Trailer: E 21 2019 Tow Vehicle: 2019 4Runner Limited
Posts: 739
Astronomy/photography
Quote:
Originally Posted by John in Santa Cruz
I have an Explore Scientific 82 deg. 30mm which is quite similar to that Nagler, but I use the ES82 18mm a lot more.
You bring up an interesting point which has to do with eyepiece selection based on frequency of use. Personally I think the 31mm Nagler is one of the best eyepieces that was ever produced. That said this 'hand grenade' stays in my box most of the time. I use it mainly to look at large open clusters which in any event is not my main interest unless I'm doing public outreach. My 'go to' eyepiece is the Pentax XW 14mm with the XW 10mm a close second. I own a bunch of Televues. However, I prefer the Pentax eyepieces.
My choice of eyepiece focal length is pretty heavily based on the focal length and f/ratio of the telescope. I use the 18mm as my main eyepiece with my 20" f/5 Obsession, which has a 2540mm focal length, this gives 160X and 0.5 degree actual field, which is a sweet spot for a lot of things. With my 10" f/4.5 Coulter (1150mm FL), I'm more likely to be using a 9mm or 14mm.
I just went out and turned my refer on, it had not been run for couple of months, so I'm exercising it until our next trip. Also will operate furnace tonite to keep bugs out....
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Jim
Sometime life gets in the way of living.......
Trailer: E 21 2019 Tow Vehicle: 2019 4Runner Limited
Posts: 739
Quote:
Originally Posted by John in Santa Cruz
My choice of eyepiece focal length is pretty heavily based on the focal length and f/ratio of the telescope. I use the 18mm as my main eyepiece with my 20" f/5 Obsession, which has a 2540mm focal length, this gives 160X and 0.5 degree actual field, which is a sweet spot for a lot of things. With my 10" f/4.5 Coulter (1150mm FL), I'm more likely to be using a 9mm or 14mm.
I have a few eyepiece FL's to choose from
Well you are definitely rigged out for planetary observations. I prefer an actual FOV of around 22 degrees (Pentax XW 14mm (21.5') That is because most of my observing sessions are focused on galaxies & Galaxy clusters. I had the astigmatism problem from hell until I got lens transplants. I do like the 20mm eye relief. I never bought into the 'galactic' 82 degree apparent field of view. I like to narrow things down a bit.
Well you are definitely rigged out for planetary observations. I prefer an actual FOV of around 22 degrees (Pentax XW 14mm (21.5') That is because most of my observing sessions are focused on galaxies & Galaxy clusters. I had the astigmatism problem from hell until I got lens transplants. I do like the 20mm eye relief. I never bought into the 'galactic' 82 degree apparent field of view. I like to narrow things down a bit.
I got the short FL eyepieces when I was using the 10" f/4.5 Coulter. On that scope, the 4.7 is 244X and 20 arcmins...
my eyeglasses correct my astigmatism very nicely as long as the exit pupil is 5mm or smaller, and the eye relief on the ES82 series means I can leave them on.
anyways, this discussion probably belongs somewhere else, like CloudyNights.com :-p
EOS 60D
EF18-200 kit zoom
EF20mm f/2.8 USM
EF85 f/1.8 USM
EOS M
EF-M 22mm f/2 'pancake'
420EX strobe
EF lens adapter for the M (hardly ever used)
Manfrotto 055B tripod with various heads
plenty spare batteries and SD cards
I'm beginning to see why astronomers are annoyed by Elon Musk's Starlink satellites. I took this 31 second exposure last night. I suspect the short streaks are his. Can't think of what else would do this & haven't seen them before. (You probably have to look at the full sized image to see them)
Based on your location, and the fact that part of the constellation of Orion is visible in your image, my guess is that you took the picture in the early (relatively) evening. Speculating, the streaks that appear 'up and down' are satellites in polar orbit. Streaks left and right are planes. O yeah, the light dome on the right is likely Blythe, CA. The light dome on the left is Eherenburg, AZ. NNW of Blythe is the Palen-McCoy Valley- one of the darkest night sky locations in SoCal, and home to a very nice Ironwood tree forest.
Based on your location, and the fact that part of the constellation of Orion is visible in your image, my guess is that you took the picture in the early (relatively) evening. Speculating, the streaks that appear 'up and down' are satellites in polar orbit. Streaks left and right are planes. O yeah, the light dome on the right is likely Blythe, CA. The light dome on the left is Eherenburg, AZ. NNW of Blythe is the Palen-McCoy Valley- one of the darkest night sky locations in SoCal, and home to a very nice Ironwood tree forest.
My location is Imperial Dam, CA. The 4 very short left and right streaks are not like any airplane images I've ever made. The long diagonal streak is typical of an airplane. I've never seen the short streaks before, particularly in a group.
Now you've got me. You didn't use a long exposure, 'cause there are no star trails. The one long diagonal streak then is a meteor, and the short dashes are planes. Stars appear to move across the sky at about 15 degrees per hour. Planes are much faster to cross the sky, and meteors are in a speed class all their own. (respectfully submitted)
Now you've got me. You didn't use a long exposure, 'cause there are no star trails. The one long diagonal streak then is a meteor, and the short dashes are planes. Stars appear to move across the sky at about 15 degrees per hour. Planes are much faster to cross the sky, and meteors are in a speed class all their own. (respectfully submitted)
I've taken many (1000's) of nighttime star photos, both star trails & images that the shutter time is matched to the particular lens to prevent trails. The 31 second exposure eliminates star trails for the 16MM lens I used.
The diagonal streak IS an airplane, I both watched & heard it while taking the photo. The 4 short horizontal streaks are something I haven't seen in 50 years of taking star photos. That is why I guessed that it was part of the Starlink system. While other satellites make similar streaks, I've never seen 4 in formation. No idea if the latest launch was in the area, but that is my best guess as to what I saw (and photographed).
Can you crop down to the level of whatever those things are? Maybe give us a blow up. I would like to see this a little closer.
I took a series of pictures for a big panorama in Glacier. It was an early sensor, 8 mb, not great resolution
Here are two pics of it (one twice). The first one is the full image over Many Glacier's entrance.
In the red circle, I blew up what looks to be something akin to a flying saucer at an angle. The cap part seems to be in the Sun. At first I thought it was a smudge from the printer on the print. So I took a closer look. You decide. There is another faint one present, but you cannot see it in this image.
Is it? I have no idea?
I have seen ufo's VERY CLOSE, and I still have no idea what they are.
I have as number of these strange blips thru the years. Not sure what they are but I do not discount them. Opinions welcome.
Here is a couple of crops. The first includes the airplane and a dim streak, the second a section with one of the brighter streaks. For anyone interested, here is a full sized jpeg of the overall image. (It is 7.5MB for those on limited data). In the full sized image you can see more dimmer streaks. Ignore the "V" shaped images at the edges - they are lens distortion.
Again, I have photographed stars, meteors, airplanes, etc at night, and this is the first time I've seen a bunch of these short streaks. No suspicion that there are a fleet of UFO's over Imperial Dam.
Here is a couple of crops. The first includes the airplane and a dim streak, the second a section with one of the brighter streaks. For anyone interested, here is a full sized jpeg of the overall image. (It is 7.5MB for those on limited data). In the full sized image you can see more dimmer streaks. Ignore the "V" shaped images at the edges - they are lens distortion.
Again, I have photographed stars, meteors, airplanes, etc at night, and this is the first time I've seen a bunch of these short streaks. No suspicion that there are a fleet of UFO's over Imperial Dam.