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Home Forums Observing and Imaging Group My week in dark skies, Brecon Beacon.

This topic contains 61 replies, has 7 voices, and was last updated by  Astrograph 2 years, 8 months ago.

Viewing 15 posts - 16 through 30 (of 62 total)
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    Posts
  • #8354

    Brian Blake
    Participant
    Topics: 187
    Replies: 409

    Nice one Tej.

    #8367

    Tej
    Participant
    Topics: 36
    Replies: 582

    First Light Optics sure work fast, I just received my flattener!  Look forward to nice round stars on the edges of my images from now on…but not for the next few days it seems, weather forecast is lousy 🙁

     

     

    #8370

    Andy Sawers
    Moderator
    Topics: 112
    Replies: 587

    weather forecast is lousy

    The curse of new equipment!!!

    • This reply was modified 2 years, 8 months ago by  Andy Sawers.
    #8376

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 745

    Arrrrrggghhh! He’s done it again! Romney cancelled tonight for sure now 😉

    #8377

    Christina Chester
    Participant
    Topics: 16
    Replies: 192

    Wow, Tej, your photography is AMAZING and I am in complete awe of  your Andromeda shot!

    I look forward to the day that I am merely able to take a look at a galaxy in as close-up a view as that, let alone capture an image of it. Stunning!!!

    #8381

    Sumitra
    Participant
    Topics: 21
    Replies: 233

    Tej these are all fabulous!
    Again, well done on Explore! Even though as Mike says, it’s a bit odd which get there, I do find it fun to land there. I found it hilarious that my timelapse with 3 ways to show the earth rotates got on 2nd place in explore, with a shed in a garden at 1st place, and a guy in a retro suit in second place, whilst a polar bear catching a fish in 6th!

    A question for you all – I read that it isn’t ‘good’ to have too many calibration files as it can be detrimental, but I have not really understood how you determine the number you should use. Anyone could give me some tips?

    #8383

    Tej
    Participant
    Topics: 36
    Replies: 582

    Arrrrrggghhh! He’s done it again! Romney cancelled tonight for sure now ;)

     

    Oh no, at this rate I am going to get banned for sure!  I hope Romney is still on for those going tonight, that was one of my favourite events 🙁  The views through Martin’s scope in dark skies was breathtaking, the one time I went. Always wish I can go again but I dont want to rob others of a place given the limited places available.

     

    Wow, Tej, your photography is AMAZING and I am in complete awe of your Andromeda shot! I look forward to the day that I am merely able to take a look at a galaxy in as close-up a view as that, let alone capture an image of it. Stunning!!!

     

    Thanks Christina, dont think we’ll be able to see galaxies through eyepiece telescopes with that kind of  detail for a long while yet but you know what gave me the most pleasure while I was there, was to actually see Andromeda with my naked eyes. Its a large blurry elongated patch but I feel such a sensation seeing it knowing how ridiculously far it is!  I mean everything else we see in the sky are practically in our backyard!   Then I get a further tingling feeling as I was imaging it live on my laptop and then looking up at the sky, seeing the blurry patch then looking back on my screen seeing each one minute exposure that appears with so much detail, yep, I do feel a spine tingle…well at the beginning anyway, as time rolled, the imaging capture did get a bit tedious, lol.

     

    But dark skies, definitely the place to go whenever we can!

     

    Tej these are all fabulous! Again, well done on Explore! Even though as Mike says, it’s a bit odd which get there, I do find it fun to land there. I found it hilarious that my timelapse with 3 ways to show the earth rotates got on 2nd place in explore, with a shed in a garden at 1st place, and a guy in a retro suit in second place, whilst a polar bear catching a fish in 6th! A question for you all – I read that it isn’t ‘good’ to have too many calibration files as it can be detrimental, but I have not really understood how you determine the number you should use. Anyone could give me some tips?

     

    Thanks Sumatra, I have been exploring the uh…the Explore and I have got rather addicted discovering people’s galleries,  most are so amazing and the ones that attract me the most are the ones of nature captured in unique and often bizarre perspectives, its a fantastic place of inspiration for photographers and although way out of my depth, I sure as hell enjoying the daily content.  Dont get me wrong, I am chuffed to have the galaxy pic in it and its a good thing Flickr has no idea about Field Flattening, lol..  But you and Mike sure as hell fit right in with those folks!

