Hi. This is an update to the suite of tools I've been developing for about 12 months based around an unguided DSLR set up.
I understand that there are several computer programs that manage image acquisition and control mounts/guiding etc. I needed something that would add control to an essentially manual setup that does not benefit from existing programs without an 1100AUD Argo Navis conversion.
The problems to solve were;
Effective control over camera shooting sequence with;
Coordinated dithering and;
Automated calibration frame acquistion.
3 components at this stage -
1. The stepper motor, roller, toggle plate, hand controller button pusher (Ditherbot-Sparehand prototype).
It was not my intention to play around with the mount electronics or start hacking away with a soldering iron - the dithering mechanism is designed not to be intrusive. It is very effective, if a little noisy. Two sets of images clearly show the effectiveness of the device in dealing with sensor artifacts and noise in general.
2. The intervalometer component for sequencing light and calibration frames (Ardastrovalometer).
Much more control than many of the intervalometers on the market, and it is an integrated part of the system, so no external timing issues with other hardware components.
3. Light leak proof illuminable lens cap for flats, bias and dark frames (LumCap)
This proved to be the most difficult hardware problem. Essentially, LEDs (EL panel), light baffles and diffuser to produce a flat field. It had to be sealed with aluminium foil to prevent stray wavelengths spoiling the calibration frames.
I wasn't happy with the acrylic diffuser having a strong green bias and dyed one side blue and the other red, to compensate. Another use for shoe polish. Need to find a material with better RGB balance, other than paper, which is pretty good but not very flat close to the lens.
Granted, this is not the most sophisticated approach, but it makes good use of the available hardware. Very small footprint and low power consumption. If anything it lacks more precise focusing available through computer programs.
The jpeg crop below shows the mounts unguided tracking over 3.5 minutes and camera focus using live view. I see no need to address guiding at this stage - there is room for improving focus - perhaps a mask.
Further improvements should be TEC cooling control, and mount power control. The plan is to leave the set up unattended.
