Browse az-observing: This Month's Archive • Main Archive Page • Related posts • Previous by Date • Next by Date
[AZ-Observing] Thanksgiving Sky

From: Andrew Cooper <acooper@xxxxxxxxx>
To: TAAA Forum <taaaforum@xxxxxxxxxxxxxxx>, AZ-Observing <az-observing@xxxxxxxxxxxxx>
Date: Thu, 23 Nov 2006 20:11:44 -0700
Sometimes you just need someone to give you an excuse.

Some time ago I had answered some questions about observing sites around 
Tucson for a fellow amateur visiting the Tucson area. Now actually here 
Renato del Rosario asked if anyone would like to join him for a night 
out. As life had conspired to keep me from observing the previous 
weekend I was more than amenable to a night out. I was not alone, Sam 
Rua was also looking for an excuse to get out and Renato offered just 
such an excuse.

Read on or read full article 
<http://www.siowl.com/index.html?thanksgiving> complete with photos and 
the animation.

The proposal was made to head for Las Cienegas, always a beautiful site, 
an entire broad valley free of lights with desert mountains on the east 
and western horizon. Better with a group as there is some concern about 
illegal immigrant traffic in the area. Plans were made, a rendezvous set 
and we caravanned together out to the site.

A few cirrus clouds concerned us as the sun set. But these only served 
to make the sunset more dramatic as they dissipated or passed to our 
north. This left us with a beautiful Arizona sky for the rest of the 
night. Seeing wasn't to sharp, maybe a 6 or 7 most of the night, and 
transparency suffered from a little dust, giving us a magnitude 6 sky, 
maybe a little better. No complaints, as I sit here the next day writing 
this it is nearly completely overcast, sometimes the weather gods smile.

As the sky darkened I sat beside the scope and contemplated the beauty 
of the scene. The thin moon setting over the rugged profile of the Santa 
Rita Mts. and beauty of the Summer Milky Way through Aquila, Cygnus and 
Cassiopea. Just what I come out into the Arizona desert for. Then the 
cell phone rings... fortunately, or unfortunately depending on your 
point of view, there is good cell coverage of the Las Cienegas site. Yes 
dear, everything is fine, yes I will remember to bring home a gallon of 
milk for Thanksgiving, Love you. A moment later the phone chirps again, 
a text message "remember milk..." She knows me far too well.

Observing as a group offers many advantages, company, sharing as well 
additional security. How many times have I had an observing session 
saved when something forgotten was supplied by an observing buddy. A 
bolt, cable, battery, or all of the little details than can cause 
trouble at the wrong end of an hour's drive. This night we swapped gear. 
Sam realized he had forgotten a Telrad, I lent him mine once I had 
gotten the digital setting circles aligned. Later in the night I 
borrowed a 2" Hydrogen beta filter. With mutual support the night 
proceeded smoothly.

Early in the evening I setup the Canon 20Da on the eastern horizon with 
a wide angle lens. With a timer set for a 1 minute exposure every three 
minutes I hoped to gather the material for an animation of Orion rising. 
This worked pretty well, even with having to shoot a bunch of test 
images attempting to balance exposure length while minimizing the 
trailing for the stars. The finished result can be seen below.

The observing list was a number of objects that I had added to my 
observing database but had no observations for. Just a smattering of 
stuff I had never before observed and a few random selections from the 
Night Sky Guide. This was between looking at a few objects in Either 
Sam's scope or Renato's, or just sitting back watching the meteors that 
streaked the night.

The real surprise of the night was NGC2359, also known as Gum 4 or 
Thor's Helmet. This great nebula is in Canis Major, a really spectacular 
object with a very visible Wolf-Rayet sphere. With an OIII filter the WR 
structure showed a sharp outer shell and several filaments. It was even 
better in Sam's 25" where the spherical structure showed even more 
detail as well as structure in the surrounding dimmer nebulosity.

A few selected observations of the night...

IC410 Very faint but distinct nebula laced through the moderately rich 
open cluster NGC1893, an irregular glow most noticeable in the cluster 
and just west of the cluster, UHC filter necessary

IC417 Extremely fain nebula through a bright thicket of stars just south 
of M38 and NGC1907, edge of nebula most evident on the north edge 
towards the clusters where the background becomes noticeably darker

NGC2359 Large, bright nebula with a complex structure, visible as a 
large glowing patch without the filter, with the OIII filter the 
structure becomes far more interesting, a circular structure dominates 
the north side, a hard brighter northern edge and a filament just inside 
this emphasize the spherical nature of the structure, a bright 
protrusion is on the south edge and continues west, there is extensive 
dimmer structure surrounding the sphere, particularly to the north and 
east, with Sam Rua's 25" even this extended exhibits structure with a 
few knots and filaments, rich winter Milky Way starfield

NGC1990 Very faint and extensive nebula centered on Epsilon Ori, best 
detected by panning though the field and noting brightness changes in 
the background, looking straight at Epsilon the background is clearly 
not very dark at the center of the nebula

NGC 2023 A bright reflection nebula surrounding the 7.8th magnitude star 
HD37903, round with no other detail, about 10' across, just off the edge 
of IC434 and the Horsehead B33

Trumpler 6 Modest open cluster in a rich Milky Way starfield, distinct 
cluster well detached, reasonably rich a good population of dimmer 
members around a few brighter members, about 5' across, fairly round.

Dawn was beginning and Mercury rising in the east when I broke down for 
the run back to Tucson. And I didn't forget the milk.

Andrew

Andrew Cooper
----------------------------------------------------
http://www.siowl.com



--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.
Follow-Ups:

[AZ-Observing] Re: Thanksgiving Sky
From: sam

[AZ-Observing] Re: Thanksgiving Sky
From: R del Rosario
[AZ-Observing] Thanksgiving Sky

Other related posts:
