Adreneline

I share your optimism however the site owner has posted a message saying it is a “catastrophic loss of data” and images will need to be uploaded again. He’s already offering free upgrades to those affected. I feel sorry for the guy - he seems distraught. 🙁

Apparently all of them! I’m sure it won’t be permanent - a gremlin in the system. Update. They’ve all gone and will need to be uploaded again. Oh well 😔

Just for comparison this is M81-M82 I took back in Feb 2017 just after I got the 414ex-osc using my ED80DS-Pro on an NEQ6. I think the focus could have been better but at the time I was still learning how to focus correctly with the software I was using at the time. This was processed in DSS and CS6 - well before I started using PI. One of these days (cloudy nights) I should revisit my early images and reprocess them. Hope this is of interest. Good luck.

I agree with Carole. I was often asked why I used the flattener at all; you might argue it is not required for a camera with a chip size of the 314 (or 414 in my case). It was easier for me to leave it in place in case I ever wanted to switch to the 70D. Why not try it without and see how you get on?

I use the same reducer on my ED80 with both a Canon 70D and an Atik 414ex-osc. This is what works for me and why: When using a Canon 70D the EoS adapter sets the distance from the reducer end face to the sensor at 55mm So I use spacers to create the same spacing when using the Atik414ex-osc - so B-D on the photo below needs to be 55mm If you're using a mono with filters the spacing will increase slightly. Others may have different advice to offer but the above works for me. I am able to achieve good focus and no odd shaped stars. HTH Adrian

Inspiring. Thanks for sharing. Adrian

@Vox45 I use a BST and found appropriate pullies and belts from here: I also had to buy a sleeve/insert to match the pulley bore to the motor shaft. The HTD belt fits perfectly on the Baader pulley. I subsequently discovered the same things are available from Amazon but not the same range/choice. The black motor mount was custom 3D printed. I use a SW dc motor with HitecAstro controller and it works a treat on my ED80DS-Pro. I rotate my ED80 so the focusser is 'on top' but it would work just as well in the more usual configuration. HTH Adrian

I've been happy with this one - works for me. Adrian

+1 for that recommendation although I tend to go for 60s/120s RGB and 120s/180s for NB as I get fewer wasted subs from aircraft arriving and departing East Midlands Airport!

I don't wish to introduce a red herring but the ASIair does not allow any adjustment of offset - it gets set to 50 and that's it; you can adjust gain to suit. Prior to using the ASIair I used SGPro and set offet to 56 based on advice from a post by @vlaiv. It worked for me but I don't know/understand enough to do otherwise. It will be interesting to see what the ASIair Pro allows.

Thanks Tom. This was also a concern for me but so far I cannot see any evidence of problems; what it has done is to put the G and B focus positions (for my 200mm) in the same place. For me (with my belt driven focus system and associated backlash) it is helpful to know which filters are at the same focus position and hence the order in which to collect subs, e.g. Ha, OIII, SII makes no sense! From my humble M45 offering this has turned into a really interesting thread - many thanks to all who have contributed. Adrian

I thought it was a relatively inexpensive thing to try - £20 for 72mm filter. First impression is that it has made a difference. As I reported above there was virtually no difference in reported FWHM for R, G or B whereas previous experience (without a UV filter) always gave higher FWHM values on B and the resulting 'blue bloat". I was also wondering about one of these which claims to "cut out both UV rays below 390nm and IR rays above 700mn resulting in just the light rays in the visible spectrum passing through the filter" but this one is quite expensive. Adrian

Thank you Martin - I'm glad you like it - it's not that I don't like it, it's more a case of could it be better and the answer is usually "Yes"! - but at what cost? I've done loads of checks and concluded thay are most certainly not parafocal, however, they are not too far away. One interesting thing I decided to try (probably goes against all perceived wisdom) was a Hoya UV filter on the front of the Canon lens. I tried imaging the Bode region last night just to see what effect it might have on focus positions / star bloating etc. These are my ZWO-EAF positions for all the filters using a Bahtinov mask pointing at Capella in preparation for Bode: R / Ha / SII 29012 L / G / B 28932 OIII 28892 As you can see OIII is some way off but the others are really not too bad. The ASIair software does not allow automatic refocussing between filters but this at least gives an order for taking the various filters. The proof of the pudding was how the RGB subs came out on the Bode region and there was virtually nothing between them. APP reported FWHM on all RGB subs of 2.1 - 2.5 which I thought was pretty good for the prevailing seeing last night and far more consistent than my previous experience. No doubt putting a UV cut filter on the front of the lens gives rise to other issues but none were apparent last night. This is 20 x 120s of unguided RGB pre-processed and integrated in APP and then using PI ChannelCombination and HT. I decided to combine and then stretch as this was more likely to reveal bloating. There is minimal cropping so some dodgy stars in the corners. As nebula season is now pretty much over from this location I shall spend the next few months trying to tease out some of the focus, star shape and exposure problems so I may well give your perfectionist's way a try. Many thanks for all your advice. I would be interested in your views on the use of the UV filter. I produced new flats with the UV filter fitted but not sure it has completely corrected the gradients - the moon didn't exactly help! Adrian

