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Posts Made By: Carlos E. Hernandez

March 1, 2003 11:02 PM Forum: Solar System Observing

Jupiter Observation (02/27/03)

Posted By Carlos E. Hernandez

I have made an observation of Jupiter under good seeing conditions. The South Equatorial Belt (SEB) looked very interesting with it's dark condensations ("clumps"). I noted a good amount of festoon activity. I welcome any comment on my observation.

Date (U.T.): February 27, 2003
Time (U.T.): 02:40
L1 011.0, L2 193.0, L3 021.1
Instrument: 9-inch (23-cm) F/13.5 Maksutov-Cassegrain
Magnification: 282x and 352x
Filters: None
Seeing (1-10): 6-7 (moments of 8/10), Antoniadi (I-V): III-II
Transparency (1-6): 4

Transit Observations:
01:55 U.T., L1 165.7, L3 354.0, WC Bay (Oval) NTrZ (NEB-N border)
02:26 U.T., L2 184.4, L3 012.6, DC Barge NEB-N
02:26 U.T., L1 002.3, L3 012.6, DC Festoon NEB-S

Notes:
South Polar Region (SPR): Appears dusky to dull (4-5/10) with thin dusky (4/10) bands across the region. The south polar limb appears dusky (4/10).
South Temperate Zone (STZ): Appears bright (7/10) and thin.
South Temperate Belt (STB): Appears dark (3/10) whereas the preceding half appears broader than the following half (with two large very bright (8/10) ovals adjacent to it over the STrZ).
South Tropical Zone (STrZ): Appears bright with two large very bright (8/10) ovals over it's following half (separated by a thin, dull (5/10) band).
South Tropical Zone Band (STrZB): The STrZ contains a thin, dull (5/10) band within it.
South Equatorial Belt (SEB): Appears dark (3/10) and complex. A thin, bright (7/10) zone appears to bisect the SEB over it's preceding half then deviating towards the south over it's following half. A section of dark (3/10) condensations ("clumps") appears along it's following southern border.
Equatorial Zone (EZ): Appears bright (7/10) containing a dull (5/10) band (EZB) and blue festoon projections (3-4/10).
North Equatorial Belt (NEB): Appears dark (3/10) and thin with very dark (2/10) barges along it's northern border (NEB-N) and very dark to dark (2-3/10) blue festoons along it's southern border (NEB-S).
North Tropical Zone (NTrZ): Appears bright (7/10) with very bright (8/10) ovals along the NEB-N.
North Temperate Belt (NTB): Appears dull to shaded (5-6/10) and thin. More prominent over it's preceding half.
North Temperate Zone (NTZ): Appears shaded to bright (6-7/10), but no detail noted within.
North Polar Region (NPR): Appears dusky to dull (4-5/10) with dusky (4/10) condensations and sections noted within.

The best of luck in your own observations.

Carlos

March 6, 2003 11:23 PM Forum: Solar System Observing

Jupiter Observation (March 6, 2003)

Posted By Carlos E. Hernandez

I made an observation of Jupiter on March 6, 2003 (05:00 U.T.) under average to good seeing conditions (6-7/10). I was able to note much detail across the Jovian disk. I noted STB ovals, a dark irregular southern border of the SEB, an active EZ with festoons/bands/ovals, dark barges and bright ovals along the northern border of the NEB and southern border of the NTrZ, and a NTB segment (section). Any comments on this observation are welcome.

Date (U.T.): March 6, 2003
Time (U.T.): 05:00
L1 121.9, L2 249.8, L3 079.3
Instrument: 9-inch (23-cm) F/13.5 Maksutov-Cassegrain
Magnification: 282x and 352x
Filters: 23A and 38A
Seeing (1-10): 6-7, Antoniadi (I-V): III-II
Transparency (1-6): 5

Transit Observations:
04:27 U.T., L1 229.9, L3 060.0, DC Sect. (center of NTB section)
04:38 U.T., L2 236.5, L3 066.6, DC Barge (NEB-N)
05:10 U.T., L2 255.8, L3 090.0, WC Bay (NEB-N or NTrZ-S)

