Hi David,
Thanks very much. I took the scope to a dark site only once in the past few months. It needed partial shroud at least as shown in the picture. At home with street and house lights it must have full shroud. There were heaters installed for both primary and secondary mirrors by original owner Daniel, which made this scope especially worthwhile to be modified. Little did I know that I could do it with scrap pool fence bars. As for M1 it was low but real problem was my 2-storey house allowed only a couple of hours of imaging every night, and yet clear nights were so few in the past 4 months here in Sydney. For pre-stretching of ASI294mm shots, I found it was best and perhaps necessary for extreme processing. I noticed this problem when I first tested the camera with my Canon 400mm/f2.8 II. Back in October weather was good. I tried bin1 first as the Canon lens was capable of resolving fine pixels and I got lots of details around M8, as seen from nebulae images by many latest cameras. However I was totally surprised that all details were clipped out after DSS stacking for default bin2 shots. Here are some samples. Bin1 image had to be downsized due to data restrictions. Maybe other stacking software would behave differently.
John
Quote:
Originally Posted by Dave882
Nice image John and well done on the modifications. I love your ingenuity!!
I recently did a version of m1 myself and find it to be a really intriguing object, although very low in the sky for us. I imagine you’d need a full shroud to eliminate dew and stray light in the suburbs?
I’m not sure about the pre-stretching methodology, perhaps there are some other settings you could employ to avoid that extra step?
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