August 2024
Featuring A close conjunction of Jupiter and Mars, Lenticular galaxy NGC 7457, and barred spiral galaxy NGC 7640.
17th August - Jupiter and Mars conjunct.
Two fairly large sunspots, plus a few minor ones:
You can click/tap the image to go to a better resolution version,
or just look at the interesting bits.
14th and 15th August - Jupiter and Mars conjunct.
Back on the 30th of July I posted a wide angle shot of Jupiter and Mars (with and over exposed Moon in the frame). At that time, Jupiter was East of Aldebaran, and Mars was sitting almost midway between Aldebaran and the Pleiades. Both planets have been moving East through the constellations, but Mars far faster than Jupiter. On the 14th and 15th of August, the two planets were quite close.
The cloud forecast for the night of 13th/14th was not great - so I was tucked up in bed. Happened to be awake at 02:00, noticed it was clear, and just got this image from my bedroom window with my phone camera.
Mars is now just slightly North West of Jupiter, a big change in just 2 weeks.
The cloud forecast for the night of 14th/15th was great - turned out not great enough for my planned scenic image of Jupiter and Mars rising over Barleycroft lake, so I eschewed the 70 minute round trip walk in the wee small hours.
By 4am it was clear enough for this wide angle shot (Sony camera on a tripod).
Mars is now just slightly North East of Jupiter.
Here's a closer look from images taken around 4:45:
Mars is top left, Jupiter bottom right with all 4 Galilean satellites visible, from left to right, Ganymede, Io, Europa and Callisto (also with a full resolution Jupiter inset).
Not up to my usual standard of Jupiter imaging, because I had to use a reduced magnification to get Mars in the frame.
With Jupiter in this part of the sky, the next opposition (the beginning of December this year) promises a lot in terms of imaging, with the slim chance of getting a full 10 hour rotation of the planet in a single nights pictures. Fingers crossed.
11th and 12th August - NGC 7640.
We continue our meander through less frequently imaged galaxies with NGC 7640. North and East of NGC 7457, NGC 7640 is in the constellation of Andromeda. Slightly larger and brighter than my previous target, I reverted to the usual 1000 mm focal length.
Even at the close to edge on angle, NGC 7640 looks like, and indeed is, a barred spiral. As usual, distance values vary depending where you look, but I'm going to opt for 29 million light years, I've also seen figures of 26 million and 36 million.
From the image here, I estimated its major axis as being 9.8 arc minutes, which would give it a diameter of 83,000 light years (not that much smaller than the 100,000 of our Milky Way).
(Click/Tap the image to go to a better resolution version)
August 12th is typically the peak of the Perseid meteor shower. I saw 8 in the not much over 30 minutes I was outside looking for them. This is not actually a bad count. None appeared in the small area of sky I was imaging.
6th and 7th August - NGC 7457.
My search for new object to image continues, so, as a consequence, the pictures get less impressive. I'm back imaging a galaxy, NGC 7457 in the constellation of Pegasus. A sign we are rapidly heading into autumn :( if this is high enough to image.
The galaxy has a distance 43 million light years, so a bit further away than the 35 million light years of the Leo Triplet of galaxies. It is classified as Lenticular, implying it has the central bulge and disk shape one would expect from a spiral galaxy - but no spiral arms.
Visibly it is quite small, about 3 minutes of arc by 1.5 minutes (about one third the apparent size of M66, the brightest of the Leo Triplet galaxies). At 43 million light years, 3 arc minutes would be 37500 light years across, well under the 100000 light year size of the Milky Way.
Because of the small apparent size, I made the decision to use the 2.7x barlow lens for increased magnification. There is one major downside to this, the image gets fainter. To counteract this, I upped the ISO setting to 12800, and took more images than I usually would in a session (risking a sudden curtailment due to battery life, for ease of setup I was using a battery to drive the mount).
The other thing of note about an increased magnification is that you don't get any more resolution, the resolution you have just occupies more pixels. For my setup, the theoretical best resolution is about 0.75 arc seconds, at my usual 1000mm focal length one pixel is 0.81 arc seconds for the Sony camera. At an effective focal length of 2700mm this comes down of 0.3 arc seconds, i.e. 2.5 pixels per maximum resolution. For what it's worth I've chosen to make the big picture below 40% of the original size, bringing us back to 1 pixel per maximum resolution. The actual resolution will be determined by the worst of: the steadiness of the sky, the quality of the collimation and the accuracy of the tracking, probably in increasing order of their effect.
(Click/Tap the image to go to a better resolution version)
The smaller galaxy to the left of the picture is PGC 70275. I couldn't find any data on this, but it will be greater than 100 million light years distant (unless it is shockingly small). There are almost certainly two far more distant galaxies in the image. They look like faint stars with fuzzier edges than stars in the image of similar brightness. In other (better) pictures, they look even more like distant galaxies, but I couldn't easily find any numbers to associate with these. They will be plus 400 million light years away. You may notice if you click/tap the image to big it, that the small and big images are not the same. The small image is from my first attempt at processing this, where I used my usual histogram manipulation, never getting to far away from a linear stretch. Examining the full-sized version of this image it was apparent that the galaxy was way below the advertised 3 arc minutes, not much over 1 arc minute in fact. I redid the processing with a hugely non-linear histogram adjust to try and bring out the periphery of the galaxy. This is the big version of the picture. In this the galaxy is about 2.5 arc minutes along the long axis.
