Austin Texas has been in the pits weather and transparency wise for what seems like six weeks or so. There is agricultural burning in Mexico, where the fields are burned prior to the next crop being planted, and then there was an almost biblical Sharan dust storm, the worst I have seen in my 20 years in Texas, and then just soupy high humidity skies.
The last couple of nights have been the first in a very long time and while still not super transparent, they were the clearest I have had in a great while.
Observation done from my red zone sky. Time for both nights was between 10:15 PM and 10:45 PM. Temps at the time of observation where in the high 80s. Yes, Austin Texas has gotten really hot at night in the summer in the last 20 years. We have set record high low temps a couple of nights this week with the low temps being near 80.
Friday was short, just using my Mod 3 binocular with filmless P43 tubes. Transparency was not great, but the Milky Way was easily visible with the Great Rift clearly evident and showing considerable sub-structure. Because it was in the light dome over down town, I had to back off on the gain a lot. This is one of the few times I really do much with gain because filters are not perfect and leak a lot of light (I use 650nm so I can see brighter nebula) and when the Milky Way is in the light dome from down town, I find that decreasing the gain heightens the contrast of the dark nebula against the sky glow. Since I was doing 1x, I focused mostly just on the big picture of the rift itself and the various rich star fields that billow through it. It never ceases to utterly delight me that I can see this even from my light polluted yard.
Last night I did a longer session, maybe 25 minutes. This time, I use the Mod 3 with thin film P43. I really like the way stars seem to pop out better in these tubes. I did also bring out Ha filters and 3x binocular lenses. Transparency seemed better than the previous night. I spent this session mostly at 3x. While transparency was perhaps a bit better, North American Nebula was not all that bright, but to be fair it was very low, being just above the trees.
3x Really pumps up the ability to see the smaller dark nebula. I have become fascinated with dark nebula and I do as much dark nebula in the summer as I do anything else. We are seeing dust clouds that dwarf almost every other kind of object in the Milky Way. The tentacles of dust are interwoven into the fabric of the home galaxy and besides the spiral arms themselves.
With the slightly better transparency, the dark nebula really popped out. Everywhere along the walls of the rift there is layer after layer of detail. Again, working the gain I was able to see structure in structure. There is often a whispyness to some of the smaller darker inclusions that make each one worthy of examination. Now 3x works OK, but I think 7x is better, but of course the problem with getting 7x from a full bincular is that you can't use SLR lenses. Now that I can print a bridge for them, I plan on going back to using a pair of 50mm CCD finders because I think they would be really wonderful for exploring these nebula. Sadly, I cannot use the on the thin film binocular because it has PVS-14 objectives but of course I do have the Mod 3 with C mount for that, though I really like the way the thin film with green punches up the stars.
I spent probably 15 minutes just poking around in this area. It is amazing how big and bright M22 is even at 3x. It just jumps out of the background and even at 3x, the halo appears to be grainy. With the 650 filters, the Lagoon was not prominent, but the Swan and Eagle were easyier. The big clusters like M7 are better at higher power, but at 3x, they are dramatic asterisms that add texture in the way that a diamond broach sets off a cocktail dress.
5 Minutes with the H-a filters. I run a 7nm on one side to allow for less dimming of nebula that are well off the center of the field, and a 5nm on the other side to bring out the nebula at the center of the field. The brain seems to easily integrate the different views together. Here, the surprise was how bright the Lagoon was. Unlike with the 650nm, now it was suddenly blazing with the big curved dark lane being the dominant feature. At 3x, the lanes in the Trifid are not big enough to be exiting, but they are visible. Even the IC 4685 was pretty easy. With the transparency I had expected it to be subtle, but it was bright enough to stand out well. The Swan shape was tiny but distinctive, and the Eagle nebula was very bright.
To the northeast, though, North American was not at all bright. Oh, the shape was very easy to see and quite unmistakable, but the Pelican was much more subtle. Likewise, Gamma Cygni was not as bright as I had expected. Again, these were lower in the sky, so I guess that was a factor. These are wonderful when overhead in September, but last night they were probably just too low to be seen well.
I have not been out with a telescope in weeks, but even though it is supposed to be very hot the next week, I can see the transparency is improving, so I am thinking of getting out to the Mansfield Dam in the next couple of days for a telescope session. From there, the core is not over the city light dome, so better for dark nebula.
Hope everyone is safe and hope everyone remains that way. Have fun out there!