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About prusling

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    Star Forming

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  1. Thanks, Kev, your 100 degree 20mm Myriad on the 250px was a revelation - closest I have come to naturally looking through a window to the universe!
  2. Thanks to @AdeKing, @kev100 and @Grumpy Martian for your great company last evening. Despite the early cloud, chilly wind and bright Moon it was nevertheless very enjoyable! Imaging was very hit and miss but I managed to pick the best 34 of the 60 1-minute frames I took of the NE Milky Way region without any calibration frames and put this heavily cropped image together with DSS and StarTools. Capella to the lower left and the Pleiades to the lower right with the California Nebula between them, double cluster middle left with the Heart and Soul Nebulae to their left, and of course the Andromeda Galaxy to the upper right. Looking forward to the next get together!
  3. prusling

    Hewlett Packard HP 2540p i7

    PM sent
  4. Hi, I plan to be there and will be bringing my DSLR/SkyTracker. Look forward to meeting you all!
  5. https://www.portsmouth.co.uk/news/politics/street-lights-to-be-turned-off-at-night-across-hampshire-1-8688439 We need to lobby for this in Dorset as well! I've copied it to the Street Lighting team at Poole council.
  6. Sorry I can't make it either - beer festival at lunchtime...!
  7. prusling

    Star discovery clutch adjustment

    A brief update - post-adjustment the tracking is still not great but probably better than before. Gotos are OK and the mount is less prone to accidental manual movements although as noted there is a fair bit of play before real movement. Will persist with it for now, but underwhelmed...
  8. prusling

    Altair hypercam 183c

    It is very dark. It's the stretch that is moving the very dark pixels up to brighter levels so you can see them. You have a mean/median pixel value of around 656 out of a possible 64k. That represents the unwanted signal from the electronics that needs to be subtracted from the pixel values to give you the real signal.
  9. prusling

    Altair hypercam 183c

    Looks good to me, though it depends on what you are doing - i.e. whether you need more gain or not. e.g. if you are taking long exposure images of DSOs it's probably fine but if you are wanting to live stack lots of short exposures you'd need to wind up the gain (in my limited experience!).
  10. prusling

    Altair hypercam 183c

    You're welcome, I may not live far from you so I'll drop you a pm. I believe that the latest APT beta has native support for Altair cameras (rather than ASCOM) though you may want to check with Ivo the product owner. There's also a good facebook group for Altair products if you haven't already found it.
  11. prusling

    Altair hypercam 183c

    Fuzzy grey is good for bias and dark frames as it shows the signal that is present. Other software won't stretch them as much and you'll just see black but that won't really tell you anything. Sorry I can't add anything more to the gain query - what software are you using and someone else may be able to help?
  12. prusling

    Altair hypercam 183c

    There are a number of programs that can view and manipulate FITS files - the ones I use are FITS Liberator 3 (ESA/ESO/NASA basic image stats), Fitswork 4 (a number of useful functions), IrfanView (a lite photo processor that can convert TIF to JPG for sharing) and GIMP (full-functioned photo editor). All are free or donation. Most will not show colour (unless a debayering function is used). Bias files (and darks) have extremely low pixel values so will display as black unless stretched a lot. My main personal recommendation would be StarTools which is an excellent post-processing program that is very reasonably priced - there's a free trial as well which disables saving.
  13. prusling

    Altair hypercam 183c

    Each software package applies its own degree of stretch to an image when displaying it - some none. You would need to use a package where you can apply your desired degree. Are your bias frames in FITS format?
  14. prusling

    Altair hypercam 183c

    Software uses different ranges for gain values - if I remember correctly SharpCap uses 0-5000 for this camera, but other software can use a different range. Maybe it should be expressed as a % - in my case around 8.6% for unity.
  15. prusling

    Altair hypercam 183c

    I believe the offset defines the signal level of black taking into account that there is always a degree of noise signal. So the optimal level of offset is just enough to lift the 'black' level above this noise. A figure of 30 has been recommended for the 183c elsewhere.

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