Friday, February 3, 2012

Lil baby steps.....afocal astrophotography with the Orion Steadpix Digital SLR mount




Wow talk about coming a long way. I have always been a visual astronomer, and to this day still yearn for my dark sky jaunts when I can hunt down some faint elusive galaxy (or galaxy clusters) with my light bucket, my GS 10" f/5 dob for sketching. But lately I have been getting the itch to dip my toes, or so to speak in some light and easy going astrophotography (if there is such a thing!). The word astrophotography usually conjures up images of super expensive, highly precise mounts and equally expensive CCD cameras and APO scopes. Then there is the steep learning curve associated with it. Well there is also the other side of the coin, afocal and webcam astrophotography of solar system (i.e. bright) objects. While that is cool, some rudimentary deep sky astrophotography is also doable. One might still need a tracking mount and some sort of device to hold the camera in place. This would not have been at all possible in the past with film cameras as one would have to expose the film for long periods of time to get a decent photo. This is where the super expensive and super precise mounts come in. With the advent of digital cameras, one can now mimic long exposures by taking short term exposures and then digitally "stacking" these images together to produce a chimeric long exposure. There are also many software packages that enables one to modify and enhance their images, the best being Adobe's Photoshop. So yes we have come a long way from the so called "dark ages" of astrophotography.


In order to do some basic astrophotography, one would need a digital camera that has a manual setting (to focus starlight at infinity). One also needs some sort of self built in timer to minimize camera shake. Any extra functions such as the ability to control the ISO settings and the exposure time (most digital's have this functionality anyway) will greatly improve your chances of getting workable images.

My initial forays into afocal imaging was met with frustration and grief. This was partly due to me using a non too suitable digital camera. I originally started imaging using my old 5 megapixel Kodak P850 (regular CCD chip). This camera has served me well over the years and I have taken some really spiffy wide angle shots of constellations, comets (McNaught and Holmes) and also some lunar eclipses by holding the camera up to the eyepiece. Seeing how I now had something that could hold the camera to the eyepiece, I though things would be easier. Wrong. Getting the camera lens to align with the eyepiece FOV was quite painful (becomes easier with practice). Also the chip on this camera was not very sensitive to low light conditions. So after playing around with the setup for a couple of weeks, I gave up as the results I got, even with bright objects like the Pleiades cluster and M42, the great nebula in Orion was dismal.



Enter my new camera, the Kodak z990. I bought this camera due to the fact that it was the first Kodak camera to have backlit CMOS sensor as opposed to a regular CCD sensor. This translates to excellent low light shooting capabilities. I have tested this time and time again and the results are nothing short of astonishing. I can hold the camera by hand and shoot constellations from a suburban setting and still get some pretty spiffy shots. With this camera I seldom have the need to resort to flash photography! Needless to say I was itching to try afocal photography again on those mentioned objects. Boy was I not disappointed. I played around with getting the magnification and exposure right to minimize star trailing. With the Orion Skyscanner with the 20mm in at 20x, I found I could push the exposure time up to about 8-10 seconds without significant trailing. Best results however were obtained from 5-6 second exposure. I also played around with ISO settings and generally ISO800 and ISO 1600 gave the best balance of brightness. Also it helps greatly when you can set a 10 second timer to reduce vibration and shakes that show up in your images. With these settings, I managed to capture some of the pastel hues in M42. Bear in mind that these are not stacked images but single images! Can't wait to try imaging under pitch black skies!!!!!!




So what's next on my list? I hope to try and shoot for some of the brighter planetary nebula's such as M57 and M27, the ring and the dumbbell, globular's M13 and maybe some of the brighter emission nebula's like M17 and M8, the swan and the lagoon nebula. Also I would like to try for some brighter galaxies from dark skies sites.....that is when summer rolls around ;)

Quick Dark Sky Fix Mount Pinos 27th August 2011

What do you do when you are stressed out and need a quick getaway to dark skies.....Mount Pinos to the rescue!!!! Was feeling stressed from stuff not working at work and wanted to unwind. That and plus the fact that I have not been under dark velvety skies since my first trip to Pinos way back in May. Seeing that the summer observing season only last between April and October (it gets too cold after that with snow and what may), one has to make the most the the 6 month window. I also wanted to go, but did not want to have to content with the crowds during the summer season. The solution....go a week before the new moon!!! Going there a week earlier can be a two edged sword though. On one hand you have the whole place to yourself. On the other hand, there is the worry that there might not be anyone there, making this kinda creepy. Good thing that there are some like minded astronomers who also happen to enjoy a quiet respite. After making the decision to go, I decided to throw everything together at the last moment. I had no intentions of staying the night as the last quarter moon would come up at approximately 11pm. Hence I only packed my 20x80's (no tripod even!), my trusty Celestron C6 on EQ converted alt-az mount and my Celestron Firstscope 75mm micro dob. I also had with me a recently acquired Orion StarBlast 4.5"f/4 imaging OTA that I wanted to try out. One of the other reasons I wanted to go was to spend time with the summer northern milky way, as well as the centre of our galaxy.

