Adreneline

I like it a lot Alan - very nicely framed in amongst the surrounding star field. Adrian

Love the structure detail toward the core region. Very nice. Adrian

Thank you Alan. I like imaging these larger areas in one pass with the 135mm + 1600. I know you trade detail for wide FoV but sometimes you are not really able to appreciate just how big some of these objects are and I like to see them set in their surrounding space. Adrian

Thanks for the kind comment. I too use the ZWO adapter having tried the TS-Optics (droops) and Artesky (a complete PITA to remove the lens!); I think the ZWO is the best of the bunch. I have also expressed an interest in ordering an adapter from Astrojolo - just waiting for him to tell me they are available. I've tried various f settings but still seem to get dodgy stars especially in my top right corner of each image. All a tad frustrating! Adrian

With a 90% moon Ha is pretty much the only option available so this is 58 (out of 60) x 300s of Ha taken with a Samyang 135mm + ASI1600MM-Pro unguided. I've struggled to know what this should look like in terms of surrounding dust/nebulosity. Images of NGC7822 vary widely on the internet with anything from pristine blackness surrounding the NGC7822 to so much surrounding nebulosity it is almost difficult to distinguish the target. I've been guided by the apparent dark/near black patches towards the centre of the nebula. The image was calibrated and integrated in APP, then processed in PI (ABE and HistogramStretch) followed by a very small amount of noise reduction in PS. The image is cropped a little to remove some dodgy looking stars in the corners - an ongoing issue with my 135mm+1600 setup I am failing to solve Thanks for looking and as ever comments and criticisms are alway welcome. Adrian P.S. There is a funny little curved artefact near the very top of the image; any thoughts on what that might be? I removed two lights that contained satelite trails but this feature is only distinguisable on the stacked image.

Hi! Well maybe I could but I no longer have the MacBook; I decided it had had its day and it was time to consign it to scrap and spares. I felt it was no longer worth the effort especially as it was only 32 bit and the battery would not hold any charge; 13 years of use was not too bad. Thanks for the input and advice though.

I am still interested please Rob. Adrian

I bought the ASI1600 mount produced by ZWO specifically for the 1600. I had to space it off the vixen bar with a piece of stock aluminium bar so that I could position the lens more or less in the centre of the lens support ring (which I bought from TS Optics in Germany). I found having the toothed belt engaged with the thumb grip worked providing it was under sufficient tension but this Samyang lens is not made like a Zeiss (which is why it is about quarter of the price!) and I have noticed it is possible to distort the barrel if you put too much pressure on it from the support rings. What I really need is a felt lined ring as per the one which support the ASI1600 but so far I've not found one. If Clear Outside is to be believed I might get the chance to try the step-down ring tonight. CO even agrees with the BBC Weather app - almost unheard of! Adrian

Sounds like you've got your focus system in place but it maybe of interest of others to see what I have now done with my continually eveolving setup. I used Araldite to attach a surplus toothed belt to the lens (great care needed!) to give a more positive engagement with the mounted SW focus motor - rather than relying on friction between the focus thumb grip and the toothed belt. It has pretty well eliminated all the backlash problems I was having. Might be of interest to someone. Adrian P.S. The brass lab weights are to balance out the d.c. focus motor in the DEC axis.

Hi. Just to be clear the recommendation was to leave the lens setting at f2 but to use a step-down ring on the front of the lens - like one of these . I have a 77mm - 67mm (which allows me to fit a 67mm filter I have to my 77mm lens for regular photography) but have not used it as yet for AP. The article implied going further to like 50mm which will slow the lens down to more like f5. If I can remember where I read about it I will post again. Adrian P.S. Should have said right at the outset that star shapes aside it is a really nice image. The H&S are one of my favourite targets to image with the Samyang. I am gradually building up a huge amount of multi-session data I need to combine; hopefully it will have been worth it!

Well not sure I really know the answer to this one but I experience exactly the same problem in the extremities of my images. I've played around extensively with spacing and the results are always similar. My spacing on the current set up achieves focus just before the end-stop on the focussing ring but I still get slightly mis-shaped stars in the corners. Can't recall now where but I saw someone advising the use of step-down rings on the front of the lens to correct/ameliorate these sorts of issues. I think they had reduced the aperture right down to 50mm which slows the system down to around f5 (still keeping the aperature setting on the lens at f2) but I've not tried that approach as yet, although I do have a ring that would step mine down to 67mm. As an aside I've also tried using the 135mm/ASI1600 combination with both 1.25" and 2" filters and the result is still the same. I will be interested to see what others think/advise. Adrian

Looks to me like you came up with something very nice indeed. I like very much the rich variety and yet understated colours. I cannot believe that space is psychedelic or garish when it comes to colours. Thank you for sharing. Adrian

