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About MartinB

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  • Birthday 15/03/59

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  1. Fireworks Galaxy (NGC6946)

    Your stars look lovely and you've split a tight double.
  2. Heart and Soul

    That is one beautiful image. Superbly executed and processed. Well done Alex!
  3. Wonderful, the detail is so delicate. Beautifully processed
  4. Julian Shaw's sombrero - with a surprise!

    It is a stunning image. However...apart from the excellent execution and processing what it tells me is that the Sombrero is very bright! The exquisite detail in the dust band is testament to the quality of an apo refractor working at F15. Well done Julian for a very logical choice. Now, what I'm wondering is...how well would this set up work on the Fireworks galaxy?
  5. Fireworks Galaxy

    Looks great to me, nicely processed (except my monitor suggests it might be a little black clipped???) and you've gone very gently on the galaxy colour. I don't think there is any problem with binning the colour with your camera and it may make sense with your ED120. However, the main benefit of binning is that it gives you a quarter of the read noise and you can then take much shorter exposures for your colour. 2 mins should be plenty and you should also try just 1 min subs. At 600 secs you will tend to burn out the stars (although your colour is good). It is worth experimenting and finding out for yourself. There is lots of comment on binning but the decision is based on your individual set up, your conditions and your time constraints and your image goals. The potential benefit of binning is that it frees up a lot more time for those critical luminance subs.
  6. Fireworks Galaxy (NGC6946)

    Love the colour, especially the stars and the Ha regions. Looks like a pretty challenging target given it's small size. Out of interest, have you tried binning with this set up? I don't want to start a binning debate, just curious to know whether you have and if so how you found the results.
  7. polar align

    Sonny, I don't think you are doing your alignment wrong, it was just the strong emphasis on getting the mount plumb level which some people took issue with. Many tripods incorporate a spirit level and have adjustable legs. It is sensible therefore to set up nice and level when this is made so easy for us. However, a level mount isn't a requirement for accurate polar alignment. I have often used a tak wooden tripod which doesn't have adjustable legs (increasing the overall rigidity of the tripod). Achieving plumb level with this kit would be a proper pita. If you are a significant way off level the direction of drift moves away from the vertical but not a huge issue. Also a level mount makes it easier to get close to correct alt if your mount has an alt scale. So definitely not a waste of time leveling if you can do it easily. Brian, there are numerous ways to polar align using various levels of technology. However, being able to quickly and accurately drift align is a skill well worth acquiring. Starting with the basics, and sorry if this is already blindingly obvious to you but the mount is aligned by correctly adjusting the altitude and azimuth settings of your mount, nothing to do with RA and dec. Get a feel for adjusting these with a fully loaded up rig. Sometimes adjustment can be quite stiff and feel clunky. As Sonny has said, an illuminated reticle eye piece will make life much easier since it makes small amounts of star drift easy to spot. Here is some detailed advice https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjXvaeE-97VAhXkC8AKHfjODB8QFggoMAA&url=http%3A%2F%2Fastropixels.com%2Fmain%2Fpolaralignment.html&usg=AFQjCNG3xYWOYiDSrIb1e6ja73b9P_Xx4A Top tips - Give some though beforehand as to which adjusters you need to move which way. Then write down a set of instructions in big type and, laminate this instruction sheet. If you are anything like me you will tend to get in a muddle. Knowing which direction a screw adjuster will alter the position of the mount (east/west or up down) isn't always intuitive. It can help if you deliberately offset the mount before starting. If you know that the mount is oriented below and to the east of the north celestial pole (NCP) then you will know from the outset which way your adjusters need to be turned. Your initial drift will be quickly apparent. You will rapidly gain an understanding of how big a correction you need to make for a given rate of drift. After 2 or 3 drift alignment sessions you will find that you become much faster and should find you can do the job in 20 mins. Some people strive for perfection in PA and like to ensure that their alignment stars show no drift for 30 mins or more. This is very sensible for an observatory mount but you will learn over time how accurate you need to be. Obviously it depends on how long you need your exposures to be and also the focal length of your scope. Your scope is not as forgiving as a short focal length refractor but a lot more manageable than a 10" SCT. Good luck!
  8. I am a big believer in putting time into luminance. Binning will gather colour data much faster leaving with more time to gather precious luminance signal. The main issue with binning is a tendency to slightly bloated stars when imaging at short focal lengths. Osc doesn't give you the option to bin just colour! I'm not familiar with your software so can't help there. It is easy enough to align and stack in DSS. I use Photoshop to combine lum and colour.There is a primer on how to do this in the tutorials section.
  9. Longer exposures with web cam

