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About davidc135

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  • Interests
    Astronomy and ATM, science and natural history, trad archery
  • Location
    Hay on Wye
  1. davidc135

    The sweet smell of honeysuckle.....

    Midges, hedgehogs and a hornet's nest in my garden. Hmm, will I regret my live and let live good intentions? Another evening of fine seeing with the grs very colourful and clearly separate from the seb. David
  2. davidc135

    Stunning Saturn and Mars

    Yes, great seeing here as well in Wales allowing detailed views of Mars in a Meade 8'' sct. Above the S. Polar cap was a dark band with some structure and above that a featureless equatorial band. Maybe a dust storm? In the Northern hemisphere a smaller dark patch less conspicuous than in the South. A bright crescent along one limb connected the S. ice cap with the North pole. I was joined by a pair of hedgehogs and, less welcome, by the sound of hornets from a nearby nest up and about their business even before dawn broke. David
  3. davidc135

    Mars in the Early Hours 20180606

    Had a look through my Meade 8'' sct on the mornings of the 5th and 6th. It was more worthwhile than I expected with the South ice cap prominent, also southern mid latitude dark areas and Syrtis major showing. Northern part all red and featureless. Very good seeing especially on Tuesday allowed some good views in spite of Mars' low position. David
  4. Might be a consideration if imaging along with tube etc materials. David
  5. x450! Great to hear everything has turned out so well and that my pessimism was nonsense. My apologies to you, Mike and Skymaxes everywhere. David
  6. Very interesting. Can you give the diameter and length of the assembly? The corrector (purple at front) looks flat. I'm assuming there is a secondary mirror behind the metal plate in the corrector. Does it seem flat or curved? The camera looks quite tall which suggests that the focal surface is internal. Following on from vlaiv's comments you could attach some paper flat to the end of a tube just narrow enough to be pushed into the back of the camera. A distant daytime view might do. The image will be bright. If the image is internal, that is. There are some components inside the tube. David
  7. davidc135

    Skymax 150 star test

    Hi Dan It could be that the zone is no more than the expression of the HSA intrinsic as you say in the design. All errors together are probably less than 1/4 wave although it would be fun to quantify if there was the kit. David
  8. davidc135

    Skymax 150 star test

    Good images. They show the difference in brightness of rings inside and outside of focus that you mentioned due (I think) to a high zone near the edge. Or even a slightly turned edge? Mel Bartels quotes John Dobson who recommended working on a mirror's zones that were bright outside of focus. Have you put this into aberrator? Looks like your original assessment of a small amount of LSA and HSA was right. There seems to be a heck of a lot to star testing! Has Suiter's book been helpful? I must get a copy. David
  9. davidc135

    Skymax 150 star test

    Looks to have fine optics. 1/8 wave overcorrected or better from that graph. Congrats. Seems there was around 1/8 wave induced SA(as well) in the first test. David
  10. What about an Evostar 72ED Ota for £265.00. Wide fields and semi apo image quality. Convenient for someone who may find a bigger scope gets in the way of the out there under the stars experience. Or a Meade ETX80 pretty well all in with goto for £299.00. But false colour? David
  11. I think it's good news, Luke. If it's collimation that can be fixed and now the chances are better that my pessimism was wrong! Looking forward to more news. David
  12. davidc135

    Skymax 150 star test

    There's a recent thread on CN in the cats and casses section: 'star test central obstruction size' including a graph for judging sa that may be useful. Says 10 waves defocus recommended for obstructed optics. Your lens likely to be a good one. David
  13. Good luck with everything. David
  14. Yes, mea culpa! But I've read them all since and formed my opinion. It seemed to me that your lengthy and rigorous assessment of the Mak was damning but that it would be unfair for all Skymax 150s to be so judged, at least as lunar scopes. Well, right or wrong, time will tell. ASSA, on a more positive note, insulating the scope was mentioned earlier. There's a thread on the cats and casses subforum of Cloudy Nights where it is claimed, with evidence, that cooling and tube current issues can be quickly, virtually eliminated in scts and Maks. Very impressive stuff. David
  15. Yes, that is what I meant. I'm sorry to sound negative and best wishes for your observing experience. David

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