To me that looks so much better - the eyes goes where the eyes are meant to go - M82! Very nice - IMHO Adrian

All very interesting and definitely worthy of a separate thread. My original M45 has taken on a life of its own but all of the contributions have confirmed it’s not just down to poor data, focus or processing - there are more fundamental issues coming into play. Thanks for all the contributions. Adrian

I'm a fan of starless images of nebula and yours reveals a lot of detail. I've been playing removing the stars from all my past nebula images just to get an alternative view of things - and to practise using Starnet++. Thanks for sharing Tom. Adrian

Nice one Mick - I think you've done amazingly well to get that much of M82 in LRGB recognising the moon. Personally I think the star of the show is M82 and not the stars - it's the glowing hydrogen coming from the core that needs to be the focus of attention for me. Thanks for sharing. Adrian

No I haven't and I didn't even know you could do that trick with stopping down the lens. I've got to say it's not easy detaching the lens from the ZWO mount, focusser etc. but it might be worth a go. I did try a stop down ring to try to correct star shape problems but it was only a single stop so had little effect. I'm not sure why stopping down might change the CA problem but it's certainly worth a go. Thank you. Adrian

Thanks Mick - glad you like it. Adrian

Thanks for pointing out the

Outstanding result!

Hi Ryuno, If you've not already seen this youtube video you may find it of interest - and entertaining! Not sure it would apply to your mount arrangement but may promote some ideas. Adrian

This is certainly my experience although as indicated above I find R, Ha and SII are the same (I'll qualify that below) and B and OIII are the same; G can be a bit tricky but is usually closer to R than it is to B. When doing NB I take Ha and SII together (assuming I want SII) before doing OIII. My experience is that R and G are very similar focus positions but B is always different. Using my Canon or Samyang I find there are a range of focus positions where the spread of HFD values varies only very slightly so I essentially go for the median position on the focusser (ZWO-EAF). When I use the ED80 (rarely at present) the B is not only in a different position but never gives as low an overall HFD value. (Not sure I've explained that very well but I hope you get the gist). I've spent the entire evening on one occasion just messing around with focussing, writing down focus position and HFD values and plotting graphs in Excel (how sad am I?) and going round in galactic circles trying to get to a point where I can establish a "best position" for each filter. Just as a footnote I have tried using the "V-curve" auto focus thingy in SGPro many times and finally got to the point where I could have thrown the whole darn setup in the hedge at the bottom of the garden. What V? W seems be what I get most of the time or a very best a flattened U! I am sure I am using the process incorrectly or got one of the settings wrong but I've given up with it out of pure frustration. This sounds interesting but I'm not sure I know what a NB blue filter is I'm afraid. Can you provide a link by any chance? Thank you Sunshine; I know I lose detail with the 200mm but I too like to see these objects in their surroundings. Many thanks again to one and all for all the help and valuable comments. Adrian

Thanks for the kind comments Tom and Bryan. I think 'blue' is my nemesis - a bit like OIII. I think I've suffered from 'blue bloat' for all of my AP life and it 's not for lack of trying to achieve optimum focus but I suspect limitations of the optical/filter train. My ED80 is terrible for it - the Samyang 135mm and Canon 200m are not as bad but it is still a problem. Looking at the subs the only thing that is apparent is that the blue stars look 'bigger' and certainly when I pre-process in APP it always reports higher FWHM figures than R, G and Ha. I did try shrinking the stars in the integrated blue image but I wanted to stretch it as much as reasonably possible to get the nebulosity to come through which resulted in the stars 'growing' again. I've tried to lose the blue halos in the outer lying stars - which on the whole I have - but then that seems to have reduced the blue in the nebulosity and some of the colour in the stars. I think I need to learn some new skills in PI or PS! Many thanks again for your helpful comments and insights. Adrian

After numerous trashed attempts at M45 over the past few months (not to mention previous years) I've decided this is probably as good as it's going to get for me. This is 20x 30s and 20x60s of R, G and B taken with ASI1600 + Canon 200mm, pre and post processed in PI and then colour tweaked in PS followed by a minimal final noise reduction. I took some Ha as well (well you never know!) but that's not in the mix. I tried removing stars with Starnet++ but that didn't help (proabably operator error) and I tried combining both Histogram and Arcsinh stretch to try to get more colour into the stars but most of that seems to have been lost again. As ever C&C are always welcome. I fear the window of opportunity in this location is pretty much done for this year so it'll be the autumn again before I can have another go. Thanks for looking. Adrian