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Three scopes for the planets

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#1 Lenny



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Posted 24 April 2013 - 10:04 PM



I spent the last week viewing both Jupiter and Saturn.  I used three different scopes and a variety of oculars.   Here are the results:


On the 16th, I took out my 8' Orion xt8i, F6 DOB.  Due to the construction of my back deck, which faces West, I am unable to lower the tube enough to view that Jupiter as it is dropped toward the Horizon.  So,, I decided to put the scope out on my front porch, letting it acclimate for about 1/2 hour preparing to observe Saturn.  The views were very good.  Cassini was easily observable giving a clear distinction within the ring system.  Also of note was the globe's shading as it enabled me to  observe a darkened portion of the Northern Hemisphere.  The planet itself provided a nice contrast with the rings giving a nice 3 D effect.  The maximum magnification I was able to obtain was 240X, using my 10MM Orion Plossl with my Celestron 2X Ultima Barlow.    However, at that power the image did "dance" a bit.  I had a better view at 192X, my 12.5 MM Celestron Ultima eyepiece and the 2X Barlow.  A very good view was also produced at 171X, using my 14MM Meade Series 5000 Plossl and the 2X Barlow.  For fun, I put in my 7.5MM Orion Plossl eyepiece.  It did a very good job, though it was a bit tight.  In all, I had about 2 hours of observing.   Though I have the  Computer Object Locater, I did not put it to use that night.  I seldom do so unless I am looking for hard to locate objects.  In that case it is very useful.   


On the 19th, I took out my 80MM Orion F7.5 ED APO.  This is my primary grab and go scope on a Vixen Porta mount.   It provides excellent views up to and often exceeding 200X.  However on this night the views were not very good.   I am able to position this scope on my back porch deck without trouble, but this night the views of Jupiter were terrible.  It danced so much that I was barley able to exceed 60X.  That is achieved when using either one of my 10MM eyepieces.   I moved the scope to the front yard and turned it to Saturn.  That planet provided a better view, but not by much.  I hit 100X using my 18MM Celestron X-Cell eyepiece with my Tele Vue 3X Barlow.  This was the best I could achieve before the image broke down.  I was able to do a bit better at 96X when using my 12.5 Ultima eyepiece and the before mentioned 2X Barlow .


On the 28th,  I took out my 114MM Tasco F8 reflector on the Vixen Porta mount.  This was my first scope.  I have been asked why I do not get rid of it, but I have a soft spot in my heart toward the scope.  Also, it does a very good job at magnifications not exceeding 175X.  I have cleaned the mirror several times and noticed it to be parabolic and not spherical.  Thus, explaining how I am able to achieve magnifications up to 175X .  The images are so good that it I was able to find a mount that properly supported the tube I would not have purchased the before mentioned 80MM APO.  The big problem with this scope is the focuser and not the size, for it is 1 1/4'.  The issue with the focuser is in it's construction.  It is all plastic and thus as a rack an pinion design is difficult to achieve critical focus at high mag. 


On this night the scope did a fine job.  However, the sky did not cooperate causing both planets to bob and sway.  I was not able to view Jupiter with any clarity, but I did get a peek at the Orion Nebulae at 53X provided by my 17MM Orion Sirius plossl.  None the less, Saturn provided a good image with Cassini visible at 120X.  This mag was achieved with a 15MM TeleVue plossl and the Celestron 2X Ultima Barlow.  That mag is a bit over 100% of the aperture and theoretically should be ideal.  I pushed the mag to 163X, with a 11MM TeleVue plossl and that 2X Barlow.  It was just too much for that night.  Backing down to 100X, my 9MM Antares Ortho and or my 9MM GTO plossl, I had very clear views.  However, Cassini was barley observable at that mag.  Contrast was good as the 3D image of the rings against the planet.  I was also able to discern some shading in the Northern Hemisphere of the globe.  Most of those observations were made at 120X.   Another good view was had at 138X, provided by my Celestron 13MM NexStar plossl and the 2X plossl.   I used my lower focal length eyepieces, such as my 6.3MM and 7.5 MM Orion Sirius plossl.  In all a good night. 


This type of week demonstrates my take on this hobby.   I want to have a good time when observing thus, I could not be described as a serious astronomer.    I know that I am often using scopes and eyepieces that will not provide the best view, but I enjoy the  variety.   I love to use different eyepiece/barlow combinations that provide similar magnifications and compare the views.  It is interesting to me that the advantages are not fixed.  There are times when a single eyepiece or eyepiece/barlow combo will out perform another combo while at other times the opposite is the case.  I like noting the advantages of a wider view eyepiece over an eyepiece with a normal FOV .  Is the sacrifice in sharpness worth the wider FOV?   Is either  advantage perceivable?  If not, is the ocular, scope, etc woth the economic expenditure? 


At any rate, I really interesting week,



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