Page listing for the category: Imaging Techniques
Welcome back!
I’ve been outside just now, trying to sneak an image of Jupiter and its moons, in between the clouds and general haze here in South-East England tonight. (Isn’t it often this way? Two hours earlier, the sky was sparklingly clear!)
Anyway.. what I’ve realised is I need more focal length on the telescope, for the imaging of planets.
I put my old 6 inch Newtonian reflector onto the EQ6 mount, then added the Canon dSLR camera.
Ancient 6 inch Newtonian reflector, plus EQ6 telescope mount
It produced this image below, nicely showing three moons of Jupiter.. but no detail on the planet. The clouds must take a lot of the blame, but I see also, I need more focal length.
Jupiter And Moons (Io, Ganymede, Callisto)
The DSLR Canon camera is working at prime focus – using the telescope as its lens and nothing else.. (no eyepiece, or barlow lens etc).
Consequently, to get more magnification and fill the image field of view with the planet, I need a telescope with a longer focal length. My 6 inch (150 mm) reflector has a focal length of only about 700 mm.
(And as a PS. . what would Galileo have given for an image of Jupiter and its moons, like this?)
So, any suggestions for a good telescope to observe the planets?
Well, what fun this week…
It’s been designated ”Spring Moonwatch” week, as part of the IYA 2009 and we have been blessed with wonderful clear skies here in South-East England.
I have helped run two public events at my local astro society . I even gave a talk yesterday to about 30 people, about the Moonwatch week and what to see on the Moon. And it used my own Moon images, taken over the last couple of weeks.
Two or three of the newcomers, became obviously enthused with the idea of Moon observing, which made it feel very worthwhile.
Newtonian 6 inch reflector on EQ6 mount, observing the 9-day Moon
Tonight, I snapped the 9 day old Moon.
To the right, is my old 6 inch reflector, which I bought on eBay in 2003.
Originally, it was on a simple alt-azimuth mount, but I have recently added new tube rings and dovetail bar, enabling it to be put on the Skywatcher EQ6 mount. (Vastly more stable and of course, driven)
It has worked really well this week for capturing images of the Moon, as it has progressed from 3-day crescent through to 9-day Moon, tonight.
(I shall put together a montage of images from this week.)
Using my now trusty, Canon 1000D dslr, I have (as always) been very pleased with the results.
Here is an image of the 9+ day Moon, I took tonight.
9+ Day Old Moon, 2009/04/04 (click for larger)
We at cadsas.com had an excellent observing night, tonight.
“Spring Guide to the Night Sky” public event.. totally horrible, rainy and windy weather at 5pm. Event starts 6.30pm..
All clear! Plus very clean skies, after all the rain. Looked at 1st magnitude stars as they appeared from the twilight, then observed Orion and Saturn.
We also saw two great fly-overs of the International Space Station (ISS) – the second pass was particularly bright.
About, 25 Cub Scouts came along with their Cub leaders.. made for a busy event.
Plus, I tried my Canon Digital SLR Camera
in the mighty Alan Young 22.5″ telescope.
Fitted well mechanically, but poor images..
Here’s an example of an out-of-focus Betegeuse in Orion.
In Sufficient Focusser In-Travel On Star Betelgeuse
Insufficient in-travel on the focusser… It was not possible to move the camera in close enough, to bring the image to focus.
The difference between the Canon and the Mintron camera that’s usually used with this telescope, is the position of the ccd chip within the camera body. The Mintron has its chip very close to the front of the lens opening. The Canon’s chip however, is much deeper within the body.
However, we were much encouraged by the likely light-gathering power and plan to modify the focusser to move it’s travel inside of the tube. (We did consider moving the mirrors instead, to push the focal plane further outside of the telescope tube, but felt this would be too radical)
Stay tuned!
This will work, one way or another and deliver good results!
