by Bob Jardine
2002 February 18
TV-85 & Celestron 8X40 binocs
My kids were out of school last week for a winter break, so we went to O'ahu. Not the best place in Hawaii for observing, I know, but I thought I'd give it a try.
Carrying the TV-85 on the airplane was pretty easy. In its case, it easily fits under the total (l+w+h) limit of 45 inches; however, with the tripod strapped to the outside of the case (to make it fit the definition of a single carry-on bag), it somewhat exceeded the length requirement, but nobody questioned it. They did make me open the case up, but they didn't ask to look through the tube, which I half expected... they just "ooh"ed and "aah"ed and said "must be expensive", etc.
The first night was slightly cloudy, and the weather report looked good for the week, and the day was already 2-hours longer than usual due to the time zone change, so I passed. The next night (Monday, 2/18) was clear, and I got three nice hours of observing in before conditions truncated my session. Unfortunately, for the rest of the week, I was clouded out every night...bummer. The local TV weather reports kept saying how nice and clear it would be the next day, but it ranged from partly cloudy to downright overcast every day, and the nights were all way too cloudy. I think this is the worst week of consistently bad weather forecasting I've ever encountered.
On Monday, I just drove East on the main road past Diamond Head and used a turnout overlooking the ocean directly south of the highway. This location made for a nice low Southern horizon (that is, the ocean surface!), although the inevitable marine layer obscured the lowest 10-15 degrees. I intended to locate a higher elevation spot for the later nights, but never got the chance.
My observing location was pretty dark, with no direct lights visible in any direction, although the light dome from Honolulu was still obvious.
I suspect that this light dome might be a problem from just about anywhere on O'ahu. The moon set around 11:30 PM, and after that I judged the transparency to be about 5.5 everywhere but West. The seeing was quite good except low over the ocean.
First stop was going to be NGC 1851 (GC in Columba), but it was already too low (not too far S, but too far W), a victim of the late start due to waiting for moonset.
I warmed up with nice views of the Tau CMa cluster (2362), one of my favorites, and NGCs 2451 and 2477 in Puppis. These three clusters are, of course, visible from home, but they are much nicer when higher up in the sky. Both of the Puppis clusters were very easy in the binocs. They remind me slightly of M46/47: one brighter, larger, and sparser and one smaller, dimmer, and more compact.
NGC 2546 was pretty easy to find in the binocs: large, somewhat sparse, but a little dimmer than I expected. This OC should also be visible from home; I don't know why I never looked for it before.
NGC 2547, on the other hand, is much farther south; but it was very obvious in the binocs: even brighter, but smaller. A nice little cluster at 30x (20 mm Plossl).
On the way to 2547, I noticed that Gamma Velorum is a very nice wide triple star, easy at 30x.
TR10 was also easy to find in binocs...nice, but not really very special, but I thought it would be a good jumping off point to find my next target...
Vela Supernova Remnant...this was my main stretch-goal target for the trip; I spent at least 1/2 hour looking for it (just after midnight). The location seems pretty easy, with a couple of bright stars curving SW from TR10 leading right there. I tried both 20mm and 32mm Plossls, and tried with and without my Lumicon UHC filter. Several times I suspected something, but ultimately, I don't think I can claim to have seen it. I guess that a slightly darker site would have been helped. Oh well, I guess that just means I'll have to schedule another trip, next time to Maui or the Big Island.
NGC 3132 (the "Eight-Burst" nebula) was next on my list. It wasn't too hard to find. I used a 9mm Nagler (67x) with and without a TV 2x Barlow. This PN was small and dim, but definitely not stellar, and slightly elongated. In the end, I couldn't see much detail...just a dim grey blob, not quite circular. Probably more aperture is needed here. The UHC filter helped only a little bit.
NGC 3201 is a large GC, easy to find in the 20mm. With the 2X Barlow it still doesn't resolve. Didn't try a higher power.
About 1:20, the Eta Carina Nebula and NGC 3532 were both getting too obvious to ignore. Wow! What a sight...like twin headlights coming at me from the south...there's nothing like this in the northern sky. To the naked eye, they're a little bit like the Double Cluster, but much bigger and brighter.
NGC 3372, which is called the Eta Carina Nebula in SA2000, but is called the "great Key-hole Nebula" by Burnham, is just fantastic. Bigger and brighter than M42, and with lots of little clusters and other nebulae all around it.
NGC 3532 is the most amazing OC I've ever seen...puts every Messier OC to shame, with the possible exception of the Pleiades. This thing is huge and bright and rich. Read the description in Burnham's if you want to drool (although Burnham has an error here...says it is 3 deg WNW of Eta Carina, but it is clearly ENE).
I also viewed NGCs 3572 (or was it CR 240?), 3766, 3324, 3293, and IC 2581, but I won't bore you with the details of these.
Around 1:45 AM, the marine layer started growing, like a large black sea monster, and it rose up and ate the bottom of the Southern Cross, Eta Carina, and most of the other far Southern stuff. However, by this time Omega Centauri was up and high enough to escape the monster's clutches, so I checked it out.
NGC 5139 (Omega Centauri). Visible naked eye, but just barely; jumps out at you with binocs. Checked it out at 67x and 133x (9mm +/- 2X Barlow). Huge and bright, fills almost half of the FOV, but still not quite resolving at 133X, but that's my max power with this set of eyepieces.
My next target was going to be NGC 5128 (Centaurus A), but a fairly large cloud had moved in by this time and decided to park right over the Honolulu light dome, brightening up the sky like a Western dawn! So I decided to leave it for another night, which, as it turns out, is going to require another trip...
Lessons learned: