§AB
24-09-2007, 10:22 PM
Took the 10" dob out for a quick session observing Jupiter and the moon. Collimation was only slightly off since last time so I gave it a quick tweak and let the instrument cool. After about 45 mins cooling time, I re-checked the collimation and was surprised how much effect a cool-down has! Tweaked it but had to wait for the clouds to clear. Melbourne's awful weather isn't going to ruin the only chance for the entire next week!
Telescope: 250mm (10") f/5 Newtonian
Seeing: 5-6/10
The weather charts show a jetstream directly over Melbourne (now why is that not surprising :screwy: ) so I didn't have high hopes.
Just as twilight was coming to an end, I swung the scope to Jupiter and was pleasantly surprised. At 166x, the planet was crystal clear, although the seeing was getting worse. No wussy sub-200x magnifications tonight! :cool:
Drop in a Meade 5000 5.5mm plossl for 227x and yes, the image quality held up. Everything that was there at 166x.....was there at 227x. The seeing was nothing great, there were good moments, but generally it was bad enough that the planet was visibly shimmering at times.
At 227x, the SEB was no single entity, but two thin belts seperated by a wide rift. A stubby streamer was visible near the planet's eastern limb joined to the southern component of the SEB. Superimposed in the NEB were 4 elongated white features. Two ovals were distinct nestled under the southern edge of the NEB. I could discern the faintest hint of the EQ belt. The north polar, Equatorial and particulary the southern polar areas exhibited obvious shading. The differences in the size of the Galilean satellites was quite obvious aswell.
Next up was the moon. The moon is a good target for evaluating seeing as it is really easy to see the severity of the wavy effect. Basically it was like a flag in the breeze. The moon was crisply defined despite the rather ordinary conditions. I observed Plato, and at 227x I could make out 8 craterlets. The 4 major craterlets (A,B,C,D) were all visible as little 'pits' and the double C,D craterlets were resolved. I could see craterlets F,G,H,K as bright 'spots' but I could just make out F as a pit. Now can we please have some decent seeing for once!!!!
It took only an hour, but was a most enjoyable session!
Telescope: 250mm (10") f/5 Newtonian
Seeing: 5-6/10
The weather charts show a jetstream directly over Melbourne (now why is that not surprising :screwy: ) so I didn't have high hopes.
Just as twilight was coming to an end, I swung the scope to Jupiter and was pleasantly surprised. At 166x, the planet was crystal clear, although the seeing was getting worse. No wussy sub-200x magnifications tonight! :cool:
Drop in a Meade 5000 5.5mm plossl for 227x and yes, the image quality held up. Everything that was there at 166x.....was there at 227x. The seeing was nothing great, there were good moments, but generally it was bad enough that the planet was visibly shimmering at times.
At 227x, the SEB was no single entity, but two thin belts seperated by a wide rift. A stubby streamer was visible near the planet's eastern limb joined to the southern component of the SEB. Superimposed in the NEB were 4 elongated white features. Two ovals were distinct nestled under the southern edge of the NEB. I could discern the faintest hint of the EQ belt. The north polar, Equatorial and particulary the southern polar areas exhibited obvious shading. The differences in the size of the Galilean satellites was quite obvious aswell.
Next up was the moon. The moon is a good target for evaluating seeing as it is really easy to see the severity of the wavy effect. Basically it was like a flag in the breeze. The moon was crisply defined despite the rather ordinary conditions. I observed Plato, and at 227x I could make out 8 craterlets. The 4 major craterlets (A,B,C,D) were all visible as little 'pits' and the double C,D craterlets were resolved. I could see craterlets F,G,H,K as bright 'spots' but I could just make out F as a pit. Now can we please have some decent seeing for once!!!!
It took only an hour, but was a most enjoyable session!