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feilimb

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    116
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About feilimb

  • Rank
    Star Forming

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  • Website URL
    http://ronnach.wordpress.com

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  • Gender
    Male
  • Interests
    Angling, Software, Astronomy, Film
  • Location
    Cork, Ireland
  1. feilimb

    Histogram Question: 3 Peaks?

    @vlaiv thanks so much for your excellent reply. It is reassuring to know that the peaks I am seeing are normal in my case, and yes the light source is very cool / bluish which explains red peak appearing left-most I guess (before the green peak). When 3 peaks appear in a histogram is it possible to judge whether a particular exposure length is a 'good exposure length' for a flat image, or is simply seeing the presence of all 3 histograms (unclipped) sufficient to know that the flat is OK to use?
  2. I got my first ever 1.25" sized filter recently and wanted to try a trial run of capturing a flat to get an idea of how good/bad the vignetting might be. Here are the details of the setup: SkyWatcher ED80 with 0.85 focal reducer 1.25" IDAS P2 LPS filter ASI294 MC Pro at Gain: 120, Exposure time: 0.05 seconds Light source: my homemade flats light source with LEDs (see: https://stargazerslounge.com/topic/325457-flatstub-a-rough-ready-diy-flats-solution/ NOTE: the scope was not exactly focused at infinity - not sure if this matters regards my query below on histogram) Histogram (grayscale): Histogram (debayered): I'm a bit clueless when it comes to histograms and I was wondering if someone might be able to explain why I am seeing 3 peaks..? I was trying to look at the histogram to get a rough idea for a good exposure length where the peak would be around the center along the horizontal, but I expected 1 peak instead of 3!? FITS File (23MB): https://we.tl/t-FsBPF6wruC
  3. feilimb

    IDAS LPS-P" 1.25" Filter - £113 inc postage

    Hi Marky could I put in an offer of 100gbp for the Idas lps p2, no worries if you want to hold out for the asking price.
  4. Sorry to bump this again, but I am now thinking of going down the 1.25" filter route. This is mainly as it will be cost saving - since 2" filters are more expensive, and since I may already the adapters required (using the adapters which came with the ASI294MC Pro). Looking at the adapters which came with the camera however, I am not convinced I can get a 1.25" filter into the image train and before ordering any filters of this size it would be great to hear from anyone who has successfully used a 1.25" filter with this camera (and without filter wheel). Has anyone else out there succeeded in using a 1.25" filter with the adapters that come out of the box, and then attaching the camera to SkyWatcher focal reducer..? I can attach some photos of the adapters which come with the camera in case they are useful for figuring this out..
  5. feilimb

    Horse Head

    Cracking result for 15 minutes Stu A racing horse! Was that using a single shot colour camera, and what F ratio was it at?
  6. @michaelmorris thanks for the really useful information, it's great to hear you have the same gear and read how you solved the filter conundrum in that thread. I think I will go down a similar route with the 2" filters and flo adapter. Have you had a chance to try out the idas filter yet with the asi294?
  7. feilimb

    DIY Refractor

    Well done that is a brilliant result, it must be so rewarding having brought the whole scope together from the start Did you get some astrometry in the end to determine the focal length?
  8. I may be investing in a filter or two for use with an ASI294MC Pro, which is connected to a 0.85x Sky-watcher Focal Reducer (in turn connected to Sky-watcher ED80) and I have little idea on what size filter I should go with and how to get it into the imaging train. Currently the ASI294 is connected to the focal reducer using the adapters which came with the camera which are: 11mm T2 ring (screwed directly onto the camera) T2 Extender 21mm T2-M48 16.5mm Extender There are some other adapters in the box also however, which may assist with getting a filter in there somehow, see the listing of what is included at eg (look for 'What's in the box' section): https://www.firstlightoptics.com/zwo-cameras/zwo-asi-294mc-pro-usb-30-cooled-colour-camera.html I think one option I might have would be to go for this adapter (and then screw a 2" filter size into the top of it) - but I think this would put the filter quite a distance away from the imaging sensor: https://www.firstlightoptics.com/adapters/flo-adapter-for-skywatcher-focal-reducers.html and I would no longer be attaching the reducer to the main scope via threading, just using thumb screws which might be a bit of a concern. Can anyone advise if they are using a similar configuration, and whether a 1.25" filter might be easier to incorporate.. and if so how! I only want support for a single filter at a time, don't want the overhead of filter wheel etc. at this point.
  9. feilimb

    Sh2-240 Single Pane, 6 x 1200s Ha

    I think that is really beautiful, I've never seen this target before. It reminds me of a lot of bubbles stuck together
  10. Thanks for trying @alacant , it looks similar to what I was getting after a quick process but it's good to know it was not just down to my processing skills! Thanks for the suggestion, unfortunately the moon is getting bigger again these days and it's probably going to be a few weeks again before the moon is not in the way but I will try your suggestion of dropping the expsosure time to 90s with unity gain. I will probably get too tempted - and go straight for a filter (I might pick up a Ha in the near future). It seems in the past 2 months like all the best clear nights for me are happening when the moon is getting bigger, and having a Ha filter would just give such a great edge on being able to image when the moon is out too. I have a CLS LP filter for EOS clip in (for DSLR's) and as a stop-gap I might try blu-tacking it to cover front window on the ASI294 ... and see how that performs!
  11. Hi alacant, I used a Skywatcher ED80 with the 0.85x focal reducer putting it at 510mm F/6.4. I'll upload a FITS file to WeTransfer shortly, I tried stacking today and have not had any success in a very quick processing session, I fear the data is just not good enough due to (a) light pollution, and (b) a quarter moon and probably most importantly (c) no filter of any kind used It's all part of the learning curve ! I took some flats also, but I fear they may not assist in the integration due to dew which had built up on the objective by the time I took them. I'll upload a single early light frame as FITS and deep sky stacker integration, the version without the flats (so lights only): Single sub (180s at Gain 200) 22MB : https://we.tl/t-0p2PONXsyB Deep Sky Stacker Stack (no calibration frames, around 38 lights) 67MB : https://we.tl/t-49TpDm7W57 @PeterCPC thanks that is beautiful! Can I ask did you use any filter at the time, or if light pollution was a factor?
  12. The transparency was OK to begin with on the night, but as the night progressed it worsened (although the frame above was first of the night). There was no filter used, my light pollution is moderate certainly not on the scale of London
  13. The above image was *not debayered, the fits was captured in raw 16 bit mode, opened in PixInsight, stretched via Histogram Transformation and then saved as JPG from Pixinsight (after reducing its size). I have not had an opportunity yet to stack and process the subs I got on the night, but when I do I'll update the thread with what came out (though I don't expect much due to the light pollution).
  14. Thanks all for the replies, I ended up shooting about 40 exposures of 3 minutes each before I packed it in with heavy dew forming (I don't have any dew heaters yet). The final few frames may be unusable due to dew which had formed, but I will stack what I have and see if there is any hint of nebula detail in there. Thanks Jim for the suggestion on short exposures, I thought if I went as short as a minute I would not pick up anything but it is definitely worth a try and as you say even with 30 minutes stacked it would be interesting to see what comes out. @wimvb thanks also, I'm new to this whole world of OSC so interesting to note that lowering the gain can work to an advantage in this way, so I have a few things to try and tinker about with on my next clear sky. Ultimately I guess a HA filter or similar will greatly aid in cutting out the light pollution and allowing for much longer exposures without the sky background being washed out but it would be nice to see what one can achieve without the use of filters (but obviously that would be more achievable at a dark sky site).
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