Monthly Archives: September 2015

Lunar Eclipse – 2015-09-27

The weather reports of the preceding days and even the day of the eclipse predicted clear skies. So i planned a photography project to create a time lapse sequence covering the entire event from penumbra advance, through total eclipse and then the receding shadow.

As it turns out, the clouds moved in about the time the eclipse started. By the time the umbra shadow started, there was a significant risk of total overcast. The clouds did manage to behave themselves for most of the waxing eclipse, but just before full eclipse the cloud cover was 100%.

I was using the Canon XS (filter removed) with the AstroTech 106 (AT106) mounted on the Skywatcher EQ5-Pro. The plan was to take images every 20sec for the duration of the event. To reduce disk space i choose the “S” setting of 1936×1288 pixels as having adequate resolution for a movie. Not having done this before, i was not prepared for the changes required in exposure settings. I started with ISO 400 and 1/2000s exposures (the scope is f/6.5). I had expected to adjust the EV (exposure value) as time went on to account for the diminished light of the eclipsing moon, but was not prepared the problems caused by the clouds.

The intermittent cloud cover exacerbated the changes to EV making it somewhat unexpected if not random. This and required dramatic changes to the TV time during periods of partial cover resulted in widely varied exposure values. I ended up with frames that were too dark as well as too bright. And whole sequences that differed substantially from the previous frames.

Because of the location require to get a clear view of the entire eclipse, it was not possible to pre-align the scope. So i also had to contend with Polar Alignment  drift between frames. This required minute by minute adjustments to the framing to keep the moon more or less in the centre of the frame. I was hoping for some auto-alignment tools to refine this during post-processing (more later).

The cloud cover was 100% a few minutes before full eclipse. I decided to abandon the time lapse project in favour of getting a high resolution RAW file of the mostly eclipsed moon. I managed only one full resolution image before the clouds covered up everything, I also choose ISO 1600, which is quite noisy on the XS with only 1/10s exposure. Lower ISO and longer exposure would have provided a cleaner image.

Lunar Eclipse 2015-09-27

Lunar Eclipse 2015-09-27

I did mange to grab 360 frames at the lower resolution to create a time lapse sequence of the event. I could not find a tool to accurately align the  images, so i manually aligned them with the Canon DPP tool. This allows alignment to the pixel level, which is adequate, but still not quite good enough. I also had to manually adjust the EV levels for groups of images as well as individual images. The resulting movie is at best interesting but not quite the epic i had planned.

The video covers the time period from 8:04pm to 10:06pm EDT. The penumbra shadow started at 8:12 with the umbra starting at 9:07. Full eclipse started at 10:11. It takes quite awhile before the penumbra is evident.

The video compresses the 122 min lapsed time into 36 seconds. So each second of video is about 3 1/2 min of real time.

Hornets -2015-09-08

I opened up the observatory this evening for a quick test of some upgraded software and a mini-guider using a finder scope. I did a quick scan of the roof before opening it to check for bugs – wasp and hornets in particular. I didn’t find anything untoward so i opened up the roof and went to work.

As there were a few misquotes and black flies, even this late in the summer, i started the Thermocell. Good thing as it it turned out.

About a half an hour into the project a large bug crawled across the laptop screen. I thought it was a medium sized spider – which i am needless to say, not too fond of. I switched on the white light light to get a better look and found not a spider, but a large hornet! Looking up, i then saw the hornets nest on the side of the dome wall and about 18″ from my nose!

I made a hasty retreat to a comfortable distance and perused the situation. The nest was small but active. It was only about 3″ by 6″ but there were a dozen or more hornets crawling around it and many more near by. They were however rather docile for hornets which i attribute to the Thermocell.

I gingerly shutdown the laptop and closed the cover of the cupboard it’s housed in. I shutdown the mount without bothering to return it to home or even hibernate. Then i went to the garage and fetched a hornet blaster. I soaked the nest and targeted several stray hornets. In the morning there were still many live hornets to be dealt with.

More frightening than realizing the nest was basically in my face, was the thought that i nearly put hand in the nest. The observatory is a skyshed pod. The half roof opens and then the open half dome is rotated around to face the sky being observed. To move the dome i just push on one of the supports which was only inches from the nest. Had the nest been located nearer to the support, i would have put my hand directly onto the nest. Yikes!

Hornets are gone and i think i will check the observatory in daylight more frequently.