# Drawing planets

Forums General Discussion Drawing planets

Viewing 7 posts - 1 through 7 (of 7 total)
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• #617170
Lars Lindhard
Participant

I have some templates that I use when I draw the planets, but the phase changes throughout the year, so they don’t fit right.

Is there a collection of templates to copy from somewhere, or is there a program where you can enter the planet and date and then get the current phase/template?

#617174
Steve Holmes
Participant

The well-known and very popular program WinJUPOS might suit your needs. It will show any planet at its correct phase at any time & date, optionally with the unilluminated sector shown as well (in a darker colour), and one can then print or (more usefully) save the image for conversion into a template. It may be found at http://jupos.org/gh/download.htm

#617176
Jeremy Shears
Participant

Each of the planetary sections has templates on their websites on which you can draw the features and record other important details. The Saturn section has a series of templates depending on the angle of the rings (which you can look up in the Handbook). See: https://britastro.org/section_information_/saturn-uranus-and-neptune-section-overview/observing-programme/saturn-uranus-and-neptune-visual-report-forms

Regarding phases,in the case of Venus the observed phase generally differs slightly from the calculated one, a phenomenon called the phase effect: https://britastro.org/2016/the-phases-of-venus. So the phase should be drawn in at the eyepiece. The time of dichotomy can be determined from your observations and compared to the predicted time.

#617185
Paul G. Abel
Participant

Hi Lars,

For Venus, use a 50mm blank circle. I crease all mine in free software package called ‘the Gimp’. The phase can be constructed using the ellipse tool, you can get it to produce the right phase using the formula: W= 5*(1-2*phase). So if Venus is 60% illuminated, you would put the phase = 0.6 in the formula and the value you get for W is the width of the ellipse.

You can use a similar thing for Mars but be aware that the terminator changes sides- in a normal mirror inverting telescope with north at the bottom, features pass from right to left (i.e from the following side to the preceding side). Before opposition, the terminator and therefore the phase is on the left (preceding side), and after opposition it is on the right or following side. The phase on Mars is not always at 90 degrees, but the value Q in the BAA handbook (or the value ‘maximum phase’ in WINJUPOS) will tell you where the widest part of the terminator lies.

Jupiter is fairly easy, you need to use an ellipse 60mm wide by 40mm in height (it cannot be a circle as Jupiter is appreciably flattened). Finally the Saturn Section has some excellent templates which can be used to draw on with the rings, Cassini Division and the C-Ring all correctly depicted.

If you have any other questions, please feel free to email me.

Cheers,
-Paul

#617188
Lars Lindhard
Participant

#617190
Lars Lindhard
Participant

Each of the planetary sections has templates on their websites on which you can draw the features and record other important details. The Saturn section has a series of templates depending on the angle of the rings (which you can look up in the Handbook). See: https://britastro.org/section_information_/saturn-uranus-and-neptune-section-overview/observing-programme/saturn-uranus-and-neptune-visual-report-forms

Regarding phases,in the case of Venus the observed phase generally differs slightly from the calculated one, a phenomenon called the phase effect: https://britastro.org/2016/the-phases-of-venus. So the phase should be drawn in at the eyepiece. The time of dichotomy can be determined from your observations and compared to the predicted time.

It seems that the links to Uranus and Neptune observing forms are dead.

The negative Saturn tilt forms link to the positive forms, but I suppose they are identical?

#617224
James Lancashire
Participant
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