howto:focus
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howto:focus [2009/02/18 18:29] – manual focus added mates | howto:focus [Unknown date] (current) – external edit (Unknown date) 127.0.0.1 | ||
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+ | ====== Focuser API ====== | ||
+ | |||
+ | Focuser presents various variables to the end user. They may look confusing on a first look, so here is a small description. You may find it also in //man rts2-focusd// | ||
+ | |||
+ | * **FOC_POS** This variable show actual focuser position. If set, it will cause focuser to move to set position. If focuser is moved to position, it shows the actual focuser position. | ||
+ | |||
+ | * **FOC_TAR** Focuser target position. This shows desired focuser position. If set, it will cause to move focuser to set position. | ||
+ | |||
+ | * **FOC_DEF** Default focuser position. This is used together with FOC_FOFF and FOC_TOFF for autofocusing. If it is changed, target position is set to sum of **FOC_DEF**, | ||
+ | |||
+ | * **FOC_FOFF** Focuser offset found during focusing. This is used to temporary shift focus. If focuser driver is restarted, it is moved back to **FOC_DEF** position. | ||
+ | |||
+ | * **FOC_TOFF** Focuser temporar offset used during focusing. You should use this variable during focusing script to probe focus at different offsets. | ||
+ | If your focuser is named **F0**, and you would like to probe focusing range 100 steps bellow to 100 steps above default focuser position, the focusing script should look like: | ||
+ | F0.FOC_TOFF=-100 for 20 { E 10 F0.FOC_TOFF+=10 } | ||
+ | When script is finished, RTS2 will change **FOC_TOFF** to 0, which will cause focuser to move to default value. You can change either **FOC_FOFF** | ||
+ | or **FOC_DEF** to set new focusing position. | ||
+ | |||
+ | The following equation should be true when you change focus with **FOC_DEF**, | ||
+ | FOC_TAR = FOC_DEF + FOC_FOFF + FOC_TOFF | ||
+ | |||
====== Focusing in RTS2 ====== | ====== Focusing in RTS2 ====== | ||
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===== RTS2 and Autofocus ===== | ===== RTS2 and Autofocus ===== | ||
+ | |||
+ | {{ : | ||
The autofocus subsytem is not yet definitively solved, but we have got already very far while getting there. | The autofocus subsytem is not yet definitively solved, but we have got already very far while getting there. | ||
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A working solution is to set up the object detection (with '' | A working solution is to set up the object detection (with '' | ||
- | Automatic focusing in RTS2 is solved using a combination of a observation scripts and observation processing. In particular, there is a special target which needs to be executed in order to (re)focus the telescope. | + | Automatic focusing in RTS2 is solved using a combination of observation scripts and observation processing. In particular, there is a special target which needs to be executed in order to (re)focus the telescope. |
=== Getting the minima === | === Getting the minima === | ||
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and if linear is not the best, the best fit of these three | and if linear is not the best, the best fit of these three | ||
functions is proposed as a solution. | functions is proposed as a solution. | ||
- | |||
==== obs_process integration ==== | ==== obs_process integration ==== | ||
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We are using NGC188 as a high | We are using NGC188 as a high | ||
density spot on the sky which is always accessible on the | density spot on the sky which is always accessible on the | ||
- | north. | + | north. |
- | '' | + | '' |
the known good focus position may be set upon start of this | the known good focus position may be set upon start of this | ||
- | script, (focpos=3500) to make sure the focus will always start | + | script, (F0.FOC_DEF=3500) to make sure the focus will always start |
at a reasonable place - even when the previous focusing run | at a reasonable place - even when the previous focusing run | ||
failed and provided a stupid position. Now it was not there | failed and provided a stupid position. Now it was not there | ||
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''/ | ''/ | ||
+ | === set the position === | ||
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+ | To set the position computed from the data, one has to execute the following commands: | ||
+ | |||
+ | '' | ||
+ | '' | ||
+ | |||
+ | The other imaginable ways like '' | ||
=== on-target focusing === | === on-target focusing === | ||
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==== Known Issues ==== | ==== Known Issues ==== | ||
- | * there is no way to feed the position | + | * the way of feeding |
- | * there was bug related to scheduling of a command to move the focuser, which resulted in incorrect values in the fits headers. (i have no idea if this is already solved or it just happens randomly) | + | * there was a bug related to scheduling of a command to move the focuser, which resulted in incorrect values in the fits headers. (i have no idea if this is already solved or it just happens randomly) |
* we do not care if the astrometry is successfull, | * we do not care if the astrometry is successfull, | ||
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howto/focus.1234978194.txt.gz · Last modified: 2009/02/18 00:00 (external edit)