by Albert Highe
On the drive to Plettstone, I recorded 99°F. The skies were beautifully clear blue. By 9PM the temperature dropped to a comfortable 74°F and never got below 68°F during the night. The %RH reached the mid 60's, making for nice dry conditions. Transparency was very good. Seeing was best early on, but degraded a bit after midnight. Even still, I hunted down faint galaxies at 286X for most of the night. No wind.
The temperature was again in the high 90's today, and dropped to only 70°F during the night. The air was even drier. The %RH never got above the mid-50 's. Seeing was about the same as on Tuesday. I think the transparency was better, allowing me to score more than 80 new objects. No wind.
The weather pattern changed on Thursday. It was cooler during the day, only reaching the low 90's. Some clouds also moved through during the day. By nightfall, the clouds had receded to the eastern and western horizons, leaving clear skies. The temperature dropped to 58°F during the night and the RH climbed to 78%. At 11PM the transparency degraded, signaling an advance warning of the cloud bands that rolled through soon after. I took a break for an hour to let them pass. I resumed observing in clear, fairly transparent skies at 12:30AM. No wind.
This was an absolutely gorgeous day. The skies were clear and deep blue. The temperature was in the mid-80's. Like Thursday, the temperature dropped to 58°F during the night and the RH climbed to 78%. However, the skies remained clear. Seeing was the best of all four nights and transparency was very good. No wind.
|Scope||17.5" f/4.5 ultralight|
|Eyepieces||mostly 7mm Nagler T6, but occasionally the 5mm Tak LE when seeing permitted.|
Four days of observing in very good to excellent conditions generates scores of pages of observing notes. Here are just a few tidbits.
I resumed my hunt for faint fuzzies in three Abell galaxy clusters. I still haven't finished my research and write-ups. However, at least the labeled finder charts for the central 1° X 1° area and most of my target lists are available at the designated URLs.
I logged 39 new objects in A2151, bringing the total to 51. There are over 100 targets left, so I expect to significantly increase this number.
I'm seen most of the "brighter" galaxies in Abell 1367 (as faint as photographic magnitude 16.0). I spent time confirming previous observations, hunting down fainter galaxies, and finding brighter galaxies I'd overlooked. I logged 27 new objects in A1367, bringing the total to 116. Six are likely not cluster members. Except for a couple of galaxies brighter than mag 16.0, I'm declaring my survey complete. Most of the remaining fainter galaxies have designations like 2MASXi and are extremely difficult targets.
Abell 1656, the Coma Cluster, is by far the richest and most dense galaxy cluster. I made a small dent observing its members last month. With members stretching as far as 5° from the center, I've got lots of area to cover. I'm still focusing on those galaxies within about 1° of the center. Even while focusing on this restricted area, I logged over 100 new observations, bringing the total to almost 150. At this rate, I expect to eventually observe well over 300 galaxies in this cluster.
One of the highlights of this week was observing M13 on Friday. Guillermo and I both coincidentally turned our 17-1/2"/18" scopes toward this globular cluster just after nightfall. Seeing was the best all week and we had wonderful views with wide field eyepieces at magnifications approaching 300X. Wanting to resolve the dense core further, we simultaneously pulled out shorter focal length eyepieces and began scanning at over 400X. Even at those magnifications, star images were excellent. Neither of us had ever studied M13 for long periods at high magnification. The distance between our scopes allowed us to easily communicate our observations to one another verbally - thus creating an audio interferometric study of M13. We must have spent at least 15 minutes studying the cluster, describing patterns of stars, and guiding one another to our findings.
I observed a galactic asterism that I've dubbed the Herdsman's Smile. It is in the SW corner of Bootes. I guess it could also be called the Galactic Banana, waiting to trip up the Herdsman. There are 10 "brighter" galaxies that make a sweeping arc across about 30 arc minutes. At the NE end are three NGC galaxies within 7' of each other (5438, 5436, 5437). SW of this triangle is a close pair of galaxies consisting of UGC 8967 and NGC 5434. At the southern midpoint of the arc is another trio of NGC galaxies (5431, 5424, 5423). Proceeding NW of this trio is the wide pair NGC 5416 and NGC 5409 at the end of the arc. In addition, there are some more challenging objects. For example, NGC 5423 is bracketed by a pair of galaxies: MCG+2-36-18 and MCG+2-36-16. A few other fainter galaxies also are nearby. Judging from their radial velocities, all galaxies except for a couple of the nearby 2MASXi galaxies are located in the same region of space. It doesn't appear to be an Abell cluster, but I think it is noted in the Zwicky catalogue.
Once again, many thanks to Michelle for being such a wonderful host. Her generosity allows me to observe as much as I do.