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Big Jim Slade

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About Big Jim Slade

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    Star Forming

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    Leafy Bedfordshire, UK
  1. Big Jim Slade

    Deconvolution in PixInsight - a written workflow

    I must admit I'm a bit confused about the PSF part here. I don't quite understand why only using just Moffat (in Steve's example) or just Gaussian as Wim mentions above, is necessary. To get the most accurate fit to characterise the PSF don't you need both? (I should add of course: thanks to Steve for doing this. I've been through multiple write-ups on Deconvolution and it's very hard to find one that makes a very complex process as clear as this does. )
  2. Big Jim Slade

    Experienced Pixel Peeper required......

    Agree with Vlaiv here. Looks like a clipping problem during stacking. I don't use DSS, but I'll bet I could reproduce it in PixInsight if I had reasonably "hot" stars and high pixel clipping turned on.
  3. Given the lower surface brightness, plus the high sky background, you may be better off with lots of short (60 secs) exposures. If you get 30 or so it may start to emerge. (Caveat - I'm a CCD guy, so someone with more CMOS knowledge may know better.)
  4. Photo of Steve's first obsy: Seriously, I'm amazed by what was done on film with manual guiding. There's a bit of me (a very masochistic bit) that fancies giving it a go sometime.
  5. Actually, the process of learning AP is all of those, repeatedly. Over a period of years.
  6. Big Jim Slade

    Takahashi scopes???

    This is a great point. I recently went for the Esprit over the Tak, precisely because I felt that I didn't yet have enough experience with acquisition and processing to exploit any extra quality the Tak might have.
  7. Not sure if this helps, but here's a stack from mine at the (almost) default 63mm distance. I've added a .3mm shim to account for the filter, but that's it. Esprit 100D -> Flattener -> Flattener to M48 -> 0.3mm shim -> Moravian 55mm back focus M48 nosepiece -> FW with Astronomik Ha (1mm) -> Moravian G3 16200 This is just over 5 hours of Ha - 32 x 600. I've done a teensy bit of NR, a few gentle stretches plus some local contrast enhancement. Stars untouched - but they are a little elongated in RA, my guiding RMS needs some work. Can also post the CCD Inspector maps if that's of interest to people.
  8. Big Jim Slade

    Astronomy Now wrong again

    You're not wrong there. My grasp of this is basic at best, but I can spot an Appeal to Authority when I see one. Its all handy-wavey "General-Relativity-Wasn't-Einstein-Clever-Oh-Look-Over-There!-A-Badger!"
  9. Big Jim Slade

    Large moon mosaic. 100 megapixel

    Wow, that is insane. Well done!
  10. Yes, hanging the focuser off the primary was always a massive design flaw with the GSO RCs. Worth noting that the current generation of truss GSOs have changed this. In the original form you can't hang anything substantial off it without the collimation slipping with every slew. The 6" compounds the problem by having the collimation screws right against the focuser mounting ring, so you can't adjust them if you fit a tilt adjuster. It also makes it impossible to swap screws for some decent sized knobs. I'm thinking about getting a ZWO OSC for mine, to go after smaller targets. It seems well suited for that.
  11. Big Jim Slade

    IAS 2018

    I suspect that will be a greater danger to my wallet.
  12. Big Jim Slade

    IAS 2018

    I shall be there on the Saturday. Have a ticket for the Astrophotography talk. I'm also planning to prowl the floor to see if there are any "serious" mounts on show - I'm thinking of upgrading and I'd like to get a sense of what I'm letting myself in for.
  13. Big Jim Slade

    Tilt on a G3, should I worry?

    I tired my G3 on my WO ZS72 whilst I was waiting for my Esprit to arrive and got similar results. As vliav says, weight is the thing here, everything needs bolting together very tightly, compression rings won't cut it.
  14. If you are using the m48 adapter on the back of the flattener, then it's 55m. Without, it's 63mm.
  15. Ah, two months earlier and you would have had even more of my money. Interested to see how you get on. The 16200 is biiiiig, and I've had a hard time pinning down image circles for the "budget" RCs. CFF/OS will cover it, but they cost ££££.

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