Dan_Paris

Thanks! I would be surprised that it is not the case...

Thanks a lot @ONIKKINEN, @mackiedlm, @windjammer, @Sunshine, @Roy Foreman and @tomato ! Well according to the weather forecast the forthcoming days will be much more quiet.... Clear skies, Dan

Beautiful rendition Andy! Dan

Very interesting topic Paul, thanks for your post. I wish there was a simple way to include extragalactic globulars databases in Pix or ASTAP annotation tools...

I really enjoyed your story as well as the pictures, congrats!

Hi, Here are my latest pictures with the usual setup (8" f/4 with ASI183mm). NGC7814 is an aesthetic edge-on spiral galaxy in Pegasus, 33 millions l.y. away, with a very sharp dust lane and many globular clusters in the halo. I imaged it from a darker site than usual (about Bortle 4/5), with good seeing (FWHM 1.6" on the stack): Crop on the galaxy: The other ones are from my Bortle 7 backyard 20km from Paris, Arp 278 or NGC 7253 in Pegasus is an interesting pair of colliding galaxies, about about 210 millions l.y. away. The aesthetic face-on spiral galaxy PGC 68543 nearby seems also to interact with a small companion. The main galaxies of this field in Pegasus, the barred spiral NGC7342 and the edge-on galaxy NGC7345 were discovered by French astronomer Stephan as the Quintet nearby. Together with the PGC galaxies nearby on the image, they form the cluster WBL685, about 400 millions l.y. away. Abell 2634 is a galactic cluster in Pegasus, about 380 millions l.y. away, whose main galaxy is the elliptical NGC 7720. The NGC70 group (Arp 113) in Andromeda, a tight group of galaxies 320 millions l.y. away, with many others in the field: A crop on the main components Arp 112 is a tiny pair of interacting galaxies in Pegasus (spiral NGC7806 and elliptic NGC7805) which is actually interacting with a third one, the arc-shaped KUG 2359+311, 216 millions l.y. away. The field contains also the barred spiral NGC7819 as well as many other distant galaxies. Crop on Arp112 Thanks for looking, Clear skies, Dan

I really love this picture of a rarely imaged galaxy in a rather spectacular setting. Well done!

A sandwich carbon tube from Germany for my 250/1200 astrograph project

Great image David with excellent processing! Did you use the Samyang at full aperture?

excellent capture, very clean yet detailed, congrats

Very nice image @powerlord I really like the "ethereal" look of it.

Thanks @powerlord and @ollypenrice much appreciated, Clear skies, Dan

beautiful, clean and sharp!

Thanks a lot @simmo39 and @geeklee! Clear skies, Dan

Lot of details in one of my favorite galactic pair, well done!

Hi. PK104 29.1 (Jones 1) is a large but rather faint planetary nebula in Pegasus. Not the easiest from Bortle 7 with broadband filters! I framed it off-center to include the interacting pair of galaxies Arp 46 ( UGC 12665) as well as the spiral galaxy UGC 12667. There are interesting details in the galaxies thanks to the rather good seeing (FWHM 1.7" on the luminance stack). Right-click for full-resolution: Clear skies, Dan Technical details 200/800 custom Newtonian astrograph with Romano Zen optics and carbon fiber tube AP900 CP4 mount on Losmandy HD tripod ASI183mm (0.66"/pix) TS 2.5" Riccardi-Wynne corrector ZWO LRGB filters Guiding : ZWO OAG + ASI120mm mini + AsiairV1 Luminance : 340 *60sec Chrominance : 30*60sec for each R,G and B. Conditions : Bortle 7 skies in Paris' suburbs, hazy skies and decent seeing (1.7" median FWHM on the luminance stack) Stacking with Siril, processing with Pixinsight

The resolution is superb. I'm like you, I always perform the final touches outside of Pinxight using a non-astro software, in my case Rawtherapee.

Here is NGC6946, the Fireworks galaxy, right on the border of the Summer Triangle as @Graeme noticed. The open cluster NGC6939 is on the "wrong side" of the border... From my Bortle 7 backyard near Paris on August 17. Technical details 200/800 custom Newtonian astrograph with Romano Zen optics and carbon fiber tube AP900 CP4 mount on Losmandy HD tripod ASI183mm (0.66"/pix) TS 2.5" Riccardi-Wynne corrector ZWO LRGB filters Guiding : ZWO OAG + ASI120mm mini + AsiairV1 Luminance : 260 *60sec Chrominance : 20*60sec for each R,G and B. Conditions : Bortle 7/8 skies in Paris' suburbs, hazy skies and variable seeing (1.8" median FWHM on the luminance stack) Stacking with Siril, processing with Pixinsight

Very beautiful Olly, I really like the empty space feeling that this image conveys...

Thanks a lot @simmo39, @glafnazur and @ollypenrice for your kind words! Clear skies, Dan

Very fine image of a galaxy that we don't see very often, thanks for sharing

Hi, when I was young I was fascinated by the famous image by David Malin of CG4 in Puppis, nicknamed God's Hand, a star-forming region in the shape of a hand which seems to be about to grab a distant galaxy. I realized recently that there is a strikingly similar nebula in the northern hemisphere, LBN 438 in Lacerta, accompanied by the distant galaxy PGC 69439. I spent two nights on this object, which is quite challenging for my Bortle 7 skies 20km from downtown Paris. Overall there is 11 hours of luminance in good seeing conditions (median fwhm 1.75" and limiting magnitude 21.5 on the luminance stack), and only 60 minutes of color data. Right-click for full resolution: Thanks for looking and clear skies, Dan Technical details 200/800 custom Newtonian astrograph with Romano Zen optics and carbon fiber tube AP900 CP4 mount on Losmandy HD tripod ASI183mm (0.66"/pix) TS 2.5" Riccardi-Wynne corrector ZWO LRGB filters Guiding : ZWO OAG + ASI120mm mini + AsiairV1 Luminance : 660 *60sec Chrominance : 20*60sec for each R,G and B. Conditions : Bortle 7 skies in Paris' suburbs, hazy skies and rather good seeing (1.75" median FWHM on the luminance stack) Stacking with Siril, processing with Pixinsight

@vlaiv without doing any FFT experiment when I look at the left-hand side looks clearly sharper to my eyes. For sure it may well be that the ideal sampling is in between though.

I think that this is the best possible conclusion: different setups and different seeing conditions so we can be both right. I'm convinced that with my setup and my seeing conditions 0.67" gives more resolved images than 1" having imaged many galaxies with both cameras attached to the same telescope. It may be that the ideal sampling is in between, I don't know. Half of the nights my seeing is in the 1.5" to 2" range, and the FHWM produced by my telescope/corrector combination is 4.8µm, i.e. 2 pixels with the IMX183, or below (an experimental value inferred from my best subs). I certainly don't claim that this holds for any scope in any seeing conditions.

I suspect it is from the last one from yesterday which is not relevant for the discussion about resolution (bin1 was scaled down to bin2 after noise reduction for noise comparison purposes). If you view the image from today full screen, don't you agree that the difference in resolution is plain obvious?