Posts Made By: Carlos E. Hernandez

Thank you all for your wonderful comments on my latest observation of Jupiter. I am glad that my observation was able to confirm many of the features in Mike's observation. Trying to record all that is visible over the jovian disk is not easy. The best of luck in your own observations.

Carlos

Paul,

An excellent image of Jupiter showing much detail. The festoon detail on the EZ is interesting. Please keep up the good work.

Carlos

Vincent,

You have received good advice on your instrument choices but I will add my 2 cents worth. Both the 10" f/6 and the 12.5" F/5 Newtonian reflectors can make excellent planetary instruments. The difference in focal lengths is not significant (1,524mm (10" f/6) vs. 1,588mm (12.5" F/5)). For planetary observation and imaging I would prefer a longer f/ratio as the cone of light is less steep (f/5 vs. f/6). The size of the secondary in the 10" f/6 Newtonian may be theoretically smaller than that used on the larger 12.5" f/5 instrument (preferably less than 20% obstruction). The figure on the 10" instrument may be easier to produce than that of the 12.5" instrument (possibly even to 1/6 to 1/8th wave). The optical axis (collimation) maybe harder to maintain in the larger instrument as well. The 10" f/6 instrument may be easier to move around unless both are made using a truss-tube design. If your seeing conditions are typically P5 to P6 then the 10" instrument may be the better performer in the majority of observing sessions (obviously the 12.5" instrument should theoretically resolve more detail if the seeing imroves to >6/10; please refer to my observations of Mars made using an excellent 12.5" f/6.2 Newtonian in 1986 http://www.astromart.com/messages.asp?message_id=207770&page= ). These are just some factors to consider in your choice of instrument.

I also prefer to be as comfortable as possible when observing the planets. Standing upon a ladder for an extended period of time (over 30 minutes and even up to 60 minutes or more!) waiting for that brief moment of steady seeing really takes it's toll on the observer. Fatigue will result in the observer missing fine detail as the body (and therefore the eye) is strained. For this reason I also prefer the Cassegrain design (Classical or Dall-Kirkham) as Jeff Beish (who is a world class ATM) suggests. A well constructed (including baffling) Cassegrain with a small secondary (<20%) can make an exceptional planetary instrument. Placed upon a solid mount this instrument can reveal all that there is to see over a planetary atmosphere or surface.

I believe that either the 10" f/6 or the 12.5" f/5 reflectors will make excellent instruments for your planetary observations but the above are some factors to consider in your final choice.

Carlos

Thomas,

Thank you for sharing with us your fine observation of Jupiter. You have recorded festoons along the southern border of the NEB (NEB-S). The NEB also appears more irregular than the SEB.

You may also consider scanning your future observations at approximately 72dpi which is the standard monitor resolution. This can be accomplished by the scanner software or image-editing software (e.g. Paint Shop Pro or Photoshop).

Carlos

Ron,

Thank you for posting your excellent observation of Jupiter. You have captured the Great Red Spot (GRS) region very nicely. I too have noted the dark section over the southern border of the SEB preceding the GRS. The blue festoons within the Equatorial Zone (EZ) have been spectacular this apparition like the one you describe. I am happy to hear that your 8-inch Discovery Newtonian reflector is a good one on the planets. We all look forward to your future observations.

I agree with Thomas that you should flip the form to draw Jupiter ("a flattened egg").

Carlos

Sol,

Welcome back as we have missed your planetary observations. Thank you for posting your excellent observation of Jupiter. The detail recorded is very impressive. The Great Red Spot (GRS) and the region of the SEB preceding it is very interesting. I too have noted many bright bays along the northern edge of the NEB. The NEB itself looks very complex. We all look forward to your future observations.

Carlos

Dannon,

Thank you for sharing your beautiful image of the planets (Mars, Saturn, and Venus) in the western sky.

Carlos

Thank you all for the kind compliments on my observation of Comet Neat Q4. I was fortunate to have observed it as my weather has been very cloudy lately. I will try to make future observations of this comet if my weather allows. I look forward to other observations and images of this and other comets in the future.

Carlos

Mike,

I am not a solar astronomer but your best bet may be to contact a real one. I suggest Richard Hill ( [email protected] ). He may be able to answer your question.

Carlos

Sol,

Thanks for sharing your excellent observation of Jupiter. You have still picked up a good amount of detail over the disk although you used an aperture stop. A well made 4-inch refractor is an excellent instrument for use on the planets and Moon. Looking forward to your future observations.

Carlos