iDK 20 Status

lukas_demetz

Hi guys,

I wanted to keep you updated on the status of the 20" iDK Astrograph in Namibia.
It is performing fairly well, but there are some issues nonetheless:

Collimation is okay, but not spot on: It looks like the secondary is not exactly centered in the tube. Also, there is some tilt in the system. Combined, those two lead to some changing star shapes while cooling down.
While the observatory allows to image down to about 21° above horizon, it is advised to keep the minimum altitude to about 40° (you can do so in the Imaging Request Wizard). Keeping very low bloats the stars up and give a bigger surface for wind gusts.
The CCD in our FLI Proline has one defective (hot) column, plus some minor aging signs. Keep a good eye on the calibration. I really recommend doing it yourself, the automatic calibration is far from perfect. Also, it is preferable to take more dithered frames and stack them to correct out the hot pixels and column. So, it might be better to shorten the exposure time for the single frames and raising their number while keeping the total exposure time constant.

I plan to fix point 1) in october on site. As for the CCD, I am considering to buy a new GSENSE 4040 CMOS camera, which would cover the exact same area with the same 9 micron pixel size, but would be far more sensitive and supposedly be easier to calibrate. I honestly need to see how things are going onwards as it would be a serious investment 😅

fernandoyang

Hello Lukas!

I'm looking forward to the new camera 😀 !

Fernando

lukas_demetz

Hehe 😀
I am waiting for an offer from Moravian, and one from FLI. Let's see. Those things are prett expensive, but I recognize the advantage there.

Eduardo

Lukas, Thank you for keeping us informed! A new CMOS camera would be great indeed.
Eduardo

lukas_demetz

Hi Eduardo,

I think we will first await the results of our QHY600 camera (which is mounted on the Veloce 200). I studied now some results from the FLI Kepler 4040 camera, and I am not really impressed. It might be great for photometry and astrometry, but the strong banding and even some sort of "quadrants" might make it very difficult to get some decent pretty pictures with it. There seems to be very little alternatives around, though... Let's see.
I also have to fix the shutter of our Proline 16803 as it is closing a little slowly, causing some vertical lines on bright stars. Hopefully I can do this next month.

Eduardo

Hi, Lukas. True, I observed this vertical lines in the two brightest stars in my last image. Not very disturbing but that's good to know you are on this. Thank you

Eduardo

lukas_demetz

As an update, you might have noticed plenty of images with apparently bad tracking. Regrettably the wind situation in the last days was bad. The guider was often unable to get a suitable (sharp) guiding star, as it kept jumping around. I will try do take some frames manually in the next nights, hopefully getting some requests done...