Wesley's Tool-Box

I haven't taken a look at nebulas and galaxies in several years - the last time I did so was back in November 2015. With the clear evening skies persisting for a few days, I thought that it was a good time to make a return observation. The easiest, and thus the first target was the bright Orion Nebula. I first made several attempts with my iPhone X, but it did not yield the level of quality I wanted and switched to Sony A5000 for the result above. As it was April, the nebula was heading towards the horizon in the southwestern sky and thus subject to less than dark background and drowning out darker portions.


Moving to the northern sky, I took a look at something I haven't checked out since moving to Naju - the Bode's Galaxy and the Cigar Galaxy. I last saw them in May 2014 in Suwon. Due to the worsening light pollution I can't say I had better observation conditions, but I did have better equipment now. And the results speak of this advantage, as the galaxies were captured in finer detail. I especially like how the variation of brightness appears in the Cigar Galaxy below.



Telescope: Celestron NexStar 6SE + f/6.3 focal reducer
Device: Sony A5000 (prime focus)
Settings: (945mm) - ISO 1000(#1) / 2500(#2) / 3200(#3) - 30s - (f/6.3)
Filters: None
Time: 2018-04-09 20:23-20:38(#1) / 22:27-22:40(#2) / 22:49-23:10(#3) KST
Location: Naju, Korea
5(#1) / 10(#2) / 13(#3) photos stacked with Deep Sky Stacker 3.3.4

Earlier this year, I took photographs of the Orion Nebula, a.k.a. Messier 42, with the Canon SX50 HS camera or with Tamron 18-270mm lens attached to the Canon 450D. This was before I got my Celestron telescope, so I had high hopes of getting even better photos once the telescope was in my hands. Alas, the Orion constellation was already hiding below the horizon before midnight at this point, so I was focused in planetary targets most of the time.


As winter times creeped up again, the constellation was again viewable in the late night to early morning. That is, if the clouds, rain, or fog weren't obscuring it. This happened in the early hours of November 12, so I brought my telescope outside for a couple of hours of astrophotography. While I snapped several targets, the Orion Nebula looked the most promising.


As the conditions were good, I took the photos mostly without any filters. Then I took a few with the Baader Moon & Skyglow filter on to see what difference it might make. Once I started post-processing, I could see that the one with the filter might have a slight advantage in bringing out the faint details, but nothing dramatic. With the individual frames ready, I used the Deep Sky Stacker for the first time for automatic selection and stacking.

After about an hour of processing, the software selected five frames from non-filtered ones and one from the filtered ones to deliver this beautiful result. If you click on the photo for a wider, larger view, you can spot a part of the reflection nebula NGC1977 at the top left as well. In the future I may try to get this properly into the frame.

Telescope: Celestron NexStar 6SE + f/6.3 focal reducer
Device: Sony A5000 (prime focus)
Settings: (945mm) - ISO 1250 - 30s - (f/6.3)
Filters: None (5 photos) + Baader M&S (1 photo)
Time: 2015-11-12 00:51-01:14 KST
Location: Naju, Korea
6 photos stacked with Deep Sky Stacker 3.3.4

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