Object Info/Apparent Data

[bigmasterdrago]

I've been interested in observing this crescent moons since the late 80s. I was looking at adding SkyTools to my observing toolkit for those planning sessions. How do I get the Apparent Data in the Object Info to feed the refracted/apparent altitude instead of the true altitude? And the Interactive Atlas view to show refracted location?

These thin crescent moons are generally located near the horizon, anywhere from 14° (easy) to only 1° (not so easy). Also, the crescent might have a very small elongation from the Sun and under 1% illumination.

Any hints on setting these up within the Interactive Atlas would be appreciated. I generally use my 10x70 binoculars to hunt these while the Sun is down ~4° - works good from a lot of experience. I'm working to incorporated ST4v into the planning of future hunts.

[theskyhound]

Hello,

Regarding the Apparent Data tab of the Object Info, the "Altitude above visible horizon" is the actual, observed, apparent altitude above a clear horizon (e.g. the ocean) including the effects of refraction.

Regarding the atlas, there are other charts that are more appropriate to this purpose. Think of the atlas like a book atlas. You wouldn't use an atlas on your desk for this task. Sure, the interactive atlas can technically be put into something akin to the modes of the other charts. But there is a reason that there are special purpose charts: they can better serve a specific purpose than the atlas can. Use either the Naked Eye chart or a telescope/binocular finder chart for this. The Naked Eye chart displays the visible horizon, taking into account the altitude of the observer and refraction, so it is well suited. If you will be using a telescope, or binoculars, then use the custom finder chart for your telescope or binoculars. Not only does this have the same naked eye view, but it can also show you want you would see in the eyepiece, and again, the horizon accounts for altitude and refraction in both views. If it were me, I'd use the finder chart for my 8x50 binoculars. Open the chart for it via the moon in an observing list, and then try time stepping forward/backward by a minute for each click. Another advantage of this chart is that it will help you find the right part of the sky to be looking at, because the naked eye portion will display any visible stars.

[PMSchu]

Hi BMD,

I think the information you want on the OI display is on the Apparent Data tab. It's called the Altitude above visible horizon, shown here for Venus: [attachment=2095]

Note the difference between this altitude & the True Altitude. As objects approach the horizon the difference between these 2 altitudes will increase. You can check it out on a crescent moon.

Again, a superior explanation by Greg.

Hope this helps,

Phil S.

[bigmasterdrago]

Thanks guys. What I was looking for. So use the "Altitude above visible horizon" in Apparent Data as it's the refracted position. Somehow, I was looking for the word apparent, refracted but not visible in the data box. Thanks. Got it.