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Found 8 results

  1. Does Focal Ratio affect brightness or is it all about field of view. Will an f/5 scope show the Andromeda galaxy more brightly in the eyepiece than an f/12 scope, or is it just about fitting Andromeda in there and seeing more of the sky? Also does the Focal Ratio of a scope have any effect on the amount or length of exposures taken in astrophotography? Thanks.
  2. From the album: CCD venture

    A h-alpha shot of the Wizard nebula in Cepheus. ED80 - ATK16HR - Ha clip filter - EQ6 - finderguider 9x50mm PhD2 - photoshop - DSS.
  3. Hello all, I have just joined and have been looking around, and putting in various searches to find the answer to my question(s). I have already found some valuable information, but i can't find a specific answer to a question i have relating to exposure times. I have shot the milky way several times before, from a tripod and a wide angle lens. I am aware of and understand the "500 rule" and that worked fine for me at first when i was shooting with my Canon 6D Mark II. When i moved over to the Sony A7III i noticed significant trailing using the same rule and that led me to the NPF rule (Via the photopills app incase people dot know). I am heading back to Tenerife once again in about 6 weeks time and want to buy a star tracker so i can get some really detailed images. I have done a fair bit of research and in principle, the whole thing doesn't seem to be too daunting or difficult. I have purchased the Polar Scope Align Pro app so i can align Polaris as accurately as possible, i will practise putting the unit together and familiarising myself with the different parts etc, but it is the exposure times that i do not understand. My best glass is the Carl Ziess 50mm F/1.4 Planar, the 18mm F/2.8 Batis, the Sigma 35mm F/1.4 Art & the IRIX 15mm F/2.4 Blackstone. I currently do not own, nor have i ever used a tracker, and I cannot find any information relating to which aperture, ISO and Shutter length any of these focal lengths should or could be shot at. Is there anything similar to the 500 rule or NPF rule that relates to using a tracker with varied focal lengths? or is it just a case of stepping the lens down for sharpness and then trial and error? Thanks in advance, Matt.
  4. I'm working on a school capstone project and decided I would try branching into astrophotography as observational astronomy has always interested me, but not so much astrophotography. Since I'm mostly concerned with observational astronomy, I just have an 8" alt-az manuel dobsonian, and I got an orion starshoot 2 camera just to try things out and see what I could image. I was wondering if it would be possible to get any detail out of a DSO if I were to take exposures in increments and move my telescope to center the object between exposures. Any otherimaging methods or object suggestions that I could image for my school project would be greatly appreciated. Thanks!
  5. Aenima

    ngc7000red ha -

    From the album: CCD venture

    A h-alpha shot of the Wall section of NGC7000 aka north america nebula. ED80 - ATK16HR - Ha clip filter - EQ6 - finderguider 9x50mm PhD2 - photoshop - DSS.

    © 2016JayBird

  6. My Fits file metadata displays the exposure duration of my images in the format "1.2000000000E+02", which converts to 120 seconds. Does anyone have a conversion table they can share or give a link to, so that I can easily make them into seconds? Thanks!
  7. Hi there I was wondering if there's a scientific way to identify that you have the correct exposure settings/time for an object, using the image data readouts provided by most capture software? I have Nebulosity, but prefer SGP. I appreciate that each set-up is different, but having taken various exposures from 30s to 10min (all guided), I'm still at a loss of how to work out my best settings. I've tried various gain settings, and found if I used g=1 on a 10min exposure of M42, the image was super clean, but not so much detail as I hoped for. This is clearly a balancing act, but I'd like to apply some logic to the settings, if possible. My equipment: Celestron C11 with CGEM DX Mount. ZWO ASI1600MC-COOL. I have great polar alignment, and guiding is exceptional, giving perfectly round stars at 10min exposures. I cool the OSC to -20 to reduce noise. Culmination is good and the optics are all clean. My location is poor as I'm working from a balcony that vibrates when traffic passes on the main road, but am still able to get decent images, even if a little lacking in fine detail. Thanks in advance Chris
  8. Hi All, My question is in relation to the exposure times of subs. A few weeks ago, I took M27 @ ISO800 and went for 5min sub frames (if I remember correctly). The RAW images were completely overexposed (attached as jpeg just for the small file size), but does this matter so much as after processing using the Levels option (Gimp) I can stretch the histogram to bring out the image (2nd attachment). Would it be better for shorter subs or using a lower ISO setting to keep the darker sky or would it be OK to carry on with longer exposures and just stretch these in the post processing? I am in a light polluted area and yes it would be better for me to travel somewhere darker but just for my learning experience I'm just in the back garden so far. Also just to note these are just lights I've taken, again I will get around to the darks & Bias frames in the near future (now the winter nights are coming) but I wondered as the data is over exposed am I loosing data by using the levels? Many Thanks. Mike
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