Wesley's Tool-Box

When I last looked at the comet C/2014 Q2 Lovejoy about three weeks ago, it was near its peak apparent brightness due to its proximity - it passed the closest to Earth just 3 days ago and shined at a magnitude of 4. The comet had now moved away, making its closest approach to the Sun two days before this observation. It was still relatively easy to capture it on the camera, as it's only dimmed back to magnitude 5.

The comet had moved to the constellation Andromeda. 59 Andromeda was below the comet, just outside the enlarged photo. The bright star directly above the comet in the enlarged photo is a magnitude 6.6 star called HR677 or HD 14272.

Some issues now complicate its observation other than the slow dimming. From where I observe, the western and northern sky is lit up with light pollution from the center of the city. And these days, constellation Andromeda is in the western sky, already starting to head toward the horizon after sunset. So I have to observe it in the early night, just when the area of the sky is not too brightened one way or another, at around 9 to 10 PM. The dimmest stars in this photo is around magnitude 12, so I think it was a success.

Device: Canon EOS 450D + Tamron 18-270mm Di II VC PZD
Settings: 432mm - ISO 400 - 30s - f/6.3
Filters: None
Time: 2015-02-01 22:29-22:39 KST
Location: Naju, Korea
8 photos stacked with RegiStax 6.1.0.8

I wanted to revisit my thought that the DSLR (Canon EOS 450D) would take better deep-sky photos than a P&S (Canon PowerShot SX50 HS). The latter has a much more powerful zoom lens, so maybe it could help overcome the limitations of the small sensor. 450D's APS-C sensor has 13.3 times the area of the 1/2.3" sensor used in the SX50 HS.

After some trial & error, I found that my iOptron SkyTracker, once properly calibrated, could be usable even at a focal length of 1200mm (35mm equivalent) if the exposure time is 30 seconds or less. So I decided to take photos of the beautiful Orion Nebula at the maximum zoom of both cameras.

The 450D was able to take a low-noise photo of the nebula with nice-looking colours. But the limit of the zoom was apparent. Also, under the below-freezing temperatures (it was around -2C) the infinity focus of the lens shifted further out after about an hour.


With the SX50 HS, the resulting photos were expectedly more grainy in general at full resolution. I felt that the ISO 100 setting on SX50 HS would still yield a grainier photo than 450D's ISO 400 setting. But the super-zoom lens and stacking were able to make up for this. After taking the photos at the maximum zoom and reducing the size, the photos still had more details than that of the 450D.

Judge for yourself with the two photos above. I should note that even when stacked, 450D couldn't get much more details out.

I guess the SX50 HS is still quite alright after all. Oh, and the focus was more or less stable during the similar long session under below-freezing temperatures. I think 450D needs a better zoom lens... or a real telescope to make it fulfill its potential.

[#1]
Device: Canon EOS 450D + Tamron 18-270mm Di II VC PZD
Settings: 432mm - ISO 200 - 120s - f/6.3
Filters: None
Time: 2015-02-01 21:46 KST
Location: Naju, Korea

[#2]
Device: Canon SX50 HS
Settings: 1200mm - ISO 400 - 30s - f/6.5
Filters: None
Time: 2015-01-31 23:12 KST (23:12-23:49)
Location: Naju, Korea
10 photos stacked with RegiStax 6.1.0.8

Since my last observation of the Comet C/2014 Q2 Lovejoy, I waited for the sky to clear up again so that I can try shooting with a star tracker (iOptron SkyTracker) installed. The opportunity came on the night of January 8. Annoyingly, all the attempts to take long exposure photos failed. I first thought the tracker may be faulty, but later I realized that the image stabilization on the camera lens was negating the tracker's movement.

I vowed to not make the same mistake again, and two days later, I went out to take photos of the comet once more. The southern sky was dark enough to let me barely see the comet with my naked eyes, so my hopes were up. And indeed, I finally got the results I wanted - much improved photos of the comet using the 30-second exposure (longest possible on Canon 450D other than bulb mode) setting. The green glow was now evident, and the center of the comet was shining brightly.

For the reference, the comet had moved to near the constellation of Taurus - the large version of the photo shows the magnitude 5 star 40 Tauri on the far upper left. Also, under the camera settings I used, the darkest stars were around magnitude 12, which is the most sensitive I've gotten out of my astrophotography attempts so far.


After taking the photos of the comet, I felt that it would be nice to point the camera at another object since the tracking setup was already in place. As the sky at my location was especially dark in the east and the south, I decided to take a look at the Orion Nebula inside the Orion constellation, which was in the east, going south.

Alas, due to being out for more than an hour in the below-freezing coldness, the infinity focus of the lens wasn't working quite right anymore and the fog on the lens was getting bad. So I took some measures to mitigate these issues somewhat and was able to salvage several shots before heading home. Luckily, those shots came out looking fine.

Device: Canon EOS 450D + Tamron 18-270mm Di II VC PZD
Settings: 432mm - ISO 800 - 30s - f/6.3
Filters: None
Location: Naju, Korea

[Comet]
Time: 2015-01-10 21:39 KST (21:25-21:52)
12 photos stacked with RegiStax 6.1.0.8

[Nebula]
Time: 2015-01-10 22:26 KST (22:07-22:31)
7 photos stacked with RegiStax 6.1.0.8

With my company's relocation, I've moved from Suwon to Naju. This city is about 300km south of Seoul, and has less than 100 thousand inhabitants. So the night sky is somewhat more favourable to stargazing. It isn't a dramatic improvement, but I'm happy to be able to continue doing astrophotography. To celebrate the arrival, I did a 10-minute exposure just outside the apartment window. The star trails came out nicely.


The following night, I tried taking a photo of the Andromeda Galaxy. It was to be expected, but the background had less light, in spite of the Moon shining brightly nearby. The resulting photo came out looking better than anything I've tried in Suwon. I have some high hopes for taking some good photos during the new Moon phase. But for now, I'm hoping to get some good view of the lunar eclipse happening in two days.

Device: Canon SX50 HS
Settings #1: 24mm (17% size) - ISO 80 - 600s - f/3.4
Settings #2: 263mm (26% size) - ISO 160 - 300s - f/5.6
Filters: None
Time #1: 2014-10-05 01:25 KST
Time #2: 2014-10-05 23:35 KST
Location: Naju, Korea

On the second attempt to photograph Bode's Galaxy (M81) and Cigar Galaxy (M82), I managed to put the lens hood on. The sky itself wasn't really darker - in fact, quarter moon was up in the sky - but this seem to have reduced the background red glare from the street lights. I should have thought of this sooner.

Anyways, the images now have blacker background, making the galaxies look more clear and natural. Taking multiple shots and stacking them improved the looks even further. Click on the image to see the version in original resolution.

Device: Canon SX50 HS
Settings: 484mm (70% size) - ISO 100 - 300s - f/5.6
Filters: None
Time: 2014-05-06 23:29 to 2014-05-07 00:15 KST
Location: Suwon, Korea
8 photos stacked with RegiStax 6.1.0.8