Hi all
Under the full moon I went deep, with the mighty 300mm F2.8 Flourite lens from Bert, coupled with Houghys cooled DSLR, sensor temp around 4 degrees.
5x15 mins @f2.8, ISO 400, Baader 7 Nm Ha filter. Processed in Iris with a dark, flat and offset (taken at same sensor temperature), and Photoshop.
Scott here is the exact same region taken with the 5DH and 300mm lens and Halpha filter. It was 6x3min at an ISO of 1600 so the exposures are roughly comparable. I will let you decide what improvement you have with that system but I think even Mr Magoo could see it.
Download both images and flicker between the two.
400K http://members.optusnet.com.au/~cheekyfish/velabert.jpg
That system would be stunning for narrowband imaging!
Scott, I do have one question. I seem to recall that when Tony originally purchased a cooled DSLR he had all sorts of problems with sensor fogging up etc..you dont seem to have any issues, is that correct?
Narayan
Thanks all
gee, Bert the benefit of sensor cooling can really be seen there. With mine the sensor temp was about 4 degrees. It was also VERY dewy too, so the inbuilt antidew heater works well, keeping dew off the sensor window.
There is definately a bit of an issue with flatfields though, to do with the HA filter I think, as I had to use Gradient Xterminator to try and get rid of brightening in centre of field, despite taking flats. I used the white screen from my laptop as the lightsource for the flats but that doesnt seem to be working
The original image's backgrounds were quite red, some moonlight getting through, I must try it again without the moon to see how much better it is. The Ha filter, being an interference filter is affected by a wide light cone, such as with such a fast f2.8 system, so dark skies would definately improve things further.
Scott
Scott I have found that a flat taken with an LPR filter (same optics) works fine for the Halpha. A flat taken with the Halpha seems to have as you say central brightening.
Hi all
Under the full moon I went deep, with the mighty 300mm F2.8 Flourite lens from Bert, coupled with Houghys cooled DSLR, sensor temp around 4 degrees.
5x15 mins @f2.8, ISO 400, Baader 7 Nm Ha filter. Processed in Iris with a dark, flat and offset (taken at same sensor temperature), and Photoshop.
Hey i want my camera back
nice work Scott.