Hi Mick If you don't have Annie's Astro Actions I would certainly recommend them; lots of useful and helpful stuff for sorting image problems/issues and a bargain at only $15. Good lcuk. Adrian

Hi. I found this very helpful when I started NB and Bi-Colour - having said that this applies to RGB, HOO and SHO in whatever combinations you like https://www.lightvortexastronomy.com/tutorial-preparing-monochrome-images-for-colour-combination-and-further-post-processing.html This takes you step by step through alignment, dynamic cropping, gradient removal and linearfit of monochrome images prior to combining as RGB or NB. HTH Adrian

I'm not sure I know of a tutorial but one way I have found to reduce the problem is to take the Blue image into PS as a tif (from PI) and run the 'Reduce star size whole image' action from Annie's Astro Actions. Sometimes I run it twice for good measure. When I take the tif back into PI I can combine the RGB without getting the blue halos. It's probably cheating but it works. You can also use Photoshop : Filter - Noise - Reduce Noise and set Reduce Colour Noise to 100% but I have concerns that this does more than just reduce the halos. HTH Adrian

I am sure that is the situation for many who have to strip down each session and bring equipment back inside. I use an iPad running a lightbox app propped up against the wall pinned by the end of scope/lens with a with tee-shirt stretched over the end. I try to take my flats and dark-flats at the same sensor temperature (-20) as the lights but I'm not convinced that is really necessary as the exposure times are typically one to two seconds for my setup; can't see that amp noise/glow is going to have any effect at all but I stand to be corrected. Good luck!

I am also with John. I find there are significant differences between the flats I take for Ha, OIII and SII and not just dust bunnies - which seem to move around or even disappear completely sometimes - but never for good. Of my three filters the OIII flat is significantly different to the Ha and SII and I have no idea why. I also take Dark-Flats at the same time - lens cap on and I use a special filter made of 'black-body' card to ensure no photons (within the visible spectrum) get to the sensor - very hi-tech! For all I use the Ha focus position. HTH Adrian

Hi Brian, Really nice image and framing. I am no expert so I hope you don't mind that I ran your image through SCNR in PI because to my eyes it has a certain green tint about it. (I achieved the same result in PS with Curves and adjusting just the green component). I've intentionally attached it as an 8 bit tiff file so you will need to download it to view. Adrian m33-aa.tif

I do and I never knew it could do that - I guess I should read the manual! Thank you.

Wow! Amazing.

Interesting! A very good first attempt at HOO. You can do exactly as the name implies and map R:G:B - Ha:O:O but I find that gives a very 'red' final result which I don't like so much. I am no expert but I thought a more common approach was Ha:R - Ha+OIII:G - OIII:B but I may be wrong. I usually go 30% or 40% Ha in the G with 70% or 60% OIII. I've always put 100% OIII in Blue. I guess at the end of the day you can do what you like as long as you are pleased with the result. In PixInsight I use PixelMath exactly as above: R - Ha G - (0.3*Ha)+(0.7*OIII) B - OIII If you use the expression editor it is easier to enter the formula for R, G and B. Also, if you double-click on the identifier at the side of the image you can type in a shorter image name, like "Ha" which makes using PixelMath easier. HTH Adrian

Apologies - I should have added the fact that FLO provided excellent service as usual in accepting the return and providing a full refund. Sorry I omitted to do that. Nevertheless it is interesting to note there is a viable alternative which utilises the included cable. Adrian

Pleased to hear you have your iOptron mount. I really hope it works out well for you. I have been delighted with my CEM25-EC so far. Tracking is amazing and with my modest weight equipment experience so far seems to indicate that for up to 300s exposures with my ASI1600 I do not need to guide. The hand controller is very nice to use as well - very intuitive - and in the absence (short-term) of the Lynx cable you could probably get straight into imaging just using the controller alone. Good luck! Adrian P.S. Don't wish to dampen anything but I found my Lynx cable wouldn't work ( I sent it back to FLO in the end) so I bought one of these and used it with the iOptron supplied RS232 lead; it worked straight away and has been faultless so far when used with CdC and iOptron Commander.

Hi Everyone, Just wondered if anyone has direct experience of using a x1.4 or x2.0 Canon extender with a Canon 200mm f2.8 lens and ASI1600 or CCD or similar. Just that combination please. Thanks, Adrian

I look forward to hearing/seeing how you get on with the rings. A problem I experience all the time when using the Samyang 135mm but not (IMHO) as distracting as those from a reflector imaging system - although I fully appreciate and accept that many feel the diffraction spikes enhance the image. Thank you! - so am I if only the clouds would go away Adrian