Adreneline

This was my last SY + 183 mosaic - O3 of part of Cepheus - with a 20% overlap! The Telescopious plan looked fine on paper/screen but in reality it didn't work out too well. I think field rotation was perhaps a factor but I don't know. It will be interesting to see if the ASIair gives the same result - hopefully it will be better. Just need some clear skies!

It worked well for me at lower elevations - my recent efforts with Cepheus have been a challenge. I'm far too old for that! ASIair + iPad + nice warm fire and a coffee - perfect!

Thank you! 🙏 I’ve done lots of mosaic with the SY+183 but not tried the ASIair tool yet. I’ve only used Telescopious in the past but recent mosaics have not worked well; it doesn’t seem to cope well with field rotation near the zenith. Sounds like the SY+GTi could be a great lightweight match. 👍 Adrian

10 Cas is not the first thing that comes to mind when composing an image; taking advantage of the slightly wider field of view offered by the Samyang 135 with ASI1600MM and Astronomik filters.

Are cable ties the greatest thing ever invented?

Thank you! I've shown you mine ... 🤣

Will this be the final, final version of my SY183 setup - it has been through so many iterations and derivations. The only feature not apparent is the 77-49mm step down ring taking the lens down to ~f2.6; helps a lot with peripheral star shapes and avoids the multiple diffraction spikes around bright stars. The EFW contains Astronomik L2, Ha, OIII and SII 6nm filters - and a blank for darks! The wires offend my OCD'ness but they don't foul on anything. The whole lot weighs in at 3.85 kg and needs just a single 12V supply connection, although I also choose to connect a wired network cable. It's just lacking the final dew heater for the guide scope - there's always just one more thing! Adrian

I decided to reconfigure my equipment and reunite the Samyang 135mm with my ASI1600MM to produce a single pane image of an area of Cepheus not covered in the Ha mosaic. In one night I was fortunate enough to gather enough Ha, OIII and SII data to create this image. Once again I have tried to process each component in an equivalent way so as not to favour Ha, OIII or SII beyond the data that was collected. As far as I can tell I have stretched the Ha, OIII and SII data to the same extent. I've used my usual approach of pre-processing in APP and using the light pollution removal tool before exporting to PI for all post-processing. The original was cloned and processed as starless; the clone was processed in an identical manner except OIII and SII stars were reduced before combining to produce a star filled image. Stars were then extracted and recombined with the original (starless image). The starless image is stunning but I thought it best to present this image with stars which hopefully do not detract from the delicacy of the nebula surrounding these well known targets. Thank you for looking. Adrian

In late August I started on a project to produce an ultra-wide field image of Cepheus using my RedCat 51 and ASI1600MM - the plan was a 40 pane mosaic. For reasons I don't understand large parts of the image failed to merge correctly so I decided to start again using both my RedCat 51 and my Samyang 135mm. This is an image made up of essentially 32 panes taken with both the Samyang 135mm with ASI183MM and the RedCat 51 with ASI1600MM with all data collected since late September, through October and November. Although the coverage varies across the image every pane was processed in as near an identical manner as I could achieve with APP and PI before combining as a mosaic in APP. The intention was to reveal accurately the extent of nebulosity throughout the region. I naively thought I would be able to create a full SHO image but lack of clear moonless nights put paid to the OIII component; the few frames I did collect provided an incomplete and very noisy coverage. Hence this Ha only image. As the object of the exercise was to reveal the nebula I have chosen to present this as a starless image. I cannot see me completing a HOO image let alone an SHO image this nebula season. Maybe autumn 2023 will present more opportunities. Thanks for looking. Adrian

There are certain nebula we are all drawn to because they are so rewarding to image. The Heart Nebula is an emission nebula, 7500 light years away from Earth and located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. My personal preference is to image the nebula is SHO. This image is 15 x 300s of Ha, OIII and SII collected in just one night using a RedCat 51 with ASI1600MM-Pro and Astronomik Ha, OIII and SII filters. The imaged was pre-processed in AstroPixelProcessor. Gradient removal was performed using the light pollution removal tool. The integrated masters were then transferred to PixInsight where following initial noise reduction using NoiseXterminator the image was cloned. The original was processed as a starless image with as near identical as possible stretch was performed on each component to produce a starless SHO image. The clone was treated in the same way with the addition of star reduction on the OIII and SII components. Stars from the clone were then blended with the starless original to produce this image. Thanks for looking. Adrian

Neither do I, and it was not my intention to imply as such. It was my intention to say, in my opinion, that there is an increasing tendency to push data beyond the limit and I agree with you that the fault is entirely with the individual if that is the case. Recognising when you can push data and just how far is a skill hard learnt and one I have yet to master; I bow to those who have mastered the skill and know exactly how far you can go. Adrian

... totally agree.

