alexbb

I see this thread has been brought to life. Unfortunately, the GEM45 only worked fine for maybe 6 months, then it went crazy. Now the PE p2p is around 60 arcsec. iOptron support received the emails in their spam initially, then we managed to exchange a few, then silence again. I need to send now the mount to Astroshop service, but I had to delay this for a while because of other things getting in my way.

Thank you, thank you, Mr.!

I avoided imaging this one as it is so low, it only rises to about 23-24 degrees above the horizon where I live and close. So for this I needed good south skies. I started it as the side target at a summer start party camp, shooting Ha with a SkyWatcher 150 PDS masked with a ~144mm baffle for round stars shape and an ASI1600MMC. The outer shell came out quite visible at almost 7h so I decided to add more to it. Back home I have a decent dark area nearly so I was able to at least double the signal, most of it with the same scope. The ASI294MM is so more sensitive than the 1600. As the forecast doesn't seem astroimaging friendly, I decided to process it at a total of almost 25h and, weather permitting, I might add some RGB later, before it's too late for the season. Seeing is bad so low so fine details are lost in the blurness, but it's better than nothing. Anyway, here it is, below, or astrobin or Flickr. Clear skies! Alex

Many thanks to all of you again! Here's a good correspondence between Bortle scale, NELM, SQM and what's expected to be seen: https://en.wikipedia.org/wiki/Bortle_scale

Thank you! As I described, it was done from different places, multiple years. But at the darkest where I gathered the 20h of narrowband with the C9.25 we measured 21.7-21.8 SQM, that meaning a 6+ magnitude naked eye or Bortle 2. Closer to home - half an hour drive - we have a decent dark place, Bortle 3, we can see villages' glow at horizon or the 300k+ inhabitants city at ~30km lighting the vest sky. But at zenith we measure >21.4 SQM, usually 21.5+. A 6 magnitude can also be visible from here. Andromeda is easily visible from a rural sky. When at zenith and the sky is clear and frozen, I can see it even from the city sky if there are no close direct lights in my line of sight.

Even before getting my hands on the Celestron C9.25 I started planning to shoot again the Dumbbell Nebula from dark skies this time. Said and done, at the AstROmania astrocamp this summer I shot 10h of Ha and 10h of OIII (and 2h of SII, but I didn't use them so far) to which I added 3x1h for each RGB from a decent dark place nearby home. The mount recently started to track worse and worse, but PHD + the new PEC kept things under control. I also had available around 30h of narrowband and 6h of RGB taken from home 2 years ago with the 200/1200 newtonian and all these were combined in a smaller amount with the new data. For the highlights I only used the crisper data I had available so I hope I didn't compromise too much on the details. The SCT or the reducer makes the stars a bit softer. Perhaps a new one should be considered... So, for a total of more than 50h, the Dumbbell Nebula, around 1"/px. Click on it for a better view or visit the astrobin link for full resolution and other acquisition details. Clear skies! Alex

Thank you all again! Removing all the stars makes processing easier, but using a larger aperture and focal lenght eases also a lot. The nebula appears only about 3 times larger than the Moon.

Thank you, Adam and Rodd! Adam, it's about 23h (in total) of Oiii with a WO Star 71 II and 294mm in parallel with a Lacerta 72ED and 1600mm, 6h of Oiii with a 150(144mm after the primary obturation)/750mm and 294mm + 8h total of Ha with the wide dual configuration.

Thank you all so much! Tips for all who want to try to image it: go to a decent sky, SQM > 21, show a large aperture to it and do it quickly while it's closest to zenith. For me 6h (one night) with the 150mm newton it was enough (should I go for 200/800 instead?). Then stretch it and remove the stars. Starnet did a great job. I'm very pleased that you like it! Clear skies to you too!

This time is Cepheus nebulae turn, more specifically Ou4 and Sh2-129, or Squid and Bat nebulae. I went outside of the city only 5 nights for this target. One night I shot hydrogen from home, mostly for framing, but it ended up in the final image too. In the beginning I shot with a dual setup of a ASI294MM and ASI1600MM through William Optics Star 71 II and a Lacerta 72 ED scopes. But as the Squid was lost through the sea of stars, I thought to try a better resolution for smaller stars and I took out the 150mm newton. 6h of exposure with the newton were not only equivalent in terms of light as the other almost 24h with the smaller scopes, but the stars were also much smaller and separating them from the nebula became much easier and I could end shooting this target sooner than expected and concentrate during the astROmania astrocamp on other targets. These are to be processed... Outters 4 is incredible dim, I only caught a very faint glimpse of the central nebula in 10 minutes subs with the highly sensible ASI294MM camera. It was only discovered 10 years ago and its real origin is not yet know, only supposed, probably part of the Sh2-129 actually. On astrobin too: https://www.astrobin.com/pyxv3l/ Next are some smaller nebulae, but first it's time for a well deserved holiday. Clear skies!

