Observing the planets

Forums Telescopes Observing the planets

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    Ian Kahler

    Hey everyone,

    Until a year ago I was  using a 5″ refractor, and  it was  OLD school. Nothing wrong with that but I had  to give  up on it because I just could  NOT understand RA and  declination.

    However  one  of  the  main disappointments  was  that I bought the  telescope  thinking that I could  a  really clear view  of  the  planets… particularly Mars Jupiter and  Saturn. However  the  refractor  turned  out to be a major  disappointment in that area  as  well. To look at the  moon with my a  21mm wide field eyepiece… yes  it was  astonishing. But it does not take  much more  than a  20×80 pair of  binoculars to get a  really good  look at the  detail of  our  amazing celestial neighbor.

    MY point now.. is that for  a  retirement present my son wants  to buy for  me, the  Celestron Nexstar SE8…. the  famous classic Schmidt Cass telescope, introduced with the  well known orange  optical tube.

    Now  I am nervous!  As  much as  I am stunned  by his  generosity, I have reservations about him wasting his money with once  again very mediocre and  generally disappointing images of  my favorite subjects.

    I know  that aperture equals light gathering power, but I need some  assurance that this  telescope will outperform the  5 inch refractor… not only for  viewing the  planets, but in viewing deep sky. I would  like  to resolve double  stars  as  well. These areas of  astronomy have  also caught my attention in the  year before  my retirement and  particularly now  that I am retired.

    The telescope  is  computer  controlled, but that does not intimidate me at all. What DOES concern me is  what I mentioned  before. I don’t want my boy to waste money if  this telescope cannot meet my expectations.  In my mind  and  heart I know that this  would be  an excellent decision, but in the  light of  constant disappointment with past experiences, I would  appreciate some  input from anyone of  you folks who can assure  me  that this  decision will be  the  productive  experience I am hoping that it will be.


    Martin Mobberley

    Hello Ian,

    An 8-inch aperture will certainly outperform a 5-inch, on the planets or anything else. However, aperture is only one consideration. When I first started observing I could not see much fine detail on the planets, even with 8.5-inch and larger apertures. When I moved up to a 14-inch I still could not see the kind of details sketched by Paul Doherty et. al. So, I switched to photography. After a few more years experience I realised that the eye and brain become trained to see finer detail the more you observe. Then I realised how crucial accurate
    collimation was. I also realised that the planets rarely look really good unless you observe a lot and catch the good seeing. Observing planets on a laptop screen, when imaging, is a revelation. The details distort every sixtieth of a second with the limb jittering by arcseconds! Then, on maybe 1 night in 20, planets look like a Damian Peach image, when the jetstream is absent and the weather is misty, or even foggy! However, unless the telescope has cooled to the night air and is precisely collimated you still won’t get great views. Moving up from a 5-inch to an 8-inch will not automatically give you good planetary views. So much depends on the state of our atmosphere and how often you observe. On this latter point some sort of user-friendly observatory, that can be set up in minutes, will make you observe 10 times more often, because you can just ‘nip out’ and check the seeing. For planets you do not need a computer control. Despite the hype, low-cost computer controlled telescopes can be more hassle than you need. Planets are easy to find, so a low-hassle Dobsonian is all that is needed… No need for star-alignment, cables and pressing buttons…just push the Dob and look through the finder….

    Deep Sky objects are obviously easier to find with ‘Go To’, but star-hopping is simple for the brightest objects.

    So, to summarise, moving up to an 8-inch will not give you spectacular planetary views unless you observe a lot, train your eyes and brain, and keep the telescope collimated and cooled to the night air. The bigger the better though, so it may be worth thinking about a Dob. You can get a 12-inch Skywatcher Go To Dob for the same price as a Celestron 8SE, but you’d want to build a small run-off shed to house it, or put it on wheels. Deep Sky objects would look far brighter in a 12-inch! One final thought….Mars, Jupiter and Saturn are horribly low down at the moment so whatever telescope you get you have a long wait until they are nice and high again.

    And the best views are usually obtained when planets are high up.


    Eric Watkins

    Ian, further to martin’s excellent advice.  Try visiting a local astronomical society on one of their open evenings.  My local society holds monthly meetings when society members bring along their telescopes to view whats on offer in the sky for members of the public.  If your lucky telescopes similar to what your considering may well be available to look through together with an experienced observer providing some initial instruction.



    Ian Kahler

    Thank you gentlemen,,,, you both make a  good point. I will not dispute  my son’s decision to buy the  Celestron. I need portability because  I /we plan on travelling to locations on the  other side of  the  mountains to areas where  the  skies  are amazing and  very dark. I live  in Washington Sate in the  US, And  there are some  really good  observing sites.

    I will admit to being skeptical due  to the  decisions I have  made  in the  past. I didn’t want to admit that the  telescope  was  NOT really good  quality… I was being cheap and  miserly lol. This  time I plan on being more  careful about quality. I am referring to the  eyepieces I will purchase  as  accessories. My son plans  on buying the  Celestron and  I must try and  bury my past skepticism, as  well as  lack of  knowledge and patience.


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