On a hot afternoon last Friday I woke up to find myself in the middle of Bandar Muadzam Shah, a small town somewhere on the peninsula. “What the hell am I doing here,” I thought; but it has turned out to be one of my greatest dark sky trips ever! :D
I joined a bunch of hardcore astronomy enthusiats from Singapore in their monthly imaging sessions. The location is in Sri Kandi Resort, Mersing where they frequently do their monthly photon collecting. The resort is just beside the South China Sea, perfect for beachgoers too! Mersing is 6 hours bus from KL, about 5 hours from Singapore… quite a tiring ride. =A=
This is Kelvin’s setup – An Orion Optics 8 inch Newtonian telescope on an Astro-Physics Mach1 GTO. The wires going in and out of the imaging setups are too much! The smaller scope on top is the guidescope used to guide the telescope to point towards the objects intended to be imaged. Note the DSLR used for imaging, a cooler was attached to it to reduce noise during imaging – the temperatures of the camera can reach sub-zeroes during operation! If you are interested in rigging your DSLR that way please visit http://www.singastro.org/forum2/viewtopic.php?f=8&t=10936. They call it the ‘Super 450Da’ haha!
Left is Remus’s Takahashi 8 inch reflector on a Losmandy G11. Right is Michael’s Takahasi FSQ on a Losmandy G8. All are very professional scopes, no Orion stuff! Orion is kinda like Tesco or Carrefour in the telescope world lol.
The Observing Gang! From left, a Celestron 3-inch, a Borg 77mm ED Apochromat Refractor, and my own awesome 22x100 Oberwerk Giant Binos! On the right pic is a Takahashi CN-212 8-inch Newtonian on a Losmandy G8 too, we observed a breathtaking Omega Centauri through this telescope! Not to mention all the Nagler eyepieces they used, makes you feel like you’re among the stars when you’re observing. Ah the pleasure of wide field goodness ^.^
Basically there are a few steps involved in setting up telescope for imaging. First you have to do polar alignment, i.e. pointing the polar axis towards the North Celestial Pole. If the pole star, Polaris is visible then you can point the polar axis towards the star, but in Malaysia Polaris is barely visible so we had to do it the hard way – drift alignment. This basically involve pointing the axis towards North using a compass. Then, by turning the motors on and observing the star’s movements through the telescope, we adjust the axis accordingly until there is no more star movements observed, then the alignment is good.
Take note that the North Grographical Pole, North Magnetic Pole and the North Celestial Pole are in all different directions!
When you’re done, next step is to point to your target! The
GoTo mount will do their jobs, but if you don’t have one you’ll have to
resort to the venerable method of star hopping :) Also,
focusing on the object is important as you want to get crips pictures of nebulae
and star clusters, not blurry ones! What do they do? They use this thing called
the Baltinov Mask (pic left) to help them in focusing. The
fringes in the mask creates a distinct diffraction pattern around a star (pic
right) when the telescope is properly focused.
Okay, the guidescope – it is used to make the target remain focused on the telescope. Our polar alignments can never be 100% perfect, and slight vibrations caused by winds or even someone stepping on the wires will make the mount vibrate! The guidescope and its program will send commands to the telescope mount to make the necessary adjustments to keep the subject in focus. In particular, they use a freeware called PHD Guiding to do the guiding. Very intuitive and effective, this has became the norm for all astrophotographers.
The DSLR will then take several photos of the target. Usually what they do is they take a test shot of 30 seconds exposure first to frame the target correctly, then an 8 minutes exposure to capture the image. The DSLR is of course controlled by a computer, many types of software can be used, one of them is BackyardEOS. I think you can also use the camera control program supplied by your camera manufacturer to control your DSLR. http://www.backyardeos.com/product_backyardeos.aspx
Take multiple shots of your image, at least 8! When you’re done, then use DeepSkyStacker to stack your images. The program will use a mathematical median to help stack up your images and make a very stunning end result! http://deepskystacker.free.fr/english/index.html
Well that pretty much sums up most things on astrophotography.. but easier said than done! You still have to edit it with Photoshop or any image editing program to enhance your image. To the skeptics, Photoshop is only a tool to bring out data that is ALREADY inside your raw file. There is no ‘fake’ in Photoshop, and all the amazing astrophotos out there. Oh and of course, you must have good skies and good equipments to begin with!
Well what do you think? Does it make you appreciate the images of galaxies and nebulae that appears on your Facebook more? :D Next up! A guide/journal driving through the Milky Way Superhighway through the 22x100 Oberwerks!