I don't know much about optics but I know enough to have had an inkling that was the sort of answer I would get.
I always look at such images with the Fermi Paradox in mind. Where are those little alien critters FFS?
You have to wonder...
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I don't know much about optics but I know enough to have had an inkling that was the sort of answer I would get.
I always look at such images with the Fermi Paradox in mind. Where are those little alien critters FFS?
You have to wonder...
Update to rig:-
Phase 1 - addition of William Optics Redcat 51
Reputedly one of the sharpest lenses in the world.
A four element Petzval apochromatic lens.
Phase 2 - will be the addition of a cooled, one shot colour (OSC) astronomy camera.
Phase 3 - will be the addition of a cooled mono astronomy camera.
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that looks expensive:eyebrows:
Astro imaging is not as expensive as hifi [emoji4]
The WO Redcat 51 is £699, which IS considered expensive compared to some of the smaller ED or apochromatic scopes bit it is already a completely flat field lens so doesn’t need additional reducers or flat field adaptors in order to use it with any camera.
The cameras are actually the expensive items. The ones I want start at around £900 [emoji33]
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i see there is a Draconid meteor shower this week...
Interesting post Tony. I was aware of the Petzval lens used for portraiture, but I had to look up the difference between 'achromatic' and 'apochromatic' lenses.
As a photographer (strictly analogue) I was aware of the work of Voigtlander and of Steinheil and of the subsequent manufacturers bearing their names (and who's lenses I use, along with those by Zeiss), but didn't know the Petzval lens was used in astrophotograpy.
Since all of the objects are 'at infinity', you are not interested in depth of field - is this what you mean by "flat field", and why would you need an adapter?
Hi Barry!
There are two uses of ‘flat’ in Astroimaging really.
One relates to vignetting and distortion at the edges in the optical field that require correction via a field-flattener lens.
That’s what I’m referring to as far as the Redcat is concerned. It doesn’t need any correction to fill a full-field camera without vignetting or distortion.
The other use of ‘flat’ is when imaging. You calibrate the image by using darks, bias and flats.
The darks are subtracted to remove any hot pixels.
The bias is to remove any inherent faults in the CMOS/CCD chip used by the camera.
The flats is to produce an even illumination over the field, to remove any vignetting and also any ‘dust bunnies’.
Tony
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Hi Tony, time is 6.50 am, and looking southwest(ish) there is the crescent moon, and to the right and up a bit, at about 45 degrees to the moon there is one really bright star - what is it? Mrs. P has been wondering for some time, as have I :)
I bought a Samyang 14mm f2.8 lens back in 2017 to use for my coastal photography but sold it a few months back to concentrate on my Nikon 20mm. I also bought at that same time a Samyang 85mm f1.4. That lens is quite simply stunning.