pi Gem - an colorful after-work double winter double

pi Gem, currently favorably positioned (J074731.20+332512.0) for 41N
op's, is visible in small refractors after sunset from urban light
polluted skies. The Belmont Society Colorful Double Star List
describes pi Gem as "orange/bluish triple" with an AB separation at 21"
and the third at 92." The primary of this colorful multiple is a v5.3
M0III star approximately 172 parsecs distant. The pi Gem multiple at ~
172 parsecs at G186.76+25.54 lies about 25 parsecs beyond the
anti-galactic center end of our Local Bubble.

Current CCDM data on pi Gem (CCDM 07475+3325, STF1135) a

C Pa Sep mag
A 5.3
B 214 21.0 11.4
C 341 91.9 10.4

There does not appear to be a Sixth Orbit Catalogue plot for this
multiple system.

pi Gem is about 3 degs north east alf Gem. A courtesy star hopping
finder chart is provided at:

http://members.csolutions.net/fisher...piStarHops.jpg

pi Gem can be star-hopped or right-angle swept by starting at alf Gem.
Using an eyepiece that approximates a 1 deg TFOV, find HR2936 (HD
61295), a v6.2 F6II, star about 1 deg north east of alf Gem. From
HR2936, there are two right angle sweeps to pi Gem.

The first right angle sweep involves going 2 eyepiece FOVs east of
HR2936, then north in declination 1 1/2 eyepiece FOVs. The second
right angle sweep route involves sweeping in north declination about 4
eyepiece FOVs to omi Gem - the first unmistakeable bright v4.9 F3III
star on a north dec sweep from alf Gem. Then sweep east two 1 deg
eyepiece FOVs, and then south one eyepiece FOV until an apparent, but
unmistakeable, two color double is seen. For some reason, I found the
longer route through omi Gem easy to execute with an alt-az mount.

Once the position is mentally fixed, pi Gem can be direct swept to
using a 3 deg 1x dot finder. Center the scope alf Gem and use bet Gem
as a intermediary reference line. Estimate where the edge of the 3 deg
finder intersects alf-Gem-bet-Gem reference line at about a 60 degree
angle. Direct sweep to that location. Odds are pi Gem will be
somewhere in a 1 deg TFOV eyepiece view.

In a small alt-az 60mm refractor under urban Bortle class 8 mag 3.0
light-polluted urban skies at 22x, pi Gem retains its nice orange/blue
color, albeit washed out. At 47x and 78x, the increased size of
diffraction disk of the M0III primary brought out more of its redish
color.

I did not detect the v11.4 C component under these light-polluted
conditions. I did not have the position angle (PA) reference for the
third C component at the time of viewing and could not definitely
confirm its location among the options within the star field. A
Schaefer limiting magnitude computation for these light pollution
conditions indicates the TLM for this small refractor is at or near the
v11.4 of the C component, so it may have not been visible under those
light-pollution conditions seen and small aperature used.

All-in-all, this was a nice 15-20 minutes of easy after-work
beer-in-hand viewing. The temperatures last night were not so
oppressively low as in prior winter nights at 41N.

- Canopus56