Humidex: 29. The forecast section: Tonight, Clear, 18°C; Sat, Sunny, 31°C; Sun, Sunny, 29°C; Mon, Chance of showers, 29°C. Issued : 3:30 PM EDT Friday 24 August 2012. Once again, a smog advisory in effect. Tonight, Clear. Low 18. Saturday, Sunny. High 31. UV index 7 or high. Saturday night, Clear. Low 18. Sunday, Sunny. High 29.

Lots of dark blue on the CSC again.

8:30 PM. I connected the Canon camera to AC power, inserted the adapter directly in the camera body. As I did this, I realised it created a problem, in terms of power. Without a battery on board, the camera would not function if not plugged in. Was that a risk? One wouldn't want to lose power during a long imaging run... Trip over a cord halfway through an exposure? Using the Battery Grip with one battery and then the AC adapter would offer the best of both worlds. That said, it would make the camera heavier.

Despite the weather reports and predictions, I noted that the skies were cloudy. Thin but clumpy high cloud! Boo! I checked the ADDS satellite site. I saw lots of stuff moving down from the north... The CAO looked bad. I decided to wait it out. Let's see what will happen...

I fired up mosquito coil. But this time I put it on a glass base. Melted and burned the plastic lid last night.

8:36. I moved the netbook computer back into the office... I'd check the skies in 30 minutes or so.

9-ish. The skies were improving. I fetched the Allen key set from the garage and prepared to collimate the Celestron 8-inch Schmidt-Cassegrain.

9:37. Finished collimating. Holy cow. The process is way easier with a camera! Especially a camera with live view! I don't think I'll ever go back!

OK. Next up was to do some wide-field sky imaging. I looked overhead... And saw... Could it be? I phoned the Horvatins. Told them to get outside. I thought I was seeing aurora. Grabbed the big Manfrotto tripod and started shooting photos!

10:00. Phoned the Horvatins back. They disagreed. Probably just high cloud. They had also phoned the CAO. But they were clouded out.

Certainly interesting cloud. Barely moving. Thin band. Wispy.

Reconfigured for long exposures using the computer to control the DSLR. In a piggy-back configuration, I mounted the Canon 40D to the SCT with the RASC camera-eyepiece adapter, strapped to the 26mm 1¼" ocular. Connected the USB cable between the camera and the netbook. Fired up EOS Utility.

Spent a lot of time trying to focus. Had hoped to see some stars on the live view capture on the computer. Double-checked the custom function menu settings in the camera, increased the brightness of the computer LCD, nothing... Considered the Moon but it was still blocked. Ending up just taking test shots and manually focused. Also abandoned the use of the lens in AF and nudging the focus with the software. Was pretty happy with the focus. Although I was worried about time consumed and repeatability. Finally had it ready to go...

Viewed the test shots. Still some wisps of cloud... Head of Draco near the top-left; butt of the Swan at the bottom-centre. 30 seconds, aperture 4.0, ISO 800, focal length 21mm, tungsten white balance.

Decided to try setting the white balance from a pre-set to custom. Found it easy to do so in the software. I eye-dropped the sky. 30 secs, f/4.0, ISO 400, 21mm, custom white balance.

I dropped down one f-stop to reduce lens problems and then tried to increase exposure time. Learned that I needed to have the camera in bulb mode to then let the timer component of EOS Utility to long exposures. Too dark. 45 secs, f/5.0, ISO 200, 21mm, custom WB.

Tracking was holding up OK. Still too dark. 60 secs, f/5.0, ISO 200, 21mm, custom WB.

Increased sensitivity. Of course, all the hot pixels were showing now. 50 secs, f/5.0, ISO 400, 21mm, custom WB.

Gathered more light. A flight path started to emerge in many of the photos. 90 secs, f/5.0, ISO 200, 21mm, custom WB.

11:29. Finished piggyback photos, shooting 5 darks. I couldn't tell how well things were going while still trying to preserve my dark adaptation, red film on the small netbook screen. I was looked forward with interest to see what I got, in full colour.

I was pretty happy how things had gone. Very easy to operate the camera with the software, despite cables, the netbook screen size, the difficulty focusing. I was also very happy about the telescope and mount operation during the shoot. Tracking worked really well. And I seemed to have a damn fine polar alignment.

The night was still young. I decided to resume visual observing.

12:11 AM, 25 Aug 2012. Returned to HR 7843 aka Kui 97. Used all the eyepieces. 36mm, 26, 18, 9. No joy even with the better collimation. I saw concentric diffraction rings. But no star. Damn. Now I was feeling a little discouraged...

12:33 AM. Viewed the Ring Nebula at low power. Pretty well start overhead. Hrrph. Needed to step away.

12:53. Returned to the deck. Back from a break.

1:07. Found σ (sigma) Cassiopeiae quickly. I had selected this object from the Cambridge Double Star Atlas, from the "top" list near the beginning of the book. Still having the netbook outside, beside the telescope, I pulled up my double star life list. σ Cas was on it but as an item to review or revisit. OK! At 55x, it was not round; at 77x, I split the tight AB pair. The primary was blue-white while the companion was light orange. I also noted that the C star was visible. It lay at 90 degrees to the AB pair, quite far from primary. I thought it 1 or 2 mags dimmer than B.

1:12. Spotted star GSC 04005-0926. ST3P says it is mag 13.73 (but poor quality).

1:29. Viewed ψ (psi) Cas. Also a repeat. SkyTools made it clear that I was seeing the AC pair. The B component was not an option. Not here. Not tonight. Not with this aperture. Not visually. B is mag 14.5.

OK, I was done. Done battling. Did a rapid shutdown.

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