Quote:
Originally Posted by kinetic
Lovely result Mike.
FWIW I reckon a crop of a bit more background really makes the horse
sing...hmmm, bad choice of verb, I think you know what I mean.
A real close crop is awesome but a zoom back out just shows how deep
you really went, emphasising the dynamic range.
Anyway, WTH would I know, great job!
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Oh yeah that area looks great in a 2deg field and I get that with the ProLine 16803 but the full frame link there is the field I have with the SX camera...so are you saying you prefer the full frame version over the crop? I only included the close crop cause, well, I was just..?.. horsing around
Quote:
Your site mentions you didn't use darks, is there simply no need to at 20C below?
I notice when I do extreme stretching, even on the humble QHY-8
which gets down to around +/- 5 deg around zero, I can see that using darks helps a lot,
mainly because it calibrates out not only hot pixels, but readout noise?
Does the flat do that, excuse my ignorance, I've never used flats.
Steve
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With the Starlightxpress it seems to not really benefit from darks. Unbeknownst to many imagers darks actually
add noise as do flats, of course you can mitigate this effect largely by taking lots of darks and lots of flats to average out the noise but in the end they do
add noise.. so in a perfect world they wouldn't be necessary...the answer is a nice low noise quiet chip (as is in in the SXVR-H694) then median combine out any residual hot pixels, have no vignetting and very clean filters and CCD window so flats are not necessary - easy! I am nearly there, I get a bit of vignetting from the small 1.25" filters so I have 36mm filters sitting here waiting to be installed.
I have been imaging at -20C since getting the camera earlier this year so while this low temp may assist I think this Sony chip is still very smooth even at higher temps.
It must be said that chips do have variations in sensitivity across their lattice and flats do address this and certainly with a big chip I think flats are probably more necessary but a small chip like the H694 I recon if you get all the variables mentioned above right you are home and hosed....super easy high class imaging
I have stretched the bejesus out of my data an not a single dust mote to be seen...touch wood..for when I change over filters
Mike