17th August - Jupiter and Mars conjunct.
Two fairly large sunspots, plus a few minor ones:
You can click/tap the image to go to a better resolution version,
or just look at the interesting bits.
14th and 15th August - Jupiter and Mars conjunct.
Back on the 30th of July I posted a wide angle shot of Jupiter and Mars (with and over exposed Moon in the frame). At that time, Jupiter was East of Aldebaran, and Mars was sitting almost midway between Aldebaran and the Pleiades. Both planets have been moving East through the constellations, but Mars far faster than Jupiter. On the 14th and 15th of August, the two planets were quite close.
The cloud forecast for the night of 13th/14th was not great - so I was tucked up in bed. Happened to be awake at 02:00, noticed it was clear, and just got this image from my bedroom window with my phone camera.
Mars is now just slightly North West of Jupiter, a big change in just 2 weeks.
The cloud forecast for the night of 14th/15th was great - turned out not great enough for my planned scenic image of Jupiter and Mars rising over Barleycroft lake, so I eschewed the 70 minute round trip walk in the wee small hours.
By 4am it was clear enough for this wide angle shot (Sony camera on a tripod).
Mars is now just slightly North East of Jupiter.
Here's a closer look from images taken around 4:45:
Mars is top left, Jupiter bottom right with all 4 Galilean satellites visible, from left to right, Ganymede, Io, Europa and Callisto (also with a full resolution Jupiter inset).
Not up to my usual standard of Jupiter imaging, because I had to use a reduced magnification to get Mars in the frame.
With Jupiter in this part of the sky, the next opposition (the beginning of December this year) promises a lot in terms of imaging, with the slim chance of getting a full 10 hour rotation of the planet in a single nights pictures. Fingers crossed.
11th and 12th August - NGC 7640.
We continue our meander through less frequently imaged galaxies with NGC 7640. North and East of NGC 7457, NGC 7640 is in the constellation of Andromeda. Slightly larger and brighter than my previous target, I reverted to the usual 1000 mm focal length.
Even at the close to edge on angle, NGC 7640 looks like, and indeed is, a barred spiral. As usual, distance values vary depending where you look, but I'm going to opt for 29 million light years, I've also seen figures of 26 million and 36 million.
From the image here, I estimated its major axis as being 9.8 arc minutes, which would give it a diameter of 83,000 light years (not that much smaller than the 100,000 of our Milky Way).
(Click/Tap the image to go to a better resolution version)
August 12th is typically the peak of the Perseid meteor shower. I saw 8 in the not much over 30 minutes I was outside looking for them. This is not actually a bad count. None appeared in the small area of sky I was imaging.
6th and 7th August - NGC 7457.
My search for new object to image continues, so, as a consequence, the pictures get less impressive. I'm back imaging a galaxy, NGC 7457 in the constellation of Pegasus. A sign we are rapidly heading into autumn :( if this is high enough to image.
The galaxy has a distance 43 million light years, so a bit further away than the 35 million light years of the Leo Triplet of galaxies. It is classified as Lenticular, implying it has the central bulge and disk shape one would expect from a spiral galaxy - but no spiral arms.
Visibly it is quite small, about 3 minutes of arc by 1.5 minutes (about one third the apparent size of M66, the brightest of the Leo Triplet galaxies). At 43 million light years, 3 arc minutes would be 37500 light years across, well under the 100000 light year size of the Milky Way.
Because of the small apparent size, I made the decision to use the 2.7x barlow lens for increased magnification. There is one major downside to this, the image gets fainter. To counteract this, I upped the ISO setting to 12800, and took more images than I usually would in a session (risking a sudden curtailment due to battery life, for ease of setup I was using a battery to drive the mount).
The other thing of note about an increased magnification is that you don't get any more resolution, the resolution you have just occupies more pixels. For my setup, the theoretical best resolution is about 0.75 arc seconds, at my usual 1000mm focal length one pixel is 0.81 arc seconds for the Sony camera. At an effective focal length of 2700mm this comes down of 0.3 arc seconds, i.e. 2.5 pixels per maximum resolution. For what it's worth I've chosen to make the big picture below 40% of the original size, bringing us back to 1 pixel per maximum resolution. The actual resolution will be determined by the worst of: the steadiness of the sky, the quality of the collimation and the accuracy of the tracking, probably in increasing order of their effect.
(Click/Tap the image to go to a better resolution version)
The smaller galaxy to the left of the picture is PGC 70275. I couldn't find any data on this, but it will be greater than 100 million light years distant (unless it is shockingly small). There are almost certainly two far more distant galaxies in the image. They look like faint stars with fuzzier edges than stars in the image of similar brightness. In other (better) pictures, they look even more like distant galaxies, but I couldn't easily find any numbers to associate with these. They will be plus 400 million light years away. You may notice if you click/tap the image to big it, that the small and big images are not the same. The small image is from my first attempt at processing this, where I used my usual histogram manipulation, never getting to far away from a linear stretch. Examining the full-sized version of this image it was apparent that the galaxy was way below the advertised 3 arc minutes, not much over 1 arc minute in fact. I redid the processing with a hugely non-linear histogram adjust to try and bring out the periphery of the galaxy. This is the big version of the picture. In this the galaxy is about 2.5 arc minutes along the long axis.
Comments
Post a Comment