Meade Image Processing Instrukcja Użytkownika Pobierz pdf (Strona 20)

(iv) Grab: this is how you take individual images. You can select if you also want

dark frames taken and automatically subtracted, or else to take only dark frames.

Autograb will take multiple images automatically, but you must be sure to change the

name and location of your image files, because otherwise CCDOPS will overwrite

previous images!

(v) Filter: the filter tab will change filters.

(vi) Self-guide: this is how you take long exposure images. You must make sure that

the guide star is located on the same part of the guide chip every time you start a new

exposure, otherwise the images will not match each other. The tracking exposure

should be as short as possible (t=0.1 sec is ideal but even t=10-30 sec might work).

Wander should end up less than 1 as. A good guide star should be at best 7-8 mg, but

11 mg still might work.

Self-guide will work only if it is calibrated. Every time the camera head is turned,

this calibration needs to be repeated (get a star on the guide chip and use the Calibrate

panel). Whenever the telescope crosses the meridian, the guide x-direction must be

flipped in the Autoguide Parameters (otherwise the mount will do the wrong

correction).

(vii) Rotation of the camera head: this should not be done very often. After rotation,

new focusing and a new set of flat frames is a must, so you cannot do it twice on one

night. TheSky’s “virtual sky” needs to be rotated to match the new orientation of the

camera. The autoguider must be recalibrated after turning the camera.

● The aiming software

The position of the telescope will be controlled by the software program called TheSky,

which is a program similar to the familiar SkyGazer, only with many more capabilities. It

shows the sky with the telescope’s position indicated. TheSky is a complicated program,

but for simple image taking purposes we will need only a few of its extensive controls.

(i) The zoom in and out controls on the toolbar, indicated with a + and - signs. Note

that CTRL-T and CTRL-B will zoom quickly to “telescopic” and “binocular” views,

with small and large fields respectively; the “home” button gives the widest view.

(ii) The FIND utility on the toolbar (or press letter F). You may type in the name of the

object you are looking for.

(iii) Click on a star to bring up the OBJECT panel, with many of its data. In the bottom

there are buttons for centering the object on the screen and for slewing the

telescope to it. Note that, once the link to the telescope has been established, you

can center only objects that fit on the screen simultaneously with the telescope’s

aim. (Zoom out if you need a larger field.)

(iv) To establish a link with the telescope use the TELESCOPE menu. You’ll need to

home the telescope to make sure its pointing is accurate. (It is automatic; only

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Meade Image Processing Instrukcja Użytkownika Strona 20