Looks better at that small scale, Allan. I've done a bit of a tweak myself. See below...
Hi Rick,
Yes - that's much better.
You also have the red nebulas much larger than I got from the smaller pic.
I pushed the yellow core a bit more with a mask which I suppose is cheating
but it looks a bit better.
I also sharpened the masked galaxy - I think it can still take a touch more on your effort.
Awesome shot Rick! I think I like exploring the background in the pics you guys take as much as the object at the center of attention. The background in the revised pic seems is a little dark on my monitor, but the galaxy is nicer.
Hmmm? Think I like the brightness of the original actually...but line ball really
Mike
Ta, Mike. I'm of two minds myself. I don't like the flat look you get from too much dynamic range compression although it does bring out more detail.
Quote:
Originally Posted by alpal
Rick,
Hi Rick,
Yes - that's much better.
You also have the red nebulas much larger than I got from the smaller pic.
I pushed the yellow core a bit more with a mask which I suppose is cheating
but it looks a bit better.
I also sharpened the masked galaxy - I think it can still take a touch more on your effort.
cheers
Allan
Thanks, Allan. I didn't draw any masks I may play around a bit more although I'm not sure the data is good enough to justify a lot more effort.
Quote:
Originally Posted by cometcatcher
Awesome shot Rick! I think I like exploring the background in the pics you guys take as much as the object at the center of attention. The background in the revised pic seems is a little dark on my monitor, but the galaxy is nicer.
Thanks, Kevin. I thought it looked a bit darker too although I didn't do any processing that should have caused that. I even measured a section of background and the stats were the same between old and new. Might have to check again when I get home to the data. I might have been tired and made a mistake...
Quote:
Originally Posted by gvanhau
Beautifull image Rick.
Pity you didn't have the best seeing conditios, but so is this hobby...
Geert
Thanks, Geert. Unfortunately, we have to do the best with the data we get!
Quote:
Originally Posted by Rex
Nice repro Rick, like Kevin, I like to search the back ground of these really deep images, so many things to look at.
I prefer the repo, a touch more contrast in the main object. Don't you just love it when you can't decide between two versions of an image, it happens to me all the time.
Very impressive depth and resolution on the galaxy !
I've used the image for some catalog testing ...
From the Hubble Guide Star Catalog II, stars with VMag 21 (the catalog limit) are easily visible. I reckon you have stars to about VMag 22.5.
There's also about 100 galaxies from the Principal Galaxies Catalogue. The faint one PGC3169353 top left (red square) has a radial velocity of 77,000 km/s, putting it about 3.7 billion light years away.
Like the microquasar you mentioned, there's bound to all sorts of other interesting things in there.
In the second version I managed to clip the background so I have restored it to it's original glory while maintaining a bit more contrast on NGC 7793 itself.
Ah ha! Sorry I missed this! I wouldn't have used wavelets but yes, that's definitely what I had in mind! More structure visible and it no longer looks, well, over exposed! Nice!
Ah ha! Sorry I missed this! I wouldn't have used wavelets but yes, that's definitely what I had in mind! More structure visible and it no longer looks, well, over exposed! Nice!
Thanks, Marcus. Although I used a chisel instead of a screwdriver I was hoping that was what you were thinking
Thanks very much, Sam! What did you use to do the annotation?
It's some code I've cobbled together over the last couple of years (in C#). I use a local copy of the Principal Galaxies Catalogue, but the program queries the GSC-II catalog online on demand (it's about a billion stars so it's too large to download entirely).
I was wondering what sky brightness you had when imaging to get the very dim limiting magnitude ?
It's some code I've cobbled together over the last couple of years (in C#). I use a local copy of the Principal Galaxies Catalogue, but the program queries the GSC-II catalog online on demand (it's about a billion stars so it's too large to download entirely).
I was wondering what sky brightness you had when imaging to get the very dim limiting magnitude ?
Nice work! I used the PI annotation script and it noted PGC687110 but not PGC3169353.
One night out of five was at a pretty dark site (Glen Aplin.) The other nights were at Hazeldean and Ten Chain Hill which aren't far from civilisation and aren't exceptionally dark.
PI annotation script and it noted PGC687110 but not PGC3169353
Not sure about the PI annotation script, I thought it would have grabbed all the galaxies from the PGC. Maybe the smaller galaxy is not displayed because it's so close to the much brighter PGC687110, or maybe there's a magnitude threshold ?
select * where al2000 > 23.93833 and al2000 < 23.99278 and de2000 < -32.2967 and de2000 > -32.9361 and objtype='G'
Also the fairly dark sites match my recent calculations on CCD Limiting Magnitude. When I put your equipment and exposure times into my spreadsheet I get a stellar VMag limit of about 22.4 (with 21 VMags/arcsecs2 skies), vs 21.9 (with 20 VMags/arcsec2), and 22.9 with 22 VMags/arcsec2.
Not sure about the PI annotation script, I thought it would have grabbed all the galaxies from the PGC. Maybe the smaller galaxy is not displayed because it's so close to the much brighter PGC687110, or maybe there's a magnitude threshold ?
It's the PGC Hyperleda I catalog. No options for magnitude. You can add new catalogs but I haven't have the time or inclination to play with it further.
select * where al2000 > 23.93833 and al2000 < 23.99278 and de2000 < -32.2967 and de2000 > -32.9361 and objtype='G'
Thanks for the pointer. It has been more than a decade since I last formulated a SQL query but I could probably manage that
Quote:
Originally Posted by SamD
Also the fairly dark sites match my recent calculations on CCD Limiting Magnitude. When I put your equipment and exposure times into my spreadsheet I get a stellar VMag limit of about 22.4 (with 21 VMags/arcsecs2 skies), vs 21.9 (with 20 VMags/arcsec2), and 22.9 with 22 VMags/arcsec2.
Do you have a model for magnitude limit for an extended source? I still like to think I captured jet R4 of NGC 1097 at 27.6 mag/arcsec^2. All that data was from very dark sites...
