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Andrew

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About Andrew

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    Star Forming
  1. Thanks for your help. I have looked at your guide Moonshane. I see where I have been going wrong (maybe). Astrobaby's guide suggests adjusting the secondary so that the reflection of the primary is centered in the secondary, as judged using the mirror clips on the primary and getting these aligned equally around the edge of the secondary. There is no mention of adjusting the secondary to move the donut in relation to the Cheshire cross hairs. When I centre my secondary to fit Astrobaby's criteria the donut does not sit perfectly under the cross hairs (as recommended in Moonshane's guide). It does seem a bit odd that I get my primary centred using her criteria yet the donut does not line up. I'm not sure if that is because the mirror clip criteria is not a good one, or because something else is amiss with my setup. But I appear to have the secondary in the centreof the focuser.
  2. Unfortunately, I don't have a laser (I last used it years ago and it died). I was going to buy a new one but decided to opt for the Cheshire instead!
  3. I wonder if anyone could help me with some basic collimation issues? I have not been out with my scope for a long time for various reasons, but have a new enthusiasm for it and decided I ought to collimate my telescope since I have not done this for a while. I had previously used a laser but was never really convinced by this method due to uncertainty about whether the laser was properly aligned. Consequently, I decided to have a go with a Cheshire, and bought a very nice one from FLO. I read Astrobaby’s guide to collimation, which was very helpful since I haven't done this for several years, and progressed through the various stages of adjusting the secondary, which only required some minor tweaking. I’m a bit puzzled about the adjustment of the primary, which I think should be simple. I have done this plenty of times before with a laser, but never with a Cheshire, which leads me to my question… I am trying to align the center ring on the primary with the cross produced by the Cheshire. However, when I look through the Cheshire I can see two sets of crosshairs. There is the obvious set which is just the wires at the end of the sight tube. However, I find it pretty difficult to focus my eye on these and on the ring on the primary at the same time, presumably because they are a long distance apart. After puzzling over this for a while I realised that I can also see a much fainter but sharper set of crosshairs on the reflection of the light from the lateral opening of the sight tube (I’m not sure if this is a reflection of the crosshairs at the end of the sight tube or from the cross that is cut into the oblique surface in the side of the tube where the light enters). These two sets of crosshairs don’t sit on top of each other, hence the ring on the primary can’t be aligned with both, and there is no mention of two sets of crosshairs in Astrobaby’s guide (unless I have missed it). I have the ring nicely aligned with the faint set of cross-hairs, but I’m not sure if that’s correct. I’m sorry to ask such a simple question, but having never used a Cheshire before I’m a bit puzzled about whether this is right and why I see two sets of cross hairs. Thanks in advance for any feedback Andrew
  4. ok - thanks. There is no mention of this on the site I got it from, but you may have just saved me £40!
  5. I just ordered a Skywatcher 200PDS OTA but forget to get tube rings! The Skywatcher site says the tube diameter is 240 mm, but the nearest size skywatcher tube rings (listed on the FLO site) have an internal diameter of 235 mm - ie too small. Surely, this is the right size? Can anyone tell me before I go ahead and order? Thanks
  6. I have had a go with DSS Live and Astrovideo with my Watec. Both work very well. However, although it's possible to stack images 'on the fly' I do feel like I'm spending too much time fiddling with settings and changing directory etc so I spend less time than I'd like actually looking at the image on screen! I also tried out a couple of monitors (both CRT according to the back of them - they were certainly large enough!) but so far my lap top provides by far the brightest image. Not sure why that is because I thought a CRT was meant to be better.
  7. Very nice sketch. Looks like you spent a fair bit of time getting the stars in the right places.
  8. I'm not sure I'd have the patience for 250 frames! Still, even a single frame shows more than I can see of M1 visually with my 12" dob.
  9. Thanks for the comments/suggestions. I'm leaning towards the 8" f5.
  10. I recently got a Watec camera and have been trying it out using a 4.5" f4 Newtonian (I've attached a couple of images below). I plan to get a larger scope to use with it and I'm wondering what to go for. So far I'm considering either an 8" f4 imaging Newtonian or the 8" f5 Skywatcher Newtonian with the shorter tube for imaging that will allow me to use a focal reducer and get to about f3.3. I'm leaning towards the f5 scope because it will be better for visual work and at f3.3 with the reducer it will give brighter images using the Watec. If anyone has any thoughts on these or alternative scopes I should consider for the Watec then I'd be interested to hear them. In relation to this, I wonder if anyone has any comments on the following... I have seen it written in several places that the Watec effectively increases the aperture of a scope by a factor of 3-ish. Being a visual observer only until recently I had been thinking that this meant the bigger the scope the more I would see with the Watec. However, based on what I've read it seems that f ratio is the key to image brightness, so for two scopes with the same f ratio the image brightness won't change regardless of aperture (although of course the field of view and image resolution will change). This makes me wonder what the advantage of a big scope is when used with a video camera and also how meaningful the 'triple your aperture' statement really is. If anyone can enlighten me about the benefits of more aperture with a Watec I'd be grateful! Slide3.BMP Slide6.BMP M82.bmp
  11. Nice images - I particularly like M1. Are these single 10 sec integrations or stacked images?
  12. Had another go with the watec a couple of nights ago. Saw several more objects using the 4.5" Newt + Watec that I can't see with a 12" Newt alone (several faint galaxies, bubble nebula, spiral arms in M81 - in the 12" I can only see the core). Tried to get the 12" on the NEQ6 but gave up because it's just too unwieldy. Could probably do it with some sort of frame to hold the scope while I lower it on! Either that or it's a two person job. Not really a viable option for everyday use. Think I may get an 8" Newt, which I should be able to put on the mount easily enough. Also started playing around with different bits of software (GSTAR, Deepsky stacker, AstroVideo). Will post some images when I sort out the best setup (assuming we get some clear skies at some point).
  13. I heard the cathode ray tube gives the best (brightest) results, but my grasp of electronics is not great so I'm not sure what's needed in terms of cables. Ultimately I hope to compare that vs progressive stacking of images on the laptop while viewing using AstroVideo. At the moment I'm still getting to grips with polar alignment and using a driven mount!
  14. I hope to get the 12" on the mount soon. If it proves too unwieldy I may get an 8" Newtonian instead. I'm using a laptop at the moment. I was thinking of looking for an old B&W portable TV (I heard these were good) although the Watec instructions suggest they can't be plugged straight into a TV (I'm not sure if I've misunderstood this). I've also been thinking about using it with the AstroVideo software (in order to stack images on the fly). The Astrovideo site suggests this software only works with Windows XP or earlier, or with 32 bit OS, but in fact it will work with Windows 7 64 bit if you change settings by right clicking and troubleshooting compatibility.
  15. After years of struggling to see faint objects I finally decided to have a go at video astronomy and bought a Watec a couple of weeks ago. I've tried it out a few times, but tonight was the first time I put it on the tracking mount. It really is pretty impressive. At the moment I'm using it with a small (4.5") f4 Newtonian. Even at quite short integrations (1-5 seconds) objects that can't be seen from my site in the scope alone show up easily (e.g. M110 & M76). Tonight the pick of the bunch was NGC891. I've never managed to see this even in my 12" scope, but with the Watec in the 4.5" it was easily visible with a very distinct dust lane at 10-20 seconds integration. The other nice thing about it is that stars are nice and tight across the whole field of view, whereas most eyepieces show a fair amount of coma in the outer 30% of the fov in this scope. I'm planning to have a go with the 12" scope, if only I can get it balanced on the mount! I'm looking forward to tracking down that long list of faint objects that I've failed to see visually before
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