Galileo's Camera

Since any celestial photography is out due to the rains, I thought I might as well capture that. All photos were taken with a Canon 18-55mm (at 18mm) and a Canon 550D. The first photo has an exposure time of 15s and all others are with an exposure time of 30s. The photos have been post-processed for contrast and exposure.

Jupiter About a week and a half back, I was trying to capture the Geminids. Given the awful location I live, it was a complete no-joy. However, just scanning the skies, figured that Jupiter was actually visible and decided to have a shot at it. Photo above is a single shot of Jupiter with Canon 550D, prime-focus on a Celestron 114EQ with an exposure time of 1/20sec and ISO 100. Quite obviously, it is very far from what it should be. But its a start. I also have a series of 20 shots which could've been used for stacking, but unfortunately all of them seem to have gone out of focus. So yes, only this one shot is all I've got. I think it still might be a good one to end the year ;) P:S: Oh and btw, the stripes are real :)

Lovers Under the Starlit Nights - Captured at Dutch Fort, Galle, Sri Lanka. The background is the Milkyway across Scorpius and Sagittarius.

About two weeks ago I finally got my hands on the motor drive for my Astromaster 114EQ. I was debating whether I really need it or not and finally decided to just go for it. And over the weekend I had it installed and tested. To start off with, the motor drive arrived with minimal instructions. But that wasn't really a problem. The product was quite well made that I was quite intrigued by the whole design. Granted, it wasn't very intuitive, but the instruction sheet was quite to the point, that it was quite impossible to screw it up. It even had an Allen key and a screwdriver that fits the relevant bolts. But this doesn't mean that everything was going smooth. Once I fitted the mounting bracket, I figured that the coupler between the motor and the scope wouldn't fit on to the RA shaft (Celestron refers to this as the flexible coupler). The inner diameter of the coupler is almost exactly the same size as the shaft. I was about to file it off when I figured that I had...

As usual my sense of timing seems to be impeccable, I decided experiment with image stacking for deep space imagery when the monsoons are about to start. Ever since I made the decision, it's either been raining or completely overcast. I even had some difficulty in trying to do solar photography. Luck turned my side when I went on a trip to one of the national parks in SL, Wilpattu. The bungalow we stayed in was right in the middle of the jungle with absolutely no light pollution. My brother was the first to spot that the Milky Way was clearly visible overhead. He was trying to experiment with a set of long exposure shots while I was trying to get a series of comparatively shorter exposure shots for stacking. Milky Way across Cygnus (20 frames of 10sec exposure) The image above (Milky Way across Cygnus) was stacked on Deep Sky Stacker using 20 images each with 10sec exposure. The stacking was done with 10 dark frames and 10 bias. The image below captures Milky Way across Sco...

For about a month's time, I wasn't able to do anything interesting on astrophotography  owing to the bad weather. I started some experimentation on solar photography and well that is not going that well either. However, last week I managed to snap some decent pics of the moon. For the longest time I thought that lunar photos do not need stacking or wavelet enhancements. I mean moon is the second brightest object you can find in the sky. For the sake of experimenting, I tried stacking them and doing some wavelet processing on registax. The result is as follows: Moon - 10 frames stacked and processed with wavelets. I was quite surprised to see that this actually did made a difference. Compared to the usual blurred photos I get, these seem to do way better. For the sake of comparison, see the photos below: Non-stacked (prime focus) Stacked with wavelet processing (prime focus) So yeah it does seem to make a difference. I also wanted to see if this was something to do ...

In the last post, I wrote about what is collimation and what sort of an effect a non-collimated telescope has on imaging. Taking it from there, let's see what are the equipment we can use in collimating a telescope. No-Tools: Firstly let's ask the question whether we can collimate a telescope without almost any tool. It is possible for someone with real good patience and a reasonable eye-sight could collimate a telescope that is not seriously misaligned just by star-light (point at a star, keep adjusting up until the slightly out of focus image stops being an ellipse and becomes a disc). However using a collimation cap makes the job much more easier. It is not necessary to collimate the telescope during the night when using this method. It is possible to perform daytime collimation by center-spotting your primary mirror. What is center-spotting? It simply means marking the exact center of the primary mirror. Some of the telescopes come with the center marked from the factor...

For any reflecting telescope, collimation of the optics is one of the most important and regular tasks. Collimation simply refers to aligning the primary mirror and the secondary mirror along with the eye-piece. However, the job it self is not that simple. If a telescope is not collimated, the image it creates would not be in the same plane as the eye or the projection plane (in case of a camera/ccd/projector is used). This could lead to various ring patterns, distortion of the image to appear when viewed. This means that even when you have focused the image properly (or brought the viewing plane up to the focal point), the image is still not clear/smeared. Fortunately, this it self provides an easy way of identifying whether or not a telescope is properly aligned. Ray diagram of an uncollimated Newtonian - Red line depicts the plane where the image is created. The green line depicts the viewing plane. To try to understand what happens in an uncollimated telescope, let's ...

