Date: Sept 23rd 2009, Wednesday
Observation Time: 8pm to 8:45pm (45mins)
Location: SD home
Weather: Okay. Moon 30% illuminated.
Instruments: Celestron Nexstar 80GT GOTO Refractor f/5
Buddies: Ashwin
Trying to understand which EPs are good for this refractor considering just basic needs. So did a quick eyepiece comparision with Ashwin on moon and jupiter.
10mm SMA vs 10mm Xcel
25mm SMA vs 25mm Elux
The scope came with the SMA EPs, but i am just trying if better EPs can make a huge difference for a newbie observer.
Tried it on Moon. (30% illuminated)
25mm => 16x
25mm + 2x barlow 12.5mm => 32x
10mm => 40x
10mm + 2x barlow 5mm => 80x
10mm SMA vs 10mm Xcel: Xcel defintely gives more wide field and better eye relief. The image seemed to be same in brightness. With 2x barlow on, Ashwin picked up 3 different objects at various locations and compared. with barlowed image, he noticed that Xcel gives sharper image. Also to him, xcel seemed to be better in brightness. On other side, Xcel is lil bit bulkier than SMA.
25mm SMA vs 22mm Elux: Ashwin didn't find any difference in the views with this one. Not much different except eye relief. Barlowed image also dint have a huge impact with Elux.
Jupiter: 25mm din't provide much magnification here. With 10mm and barlowed image, definitely gave lil more in the Jupiter. At 10mm 50x, Ashwin had hard time seeing any bands on jupiter. Probably i can see them, because i know they are there. with 5mm 100x, he can make out the bands on the disk.. but color aberration indeed hampers the image.
M22: Wasn't a great view of M22 in 2mm @20x. Moon Light pollution also just makes it bad.
Overall with the EP comparison, I realized that it doesn't make huge difference for a beginner to differentiate.. probably for my dad, it wont make any difference either :) !!
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