Quote:
Originally Posted by ballaratdragons
Absolutely agree with Jason.
Even here in my dark skies I have used my 6mm twice in the years I have had it. Both times for about 1 minute. Waste of time.
I also have a Very expensive Pentax XW7 which I have only had the opportunity to use about 5 times in 5 years. The seeing needs to be excellent and that is rare.
But my 9mm is quite happy to give pretty good views, so that is as far as I push it.
All this in a GS12" Dob  |
Hi all,
This is a very location specific thing.
At my house on the Central Coast I regularly push both the 14" and 18" scopes to well over 300X on appropriate targets. Occasionally I get to 500X plus and 3 or 4 times a year I can get to 700X plus. On a couple of occasions over the past 5 years I have had the 18" Obsession to 1050X on the Moon and Saturn using a 5mm Pentax XW in a 2.5X TV Powermate.
I live right on the Southern edge (less than 50 metres to the water) of a very large lake. As some of you will know the temperature of a large body of water can take days to change by 1 degree and it is not affected by rising and falling day and night temperatures. Consequently, when there is no wind, the air above the lake can be very steady and provide excellent seeing.
Rod Berry (Rodstar), who lives less than 20km from me basically lives at the base of a large hill or ridge. This ridge causes an enormous amount of mid level air turbulence and Rod experiences "abysmal" seeing conditions at his house, where he can rarely get the 20" SDM to anything over 125X with his 20mm Nagler in the 20"/F5 scope. Under good seeing a month or two back at the Pony Club we had tack sharp images at 280X with a 9mm Nagler in the 20" scope. Rod has never been able to use that eyepiece at his house.
If you wish to observe the moon and planets at high power it sometimes pays to seek out a location which experiences very good seeing conditions. Places with good elevation are a good place to start as you automatically eliminate all the thermals emanating from the domestic environment. If you can get there on a night with no wind chances are you will get very good seeing and with a decent 12" scope you should be able to easily do 300X plus.
Cheers,
John B