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Adreneline

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Adreneline last won the day on December 14 2019

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About Adreneline

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    Mathematics, Music, Motorbikes
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    Derby
  1. Hi Adam. I have owned and used an EAF now for over a year in combination with a belt drive to either a Samyang 135mm of Canon 200mm. The unit itself is amazing and I am delighted with the way it performs with an ASIair. In terms of repeatability it works perfectly with my 135mm because I have glued a toothed belt to the outside of the lens so there is no 'creep' or 'procession'; I've not taken that step with my Canon lens so repeatability is not great. After the best part of three years doing battle with autofocus in various programs I have given up and am a total convert to the BM and manually focussing between filter changes and rarely checking during imaging with a given filter (like tonight when I am hoping to get 40 SII images over three hours and will probably pause image collection and check the focus half way through). I should qualify my conversion to the BM approach by saying that using the ASIair interface on an iPad lets you use the 'zoom' feature on the iPad screen which makes it very easy to interpret the BM interference pattern. I pre-process in APP which gives an FWHM value for each frame - I typically achieve 1.3 - 1.8 whereas I used to be lucky to get below 2.5 prior to using a BM and adopting a manual approach to focussing. HTH Adrian
  2. This is an amazing result for a Bortle 8 location and the more you look the more you see in the image. On my MacBook there is a distinct albeit mild green cast so I applied SCNR in PI - I think Hasta La Vista Green does the same thing in PS (Windows only). Hope you don't mind me sharing the result: Adrian
  3. Despite the Moon I managed to get some half decent OIII (23 x 180s) to add to my Ha. With luck I might even get some SII tonight. As ever C&C welcome. Thanks for looking. Adrian
  4. Thank you! Mosaics are fun and revealing - it shows just how big Sh2-240 is compared with the region containing IC405, IC410 and IC417. Adrian
  5. Thanks Olly for the kind comments. I used the curves technique you passed on to me but not sure I got it quite right really - I wondered if I had over stretched the starless image. Thanks again. I centred up on 19 Aurigae using Sky Safari to help me frame the image. I managed to get 30 x 180s of OIII last night and was hoping I might get lucky and get the same of SII tonight and/or tomorrow night. All depends if the forecast can be believed. Adrian
  6. Hi - sorry - only just seen this reply. The frames before and after show nothing - not a trace. It looks a bit odd to me too. Lots of frames contained satellite trails, which were all much more feint. There were also plenty of aircraft tracks - dotted flashes. This was the only one that came close to looking like a meteor. Adrian
  7. Thanks for the kind comments guys. I like the results I get from my 135mm and 200mm. They don't stand up too well to pixel peeping but that is made up for by seeing them in their setting and in context. Adrian
  8. I like everything about the image! Very nice. Adrian
  9. Well I've messed around with a twelve panel around IC1396 and NGC7822 .... ..... and this one .... ... and a couple of others but you'd hardly call it serious imaging - it's more having a bit of fun with APP. Thanks again. Adrian
  10. Thank you Lee. I have to say I quite like the mono images too. Ha is very rewarding in a high LP region. It is too easy to spoil a nice Ha image with some mediocre OIII just because you feel under pressure to colour the image - and with a HOO image there can be twice as much mediocre stuff! I imaged the above whilst waiting for Sh2-240 to appear from behind the tree. I stopped off at Chi Auriga (8 x 180s) and then imaged Sh2-240 (40 x 180s) and then threw together a dodgy mosaic. I'm hoping to get more on Sh2-240 tonight if the weather gods are kind. Even with 3 hours of imaging it's still very feint. It's a bit of a starless WIP! Adrian
  11. Most images are improved with colour but OIII from here is getting more and more difficult as LP levels are increasing with new house building going on all around and neighbours who have decided they need security lights on all night! LED lights are great because they are cheap to run, but, because they are cheap to run people have no problem leaving them on all night! I am sure there is also a direct correlation between clear nights and the size of the moon! If it was easy it wouldn't be worth doing Thank you very much. Adrian
  12. This is 20 x 180s of Ha using my Canon 200m with ASI1600, unguided. I found it hard to balance the noise reduction with not losing detail - not sure I've managed it really. I think I may also have over done keeping the lid on the stars. Hopefully get some OIII another night. C&C always welcome. Thanks for looking. Adrian
  13. I have read somewhere - can't exactly remember where now - that modern lenses focus "beyond infinity" although I'm really not sure where that is! Whatever, the same article stated that when focussing at infinity the focus mark should be within the confines of the 'L' mark on the lens. My personal view is unless you are very, very lucky you will not get perfect shaped stars all the way to the extremities of the image because camera lenses are not specifically designed for astrophotography whereas astrograph telescopes are. The stars in the middle region of my images are acceptably round with both the Samyang and the Canon to the extent that I can tell recognising the significant undersampling that is going on with the ASI1600 sensor. There is some distortion toward the edges and in the extreme corners which I cannot get rid of although I believe I have reduced as much as I can by getting the spacing as optimal as I can. In many cases I end up cropping the image to some extent which gets rid of the worst of the elongated/oval stars. Not sure I am qualified to answer this - I can't help but feel this is more a function of the quality of the optics in the lens. We need to keep in mind that the amount of curvature we find unacceptable in astrophotography is essentially imperceptible in terrestial photography. You get what you pay for and I can't afford or justify a Takahashi! Adrian
  14. My understanding is that connecting a Canon fit lens to this adapter with the 11mm spacer between the adapter and the camera will give an end of lens to sensor distance of 44mm - theoretically the correct spacing. My experience with Canon/Samyang lenses combined with a filter is that 44mm is a good starting point. With my Canon 200mm combined with Astronomik filters my spacing is 44.5mm which allows me to focus my Ha, OIII and SII filters within the 'L' marker on the lens. With my Samyang 135mm the spacing needs to be 44.75mm to get the focus within the 'L' mark. If I then switch to my Baader LRGB-C filters the focus point is outside the 'L' mark because ideal spacing needs to be increased by a fraction of a millimetre because the filters are thicker - and we are talking changes of .2 mm making all the difference. One day I will change my LRGB-C filters to Astronomik so they are all the same thickness. I have spent hours and hours trying to find the right spacing to get the best shaped stars I can whilst maintaining the focus position within the 'L' mark. Good luck!
  15. My Canon dlsr cameras have built in UV/IR cut filters but that didn't stop the bloating experienced with the Samyang lenses (or indeed my Canon 200mm) - the HOYA UV filter definitely made a difference. Maybe it's just a feature of the lenses! Interesting! Adrian
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