Sunday, May 23, 2010

The Crescent Nebula in Cygnus


This the second object I planned to capture last Saturday. The H-alpha subs were taken at home and waiting for the color exposures. Finally, I was able to take a total of 2-hour color exposures from Buso. I did not use my focal reducer/field flattener as I thought that the resulting image would be small. However, I had to crop half of the image size to remove the elongated stars. I still want to gain experience in combining H-alpha with color and this was a good exercise for me.

Blue Horsehead in Scorpious



I was not able to process the shots from last Saturday in Buso-buso as we went on a family vacation in Hong Kong. As soon as we arrived, I started to process the first object which was a very faint reflection nebula in Scorpious. I have been waiting for a trip to a dark site for this as the Scorpion was not visible from our house. The sky at Buso was remarkable last Saturday. The Summer Milky Way was beaming and I could feel the perspective of being in its outer spiral arms. The temptation of shooting many objects that night was simply overpowering. But I had to stick to my two planned objects. I did not use my telescope for this object as it was large. The 70-300mm lens was used on the 350D for capturing IC4592, the so-called Blue Horsehead. There's not much images of it on the web and most if not all were taken using very high end equipments. I was wondering how it would look like using just a camera zoom lens and DSLR. At first I felt I was just wasting my time as the subs did not register even the slightest hint of nebulosity. I merely used the guidepost stars to approximate the nebula's location for framing. Worse, I made a mistake in getting the flat-light frames. Just what I had expected the stacked image didn't turn out well. The image was very faint, the background gradient was uneven, and noise was unbearable. Initially, I wanted to give up on it but I tried to convince myself that I could learn more by challenging my skills on Photoshop. I made aggressive stretching to bring out the colors in addition to heavy background gradient control. This is a 3-hour long total exposure at F6.3, ISO 800. I planned to re-visit this object using my Megrez 90 and do some mosaic.

Thursday, May 13, 2010

Cygnus Dreamin' Part 2


Hey, its been clear night skies since the start of the week and I just felt guilty of wasting three nights in a row doing nothing for the advancement of amateur astronomy in the Philippines-meaning, I was too lazy to set-up my gears. Scorpious was awesome at midnight and the Summer Milky Way was simply fantastic! So, to redeem myself of my inactivity, I set up my astro gears last night, tested the alignment and covered everything with a big plastic sheet for an astrophotography session the following dawn. I intended to shoot some nebulosity in Cygnus as this was visible from our roofdeck. Actually, I have always wanted to shoot objects in Scorpious but the Great Wall of our house blocks the beautiful southern skies. Anyway, I went to sleep and set my mobile phone to alarm at 2 am - just in time for Cygnus to be well placed in the northeastern sky. I had difficulty rising up when my phone sounded its wake-up alarm. I just had a couple of hours sleep and the warm bed beckoned me to sleep a little more. Heroic minute-for the love of astronomy immediately flashed in my head and I found myself booting-up my laptop for imaging session. The sky was relatively clear and I had no trouble finding the guidepost stars in Cygnus. I looked up the position of the Crescent Nebula from The Sky software and manually star-hopped until I found it. I thought that it would be better if I removed the Focal Reducer to gain some better image scale but that proved to be costly mistake. I had to focus again and it took me almost an hour to nail the focus and re-acquire the image. Time flew fast and it was already 3:15 am when the first sub was taken. I set 30 subs at 3 minutes each on the GuideMaster software and let it do the acquisition and guiding. I went down and took a catnap until my wife woke me up to tell that its already bright outside. I hurriedly went outside and was amazed that the sky was really bright even it was still 5 am. I had to thrash several subs due to skyglow and left me with only 20 useable subs. I dismantled my gears and started to do the processing while having breakfast. Here is the result of the beautiful Crescent Nebula in the star-filled region of the Milky Way. This is a work in progress and I hope I can add some color data later on when we go to Buso, Antipolo this weekend.