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About mbrickley

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    Minimal astronomy using light weight refractor and lightweight camera
    Imaging and photometry
    Image analysis
    Astronomical sketching
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  1. I know this thread is old but I’ve been looking at this too and thought it was worth adding that the f3.6 scope is based on a f5 not an f4 scope, it’s the f2.8 one that’s based on a f4 scope. This means the f3.6 version is both less critical in collimation and can easily be used as a F5 imaging scope without the reducer but with a coma Corrector
  2. Hi i was considering that too and will indeed try it before buying anything but the potential problem for NRT is the download time... which could well be several seconds as against 1-2 frames per second with the 414 or infinity... it might not matter at all or be annoying depending on the sub time... otoh I could always also use a subframe and on chip binning to give quite a high speed download and this might work very nicely. Don’t we live at a truly amazing time when there are so many options to observe and image that even 10 years ago would just be complete fantasy, we are really very blessed
  3. Hi Olly fairly sure *but* I should have made my intention clearer in my first post, I have a 460 that I like very much, I tend to use it with a 540mm FL refractor and the image scale and res are great but in this context I was thinking specifically about near real time viewing for fun and ‘live’ observation rather than image quality ... in this context I’m mulling trying to get the fastest usable image I can with a metre or so focal length newt and thus it seems worth trading absolute resolution, ie small arc sec per pixel for sensitivity which the larger pixels will give. Hence also the question about sensitivity...it seems to me the critical factors as to brightness per pixel are pixel size (which governs how many photons hit the overall pixel per unit time given a constant scope setup), qe which governs how many of these get converted to electrical signal and noise esp read noise which governs how much the snr is degraded by noise ...
  4. Thanks guys ... this looks potentially a good camera for galaxy close ups on a metre or so focal length system
  5. Hi im interested in the 414ex to supplement my larger but smaller pixel cameras for imaging galaxies. I’ve been interested in the line in the Atik blurb which states that this is more sensitive than the kaf3200. The best figure I can find for it’s QE is about 77% which is less than the 80% or more that the 3200 has as a peak QE and furthermore the 3200 is v sensitive in ha. not in any way knocking the 414... it looks to be a great camera but wonder if anyone knows where the data is that suggests it’s more sensitive than the the 3200 which is just amazing (still) for these small faint targets albeit with lots of problems like horrid dark noise and rbi. cheers mark
  6. HI Nigel thanks so much for this, I really do appreciate the advice and this got mew started really well. Can I just check though since magnitude is a log scale don't I need to relate the adu (effectivelty the flux F1) and magntiude (M1) from the star with the flux from a single pixel (say F2) by the relative magnitude formula .. m1-m 2 = -2.5 log (F1/F2) to get the total magnitude of that pixel (m2) rather than just an arithmetic scale before dividing by the pixel area? again thanks for the help Mark
  7. HI I'm working on a long term project looking at galaxy fields and I want to do some v and b band photometry on the target galaxies. Does anyone have any experience of calibrating images to allow extended object photometry. In particular most analyses use a surface brightness measure in mags per arc sec squared to map the surface intensity, does anyone knopw how to intensity calibrate the flatted and dark subtracted image so that pixel intensities are related to this brightness measure not to the instrument intensities. Lots of professional literature comments on what to do with the calibrated data but I cant find a good reference as to exactly how to calibrate the intensity. Thanks so much Mark
  8. Hi Nick Thats a good point and Wolfram do publish their sources (in this case the strasbourg site actually) but no its purely for fun on my part. Something to fill the dark night void thats coming up in June July. My idea is to see how deep in terms of redshift my relatively small refractor and a couple of different cameras are going but in truth I much prefer playing with data than making nice pictures and this is just a project that has piqued my interest. Having said that I had a look at the redshift data for a few returns and it matched the data from a manual search on the strasburg site so I would be fairly confident of the data. Have a good evening Mark
  9. Having been playing around with both these last few days one thing that seems strongly in favour of mathematica is the link into the online database Wolfram Alpha. In particular there is a language command AstronomicalData() which looks up data on a huge range of objects from the database which is curated and online and returns these values for use. I'm working on a reduction system for wide scale galaxy images which are identified using Aladin. To give one example I would like to histogram the redshifted of detected galaxies. In this case assigning the retuned name of a galaxy in the text file from aladin to a string variable then doing a lookup AstronomicalData(name,"redshift") returns the redshift which can then be assigned to a column in the matrix holding the data. Repeat and histogram this column job done. I can see myriad uses for this dynamic lookup of data and the available range of info is huge. Mark
  10. Thanks, it is really good indeed isn't it. They host the aladin program as well which is amazing for spotting galaxies etc on your images
  11. Hi No the £99 was just a guesstimate of the 85 plus vat. Inconsistently on my part the 25 for each toolbox is ex vat so I suppose hey are nearer 30 with. I do agree about the toolbox costs .... Bit like pick and mix sweets.... The bag is always heavier than you think!!
  12. I'm thinking of getting mathematica too and there is a lot of crossover between the 2 although surprise given the name matlab is particularly good at handling matrix data like images! Lots of fun to be had here I would say
  13. Hi I would have agreed with you but matlab now offer a £99 package and £25 for the image processing toolbox for non commercial home use so it's much less expensive than it was. I csn only speak for me but it seems well worth that Cheers Mark
  14. Hi Robin Nice to meet you. I also do some visual hunting but my eyesight is not great so ccd imaging is very good for me for the faint stuff!
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