Adreneline

Why not set APP to save as .fit and retain the header information which PI uses? I didn't think linear tif files retained the .fit header but please tell me if I am wrong.

Don't bank on it. AI rules.

This has been a really interesting and at times exciting thread to read so I thought I would add my two-penny-worth of real experience. In 2016 I started with a NUC and SGPro/BYEoS - NUC inside, OTA outside with long'ish cables - and an Atik CCD camera. Then I moved to the NUC to the mount - much better arrangement in terms of cables but not so comfortable to use. The I moved the NUC back in doors and used very long cables - not good at all - a bad move. At the same time SGPro got updated and became for me more of a pain than a gain. (Sold the Atik(s) and bought my first ZWO cmos camera). Then I put the NUC back at the mount and bought a cheap reconditioned laptop and used Windows Remote - that worked pretty well most of the time. It is a fact that Windows can be a bit tricky at times - full of surprises when they are least needed. Then I bought a RPi3B+ and installed Ekos/Kstars and all that other stuff. I tried and tried and tried again - and every time/night there was a problem which ranged from trivial to show-stopping, like driving the mount into the tripod. Then I bought an ASIair Original - very good. Then I bought an ASIair Pro - very, very good. Wifi a bit disappointing but there are work-arounds - like a cable for me. Then I bought a MeLE Mini-PC - see below. Then I bought an ASIair Plus - exactly what I expected. Guess what, I hardly ever use an PC and when I do it's to get my fix of using BYEoS - which I love, love, love! Based on a recommendation I bought the MeLE and installed NINA - so much to like and so much to frustrate - too many hours lost to solving problems rather than imaging. All the problems may well have been of my own making (like trying that Green Swamp thing - what was I thinking?!). For me, in the evening of my life, I absolutely love the ASIair. 99% of the time it is stressless, reliable and as easy as the proverbial 1, 2, 3. I can be fully set up and imaging in 15 minutes. Platesolving 100% reliable. Meridian flip - go to bed and let it happen. Setting up guiding a breeze. PA a bit fiddly (maybe my mount) but works just fine. Storage - okay it's not good on the Original, loads better on the Pro and 'problem solved' on the Plus. I have sold my soul to ZWO and I am in no way ashamed of that fact, and neither should anyone else be - ashamed of me As for the argument that the ASIair can only be used with ZWO products (excluding mounts and two dslr brands), so what? If you haven't tried it don't knock it. I haven't tried so many things in my life and I 'knock' myself for not having done so - except wingsuit gliding. Do whatever works for you and don't forget to enjoy! It's a hobby.

🎶"It ain't necessarily so"🎶 ... least not here! 🤣 Good luck if it's clear for you though 👍

Very nice Göran. Love the colours and depth you've managed to achieve - very sympathetic processing. Adrian

Hello Steve. No magic I'm afraid 🙂 - and nothing "embarrassing" about your image. (you want to see some my early attempts 🤪) I used AstroPixelProcessor to remove the background gradient(s); APP is also my software of choice for all pre-processing. I used PixInsight to process the image. It has a reputation for being user unfriendly but in my opinion it is no different to PS - you have to get used to it and the way it works and does things. I am very much of the view that PI is worth every (one off) penny and represents a small percentage of what I've spent on hardware over the years; it lets me get everything there is to get from my hard earned data. PS is part of Adobe's Creative Suite - PI is anything but "creative". Okay - I lit the blue touch paper! 🤣

Hi Steve. I've had a very quick go at the .fit file and once the background gradient is removed and a little tweak with colour calibration quite a lot more detail is revealed and a nicely aligned histogram. I am not at all familiar with the 585 but generally I would say stick to one gain setting and vary the exposure. M42 is a very bright target and I've used exposures as short as 15s in the past; 180s and above would seem excessive to me. I've not used ASIStudio so cannot offer any advice on that one, but I do use an ASIair and love it! HTH Adrian

Two at once on a freezing cold night - must be mad!

