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About GarethA

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    Star Forming

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    North Dorset
  1. Win XP for the 'astronomy laptop' because everything for controlling cameras/mounts/etc only really works on windows (phd guiding, camera drivers, CdC, DSS + other astro software). This machine has networking disabled, updates switched off and just *works*. For everything else in life (including image processing in gimp) I use linux.
  2. that last process looked a bit extreme so here's one last one I'm done Next step - more data!
  3. GarethA

    dss issue

  4. I moved from sony to canon and have a spare sony T ring in the drawer - so if you decide to go down that route PM me before you buy one i used it with an a210 and a580
  5. Thanks folks - ok so I now know what dithering is I don't use capture software yet - just have the intervalometer clicking away. After a bit of investigation: It's not the camera. Here is a hyper stretched sub which does show some faint HORIZONTAL banding but my bias frames seem to deal that pretty well. I pulled the temp data and there's hardly any difference between subs. Sub length could have done with being a little longer. The various DSS methods don't seem to have any impact - (though now I've discovered kappa sigma by previously discarded subs with plane/satellite trails are now back in the stack!) After a bit of processing I've got an image I'm happy with I'm still not totally sure what caused the issue but onwards and upwards!!
  6. I think folks are right that the best way is to go to an event and try both. I have a 130mm truss dob with a 24mm ep in that my 8 and 10 yr olds can lift out the garage onto the drive, turn on the rdf, point it at something, sit on an upturned bucket and be observing in <1min...
  7. Cheers Stuart - I hope it's not the camera or I'll have to break open the 'CCD Piggybank' earlier than I was planning to Am home tomorrow so will try the various DSS clipping and dithering techniques that have been described. Appreciate the compliment re the image itself - just wish the stripes would go away
  8. Cheers Peter, yep, I have an exif tool and will pull the temp data and have a look - hadn't really considered it before.
  9. good luck! Let us know how you get on. Also bear in mind that the primary is factory aligned/set-up . Get your secondary spot on and take some images to review - unless you're absolutely sure your primary is out it might be best just to leave it. Adjusting the primary is a fiddly old job requiring microscopic turns of the allen keys!
  10. I have 25 decent lights. I can't see the issue on individual subs (even super-stretched). I'll post one of the subs when i get home but i cant detect the issue. When i stack the lights (with no other calib frames) then the problem is visible on the stacked image before any stretching or post processing.
  11. i cant see the issue on single subs - looks like dss is introducing it. The camera was modded professionally and I haven't cleaned it so I dont think it's a camera issue...
  12. and I had the focal reducer in so was running at F7.2 which isnt the slowest ever! was hoping 5 min subs would be a good length...
  13. Maybe 5mins was a it short... though m51 isnt exactly dim, certainly brighter than m101. I can see the lines on the stacked image even before I stretch it...
  14. Thanks Louise / James that's a good point. I only had 5 seconds between subs so maybe the temp did start to build... Though I tried just taking the first 5 subs and stacking them and i still got the issue so I'm pretty sure my issue isn't temperature related.
  15. thanks peter - no, the subs were all taken in the same 2 hour slot between about 2230 and 0030 so not much temp difference
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