Bump
Interesting thread, I need more information and people's perspectives on this topic. I have for a long time been a proponent for sky flats. They've always worked well for me with the various scopes and imaging train configurations I've had.
However, I have come to acknowledge that with the new set up with the precision instrument rotator (PIR), I'm going to really struggle getting the needed flats done in the short period of available light at dusk and dawn. The PIR being a necessary evil for long guided images means flats taken at a PA of 0 must also be taken at a PA of 180 to handle meridian flips. This is not news to me and I well knew what I was getting myself into but I was seriously hoping that I could continue to use sky flats with the needed high output of flats.
Based on this I'm on the market for a flat panel. There seems to be a magnitude of vendors these days offering different bells and whistles. Here are my requirements;
- Must endure the elements of being permanently mounted in the observatory. Its a reasonably clean environment but not pristine. Condensation can be bad at different times of the year. Heat, frost, wind etc. less of a problem
- Should be easily mountable with the appropriate fittings to support the unit. I don't mind a trip to Bunnings to get other components as needed but I don't want to be making modifications to the unit itself just to mount it. So this is something I expect the vendor to supply. The mount will need to support adjustments so its perpendicular to the OTA
- Must not require physical intervention to turn on or off. The observatory is operated remotely. I have an eight port remote power switch that I use to turn gear on and off as needed so this isn't too much of a problem providing it is as simple as turning it off and on. If there is some other initialization step that can't be performed remotely, the unit fails to meet this requirement.
- Should be able to adjust the panel's brightness remotely and support a command line interface for the adjustments so that it can easily be scripted into ACP for automatic flat panel flats. This is a 'should' as opposed to a 'must' as I'm working on the principle that I could install an ND filter so that I reach a happy medium between both broadband and narrowband flat exposure times. Providing I don't get shutter shadow on broadband filters, the narrowband flat exposures can take as long as they need. In addition, at F/9 I'm likely to need all the light I can get.
- Must be thin. Yeah sounds stupid as they're all thin, but I will emphasise this point as the telescope in the park position I have 4" of room between the telescope and the observatory wall. I may end up having a different flat position but the park location seems most logical. If I mount the panel on the dome itself I would have slightly more room between it and the telescope, however I then need to consider how to power and remotely control it, all on a rotating platform. Running it off the 12v shutter control battery is a less then desirable option (for obvious reasons).
- Must have good vendor support, preferably a local agent and warranty offered.
Personally I don't think I'm asking much as I'm sure others have walked the path before me and are doing exactly what I want to achieve. I'm looking for unbiased input in order to select a product that matches these requirements.
Thanks