Notes:
South Polar Region (SPR): Appears dull (5/10) without any other detail noted within.
SSS Temperate Zone (S3TZ): Appears thin and bright (7/10).
SSS Temperate Belt (S3TB): Appears thin and dusky (4/10).
SS Temperate Zone (S2TZ): Appears thin and bright (7/10).
SS Temperate Belt (S2TB): Appears thin and dusky (4/10).
South Temperate Zone (STZ): Appears thin and bright (7/10).
South Temperate Belt (STB): Appears dusky to dull (4-5/10) containing two large very bright (8/10) ovals (the preceding oval appearing to extend into the South Tropical Zone (STrZ)).
South Tropical Zone (STrZ): Appears bright (7/10) without any other detail visible within.
South Equatorial Belt (SEB): Appears dark (3/10) with an irregular southern border composed of very dark (2/10) condensations.
Equatorial Zone (EZ): Appears bright (7/10) containing festoon projections/bands and very bright (8/10) ovals.
North Equatorial Belt (NEB): Appears dark (3/10) with very dark (2/10) barges and very bright (8/10) bays along it's northern border and very dark (2/10) festoons along the southern border.
North Tropical Zone (NTrZ): Appears shaded to bright (6-7/10) containing very bright (8/10) ovals.
North Temperate Belt (NTB): A dark (3/10) section is visible preceding the CM whereas the rest of the belt is dull to shaded (5-6/10).
North Temperate Zone (NTZ): Appears shaded (6/10) without any other detail visible within.
North Polar Region (NPR): Appears dull to dusky (5-6/10) with diffuse, dark (3/10) condensations visible within.

The best of luck in your own observations and imaging.

Carlos E. Hernandez

March 6, 2003 11:28 PM Forum: Solar System Observing

Mars Observation (March 6, 2003)

Posted By Carlos E. Hernandez

I have made my first observation of Mars for the current apparition. The planet's angular diameter is still small (6.3 arc-seconds), but I was able to make out a good amount of detail (described below). I welcome any comments on my observation.

Here is a description of my observation:
Date (U.T.): March 6, 2003
Time (U.T.) 04:45
CM: 327.3
Ls: 147.6, De: -3.5, Ds: 13.0
Diameter (arc-seconds): 6.3, Phase (k): 0.89
Instrument: 9-inch (23-cm) F/13.5 Maksutov-Cassegrain
Magnification: 352x and 620x
Filters: Wratten 23A, 38A, and 58
Seeing (1-10): 6-7, Antoniadi (I-V): III-II
Transparency (1-6): 5

Notes:
South Polar Region (SPR): Appears to be obscured by an extremely bright (9/10) South Polar Hood (SPH).
Mare Australe (3/10): Visible bordering the SPH
Noachis (6-7/10) and Deucalionis Regio (7/10): Visible north of Mare Australe.
Mare Serpentis (3/10)/Sinus Sabaeus (3/10)/Meridiani Sinus (3/10): Visible from the south-preceding (Sp) limb past the CM.
Syrtis Major (3/10): Visible bordering an extremely bright (9/10) evening limb haze (ELH).
Aeria (7/10)/ Arabia (7/10)/ Moab (7/10)/Eden (7/10): Bright desert region visible over the center of the disk.
Cydonia (7/10)/Dioscuria (/10): Visible towards the northern limb.
Ortgygia (3/10)/Cecropia (3/10): Dark region bordering the extremely bright (9/10) North Polar Limb (NPL).
Mare Acidalium (3/10)/Niliacus Lacus (3/10): Visible towards the north-following (Nf) limb.
Chryse (7/10)/Xanthe (8/10): Visible towards the following limb between Mare Acidalium and Margaritifer Sinus.
Margaritifer Sinus (3/10): Visible as a wedge towards the south-following (Sf) limb bordering an extremely bright (9/10) morning limb haze (MLH).

The best of luck in your own observations.

Regards,
Carlos


March 8, 2003 02:31 AM Forum: Solar System Observing

Planetary Eyepieces (Part 1)

Posted By Carlos E. Hernandez

I am probably opening up a can of worms by posting this message, but I will put in my two cents worth.

I must first state that there does not exist a perfect planetary eyepiece. Various designs are endorsed as being the ultimate design for observing the planets but this depends upon many factors. The primary factors are the following;

1) Sharpness
2) Contrast
3) Color correction
4) Eye relief

Sharpness:
One often hears of the "on-axis" or "off-axis" definition, or sharpness, of an eyepiece design. The planetary observer is primarily interested in the on-axis definition of an eyepiece design as the target (e.g. planet) is normally placed in the center of the field of view. Admittedly a well corrected eyepiece design will have good to excellent off-axis definition as well. Popular eyepiece designs such as the Abbe Orthoscopic (named after it's German designer Ernst Abbe in 1880) and Plossl (G.S. Plossl of Austria in 1860) enjoy excellent on-axis, as well as off-axis, definition. This is due in part to the fact that these designs maximize their corrections over a smaller apparent field of view (45-50 degrees) compared to a wide-field design (e.g. Nagler) whose off-axis definition falls off sharply over the outer 50% of the apparent field of view.

Contrast:
The perceived difference in brightness between two adjacent objects. This is accomplished by various factors such as the figure of the eyepiece lens (including polish) and light transmission (affected by the number of elements (lenses) and enhanced by the application of coatings (e.g. magnesium floride). Multicoatings on an eyepiece lens cannot make up for inferior glass/figure/polish. The simpler element (e.g. 4 elements, as in the Orthoscopic and Plossl) eyepiece design tends to produce higher contrast images at the focal plane compared to the multi-element designs (e.g. >6-7 elements, such as the Nagler and Meade Ultra-wide).

