Quote:
|
Originally Posted by ThunderChild
Thanks for the advice.
A x2 barlow would make x266 with my 9mm. Is that getting too high?
Would that still resolve a viewable image?
Chris
|
no, i have been using a 5mm vixen recently on jupiter and saturn and earlier mars. it gives me in my 10" 1250 = 250x. I got to use it say 8 or 9 times out of 10. The only times i couldn't were over xmas when the jet stream (
http://www.wunderground.com/auto/vir...JetStream.html) was yellow!!! If the stars are really twinkling, then the atmosphere is really shifting about and your image will shift about.
At times i was able to barlow this with the 2.4x and 5x for horrendously stupid magnifications, but there was only one night where this worked for the 2.4x ie 600x.
Last november, the "seeing" as we term it (
http://www.iceinspace.com.au/index.p...06e5c9e6c4e508 although we tend to say 9/10 or 10/10 is perfect) was so good that saturn had just risen and we thru all sorts of magnifications at it and the image was great ie 600x and above
You will get a better feel the more you go out. You need still conditions ie no wind, still atmosphere ie no jetstream etc and then steady temperatures so that you main mirror is the same temperature as the surrounding air. Then and only then can you push the magnifcation up over 200 and beyond.
A 2x barlow will be good, it turns your 9 into a 4.5 and your 25 into a 12.5