I'm happy that you like them, thank you!

Thank you! I usually don't stretch the blue so much, but this time I stretched it more than usual for the blue flame effect. I made a composition of HOO as RGB for the initial support image, then stretched in GIMP in lighten mode the Ha channel as red and OIII as blue until I considered enough.

WR134 is a variable Wolf Rayet star shedding away and radiating gas. I knew about it, but I wasn't aware exactly where it is until last year when I shot a wide region of the Cygnus area. It is a little towards the south away from the Crescent nebula. The surrounding nebula has an interesting appearance, especially in OIII. In my view, it resembles a blue gas cooker flame. It is a difficult to process area with so many stars and the nebula it's pretty dim too. For a better idea, I will post a simple stretch too. Even though I used StarNet to remove the stars and Topaz Denoise on the background too after PI denoising routines, I tried as much as possible to keep the real details unaltered. For this image I chose to stretch less the green channel for a more vivid red/blue image to resemble a burning flame. Most of the data is OIII. The Ha was strong enough, I needed less of it to match the oxygen channel. Image on astrobin too: https://www.astrobin.com/le8to5/ Clear skies!

I'm behind lately with posting images. Now it's Pinwheel's galaxy turn. Shot until April this year, it took me a few trips to dark/dark-ish sites to gather all the data. It's hard to believe even now how cold it was at the end of April. At the end of the last session, when I was packing, it was -5C. Now the temperature doesn't drop below 20C anymore during the night and during afternoon we have consecutive days with 38C+. I used, as almost always, a combination of LRGB data shot through multiple telescopes, for a total of almost 13h. The 150mm newtonian was moody, not sure why I always had something that looked like astigmatism, but only in one corner. I hope it was the CC, and I'm eager to see if the GPU CC is better than the Baader MPCC. An astrobin image is available too here: https://www.astrobin.com/23m3rv/ Clear skies and thanks for watching !

I use a fixed ring at the back of the scope and a large guiding ring at the front of the scope and never had any differential flexing. However, I never exposed longer than 5 minutes.

I sometimes do this, but only if I can setup 2 scopes in parallel (mono + DSLR) or the mono cameras are unavailable since they shoot something else. https://www.astrobin.com/1p6b1c/F/

Thank you! Looking forward to seeing your results

Thank you all so much! Clear skies to all!

I'm calling collecting data enough for this season. 5 years ago I put the DSLR for the first time at the back of a telescope and I took my first shots. Some of them were aimed at M81 and M82. For the next 5 years I collected more data with various scopes, cameras, carried by many mounts. The newest one is still fresh, I finished collecting RGB and Ha data for it this morning so more processing versions will come. I used for it also some Lum data I shot in 2019 with the large 200mm newton from home (for highlights only), Lum data I collected last year during the emergency state with a poorly corrected 102ED and some Ha with the 150mm newton. To these I added this year Lum shot through the same 102ED, a better 102ED and the 150mm newton improved with an aperture mask holding the primary mirror, totaling almost 17h of good (dark/dark-ish skies) Lum. And 1.5h each RGB and 4.5h new Ha last night. If you lost track of the data acquisition description, don't worry, me too. Quite a challenge to add the data together in the best way. Starting with the newest, click for larger resolution: 2021, first version 2020 2019 2018 2017 2016 - May and 2016 - Feb, the first one

It would definitely cause severe vignetting on the OAG prism as I have it set up now as the OAG is the closest to the corrector and I want the prism to stay out of the cone of light that falls onto the main sensor. I can insert the prism more in the OAG, but not too much. As I use a dual setup, I need a second corrector besides the 279 and I wouldn't buy the small one. Perhaps I'll wait for the https://www.teleskop-express.de/shop/product_info.php/info/p12938_TS-Optics-REFRACTOR-0-8x-Corrector-for-TS-70-mm-f-6-CF-Apo.html

I have a WO Star 71 II, a Lacerta 72ED and a SkyWatcher 72ED. The doublets seem similar regarding the correction and the focal length at ~430mm. For me, the TS RED279 is actually the only one that works properly with the above scopes. The correct backfocus seems to be around 65mm. The WO corrector gave me elongated stars asymmetrically over the frame with the WO triplet. The TS RED JM63S doesn't seem very asymmetric, but does not correct a 22mm imaging circle and I tried to adjust the backfocus from 55mm to >65mm. On the wider field of the WO 71mm triplet it seems to be worse than on the 102mm F/7 doublet which it manages to correct decent, but still very obvious not perfect towards the corners. The 70-72 dedicated reducer doesn't correct a 22mm imaging circle and it has an asymmetric elongation on both the WO triplet and the Lacerta doublet. I am too looking for a good reducer/flattener for these small scopes, but it needs to end with an M48 thread so that I can easily move the OAG + EFW + camera easily between the scopes. The TS RED279, although good, ends with a T2.