     

    Good question about the calibration frames.  I look forward to hearing Mike’s view…Andy’s too once he has finished that particular lesson! lol.   From what I have learnt, we should take about 1/3 of total exposures or 20-30 frames.  But I never learnt how to guage how many are actually needed.

    #8384

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 745

    OK. I’m going to be really controversial here.

    Bias frames are a complete waste of time if you are using a DSLR. Any bias is present in the dark image as well as the photographic images and therefore is subtracted when the dark frames are subtracted. I’ve only ever used bias frames with CCDs, where the idea is to take a zero second exposure. For DSLRs, don’t bother.

    Even more controversial, I’d question the value of dark frames. Even with accurate tracking, stars are not in exactly the same place on every frame. So therefore, the noise and hot pixels also move with each image. The process of stacking will remove much of the noise and hot pixels.

    Flats are probably the most useful of calibration frames, but they are also a pain to produce.

    So. My conclusion? Don’t bother with calibration 😮 😉 !!

    #8385

    Andy Sawers
    Moderator
    Topics: 112
    Replies: 587

    its an absolute joy capturing these ancient photons!

    Funniest scientific thing I’ve read all day, Tej! And thanks for the mini-astrophotography course. I expect you to be the course tutor next year!

    #8386

    Tej
    Participant
    Topics: 36
    Replies: 582

    Haha, that was unexpected. Quite a left hook to the general consensus of imaging there, Mike.  I like it.  I’ll try put your theory to the test and process some stuff with and without the darks.  Flats, I realise I dont actually need when imaging on my Equinox refractor but on the Celestron 8″ cassegrain I do as there is vignetting with that scope.

     

     

    #8387

    Christina Chester
    Participant
    Topics: 16
    Replies: 192

    Then I get a further tingling feeling as I was imaging it live on my laptop and then looking up at the sky, seeing the blurry patch then looking back on my screen seeing each one minute exposure that appears with so much detail

     

    Yes!!! This is exactly what I’d like to experience some day! I’ve only ever seen it as a teeny, cloudy, blurry patch. Need to get closer to it (somehow) but I suspect photographing a deep sky object needs tracking and a wealth of other gadgets? I’m a complete astrophotography newb and I’ll confess, I have no idea what is meant by all these biased flat frames 🙂

    #8395

    Sumitra
    Participant
    Topics: 21
    Replies: 233

    So. My conclusion? Don’t bother with calibration !!

    Wow… I’m kinda glad to hear that! I find it a pain to do them as well… and on top of that, for some reason (perhaps I’m overworking my computer), DSS just crashes before the end, so since this summer, I’ve only been using DSS Live (which is a new lighter version but you can’t put all the calibration files on it).

    Thanks for the explanations as well, Mike!

    I’ll try put your theory to the test and process some stuff with and without the darks.  Flats, I realise I dont actually need when imaging on my Equinox refractor but on the Celestron 8″ cassegrain I do as there is vignetting with that scope.

    Actually when I read what Mike wrote, I was wondering if I could ask you to redo your Andromeda without anything to be able to compare?? Well if you have time 🙂

    I’m asking because my computer crashes when I ask it do it it :'(. Which kinds of give me the excuse not to calibrate any more!

    #8396

    Sumitra
    Participant
    Topics: 21
    Replies: 233

    PS.

    Dont get me wrong, I am chuffed to have the galaxy pic in it and its a good thing Flickr has no idea about Field Flattening, lol..  But you and Mike sure as hell fit right in with those folks!

    That’s nonsense! You’ve got fab photos, well deserved on Explore 🙂 I hope you get more there again, I love it when my Flickr apps starts randomly beeping like crazy with a dozen instant faves! First time it happened, I was confused and irritated thinking there was a bug on my phone until I realised what it was :p

    #8398

    Tej
    Participant
    Topics: 36
    Replies: 582

    Yes!!! This is exactly what I’d like to experience some day! I’ve only ever seen it as a teeny, cloudy, blurry patch. Need to get closer to it (somehow) but I suspect photographing a deep sky object needs tracking and a wealth of other gadgets? I’m a complete astrophotography newb and I’ll confess, I have no idea what is meant by all these biased flat frames :)

     

    Oh you could have joined Andy on the beginners astrophotography course!

