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pete_l

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About pete_l

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    http://www.under-a-dark-sky.com

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    Benamaurel, Spain 37N

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  1. Going from a 6 inch aperture to 8 inches will reduce the Dawes limit (i.e. increase the resolving power). At least, in theory! The value changes from 0.77 arc-sec to 0.58. Both of those will be smaller than the resolving power limit imposed by atmospheric seeing.
  2. There's no reason not to use a single power supply. Though I have to say I'm not keen on fans in outdoor equipment. You never know what they will suck in to the equipment . In addition, they seem to me to be the weakest link - often cheap units that cannot withstand long periods of use before becoming noisy (poor quality bearings, or ones that fill up with dust) and unreliable. Plus with a unit like this, it's meant to be incorporated into a "finger proof" cover, so you have to plan for airflow when designing your enclosure. When the fans do fail then your heat dissipation stops too. I pr
  3. Locations never have one, fixed, SQM value. They change with all sorts of factors. Mine varies by over 0.5 magnitudes, depending on transparency (i.e. how much light is reflected compared with how much passes through and out of the atmosphere), sunspot cycle and probably lots of other things apart from the Moon. So I wouldn't get too tied up with what other websites say it should be. I suspect that all they do is look at the population of towns and villages and make a guess based on nothing more than their distance away. What is interesting from your all-sky image is that the brightest
  4. I think you would need a very large refractor to see colour - or possibly a good imagination, which is defintiely cheaper People's tolerance of imperfections varies a great deal. Just like some people would never dream of drinking a wine that cost less than £100, or listening to music in MP3 format. So some will call CA "unacceptable" when others are quite relaxed about it. Personally, I do not find it all that objectionable on the few objects where it is noticeable. But then, I have no problems with cheap wine, either! I would say there is no hard and fast rule. Some achro's are bett
  5. Briefly, the OP has an 8 inch Dob. They bought a Baader Hyperion mk IV zoom and a matching Barlow. They like it.
  6. I own a Primaluce Labs C82 pier. This comes with a detachable adapter plate. While the range of mounts they stock adapters for is fairly small, the plate itself is not that complicated and the company supplies drawings that a local metalworking shop could customise for whatever mount the user needs. And at €500 for the whole shebang, I reckon it's a pretty good buy. Though shipping one a few thousand miles from Italy might jack up the cost a tad, better look for a local dealer.
  7. My personal experience is that the HEQ5 Pro is boringly good. Simply put, it does what it should. Without fuss or drama. Just stay within its weight limit and stick to short-ish OTAs and it delivers. I've had one for 7 years and it has given no problems or cause for concern.
  8. The last "toy" I got was a large refractor. It came in a shipping carton with dimensions 1.3m x 0.35 x 0.30 metres. That is a cubic capacity of 0.1365m³ A 40 foot container will hold about 55m³ of stuff, or about 400 boxes the same size as what I was sent. So the cost of the space in a container for my refractor will have risen from £2000 / 400 = £5, to £16,000 / 400 = £40. An increase of £35. I just checked what I paid in December. Since then the price has risen by €45, so an amount that is commensurate with Tim's experience. If other retail prices go up by significantly more
  9. Many, many years ago an astronomer whose word I have no reason to dismiss told me that if you can make out the colour of the light from your torch, it's too bright to not affect your night vision.
  10. A fuse is not a universal protection. For example it won't stop your gear being damaged if the polarity is wrong (positive and negative swapped over). At best, it will prevent a fire from starting. Although that is a good thing to stop!
  11. When I contacted them I couldn't get a pick-up on their phone. I emailed them, waving money, and got a reply 2 weeks later.
  12. My first reaction is that this is nothing more than an upselling ploy. To the best of my knowledge there are no telescopes or types of telescope that are designed specifically for light polluted areas. Nor are there any telescopes that are marketed as "best for" that. However, there are types of light pollution filters available as add-ons for practically any sort, size or price of telescope - so the problem is acknowledged. Just not with special models of equipment. On the subject of light pollution filters, these do cut out certain types of LP. Mainly that which comes from streetli
  13. Or even a few €€€€s cheaper from other vendors
  14. You can use eyepiece projection to get a larger apparent focal length beyond what prime focus photography will give you. If you are using an unmodified DSLR, it probably has a moire filter in front of the sensor. This acts to blur images thus reducing the resolution of the camera below what you would expect from doing the maths on pixel size / focal length. However, you ultimately run up against the effects of the atmosphere and then against diffraction of the light coming in. You might get some further improvement by imaging in the infra red, although that will worsen the diffract
  15. Be aware that the chinese new year is on Feb 12. Expect a delay of up to a week in processing orders taken around that time.
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