LACERTA M-GEN Stand-Alone AutoGuider

Transcription

1 LACERTA M-GEN Stand-Alone AutoGuider Changes from Firmware to (pre-release of FW 02.00) Created by: Zoltán Tobler 13 February New features Hardware binning operating modes: Binning mode CCD area Binned pixel size (um) The default is 1 1, used in the older Firmwares. Note that the guiding window is constant pixels, for example at 6 6 binning mode the guiding window covers half of the available vertical area (48 out of 97 pixels). You can see the guiding window sizes on the LiveView screen. As the pixel size grows (one binned pixel) so do the other parameters. The thermal dark current is multiplied with the binning block size (N N) but the total sensitivity of the binned pixel changes the same way. There is some amp glow (at left top) due to the CCD construction, You could see this in LiveView with long exposure time. This also increases with the binning as a part of the increased sensitivity. The left top area of the CCD may be not used if the glow seems to be too hard. We are planning some software compensation to this effect. Due to the increased horizontal transfer time (binned pixel), the readout noise grows some with the binning size. My measures showed less than +40% for the 6 6 mode so the read noise is still below 10 electrons for most of the Camera instances in any modes. The CCD binning setting can be found under the Guiding / Guider setup menu. Changing of the binning value take effect only when You leave that screen with altered setting, and a question will pop up to ensure the change. To change the value LEFT and RIGHT buttons must be used. The CCD binning variable is a profile variable

2 Automatic continuation of following the star (in the old position) after a LiveView usage (without setting a new guiding position) when re-entering the guiding screen. More fine LiveView dark compensation. A whole CCD image will contain some vertical ramp due to the higher dark current present in the CCD s vertical register. (As the CCD is a camera-cdd, is designed this way.) This was compensated by software and some horizontal defect (blocks) could be seen (at low threshold). Now the compensation mode is dithered and does not disturb the image that much. The optical black level is changed from the default 16 to 4. This allows a little bit higher dynamic range for the star photons (long expo or >1 binning). The interlaced readout (1x1 binning mode must use this) and software compensation is bettered and is more precise. This gives slightly better quality guiding f rames. Camera OFF state is displayed wherever is necessary. 5 th page ( extra ) is introduced for the guiding screen(s) ( Guiding / Current guiding ). The changes are: o Camera can be turned ON and OFF manually on this page. The position of the guiding window is memorized except between binning changes. (Useful when You need to screw (T2) the camera off from Your equipment temporarily then restart the camera operation in the latest position. The Camera is highly recommended to be turned off before pulling out its cable!) o The wait time variable is moved to page 5. (Most of the users don t need this at page 1.) The guiding window display mode can be changed now from all the pages. The guiding window display mode maxy is renamed to profile as the image shown is the guiding image s (vertical) profile. This is NOT a histogram. The used threshold level is shown as an inverted horizontal line at the profile display mode. (See above.) The drifts display mode uses ± 4 pixels as the tolerance interval. If the drift exceeds the display area (± 12 pixels for each axis) it means that drift reached the emergency interval, which is 3 times the tolerance interval. (See the user s manual of fw 1.22.) When a star is present in the guiding window, the window will follow (move) as the star moves on the CCD s surface. This behaviour was constantly operating before. In the new firmware the window is fixed when the autoguiding is enabled. The only exception if the RD is active (moving the mount and the guiding star). The motivation of this behaviour is the wind (or accidental push), that could move the guiding window off from the star if an axis is well balanced and has high backlash on the gear. Text (detailed) error display. (Except some rare cases.) - 2 -

3 BUGFIX: there was a sidereal speed calculation bug using manual guiding settings (= if no calibration was used)

4 2 Some demo images for binning modes The common setup and settings: LMG gain 5 (11 e - /ADU) Objective: (old) Canon EFS 22mm (f/4.2 approx.) Filters: Baader UV/IR block + 30% polarizer + 30% neutral Light condition: 40W bulb 2 metres to the objects 1 1 (no binning) full frame 1 second exp.time - 4 -

5 2 2 full frame 250 msec. exp.time - 5 -

6 4 4 full frame 62 msec. exp.time - 6 -

7 6 6 full frame 26 msec. exp.time - 7 -

8 3 Notes on LMG_SAAG_App.1.99.exe 3.1 File downloading and processing If the application cannot create a folder (using -f or -r, the file menu mode) when saving a raw file from the device, use the folloiwng method instead: 1. start 'lmg_filemenu_nodir.bat' and download the file(s) content into the same folder as the executable. Downloading of a raw file will not create formatted output files yet. 2. start 'process.bat <file>' with the raw file's name as an argument that You want to generate output for. For exmaple: process MG00001e.dat 'process.bat' will create a folder (named '<file>.content'), copy the raw file into the folder and generate formatted output files in there. If You download the same file more times (because You reopened the file in the device since), the old raw file is back-up (<file>.bakxy) in the used directory if a raw file with the same name already exists. I apologize for the inconvenience, on some operation systems / user modes the directory/folder creation from the application fails for some unknown reason. If the application can create a folder, only the raw file is saved there and the usage of process.bat is necessary to create formatted output files. For example You download MG00001e.dat into MG00001e.dat.content folder with the -f switch, You can generate output files by: process MG00001e.dat - if MG00001e.dat doesn t exist in the app s folder or process MG00001e.dat.content/MG00001e.dat 3.2 Extension for CSV formatted output The drift type event format is extended as follows: if there was no guiding star present on a guiding frame, four zero numbers (columns for RA,DEC drift and RA,DEC autoguiding signals) is written to the actual CSV line and the fifth parameter of this event says no star. In this case the HandController had broken instantly the current autoguiding signals if there were any active

9 3.3 Other Some little bugfixes were done to the formatted HTML generator. Besides the images are now coloured insted of grayscaled. On the Guide star drifts diagram the no star frames are shown with a dark red background and zero diagram value. These frames are excluded from the statistical data (total number of star positions, RA/DEC mean and standard deviation etc.)