Declination for a launch?

[Mattyv]

This is a very quick question. I was using this, and I was wondering: In the destination parameters for an escape trajectory, it asks for the declination; What exactly is this? There doesn't seem to be anything in the documentation provided on it.

:tiphat:

 

[Scav]

Quick answer: [ame="http://en.wikipedia.org/wiki/Declination"]Declination - Wikipedia, the free encyclopedia[/ame]

Has to do with coordinates in astronomy.

 

[Mattyv]

I do know that. I should be more specific: say I want to go Venus (I know the perigee and c3) what is the declination value and how do I figure it out?

 

[Scav]

Yeah, I kinda saw 'quick' question and paired it up with 'quick' answer, so there was a bit of cheek in that answer.

Since you mentioned Venus, I checked wiki for grins, and they have those values for that planet:

North pole [ame="http://en.wikipedia.org/wiki/Right_ascension"]right ascension[/ame]

• 18 h 11 min 2 s
• 272.76°[5]

North pole [ame="http://en.wikipedia.org/wiki/Declination"]declination[/ame] 67.16°


http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html

-That- should help you out more specifically for Venus, and I'd think you'd be able to search other planets/objects out there from that site as well.

As for how to *calculate* RA and declination? That's a bit over my head, I'm afraid.

 

[tblaxland]

The declination of Venus' north pole will have zero effect on the launch of the vehicle from Earth. What you want to know is the declination of the transfer orbit.

For a target in the ecliptic, this will vary the same as the declination of the Sun IIRC, ie, 0 deg at the equinoxes and 23.5 deg at the solstices (approximately only, because your target won't lie quite in the ecliptic). To work out the declination, you need to know what time of year you are launching. For that I recommend a pork chop plotter: http://www.orbithangar.com/search_quick.php?text=Pork+chop&submit.x=0&submit.y=0

Table of the Sun's declination: http://www.wsanford.com/~wsanford/exo/sundials/DEC_Sun.html

 

[Quick_Nick]

Ctrl+I ought to do it.
At least for input asked by Orbiter I'm not positive about other programs. If it's what tblaxland is talking about, I can't help you!