Every year I decide to do widefield Milky Way imaging and a mosaic of the whole thing and I've missed it for the last few years.
I got prepared a bit earlier this time.
There's a little bit of time left to image the Milky Way in its widefield glory.
The setup is a FLI Proline 16803 camera, with a Losmandy D mount on a double sided dovetail. A FLI colour filter wheel, FLI PDF Focuser and a Precise Parts adapter to take Pentax 67 (medium format film size) lenses. Autoguiding using an SBIG ST402ME and efinder mounted using a Losmandy D adapter and double sided dovetail plate.
Richard Crisp put me on to this setup as the Pentax 67 lenses are designed to illuminate 60 x 70mm film which is bigger than these large CCD chips plus they have about 87mm of backfocus which is unusual for lenses.
They are also fiarly "cheap" on Ebay and reasonably plentiful (except the rare 300mm 67 F4 EDIF).
I have 55mm F4, 165mm F2.8 and 300mm F4. The 55mm F4 tends to give some coma which weakens with 2x2 binning and stopping it down to F5.6.
This image is with the 165mm F2.8 which seems best wide open which is fantastic. Stopping down a lens tends to reduce the aberrations but it causes those multiple diffraction spikes on bright stars which I am not a fan of.
This one ideally would be a mosaic but only one night was available due to moon and weather.
HaLRGB 10 30 10 10 10. Luminance was shot 1x1 (it is noticeably better at 1x1 than 2x2 with this lens). Colour and Ha was 2x2. There is very little Ha blended in as it did not add much except a bit more depth and contrast to the dust areas and a bit more colour to the Lagoon area.
I intend to do a series of lens widefield images next no moon and probably several mosaics.
I am very pleased with this lens.
http://upload.pbase.com/image/137896676 large
http://upload.pbase.com/gregbradley/...37896676/large regular
Here is a photo of the lens setup:
http://upload.pbase.com/image/137897274
Greg