The Inferior Planets

Mercury

Lunar addendum

Venus

Reference

Techniques

Scout out a site

I scouted out a site to observe from that would be close to home. I wanted someplace that would be as convenient as possible to encourage frequent observation. After checking a few prospects near to my home, I realized that the best place is my nearby (close-in) dark sky site. It is on a rise that looks out to the eastern plains of Colorado from quite a lofty perch. You want a view of the horizon as ideally free of obstruction to the East to Southeast (morning) and to the West to Southwest (evening) as possible. Having to deal with clouds on the horizon is bad enough. Trees and structures only increase the problems. Note the travel time to your selected site. This is handy and necessary for planning.

Telescope Alignment

Less of a concern for morning observations because you can time your arrival to the site with sufficient time to align to Polaris (or other stars in the case of AltAz goto scopes). For evening observations, find a way to daylight "polar" align your telescope and mount, so you can be setup as the Sun sets, giving you the biggest jump on locating your evening star(s).

use GO-TO

Morning and evening observations of the Inferior Planets are problematic enough. Use any advantage to make that observation. For my first Mercury session with my ETX105/EC and Autostar, I had the tripod/wedge pointed pretty close to North, but I did not take the time to adjust the latitude adjustment or attempt to level the legs, so I was several degrees off of the celestial pole for my polar alignment. Also, in my haste, due to an error of user input into the Autostar, I had to start all over. After turning on the GPS to get accurate time again, my stars had faded into the dawn significantly, but I still got two stars (Vega and Arcturus) for my alignment. Upon breaking down my telescope, I also noticed that I had only put one bolt into the base of the scope to attach it to the wedge. Besides not having use the other two bolts, I also noticed that I hadn't even tightened the one bolt down! It was fine because I didn't seriously bump the tripod while I observed.

Plan and Prepare

The day before you think you might observe, study up on the location and the projected phase of the target using Ottewell's Astronomical Calendar. If you have a planetarium program (or other suitable reference), check the rise (or set) time of the planet, the Sun, and the beginning (or end) of Astronomical twilight. Pack up everything you will need in advance. Dress appropriately for the weather.

Weather Forecasts

Check the weather within twelve hours (if possible) of your planned session. This is one key to success especially for morning sessions.

Rise and Shine

There are several advantages to morning apparitions of the Inferior Planets: better atmospheric seeing; arriving early allows you setup your telescope using the last of the night sky (alignment stars); automobile traffic congestion is lighter for travel purposes, especially at the time and direction of your trip to your site. If you get to bed early enough, you can wake rested and refreshed, and you can be packed up and ready to leave as the Sun rises (always nice to witness). Also, if you have the time, you can stay setup, and tracking your planet(s) well into daylight. For the Inferior Planets, this is good because it gives you the chance to track and observe your target as it reaches a higher altitude from the horizon. Then dependence upon a smaller telescope is not a detriment.

Small Scopes, Lower powers

Catching an elongation of an Inferior Planet may mean low altitude in the sky. The smaller the aperture, to a point, the better. Small aperture telescopes better mitigate the effects of bad seeing, which is more pronounced at lower elevations above the horizon. I think my 105mm f/14 (focal length 1470mm) Maksutov-Cassegrain telescope is ideal for this purpose.