Leaving at 5.30pm from home proved to be a really stupid idea, especially since I know how bad LA traffic can be, even on the weekends. I was surprised to encounter traffic this late on the 405, and on a Saturday! After driving frantically, I managed to get to the top of Mount Pinos before sundown. The views of the mountains as the sun was settling was magical. There is a feeling no words can describe when you are driving, on your way to dark skies, as the sun sets after a gloriously clear day! The temperature was also quite pleasant when I got there, and since I was not staying the night, I did not have with me a beanie or gloves. Bad move on my part (read on later to find out why). I now know never to go up to Mount Pinos without those two essentials. I was also glad to see Dave and his Meade 12" SCT up there. At least I was not going to be there by myself. Another astronomer pulled up later as well, also sporting another 12" SCT. Setup time was minimal for me as did not even bother folding up the tripod. I just collapsed the legs and stuck it in the backseat. As soon as it got dark, about 1/2 hour after I arrived, I started to look at some of the more familliar sights. First up was M57, since it was almost overhead at that time. The ring looked spectacular in twilight skies. Kinda weird, seeing that the views were markedly better than from night skies over suburban Culver City. I noted how the NPB filter made the views even better under such skies. I next looked at M27, the dumbbell nebula, also with the filter in place. As the skies were not totally dark, the views were not as good as when I revisited it later. The dumbbell looked like a ghostly football suspended in space!

Looking south, Scorpius and Sagittarius were looking good and most of the scorpion's tail was above the pine tree line. Now's a good time to revisit some old friends before they get too low when I come here next month. The centre of our milky way was, by now, very evident. I started off the region by just scanning the region between M6/ M7 and M17 using the Celestron Firstscope 76mm. The best views came using the Meade SWA 24.5mm and the Shorty 2x barlow. M22, the crackerjack cluster in Sagittarius and M4 in Scorpius was nicely resolved. The butterfly cluster and Ptolemy's cluster, M6 and M7 filled the FOV with nice sparkly stars. The butterfly shape was clearly evident. M8, the lagoon and M20, the trifid nebula fit in the FOV. I also noted how nice and tight the stars looked and did not notice any spherical abberation. I must have gotten lucky with this scope as they have spherical mirrors and the primaries cannot be collimated. I, however, only use this scope for low to mid power scanning and generally do not use it for high power study. For that I have the 6"f/5. With this scope, both M6 and M7 were much prettier, with more stars visible. M22 and M4 showed even more resolution, with M4 showing the bar of stars clearly, as did M80 in Scorpius, although this cluster was not totally resolved. I next wandered over to Ophiuchus and scrutinized M10 and M12, both globular's showing nice resolution in the C6 at high power. M8 and M20 showed so much nebulosity, even without the NPB filter in place. I like getting lost in the twirling mist of nebulosity, with some dark nebulae splotches thrown in for good measure (i.e. I really miss the Eta Carina Nebula).

Using the lagoon and the trifid as jumping off points, I wandered over to the small Sagittarius star cloud, which appeared "congested" with stars even in the small Firstscope minidob. M17, the swan nebula showed its characteristic swan shape, as well as feathery structure coming off its back (I liken them to vapours rising from its back after a swim on a hot day!). The extra nebulosity around the swan was also very evident. M16 the eagle nebula could easily be made out, resembling the little ghost (as O'Meara puts it). M11, the wild duck cluster was pretty in the Firstscope, with some resolution, but was totally resolved in the C6! I also spent some time with the bug nebula, although details were not as evident when compared to the views I got in my 10"f/5 dob.  Also spent heaps of time perusing globular alley in Sagittarius. I have not done this in a while so it was a blast using the C6. Most of the globs just showed central condensation with little or no resolution. By now my fingers were starting to numb up from the cold, so I decided to have one more look at M27, the dumbbell nebula, then the North American Nebula (it was visible to the naked eye, but almost overhead and very painful to find in the scope) in Cygnus, M13, the great Hercules cluster (nice propellar effect evident in the C6 at 150x) and finally the veil nebula. Have not looked at this supernova remnant in ages so this was a real treat. I spent some time admiring the ghostly cigarette smoke wisps around 52 Cygni and its surrounds. Was all packed by the time the last quarter moon was up...till the next time....