September 26, 2011

SKY OBSERVATION THROUGH 10-inch DOBSONIAN



I just bought a 10-inch Sky-watcher Pyrex Dobsonian Telescope. I got the delivery on 20th September. After assembling the telescope’s Dobsonian mount with the help from my club members Mr. Narendra Gor and Amit, I put it to the test.

The conditions were not ideal for observing so we decided to observe Jupiter which was well up in the sky.  This telescope, operating at 48x provided very nice, detailed view of Jupiter. The two cloud belts were clearly visible and I saw a dark spot in the Northern Belt of Jupiter. Using 10mm eyepiece (giving 120x) improved much detail. I could see the two belts with their own different shapes as seen in the photos. 

On the early morning of 23rd September, I woke up at 4:00am to begin a new session of visual comet hunting. The sky up to 30 degrees was very hazy so I avoided comet hunting and decided to test my new telescope on deep sky objects. Orion was high in the sky so what could be better than The Great Orion Nebula? I have also purchased an Orion 38mm 2” Q70 eyepiece along with this telescope. I used this eyepiece to observe M42.  This eyepiece using with a 10-inch, f/4.7 gives nearly 2 degrees field of view.  The entire Orion’s sword appeared in a single field of view! The entire view was very nice and gave me the “lost in space” feeling! Observing at 48x brought more detail. The view was far better than my old 8-inch Newtonian. The Fish’s Mouth feature nicely appeared. I could also see another dark feature SW of the Trapezium.


the sky on 22nd September

I then set the telescope on Iota Orionis star (Struve 752) and used a 10mm eyepiece giving 120x. The main component appeared bright blue.  The other two members came into view easily. The four spikes around the main star made the view very impressive! I then pointed the scope to the Waning Crescent Moon. Operating at 120x the telescope showed wealth of detail.  The 5.5th magnitude star 3 Cancri had just come out from its occultation.  The craters Gassendi and Kepler were eye-catching. I saw many tiny craters within Gassendi. The ray system around Kepler was impressive! I then saw the half buried crater Prinz and the cluster of lunar mountains Montes Harbinger. The shadows of Montes Harbinger attracted me and I could not shift my vision from this region for a couple of minutes.  

I am really impressed by the quality of this new telescope. The Dobsonian mount is very sturdy and moves smoothly on both altitude and azimuth movements. It takes very small time to adjust the viewfinder. The crayford focuser is lovely! The 25mm and 10mm eyepieces provided with the telescope are also of a good quality and gives nice views.  


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