TS have a dedicated reducer/flattener for 70-72 refractors, but check also the return policy. I only had an issue with a camera that I bought from FLO which they solved very quickly and sent me a gift too (a collar for the camera if I remember well), but dealing with issues with TS is going slower for me. My copy of 70-72 reducer/flattener is a bad one and I'm waiting for about a month now for a reply from TS to return it. In fact, out of 4 reducers I bought from TS, only an old 279 was good, a newer RED JM63s is only almost decent and the other 2 were/are complete rubbish. I returned the WO flat 6A III, and I'm still trying to return the 70-72 one. I also had the Photoline 72 scope you mention, but that also was a bad example which went back. The 102 Photoline doublet I have is an excellent one though. The point is that all these being mass produced, getting a good item seems like a gamble. Unless you have an option to buy a tested corrector, there is a high change that you'll need to return it, whether is a QC passed WO or another brand. On the good side, the larger summer targets are coming back only in a few months so you have time to sort it out.

I saw the tremendous amount of data that you shared so I downloaded it and gave it a try. Thank you for making it available. Here's what I did (what I remember): In PixInsight Luminance Deconvolved the luminance layer Applied some TGV denoise with an inverted duplicated layer, stretched more than STF Stretched it partially with arcsin stretch Stretched it more with Histogram Transformation Duplicated it and applied HDR with an inverted duplicated layer, stretched more than STF. Kept this layer mask Combined 5 and 6 at around 60-40 Duplicated 6 and applied MLT for a star mask Applied Morphological Transform (MT) on 7 with dilation and erosion for 2 masks, subtracted the smaller stars from larger for a contour star mask Eroded the stars contour a bit, the larger ones more Removed the stars from the mask at 5 and applied convolution for a new mask. Applied LHE in more steps (256, 128, 64, 32 at 0.25 amount) with the mask at 10. Applied MLT mostly enhancing the larger wavelets (10-12 layers) Combined 6, 11 and 12 at a ratio that I liked RGB Combined RGB DBE Arcsin stretch HT stretch Duplicated 4 and HDR Combined 4 and 5 Increased saturation in the highlights Maybe some ACDNR ?! Ha DBE Arcsin stretch HT stretch Then moved to GIMP Combined L as luminance (~60-70%) into RGB at a ratio that I liked Increased saturation for the highlights and lowered for the background Brighter stars have a magenta cast at the top-left and green cast at bottom-right Back to PixInsight SCNR and save Invert, SCNR, invert and save (this kills magenta) Back to GIMP Imported the LRGB, the SCNR-LRGB as color layer and the Invert-SCNR-invert-LRGB as color layer Added a star mask as a layer mask for the SCNR-LRGB and Invert-SCNR-invert-LRGB Blurred a little the layer masks and shifted them towards top-left and bottom-right in small steps until the magenta and green casts disappeared from the stars Merged the results, saved as LRGB_p01 Duplicated 4., added a grayscale mask, stretched heavily the mask and setting the black point high so the background became black in the mask. Blurred a little the mask. Set the black point high in the layer itself too so that the dark areas in the highlights became darker for an increased contrast. Adjusted the saturation again Saved as LRGB_p02. This was the final LRGB Imported the Ha layer as lighten only and made it red. Stretched 8 heavily and moved the black point high Tamed down the ratio of the Ha layer, then merged over the LRGB Crop and saved as M33-IKI-alexbb-LhRGB_p03_crop.jpg Upload Edit: Moved higher the black point and upload Crop and upload again

Thank you, Martin!

Thank you, Margin and Craig! I sold the 200/1200 newton. At F/6 I never had issues with it, but it was too large for me to handle lately. I want to travel more so I downsized my gear. The bulkiest setup I use now is a dual 102 F/7 refractor setup on a GEM45. Also the EQ6-R went away, but I don't regret it compared to the GEM45 which is much lighter and more precise.