Hi Lee. That may be the case if the data can take being 'super stretched' in PI. A purely personal view is that we are seeing a great many images that have been 'stretched' beyond their means, whether they are taken with a Samyang, RASA, Takahashi or an iPhone! There is no substitute for imaging time to reveal data - or that always used to be the case, and certainly the mantra that was preached by so many when I started this mad hobby only six years ago. I do wonder if in the 'smash and grab' world in which we now seem to be residing with photon hoover scopes and ever more sensitive cmos devices there is too much emphasis on using processing to expose detail that is barely there in the first place because there is insufficient data. It has always been the case that rubbish data produces rubbish images but next to no data surely cannot produce a credible image. The likes of StarX and NoiseX are not the holy grail of imaging if all they do is encourage super-stretching and over-processed images to reveal noise as data/nebulosity. We are kidding ourselves. Or have I got it all wrong. Apologies if I have derailed this thread. Adrian

I've settled on using a second long Vixen bar which extends out behind the focuser - works a treat with my RedCat and on my Samyang. I also attach a mini-Vixen clamp to the lower rail as a fail-safe to stop it falling out of the mount saddle. HTH

It looks really good to my eyes Adam. What, if any, noise reduction have you done?

I found these invaluable. A bit dated now but the fundamentals and approach are still sound. https://www.lightvortexastronomy.com/tutorials.html

Thank you Adam. Having finally settled in Lincolnshire the skies round here are seriously dark once the few street lights have gone out so data tends to be very clean providing the 'seeing' is good. Hopefully last night's SII will hold up to scrutiny once I start processing. Adrian

Thank you Lee for the generous comments. I am trying to keep everything in balance by not overstretching the OIII data and increasing the noise disproportionately. I am also trying to keep the histogram aligned which is difficult when using Ha and L - maybe I need to experiment in this area a bit more. I used 0.3*Ha + 0.7*OIII for G with pure Ha and OIII in R and B. Managed to get some SII last night - 30x300s worth - so I'll try and pull together an SHO version and add that to the GIF-mix! Thanks again. Adrian

Clear nights have been a rarity of late. Even getting a modest amount of Ha and OIII has proven to be frustratingly difficult. As for SII - no hope. This is 20 x 300s Ha and 22 x 300s OIII using a RedCat 51 with ASI1600MM. Hardly enough data to do this justice but enough to make a GIF. Pre-processed in APP and post-processed in PI. I used one of the many online tools to make the GIF. Adrian P.S. The GIF was compiled from these images:

This is always a difficult call - what is natural and what is not natural. My personal preference is no hint of magenta in an image but that is purely a personal thing - I know lots of folk like to see magenta (or hints of) and I know some really like the Hubble'esque look on narrowband images. Hope you don't mind but based on your comment above I took a look at the image in PI and in particular the histogram: I then applied iSCNR and looked again: I guess the question is "which is more natural"? Does an aligned histogram imply more "normal" - whatever normal might be. It's a tough one. All down to personal preference I would suggest.

Very interesting - looking forward to hearing how you get on. 🤞

This was SharpCap working last night after using PoleMaster to align my CEM25-EC: I had to update the SharpCap software before using it and there was close to perfect agreement with the PoleMaster - the "Good" kept changing to "Excellent" - try as I may I couldn't get it to stay on "Excellent". Totally agree.

My Limit is set to zero degrees. I cannot tell the other setting by looking at the display. My mount is the 25-EC and it works and flips perfectly under ASIair control; I’ve never seen any warnings. HTH.

Interesting to read your experiences. I have used the PoleMaster camera with SharpCap - it gave a different result to using the PoleMaster camera with its own software - hence my confusion and doubting as to which is best/better. I did try using the PoleMaster software with another camera but the QHY software will only connect with the QHY (PoleMaster) camera. I can't help but feel that a camera mounted on the mount RA axis is a good starting point so differences must (?) be in the software and the way the underlying mathematics is performed. @StevieDvd's comment that "Each PA software has it's own way of doing essentially the same job but don't always produce the same accuracy so they will vary from one another." is I am sure correct. The problem is in the central words "don't always produce the same accuracy" which begs the question "how accurate do you need to be?". It also makes me wonder how many ways are there of "doing essentially the same job". It seems it would be preferable if all the different software did exactly the same job (perfect polar alignment) to the same degree of accuracy - but what do I know?

Exactly my point.