Color Correction:
The ability of a lens to bring together the various wavelengths of light to a common (focal) point. Properly matched lenses will bring the various wavelengths to a focal point to a degree that will not be perceived by the observer extending beyond the object in the field of view. Various designs (especially using different lens material) accomplish this rather well. The popular Orthoscopic and Plossl designs provide good to excellent color correction whereas some wide-field designs (e.g. Televue Radian) exhibit lateral color towards the periphery of the field (especially noted when observing the Moon). This may not affect the choice of a wide-field design but is a factor to consider.

Continued in Part 2



March 8, 2003 04:09 AM Forum: Solar System Observing

Planetary Eyepiece (Part 2)

Posted By Carlos E. Hernandez

Eye Relief:
The distance between the outer (or eye) glass lens and the observer's eye in which the entire field produced by the eyepiece is visible. This is an important consideration as a small eye relief (<5mm) becomes frustrating and more importantly produces fatigue in the eye of the observer while monitoring the planet for delicate detail. Some manufacturers have improved this factor by placing a barlow lens before the inner (or field) lens (e.g. Lanthanum eyepiece with a 20 degree eye relief). A quality barlow (e.g. 2x Ultima) coupled with a medium focal-length eyepiece (e.g. 12-18mm) can provide adequate eye relief at higher magnifications.

The above are vital factors that must be considered in the purchase of an eyepiece to be used for planetary observation.

The following are secondary factors that must also be considered in the purchase of an eyepiece;
5) Apparent field of view
6) Cost ($)
7) Weight (of the eyepiece)

I personally use the University Optics Abbe Orthoscopic, Zeiss Abbe Orthoscopic, Televue Plossl, Apogee Easy-View, and Meade Ultra-wide in my planetary observations. I would like to hear from other observers what their experiences are with different designs and brands of eyepieces.

Respectfully,
Carlos E. Hernandez



March 16, 2003 12:14 PM Forum: Solar System Observing

Mars Image (March 16, 2003)

Posted By Carlos E. Hernandez

I have attached an outstanding image of Mars obtained by a well known optical designer friend of mine, Michael Palermiti. He obtained this image of Mars showing an impressive amount of detail (labelled) while the planet's apparent diameter was less than 7 arc-seconds! The 6-inch refractor (F/15) that he used was designed by him (a very impressive instrument for planetary observation and imaging).

I hope that you all enjoy it as I do. The best of luck on your own observations of Mars.

Carlos

March 31, 2003 01:37 PM Forum: Solar System Observing

Re: C-9.25 on planets?

Posted By Carlos E. Hernandez

William,

Congratulations on your new C-9.25 OTA. I hope that you enjoy it to the fullest as it is reported to be one of Celestron's best scopes. I would strongly recommend that you check the collimation frequently (at a higher magnification than you will be observing at). You may want to consider a small investment in Bob's Knobs for the instrument. We look forward to your future observations using this instrument.

Carlos

April 2, 2003 11:22 AM Forum: Solar System Observing

Mars Observation (April 1, 2003)

Posted By Carlos E. Hernandez

I have attached an observation of Mars I made this morning (08:15 U.T.). I noted much detail over the disk as can be seen in my drawing. Any comments will be welcome. The best of luck in your own observations and imaging.

Date (U.T.): April 1, 2003
Time (U.T.): 08:15
CM: 053.9
LS: 161.1 (Martian Northern Summer)
De: -10.0, Ds: 7.8, Phase (k): 0.88
Instrument: 9-inch (23-cm) F/13.5 Maksutov-Cassegrain
Magnification: 282x and 352x
Filters (Wratten): 23A and 80A
Seeing (1-10): 5-6 (brief moments of 7/10), Antoniadi (I-V): III
Transparency (1-6): 6

Notes:
South Polar Limb Haze (SPLH): Appears brilliant 10/10 and obscures the south polar limb.
Mare Erythraeum: Appears dark (3/10) with a central bright (7/10) area (Pyrrhae Regio?).
Aurorae Sinus: Appears dark (3/10) connecting to the south to Bosporos Gemmatus (3/10).
Argyre I/II: Appears shaded to bright (6-7/10) adjacent to the SPLH.
Solis Lacus: Appears dark (3/10) and oval-shaped. Adjacent to an extremely bright (9/10) morning limb haze (MLH).
Chryse-Xanthe: Appears bright (7/10), but no other detail noted within.
Cydonia: Appears bright (7/10) adjacent to an extremely brilliant evening limb haze (ELH).
Niliacus Lacus: Appears dark (3/10) and separated from Mare Acidalium (3/10) to the north by a bright (7/10) haze over Achillis Pons.
Tempe: Appears bright to very bright (7-8/10) following Mare Acidalium.
Tharsis: Appears bright to extremely bright (7-9/10) towards the following limb.

