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Stub Mandrel

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About Stub Mandrel

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  1. Bear in mind I don't last long at an eyepiece, so see this from an imaging perspective If I was to get a new scope to add to my collection, it would have to be either a longer focal length than my 150PL (1200mm) to gibe me a 'planet killer' or shorter than the 130P-DS (about 570mm with CC) to give me a wider field scope. I have several camera lenses, one of which is a 400mm f6.3, Prinz galaxy which is better than it ought to be, but does show a fair purple halo around the stars. So, I had been dreaming of a Celestron C8 or even a C9 (some hope!) although with the planets drooping down just above the horizon, this might be something for six or seven year's time... But now I've spotted the Williams Optics Zenithstar 61 APO, focal length 360mm, f5.9. With a field flattener it's 288mm. Lots to like: APO (well ED) so nice pin-prick stars Focal length a bit shorter than the 400mm lens so it can replace it, but also over twice that of my lovely 135mm Sonnar so not clashing with that. Short FL and good optics might mean something I'm more comfortable with LOOKING THROUGH! (there's a thought!) Could even function as a very posh guide scope(!) although my little achro frankenstein scope works well. Ideal for my 'light mount' approach. Small enough for grab and go AP, even for use with a tabletop GOTO or a star adventurer mini. But to be brutally honest: Probably the only scope I've seen that actually made me say 'wow' (sorry Tak fans). So folks, I know what to save up to buy myself for Christmas. And you are all wondering what is the question... Well - which colour should I be planning on?
  2. The banding goes with the 450D territory, it isn't thermal noise, it's some sort of read noise as it is present on bias frames.
  3. With the 450D I find the 30-second setting gives a slightly brighter and cleaner preview image than bulb.
  4. I've seen worse!
  5. Your ability to guide with an EQ2 is impressive.
  6. One could argue that any stray light that gets in also needs to be compensated for by your darks, so perhaps you should generate them simply by capping the scope... There's a contentious suggestion! At the very least we should be taking precautions to keep out as much extraneous light as possible...
  7. It won't be... there's no such thing as a sensor without hot pixels...
  8. Someone who can machine it for you can probably drill and tap a screw hole too?
  9. A dumbbell weight will cost a fraction of an official counterweight. Do you have anyone local with a big lathe or a milling machine who could open up the 1" hole to 32mm?
  10. Here's an approach to Registax wavelets on the web I found that works very well. RGB align if needed Choose dyadic wavelets. Set number 2 to 100% Increase denoise until it stops looking horrible repeat for number 3, number 1 and optionally number 4 in that order It is important to get rid of ALL artefacts generated at each step. Any further wavelet changes should be small. If you cant get a sharp image without having a 'ring' around the edge of the planet, use the denoise/deringing function.
  11. The secret is to use PIPP 'Planetary Imaging Pre-Processor' (it works for the sun and moon too). It takes your video and uses all the frames with a complete planet to create a new video with a smaller frame and the planet centred ready for stacking. It can do some other useful stuff which can help with making the best of things like under/exposed video. My workflow has changed a bit, but now it's: Prepare in PIPP, stack in AS!2, wavelets + RGB align + (sometimes) gamma adjustment in Registax, derotate in Winjupos (if stacking a lot of good data), sharpen & noise reduction in Astra if required. You can get great results with just PIP --> AS!2 --> Registax
  12. Looks like the auction was 'ended' rather than won.
  13. I started by taking short videos and when the planet got to one side of the screen I would stop the video twiddle, the knob until it went back off the other side, then restart the video when it reappeared. It all became quite easy, in fact I worked out how long a video I could shoot in each run, so all I had to do was click 'record'. Done on a 150PL and EQ3 with no tracking or goto and a cheap webcam.
  14. I've reduced the dropper resistor to 50R from 220R but the way the maths works this will be a lot more than four times as much warmth, about a quarter of a watt, which is what some other folks use.
  15. In the beginning, people used EQ mounts with a clockwork drive. As long as you can achieve focus, you can do something. Anything that tracks the stars will increase the length of your exposures. Things like focal length, aperture, rigidity, motor accuracy, polar alignment will all affect how long you can get away with, but virtually ANY setup will get you started. A 135mm telephoto lens will give useful results with almost any setup as even 8-10 second exposures will show you something if you stack enough of them (and point it in the right place). See what you can achieve with what you have got, 'push the envelope' to discover its limitations and learn as much as you can from it, you will then be in a good pl;ace to know which upgrades/changes will make the biggest difference.