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SteveP

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Everything posted by SteveP

  1. It may help but I wouldn't risk it. I've heard one blow.. and it's loud and wrecked what was connected to it. It was on a construction site and in slightly misty conditions. The idiot who decided it would be OK to use one to power his laptop(!) should have known better when waterproofed three phase is the standard for small items. The letter from HSE was not complimentary Steve
  2. Paul That's very sensible... and how I use mine! Steve
  3. PByrne This type of PSU is used widely. Whether the 3amp version is sifficient depends on what you intend to power. If it's a small mount then 3amp will be sufficient (for example an HEQ5 pulls upto 2amp when slewing on both motors) but you need a little headroom above that. But once you start to add other items then a larger unit might be more appropriate. You do realise that these types of units are intended for internal use in a well ventilated environment. That's why they're called Bench PSU's! They are not suited for uses where they might get damp. I certainly wouldn't use one externally without ensuring that the very large, powerful, dangerous transformer lurking inside the casing can't come into contact with moisture. You can probably get away with it in an obsy if it's protected in some way If you are intending to use it outside, I'd recommend one of the sealed unit type adapters, preferably regulated for a mount Steve
  4. Peter I doubt very much whether Phd and Nebulosity would blow up your hard drive. Probably just a very bad coincidence. Like Rob, I use a very old steam driven laptop for guiding, mount control, sky navigation, focuser control and image aquisition. So i think you just had a bit of bad luck. I'm not sure why you'd want to use different software when Maxim will do it all for you. But that's your call. If you are considering using different software (and it can sometimes be useful if your download speeds are slow and the guider stops guiding during downloads) then an alternative might be to use SX's own guiding software which should have been come with your Lodestar. It works well from my experience and certainly works in parallel with Maxim Steve
  5. Karl You might be better asking this question on the Pempro forum. Ray Gralak (its author) is usually around to respond to questions such as yours Welcome to CCDWare Steve
  6. Peter Your image indicates just how big an object M31 is! I recommend two issues for you to consider ... 1. Use the advantage of the focal length of your scope on smaller objects 2 Buy a smaller, ie shorter focal length scope, say 500-600mm, for imaging the larger objects such as M31 HTH Steve
  7. I'd use rings just for the feeling of security! Have you seen the size of the 4 tiny set screws which are used to attach a dovetail/radius blocks to a Meade OTA? Steve
  8. It's a fair question ... but I suspect there are criteria other than just the design of the optics. As rik says, there's the little issue of the field being flat especially with the trend towards larger sensors. I'd also add the quality of the optics rather than their underlying design; the quality of manufacturing of the OTA; the imaging circle; the focuser design and quality and probably a few others But of course all this costs extra. So you pays your money ...
  9. In simple terms, the design of achros prevent them focusing all wavelengths at the same point. However, when taking separate R, G & B images, the spread of each filter's wavelength is much less than for 'white' light and thus avoids this problem. In other words, that part of the colour spectrum which hasn't been corrected is effectively ignored. The downside is that re-focusing is a must-do. However once you want to start imaging LRGB and the problem part of the spectrum isn't being filtered out then the problem returns to some extent. The design of APO's is such that they dont have these compromises ... or rather, they are much much less obvious Steve
  10. Ben So far as your first question is concerned, you will still need to have a good polar alignment even if you are guiding. You will be able to get away with a less than accurate PA by using shorter subs (depending where you are pointing) but once you start to take longer images, any deficiencies in your polar alignment will give rise to 'star trailing' better known as field rotation with the guidestar at the centre of the rotation. Guiding, when working correctly, is great at keeping the guidestar in a fixed position but it cannot cope with field roattion as well HTH Steve
  11. Demon The simple answer is yes it does. But you will need to re-focus after each filter change. Although you might be lucky and get away with not having to re-focus if your scope is on the slow side If you stick with RGB then CA becomes a non-issue when imaging with an achro. However, if you start to image in LRGB, there is a tendency for some minor star bloating but nothing too serious Steve