    I'm not sure but have a look at k3ccd tools https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.pk3.org/k3ccdtools/&ved=0ahUKEwjRzaeA1dPVAhUTOsAKHewmApIQFggmMAA&usg=AFQjCNG7Ktk0QqGN-sPtI7Mo84TfBAfqYQ
  10. the stability of the wedge

    Some years ago I used a wedge with an 8" Nexstar to enable long exposure imaging. Initially I had the Celestron heavy duty wedge. Whilst this supported the scope well enough the alt az adjustments for polar alignment were awful making it almost impossible to do an accurate drift alignment. I eventually bought an APT wedge which was more solid and very easy to adjust for accurate PA. I don't think think APT wedges are available now but believe the Milburn wedge to be of good quality. The use of a wedge with your scope makes a lot of sense. It is, however, a long focal length which is always a challenge. Performance will ultimately come down to whether the gears are smooth enough. My 8" Nexstar performed pretty well.
  11. Mono or Colour?

    Jez, I have am lucky enough to have both a mono and an OSC astro camera. I have used the OSC a few times, on carefully chosen, broad band targets, and have been pleased with the results. However, despite having a smaller sensor my mono camera has had far more use. It is my goto camera. I now only tend to use the OSC if I need the benefit of the larger sensor. I find mono quicker, more flexible and a world ahead when it comes to narrow band. I could go into great detail as to why this is the case but there is plenty of discussion on this already
  12. Adaptive (active) Optics

    Sorry to be coming late to this but thought I should chip in because I have quite a bit of experience using an SX AO unit with my 10" LX200 ACF focally reduced to around 1750mm. My mount has predominantly been a Tak EM200 which has excellent tracking. The impression I have gained is that when used with a suitable guide star which allows guide corrections of greater than 4 per second resolution can be improved and this most clearly manifests itself in tighter stars. It is a tricky unit to get up and running but when everything comes together it is a joy. These are the challenges :- The imaging train is significantly extended so you do have to make sure everything is as rigid as possible to avoid flex. Back focus is no problem with an SCT but may well be with other scope designs Not all targets will have a suitable guide star. With my set up I really need a guide star of Mag 8 or less. To avoid a lot of frustration I pre plan using the sky and use field of view indicators which show both my camera and guide chips with appropriate offset to determine whether the target is suitable and the required orientation. Life is much easier with a focus rotator. Using Maxim the drivers are sometimes a little flaky especially when it comes to running the calibration routines but the the most part they work ok The AO window has limited adjustment and it is very likely that the mount will need to make an adjustment every now and then. You therefore need to calibrate both the mount and the AO Hot pixels are a nightmare when calibrating. Unfortunately (and I haven't checked whether this has been sorted yet) the driver doesn't allow for a simple dark frame correction for running the calibration sequence. It is best to run the calibration on a near by bright star rather than the guide star you are planning to use. Except in the case of the Horse Head nebula where I used Alnitak as a guide star! The bigger and more sensiitive your guide chip the better. A lodestar works well and a lodestar 2 even better My AO is marginal for an APS sized chip but newer AOs have a bigger aperture. You have more wires to deal with! Using my old laptop I managed to get up to 12 cycles per second with mag 6 stars or brighter. At this point the system rather than guide star brightness becomes the limiting factor. In my opinion the AO unit has a learning curve but does have it's potential rewards.
  13. Terrific, love that image scale
  14. Thanks everyone. Thanks for tip on Monkey Puzzle seeds Kat but I might give that one a miss!
  15. In celebration of satellite night fever I strutted my stuff down the drive to get a pic of Luna sporting some earth shine bling and the satellite of lurve cruising above a non orbiting monkey puzzle tree. Canon 6D with a Tamron SP 24-70mm F2.8 zoom @ 70mm F9 ISO 1600 0.5secs. Primped and primed in Lightroom