We are going through the monsoon season again, and well needless to say, not a very great period for astrophotography. Had somewhat of a clear sky today and decided to snap some quick photos and stack them using Deep Sky Stacker. Crux - The Southern Cross In the image above, in the thumbnail view, the main stars of crux is quite obvious. However, when you see the full sized image, you will see that the image is pretty detailed. The top most star is Gamma Crucis. The right most point of the cross is Delta Crucis. The brightest start of the constellation is Alpha Crucis, or the bottom-most star in the constellation. However what interested me was Mimosa (or Beta Crucis), the left most point of the cross. The open cluster NGC4755 resides close to Beta Crucis. This being my very first deep sky imaging attempt (or at least the first decent one), I did not expect much and kept shooting with my 75-300mm lens on a 550D. NGC 4755 Obviously the shot isn't great. But I believe ...

With all the preparation yesterday and day before, I was quite hopeful that I could get a few decent shots of the transit. I was specifically planning for one good shot through the telescope and a time-lapse shot of the transit across the solar disc. So imagine my delight when I work up today morning and found this greeting me: So much for the plans of scope photography! Managed to capture this during the small time sun was visible, and had it not been for that, my plans for the next century might have needed considerable reconsideration. Transit of Venus - 06 Jun 2012, between 09:10-09:15 local time Sri Lanka

Just a quick post on viewing the transit of Venus tomorrow: Timing You can find timing related information from http://eclipse.gsfc.nasa.gov/transit/venus/city12-1.html and http://eclipse.gsfc.nasa.gov/OH/transit12.html . For those of us from Sri Lanka, the transit will be visible from the sunrise it self. The peak of the transit would be around 07:30 AM. The transit will end around 10:21 AM. The latter link actually has a nice image of the path of Venus across the sun. Viewing Do not use sunglasses or xray film to look at the sun. Most of the damage that happens to the eye can happen due to the wavelengths which are not visible. If you do have xray film and a camera/webcam with a reasonably good zoom, put the xray film in front of the lens and use the live-view of the camera to view the transit (or you can hook it up to a laptop). It is also possible to use a pinhole camera to project the image of the sun to a wall. During 2010 annular eclipse, I came across a natural pinho...

After getting necessary film to cover the whole aperture of the lens, I decided to try out a few shots in the morning. Starting off with the highest shutter speed of 1/4000, I realised that even that gives a VERY bright picture (as opposed to the 1/80-1/40 shutter speed which gave a "reasonably ok" view yesterday). Now here's a bit of math. The "brightness" of the image is dependent on both the expose time and the aperture. The expose time has a linear effect (i.e. you expose for 2 seconds, you get twice more light than when you keep it open for 1 second). What sort of an effect does aperture have? Assuming aperture is measured as a diameter of the lens/opening (and that it is circular), the area that is open is given by pi*(d/2)^2 where d is the diameter of the aperture. The area it self has a linear effect on the brightness as well. I.e. you let twice as much as light in for the same period of time, you get an image that is bright twice as more. If the tw...

I noticed quite late that we are going to have another Venus - Solar transit in a few days and that is going to be the last Venus transit for almost a century. I have not done any serious solar viewing or photography before this. But the rarity of the event and the equipment I have now wants me to take a shot at it. It goes without saying that you need a solar filter. Over here in in SL, they are a bit too hard to come by. Previously when I was photographing and viewing the annular solar eclipse in 2010, I used a cut up x-ray film with my Canon S2IS (this method is debated). The problem this time is that I now have a Canon 550D, whose lenses have a much larger aperture and the original x-ray cut ups wouldn't work anymore. 1st attempt: Use a type of coloured cellophane that is available over here as a filter. A single sheet is way too thin so tried stacking up about 10-12 on each other. However it diffuses the light so much that it is barely of any use. 2nd attempt: Center the...

For anyone who wants to get in to astrophotography, one of the obvious first questions is "How do I connect my camera to the telescope?". Well Celestron has an instructional video on how to. The 10min video covers all types of mounting/connecting methods like A-focal (mostly used with point and shoot cams), prime focus (used with DSLRs), web cam astrophotography, CCD based photography and  piggybacking. Of course, it is a promotional video from Celestron, so obviously they promote Celestron products, but it is a good start :)

Full Moon Shot using Canon 550D with a 75-300mm camera. No telescope is used. Lunar cycles must've been one of the earliest cycles that have been identified by humans. In this series, we will be covering its entire change of phases with 27 photographs, one for each day between a full lunar cycle. The photograph shown here is taken using a Canon 550D with a 75-300mm telephoto lens. Although the moon is the brightest on the full moon, it is not a great phase for astrophotography. When the moon is waxing or waning, the shadows on the ridges accent the actual shape of the ridge. However, when the entire moon is (reasonably) uniformly illuminated, all you can see are the larger craters and seas. In the photo below, you can see the major craters and seas of the moon marked on the same image as above: Moon - Major Crates and Seas

Since a very young age, I have been interested in astronomy. When I was around 12, I built a telescope made out of a lens of my father's spectacles and an eye piece from a toy binocular. If I recall properly, it had a magnification power of x12 and I managed to see three of the four Galilean Moons of Jupiter. About a decade and a quarter later, I started getting interested in photography. I am now on my second camera and the first DSLR and pretty  much all of my "stuff" can be found at http://picasaweb.google.com/115925656791968631335 . Around the same time, I got my hands on my first "proper" telescope. And in pretty much no time, I was wondering if I could put my two hobbies together. This blog, is an amateur attempt on astrophotography. For how long I would continue this and to what depth, I do not know right now, but it is very possible that I would do it for a long time, even with astronomical pauses between posts. :)