  12. Sarah I'm suggesting an adapter which screws onto the rear of the 'tubing' (aka focuser tube) and onto which your field flattener then screws. Then attach your camera to the flattener as you do currently. All that's happening is that you're swapping the extension of the focuser tube with an adapter. And consequently retain much of the length of the focuser tube inside the focuser itself. As you say, the aim is to reduce the amount which the focuser tube extends and thus minimise the sag created by the focuser itself Does that make sense? Steve
  13. Unless I'm missing something, I beg to differ since I use a similar arrangement when I need to use a field flattener on another scope where the BFD is equally critical. To simplify the arrangement in Sarah's case, the setup would be ... Focuser tube > Adapter1 > Reducer > Adapter2 > Camera The length of Adapter1 is whatever is needed to bring the DSLR to focus with the reducer in situ and with 2-3 mm of draw tube extension. Steve
  14. Sarah I know from my own experience that adjusting the focuser to keep the draw tube orthogonal can be a right PITA. It's surprising how very small adjustments to the tensioning screws, say 1/8th of a turn, can have an impact. In the end, I decided to minimise the draw tube extension (and thus increase its stability inside the focuser housing) by using slightly longer adapters in the imaging train. I now only extend the focuser by 3-4mm to reach focus and the problem has been resolved... and that is with 4kg of filter wheels, OAG, camera etc hanging off the end of the focus tube Also, looking at the pictures you posted elsewhere, the fact you have scoring on the draw tube suggests to me that the screws are already too tight HTH Steve
  15. Rob Have a look over on Cloudy Nights - there are a few satisfied customers there with the AT65. Also, have a look here .... http://www.astrobeli.info/Hires/M46&M47.jpg The image appears to be flat to the edge. Taken with an ATB65 with QSI583 - and I think that has a larger sensor than the H16 HTH Steve
  16. Dave There are several ways to do this in PS as you've probably now realised. I usually do the RGB combine in Maxim or wherever, import the combined image and the L image into PS and combine the two images there by pasting one layer onto the other. Have a Google for Don Waid's site where he describes this technique more fully. Alternatively, if you have a spare $14, have a look here for Annie's Actions. They're very good value Morris Astronomy: Annie's Astro Actions Version 2.0 Released! Steve
  17. How DSS processes darks and bias frames doesn't make sense at first glance. As others have said, every dark already contains the bias 'information'. My only explanation could be that DSS' dark fames are not really dark frames but rather flat darks, ie having had the bias component already removed, which makes any subsequent scaling of the 'darks' that much easier Steve
  18. Are you already using Maxim on a routine basis? Are you also familiar with how to set up a focuser in Maxim? If so, it would appear that the problem is with FMax. Make sure you have the latest version 3.3.40. This can be found by joining the FMax user group on Yahoo. FMaxUG : FocusMax User Group Steve
  19. John Can you post an image showing the star elongation? You may have to resize it first if it's 48Mb. Although your problem may be as a result of flexure in the system, I wouldn't rule out poor polar alignment at this stage. If your guidescope is so far removed from the imaging scope, any field rotation will be centred off of your image, ie on the guidestar itself Steve
  20. Kostas What imaging software are you using? You may find some suggestions in the software or as a minimum a means of connecting to your Ascom focuser Steve
  21. Sara That's all that it is and merely a consequence of the mount having gone past a particular point requiring it to do an almost 360degree move to get back onto the object. Some imaging software (I don't know about DSS in particular) can make the necessary re-orientation automatically and stack the images accordingly. The major problem however is that most mounts are not aligned sufficiently well to get back onto the object in exactly the same position prior to the flip. The result being that the images on one side of the meridian may not match up with those on the other side. I try to avoid flips if I possibly can. Steve
  22. Gary You need what are called 'radius blocks' which match the curvature of the OTA. They attach to existing pre-drilled holes on the ends of your OTA Have a look here for what I mean ... D Series Dovetails Steve
  23. Sarah Sorry to hear of your problems. I've no idea how PHD works so best not to comment on something I have no experience of. However 6 hours is way way too long. Using Pempro and my CCD on my mount it takes me about 20-25 mins to get my mount polar aligned. That's pretty normal once you've done it a few times Good luck Steve
  24. Sarah Five hours? You deserve a medal. More seriously, your original star will almost be due west now so unfortunately you will have to select a new star I wish I could offer you some advice on PHD but I don't use it Steve
  25. John Certainly the 'clip' based methods are sufficiently similar as to not worrying about the difference. SD Mask is a bit different in that it's an iterative process so can be resource heavy when the data is being processed. That's one reason why it's not recommended for lots of subs Steve
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