alexbb

And a first RGB-HOO processing attempt

The area looks about like this: There seems to be some uncharted nebula also in Ha at ~07h, 18deg DEC This time I didn't restrict too much my search on https://planetarynebulae.net/EN/page_recherche.php, but I still could not find anything.

There are no images of the whole Monogem ring yet. I spoke to a friend already and we'll point our lenses the following nights. The Sigma 135 1.8 and the 2600 mono seem to make a good pair under decent skies.

The outer shells seem to be part of the Monogem ring and Marcel pointed me to https://planetarynebulae.net/EN/page_np.php?id=83 which is the big circle at the top (left). For missing this one, I am to blame, since the information was already available, but I missed it somehow. I believe I filtered for RA 6-7 only and RA for it was 7+. Which seems to be obvious even from my images, but sometimes my mind fails at simple things...

Thanks! I knew you captured a part of the Monogem ring and I also saw some arcs near the Rosette nebula. Perhaps there are simply no images of the full ring in the visual spectrum and they are waiting to be captured. I'll try to get in touch with Marcel and see if he knows and can share some more info. This area is a 4 panel composition with a Sigma 135 F/1.8, ToupTek 2600 mono and an Astronomik MaxFr 6nm O[III] filter. 1h exposure / panel. Skies would be SQM ~21.2 in that area, captured at no lower than 30 degrees. Skies and time allowing, I'll add to it. Though I also want to cover the missing panels already covered in Ha and RGB this season.

Hello, Cara! I was asking about those marked with a question mark in my second image in the first post. The common ones can be easily identified. I believe that the fits header should have also information about coordinates. However, you can use the cone nebula for center, 5.8um for pixel size and 100mm for focal length. Image solver with auto catalog should do the job. I tried the available catalogues in pixinsight already (except the stars only and galaxies only ones), but without success. I could try to export/import the catalogue at planetary nebula .net, but I checked the nebulae around that RA and Dec and wasn't able to find one. Perhaps I need to shoot at least 2 more panels towards east to see what's lurking there, but this season is ending very soon.

On the Lite version, I find nothing. And I don't know yet how to use the desktop version. Here are an unstretched fits and a stretched jpeg. O3-panels-78910_050.fits

I tried, but astrometry.net provides limited results. I tried http://cdsportal.u-strasbg.fr/ and browsed around the area in https://planetarynebulae.net/EN/page_recherche.php If there's a big loop, its center might be somewhere else

I tried (actually still trying) to make a large image from Monoceros to Auriga - from Rosette to Flaming Star in 2x5 panels. Currently, of O[III] I only have 4 panels, but I still tried to put them together to see if the plan is going on properly. I tried to identify the less know nebulae in the image, but there are a few shells that I cannot identify. I marked the ones I already know. The bright obvious ones I skipped. The ones remaining are contoured and have a question mark nearby. Can you please help me identify them? Are they part of a larger loop? The Monoceros loop doesn't include them as far as I know. Thank you and clear skies, Alex

For a quick look of what's going on in a dataset, an usual workflow could be like this: DBE, crop, background and colour calibration, Blur XT, arcsin/HT stretch, Noise XT at 50-75% with inverse luminance mask, Star XT, additional HT stretch to different level on the RGB channels if needed, maybe a SCNR, then add the stars back with pixelmath and run another Noise XT if needed. Star XT usually gives a cleaner output compared to Starnet 2. If you're using Starnet v1, try upgrading to Starnet 2, it provides better results.

Can't answer all your questions, but: The platform doesn't have a true DEC compensation. I tried to do this to my DIY modified platform and it helps only over some sky areas. iPolar also needs some calibration, at least that's what I remember since I set up for the fist time my iOptron mount. True north is at ~40 arc minutes between Polaris and Kochab. The full moon is ~30 arc minutes. So the true north is at a distance of 1 1/3 moons away from Polaris, towards Kochab (Little Dipper).

Regarding your original question - have you tried to remove the stars after a stretch? A 5 minutes play in PixInsight with the XTerminators + LHE and MLT can easily reveal some additional signal and details. Spending more time can improve the outcome, of course.

I can see the arc on the left side in my image in the one you mention, but barely the arc on the right side. I had some trouble in finding the right backfocus for the C6 Hyperstar, but in the end I found a working distance and the results are on the rather good side. Stars are not perfectly round, though, they are a bit fuzzy, perhaps also due to the cables in front. It does the job and gathers significant more light than a ~70mm refractor. Plate solve measured focal length is ~315mm. I would prefer a RASA8 and an ASI2600MM, but for now I won't complain. Interesting article! I can hardly see the arc on the right side, not much more visible than in the image Elp linked. I'll add a few more hours the following clear nights, shifted a few hundred pixels to the north to try to catch it fully. If I look more carefully, it seems that it is a full oval through the Rosette. Or is it just my imagination?

Saw the other day that @gorann found a large bubble near the cone nebula. I also found a big bubble which I don't recall seeing next to the Rosette nebula. This is a heavy stretch of 3h of O[III] taken with a C6 and hyperstar + an ASI294MM. I need to shoot more and a bit above to catch it entirely. Have you seen it before? Where and how can I find if there's an already know nebula there? I surrounded it with orange strikes in the image below.

Exciting, never seen before. Maybe it's time to discover new objects in Monoceros? Found something similar too the other night next to Rosette. Great image, I really love the closeup around the cone nebula.