Meade Image Processing Bedienungsanleitung PDF herunterladen (Seite 22)

Start up CCDOPS; on the SETUP tab, set the temperature 30

C below ambient temperature

and start the cooling. Start up TheSky, establish the link to the telescope; home the mount.

Choose a wide view, and slew the telescope to a bright star in the general area of the target.

In CCDOPS, set the red filter and start FOCUSING in FULL LOW resolution mode with

t = 0.3 sec, and slew the telescope to a nearby ~ 5

star. Start FOCUSING in PLANET MODE,

with t = 0.3 sec and use the manual focuser to achieve focus with the largest possible

maximum pixel reading. (If the star is too dim or too bright, you might want to change the

exposure time: you need a maximum pixel reading between 500 and 20,000). Expect that

focusing will probably take ~ 15 minutes; it is a tedious but crucially important step.

Now start DUAL CCD VIEW, with longer exposure time so that your object will show up.

Usually t = 5-10 sec will suffice, except for very dim objects. Slew to your object. Aim

exactly at your object, so that your guide star is in the tracking chip. Record (draw) the

position of the guide star in the tracking image and save the view.

Grab one t = 15 sec exposure of your object in each of the three colors, and decide on

exposure times. You’ll need to make sure that none of the images is clipped (i.e. the

maximum pixel reading does not exceed 40,000), unless this is necessary as a compromise.

Keep in mind that a few multiple exposures can be added, and that exposures longer than

30 min often break down before completion.

It is time to start taking the real pictures. Set the color filter, and use the SELF-GUIDE

button (SlfG/SG on the toolbar) to start guided imaging. You’ll need to set the tracking

exposure; use the shortest time that still makes the guide star clearly visible to get guiding

corrections as often as possible. Ideal but rarely possible is t ~ 0.1 sec; we often use

t ~ 1 sec; it is possible to use even t ~ 30 sec if really needed. The longer the exposure the

more is the remaining wander (which should be under ~ 1 pixel worth), and the more the

chance of losing the image before completion due to occasional tracking errors.

After each exposure you’ll need to take a new DUAL CCD VIEW and get the guide star back

to the same place as on the first image; and the color filter might need to be changed. Note

that the tracking exposure may need to be different when you change the filter.

It is good practice to take all exposures equally long (and take multiple exposures). The

guiding utility does not subtract dark frames, so you will see very little on the raw images.

Unless you have the right darks in the dark library (check!), take dark frames after you are

finished. Use autograb to take ~ 40 darks for later averaging. (Don’t forget to change the

name and the location of the files!) Darks need to be taken with the exact same temperature,

exposure time, etc. as the light frames – make sure you take them for each image.

If you decide to leave while the camera is still taking the darks, make sure you PARK the

telescope, switch off the telescope’s power (but not the camera’s), put on the lens cap, cover

the scope, close the slit, quit TheSky but not CCDOPS and make sure someone closes off

completely when all is finished. To switch off the camera, set the temperature regulator OFF

first, and wait for the cooler power to reach 0%. Then shut down the computer as well.

Don’t forget to turn the streetlights back on!

The duedate for processing preliminary images is one week, and two weeks for the final

images. Doing it all right means to end up with some very pretty pictures!

1 2 ... 17 18 19 20 21 22 23 24 25 26 27 28 29

Kommentare zu diesen Handbüchern

Keine Kommentare

Meade Image Processing Bedienungsanleitung Seite 22

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Teleskope Meade Image Processing