They screw on as would any end of lens filter. I bought one of a well known online supplier! The thread might be a bit tricky and you really need a very clean edge on the inner diameter. HTH

Hi Stu. The SY135 is a great lens but it a real challenge to set it up with an Astro camera and filters. My thinnest spacer is 0.1 mm and I wish it was 0.05! I’ve even been known to try tissue paper spacers - not recommended! All my experience with this lens tells me achieving focus with the registration mark within the base of the L is essential. It’s also very beneficial to stop the lens down with a step-down-ring - I step down to 49 mm giving an effective aperture of about f2.6 - it really helps with peripheral stars and the reduction in aperture/speed is a small price to pay. I also have a RedCat and what a joy it is to use. My ASI1600 on the RedCat has a very similar f.o.v. to the ASI183 on the Samyang - a great combination. Good luck with getting optimal spacing on the SY - the pain is definitely worth the gain. Adrian

Forgive me if I am misunderstanding what you've described but to me this seems to be exactly the wrong thing to do. All camera lenses, but let's just stick with Canon, are designed to work optimally when the spacing is an exact value between the back of the lens and the camera sensor. The front face plate of a Canon dslr camera is an exact and carefully controlled distance in front of the sensor - the end plate of a Canon (fit) lens is specified as an exact distance from the last lens element within the lens. When the lens is fitted to the camera there is an exact optimal distance between the camera sensor and the last element of the lens. When focussed at infinity the registration mark on the lens should be positioned within the base of the 'L', whether the camera is a Canon dslr or a cooled astro camera. If the spacing between the last lens element and the camera sensor is incorrect the registration mark will be be either before the 'L' or after it. There are countless references on the web to ensuring that at focus the lens registration mark is within the base of the 'L' whether it be a Samyang, a Canon, or whatever the make of lens. That's one reason why we all want to know the exact back focus on an astro camera. I understand fully your comment about the EAF driving the focus ring into the end-stop (not good for the EAF or the lens) but that is easily fixed on the ASIair by 'reversing' the direction when the EAF first offsets the focus to start to generate the 'V' curve. When I AF my Samyang the EAF moves the focus ring way round to before the 10m mark and then progressively comes back to the 'L' and just slightly beyond; it does not come up against the end stop. As I know you know spacing is so critical on the Samyang 135. It was equally so on my Canon 200 mm lens although the focus ring on the Canon 200 had like a 'slipping clutch' so that if you attempted to rotate the focus ring beyond the infinity mark it would effectively slip and not come up against a hard stop. Changing the spacing by as little as 0.1 mm can make a significant change to the focus position. Until recently my biggest challenge has been ensuring that I can focus my 1mm thick Astronomik Ha and SII filters 'within the L' whilst achieving a focus position with my 2mm thick Baader OIII that was as close before the 'L' as I could manage. The 1mm difference in thickness requires a change in spacing of 0.33 mm - that is huge for a Samyang 135 lens. If the spacing is incorrect then star shapes are likely to be compromised especially toward the periphery of the image. Please tell me if I have completely misunderstood your post above and you are indeed still achieving focus with the lens registration mark within the base of the 'L'.

As an aside the gear ring allowed me to establish accurately the backlash in the system: Photo dates from when the EAF was above the lens.

I don't doubt that it works but I do have doubts about using that arrangement based purely on my experience. I found that despite the level of tension in the belt the belt would precess on the focus ring and so I found there were issues with repeatability over time. This problem was exacerbated for me because I was using Astronimik 2" Ha and SII filters and a Baader 2" OIII filter; the Astronomik filters are 1mm thick whereas the Baader is 2mm. This difference in thickness required very different focus positions (~500 on the EAF) and over time the belt would 'walk' around the focus ring so although the relative difference for Ha/SII and OIII remained the same the absolute positions on the EAF changed. In the end I adopted the same approach as @geeklee and installed a toothed ring which works perfectly. With regard to mounting the EAF @ollypenrice I have tried under, over and at the side. The under-lens mounting I didn't like because it sets the lens high and the guide scope even higher above the Vixen bar and flexing problems start to surface. Mounting the EAF above the lens screws up any chance of mounting the guide scope. In the end I have settled for 'at the side' mounting of the EAF leaving the top bracket clear for the guide scope. The downside with 'at the side' mounting is it throws out the whole issue of DEC balancing which is partially resolved by rotating the EFW but even this requires the addition of a 100g laboratory weight to achieve perfect balance on my CEM25. Rotating the EFW however does allow space to fit the guide scope so it all seems to be a win-win in the end. I am a 100% fan of using the WO mounting ring and buying the WO handle to mount the guide scope. I also use the ZWO camera support ring to ensure I don't get any misalignment of the camera-lens combination - no droop! Even though I use the Astrojolo M42 replacement end mount for the lens I was still getting a tiny amount of droop - the ZWO support fixes the problem completely and provides a very rigid mounting platform. All personal experience over the last three years of tinkering and messing around - exactly what you do on cloudy nights! Adrian

That'll be perfect for Santa spotting!

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