     

    But you  can start deep space astrophotography using what you have already…assuming you own a dslr camera?  You can get a nice shot of Andromeda with just that and a tripod.  Have a look at this example I found (click on the image to see its higher resolution):

     

    http://www.astrobin.com/25654/

     

    OK that’s not awfully close as you dream about but there is Andromeda in its distinct galaxy formation, with its unmistakable core amongst densely packed starfield.  No tracking, just a camera on a tripod with a  moderate wide zoom lens at just 35mm. The key is that its a stack of 50 ten second exposures, short enough to avoid star trails.  Thanks to awesome stacking software available for free.

     

    Then you can step up to purchasing an equatorial tracking mount to take longer exposures.  They can cost under £100 I think …and it goes on!  Its an addiction, in which you just want that bit more while the wallet gets thinner!

     

    Here is another image with just a dslr but on a low cost equatorial mount  (again, click on the image to see it in its full higher resolution):

     

    http://www.astrobin.com/79570/

     

    In truth, the extra expenditure on “gadgets” is really to achieve image perfection, more polish, more details, pin sharp star fields, eliminating vignetting, faster exposures for the same light gather,  etc etc.

     

    For instance, that galaxy image I captured got some very nice comments from all of you which gives me a such a warm encouraging feeling  and pride in my image…yet I just spent another £69 on a component that will just simply make my stars at the edge of the field more round!  Something that hardly anyone noticed apart from the knowledgeable astrophotographers, such as blooming Mike…who did notice, lol.

     

    There are so many different paths both low cost and high cost to enjoying and expertising in astrophotography.  Sumitra and Mike excel in just using their DSLR and a tripod.

     

    But your desire is to “get close to a galaxy”, so I’d recommend follow a path to that will eventually get you to that destination 🙂  That was my ultimate desire too and after over a year of walking a drunken zig zag path, I finally got there last weekend!

     

    So ok, here’s what I needed to get close to Andromeda as you saw in my image.

     

    My Camera.  A mid range dslr, Canon 650D .   Cost £350.  But alternatively a Canon 1100D for  £150 would have sufficed,  noisier at higher ISO levels but fixable in post processing.  The better the camera the least work needed in eliminating the high ISO noise.

     

     

    Telescope:  A Skywatcher Equinox 80mm apochromatic refractor.  Cost £550.  But alternatively , an 80mm achromatic f5 refractor for £100 could be used.  The compromise would be vignetting, colour distortions but still, all fixable in post processing.

    Mount/tripod:  An HEQ5 Pro Synscan.  Cost £750.  But alternatively, £100-£200 for a lower model but still decent tracking equatorial, perhaps an EQ3.  Difference: quality in periodic error tracking and load capacity.  My mount can take bigger scopes but a cheaper mount would have sufficed for an 80mm refractor.

     

    Accessories:  Bahtonov mask for focussing (£10), Camera adapter (£20-30), timer remote shutter control (£20).  I use my laptop as the timer control.

     

    So although my setup cost apprx £1700, you can still get up close and personal with Andromeda using the alternative equipment costing around say £400-£500.  Its  just the quality of images wont be as good or a lot more work needed in post processing or a lot more  exposures will be required etc.

     

    Have you got a telescope already?  is it the 5″ reflector by any chance?  The one  that  you imaged Mike in his rocket? 😉  If so, you probably nearly there already and all you need is a camera adaptor!

     

    • This reply was modified 2 years, 8 months ago by  Tej.
    #8399

    Tej
    Participant
    Topics: 36
    Replies: 582

    Actually when I read what Mike wrote, I was wondering if I could ask you to redo your Andromeda without anything to be able to compare?? Well if you have time :) I’m asking because my computer crashes when I ask it do it it :'(. Which kinds of give me the excuse not to calibrate any more!

     

    Sure thing, I’m on it 🙂

    • This reply was modified 2 years, 8 months ago by  Tej.
    • This reply was modified 2 years, 8 months ago by  Tej.
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