Regards,
Carlos E. Hernandez

P.S. This is no joke.

April 3, 2003 12:30 AM Forum: Solar System Observing

Planetary Color Observations (Part 1)

Posted By Carlos E. Hernandez

Sol Robbins asked me a question as to what material(s) I use for my color planetary observations. This has to be explained in more detail.

I have always found it difficult to accurately render color upon the disk (on an observing form) of a planet, especially a multicolored planet such as Jupiter. What I would consider a "red" color upon the surface of Mars another observer may call "salmon." The question of color upon the surface (or atmosphere) of a planet is therefore a subjective one (unless measured photometrically of course). Several factors affect the visibility of colors upon the surface/atmosphere of a planet.

The eye itself is the primary factor that must first be addressed. Light entering the eye is focused by the lens and an image is formed upon the retina. The retina of the eye is composed of photoreceptors, namely the rods and cones. The cones, involved with color perception, are located primarily in the central zone of the eye, especially over the macula. The rods, involved in the perception of shades, are located towards the periphery of the retina (http://www.tedmontgomery.com/the_eye/index.html). A certain amount of light must strike the cones within the retina of the eye for the perception of color to take place. This depends upon the luminance (or brightness) of the object (candles/meter (squared)) and for our purposes while observing objects with small angular diameters (e.g. planets) this is a function of aperture.

The aperture of an instrument is vital in the detection of color upon the surface/atmosphere of a planet. Apertures smaller than 5 to 6 inches (or ~13-15 cm) will allow color to be visible upon the surface/atmosphere of a planet, but the limited light transmission of the objective (lens or mirror) may not allow subtle (or faint) colors to be perceived by the eye (retina). Some observers may now be saying "I can see many colors over the planets with my fine 4-inch refractor" and while this is true many delicate colors (especially over a planet such as Jupiter) will be missed using a smaller aperture. A good experiment is to place a quality 4-inch refractor (assuming acceptable suppresion of chromatic abberation) next to an 8-inch reflector and point both instruments at a planet (e.g. Jupiter). While the 4-inch refractor will provide a sharp and high contrast image of the planet the larger reflector will show the colors visible much more readily. This is not an attack against smaller apertures but only a scientific fact.

April 3, 2003 01:58 AM Forum: Solar System Observing

Planetary Color Observations (Part 2)

Posted By Carlos E. Hernandez

Assuming we are now using a quality instrument with sufficient aperture (e.g. 6-inch refractor or 8-inch reflector) for the detection of color upon the surface/atmosphere of a planet what are other factors that one must consider.

The altitude of the planet above the horizon is important in the accurate determination of color upon it's surface or atmosphere. A planet located less than 30 degrees above the horizon will be subject to the phenomena of prismatic dispersion. We all see this while observing a bright star close to the horizon as it shines erratically in many colors. Observing a planet less than 30 degrees will make color assesment very difficult while observing through a thicker layer of the Earth's atmosphere. Observing the planet as close as posssible to the zenith will make the assesment of color more acurate.

Assuming that all the factors listed above have been addressed then we arrive at the question of what material to use to depict the colors observed over the planet. Unfortunately the colors visible upon the planets do not always conform with colors such as "passion pink" or "aqua blue" as included in our selection of color pencils. The observer may decide to use pastels or watercolor to arrive at the observed color instead. This is a time consuming process at best and requires adequate illumination using a white light (versus a red light that we sometimes use to make our planetary observations). The fact that some planets have a rapid rate of rotation (e.g. Jupiter with a rotation rate of less than 10 hours) makes the accurate determination of color more difficult.

An objective way to get around the accurate determination of a color observed upon a planet is the use of a Pantone color scheme (first proposed by an ALPO member who I will later identify). This is a color swatch containing over 3,000 colors used by graphic designers (an example being http://www.misterart.com/store/view.cfm?store=001&group_id=2810< I am not compensated by this store in any way). It can be obtained at most art stores for approximately $60 to $70. An observer using a Pantone swatch (under white light) next to the instrument can determine that the Great Red Spot (GRS) of Jupiter appears closest in color to Pantone DS 97-3 C (http://www.colorguides.net/process_guides.html) rather than stating "orange-red." This is not an absolute requirement but instead a suggestion in arriving at objective color assesments.

I personally prefer to use Prismacolor color pencils for my planetary color renditions. If using the 72 color palette this will provide a rather complete selection of colors although some mixing of colors will be required. An artist's stump and kneaded eraser will be helpful as well.

I have given a lengthly explanation of what appears to be a simple question which in truth is far from being so.

Respectfully,
Carlos E. Hernandez