US ASTRONOMY
sxinias : 02-19-2011, 02:17 AM from Marathon Greece
Getting a good focus is one of my biggest difficulties. Nice to hear that the Hartman mask works for you. Here, nothing but clouds and more clouds.... had two nice nights last week on the day my new telescope arrived and since then, clouds and more clouds.
Joe
MANDII : 02-19-2011, 11:28 AM
Dear Joe , yes the mask did work before when I was using it with my MIZAR newtonian , for these kind of territorial pictures . But I still haven't succesfully make better focus when I was taking Moon pictures , and the stars of DSO pictures as well . I am not sure my self made Hartnman mask is a good one or not actually . But the idea of Hartnman mask that invented by Hartnman should be very great ! Recently , I am ordering a Bahtinov mask from the net , it's very cheap one only costing 30 RMB .
2ndly about focusing , for this picture last night , I didn't use any mask yet . The new Orion newtonian has better focuser than the previous one (MIZAR) , I can control the focusing movement much more smoothly and steadily , that is much better than before , and at the same time check the image sharpness on the computer screen . However , one point is that I still cannot control the focus movement in more precise . I always thought about to change the current focuser by using some kind of gear box , let say the gear ratio around 1: 20 , somehow it can be DIY by adding a gear box externally . In such case I can have much better controlling on the focus sharpness and accuracy . Anyway , at first looking forward the new Bahtinov mask can helps in focusing . |
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