Planets are far away objects. If you want to capture images prime focus - so just put the cam in your eye piece holder - you will soon see that the objects (planets) you see on your screen are rather small and obviously you want them bigger to see more details.
As it is impossible to get closer to Saturn - well, you could use a space craft - you have to magnify the image. For that you can use a Barlow or eye-piece projection.
Barlows come in 2x, 3x and even 4x magnifications. You have experienced already, that it is not easy to get a planet's image on your screen even without a Barlow, because the CCD chip of your cam is so small: something like 4,6 x 3,97 millimetres (Vesta Pro example).
So your scope must be aimed very accurately at the planet, otherwise the light of the planet does not fall on your CCD chip and you see: nothing.
On my TAL-2M telescope I use the following scenario: (whereby 'perfect' means: I do the best I possibly can)
| 1. | Perfect polar alignment, so that your object does not run off the screen and you are chasing rather than imaging. |
| 2. | Perfect collimation |
| 3. | I use my RA motor corrector because there is a lot of slack in the RA train of my telescope (maybe typical for TAL-2M only?); when I use the manual knobs and have centered the image I always see that the object runs away, which is even worse with the camera mounted: I see nothing then on the preview screen! There are 2 ways to overcome this slack: 1) I do NOT use the manual knobs but push the OTA by hand so that the object is East of the center of the eye piece, then I switch the RA motor off and let the object drift to the centre of the eyepiece. I switch the RA motor on again when the object is nicely centered. 2) use a motor corrector which enables you to stop, normal run and advanced run in RA, so I can control RA without using the manual knobs, thus without touching the RA train and telescope |
| 4. | Aim at object (take a bright object, but NOT THE SUN !!!!) with the 25 mm eye piece and also use the crosshairs that came with your telescope |
| 5. | Now adjust the finder so that the object is nicely positioned at one of the tips of the points of the finder's crosshairs: easy to reposition the telescope ...
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| 6. | Insert the 4x Barlow with the 25 mm eye piece and redo 5 and 6 |
| 7. | Now use the 15 mm eye piece and fine tune your aim. |
| 8. | Redo 6 (it is important that the finder points accurately at the object, because with the camera on I will be in the blind) |
| 9. | Now gently gently replace the eye piece with the camera |
| 10. | I put the camera settings at max brightness Hint: try before when it is getting dark how to do that!) |
| 11. | Now I should see something - maybe a vague and blurred image - and now it is focusing time. By hand it is difficult, because I might (and will !) accidentally apply too much force at the telescope and the aim is lost: alas, I have to restart from 4. But now it goes faster, because the finder is true! And a home made electric focuser is like gold in the bank :o)
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| 12. | I use K3CCDTools to focus: it gives a nice screen with finder circles and has also 2x zoom facilities. Want to look over my shoulder how I focus on Jupiter? Here is my procedure:
I aim at one of Jupiter's moons and focus rather decently. 
I de-focus a bit, so that I can clearly see all four dots instead of only one.
From here on I do not touch the focusing and aim at my object. |
| 13. | When you are happy with your aim, focus and camera settings: shoot |
| 14. | Continue with the next hint and tip: Mastering your camera and imaging software |
| 15. | You want me to add/change something here? E-Mail me, please! |
Of course: for aiming you can use a flipmirror, but they are expensive. But it is possible to make one yourself: Carsten Arnholm made his own PlanetFinder!
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