Had another crack at M83 this year. I spent a bit over 10hrs gross on this, and netted about 6hrs of data. I was shooting mere 35s exposures at high gain (250) for all LRGB filters to try and optimize resolution. The problem with that is with SGP and my imaging computer, the overhead between downloading frames, settling and filter changes it about 17-18s, so I lost a *heap* of imaging time doing it that way.
On the bright side, I got some of the sharpest broadband subs I've gotten, with some G frames down to 1.6" The resulting super luminance had a median FWHM of 2.17" in the central 1000px of the frame (flattener spacing isn't *quite* perfect, so I tend to focus on the middle :p)
Not sure about the processing on this one. Optimised for the stars and thus compromised some other aspects of the image. May re-do it yet...
Exceptional job for a sub 5" scope Lee! The resolution is fantastic!
Out of curiosity, how often were you changing filters?
I must say that settling time is the absolute biggest improvement that I get upgrading from the EQ6. The EQ6 would sometimes settle nicely in 5s, sometimes 30s+!
I don't even have one anymore Due to the theoretical smoothness of your guide graph, your Linear should be significantly better than your EQ6 was in that regard too
Exceptional job for a sub 5" scope Lee! The resolution is fantastic!
Out of curiosity, how often were you changing filters?
I must say that settling time is the absolute biggest improvement that I get upgrading from the EQ6. The EQ6 would sometimes settle nicely in 5s, sometimes 30s+!
I don't even have one anymore Due to the theoretical smoothness of your guide graph, your Linear should be significantly better than your EQ6 was in that regard too
Thanks Colin :-) In order to try and balance out overhead whilst overcoming FPN, I was running LLLLRGB<dither>. I could have run multiple RGB but that would have come at the cost of less luminance and wouldn't have decreased the overhead that significantly.
Settling isn't *too* bad, usually a couple of seconds between frames. To be honest I only want to settle when dithering, but that's not an option as far as I can discern. Currently I settle at < 1px for 2s which means guaranteed 2s overhead every frame. After dithering it can take a bit longer to settle (I use extreme dithering x2).
Quote:
Originally Posted by atalas
Very nice result Lee
Thanks Louie :-)
Quote:
Originally Posted by glend
Great Lee, nice central detail coming through.
Thanks Glen :-)
Quote:
Originally Posted by cometcatcher
Very sharp Lee. 35 sec subs hey..... Well you've just given me all sorts of ideas now with astro cams.
Thanks Kevin :-) Short subs can work well but you need a camera with low read noise. I wouldn't try this with an 8300 for example, but with the new low read noise CMOS chips it becomes an option. Of course you don't really *need* one of those cameras, but it hurts your integration a lot less with them than with traditional higher read noise CCDs.
....Short subs can work well but you need a camera with low read noise. I wouldn't try this with an 8300 for example, but with the new low read noise CMOS chips it becomes an option. Of course you don't really *need* one of those cameras, but it hurts your integration a lot less with them than with traditional higher read noise CCDs.
Thanks Lee. That is a VERY useful piece of information that I was looking for. The ZWO CMOS cams are in my sights. Don't know which one yet exactly but I'll decide when Bill stops sending me letters.
Thanks Lee. That is a VERY useful piece of information that I was looking for. The ZWO CMOS cams are in my sights. Don't know which one yet exactly but I'll decide when Bill stops sending me letters.
No worries Kevin, glad I could help. That Bill's a right ol' prick! It's hard to beat the ASI 1600 in this price range.
Quote:
Originally Posted by topheart
Very very nice...lovely colour!! Sharp!
Cheers,
Tim
Thanks Tim :-)
Quote:
Originally Posted by traveller
Very nicely resolved Lee.
Great job.
Bo
Thanks Bo :-)
I've uploaded a reprocessed version, which I'm happier with. Stars aren't as nice, but the target is better. Pretty sure I'm going to get a visit from Mike soon though, muttering something about worms... ;-)
Hi Lee,
great work - one of the sharpest M83's ever posted.
That ASI camera is really performing well for you
& enables the shorter frames to be stacked well.
The low read noise of 1.2e @30db gain is making a difference.
You also had superb guiding & a low FWHM.
Very nice, Lee! The detail is great. That's definitely an advantage of a low read noise camera and short subs. I would have gone for a less cyan look and fixed the pink stars but not everybody agrees with my sense of colour (especially my wife...)
Hi Lee,
great work - one of the sharpest M83's ever posted.
That ASI camera is really performing well for you
& enables the shorter frames to be stacked well.
The low read noise of 1.2e @30db gain is making a difference.
You also had superb guiding & a low FWHM.
cheers
Allan
Thanks very much Allan, I'm pretty pleased with the resolution given a 5" scope in Australian skies :-)
Quote:
Originally Posted by cometcatcher
That's even nicer.
Thanks Kevin! :-)
Quote:
Originally Posted by RickS
Very nice, Lee! The detail is great. That's definitely an advantage of a low read noise camera and short subs. I would have gone for a less cyan look and fixed the pink stars but not everybody agrees with my sense of colour (especially my wife...)
Thanks Rick :-) Funny you should say that, I just had it open in Photoshop and was thinking it looked a little too cyan. I think pink stars is due to some bloating in the blue channel and me being too lazy to reduce the stars to compensate.
I'm thinking I may actually get a bunch more data (skies/weather permitting), perhaps switching back to more traditional exposure lengths, at which point I'll reprocess and probably tweak the colour some.
If I had an infinite amount of spare time I'd like to write some software that minimizes the overhead for this kind of capture, but right now it's pretty nuts to try and go deep whilst throwing away ~40% of your imaging time.
I love it! So many little galaxies in the background!
It would be awesome to add more data and thus give a bit more contrast to those tiny smudges and fuzzies. Cannot see anything wrong with flattener spacing either.
Due to the theoretical smoothness of your guide graph, your Linear should be significantly better than your EQ6 was in that regard too 
