Arp’s Peculiar Galaxies
Page 5 of 10
Arp observations 41-50 of 99 total to date.
| Thumbnail | Title/link | Arp Category | Date Observed | Observer Description |
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Arp 120 / Eyes Galaxies | Elliptical galaxies close to and perturbing spiral galaxies | 2024-03-13 12:11:14 | What a fun target! The two galaxy centers are bright and were evident from the first 30 second frame. So the two galaxies "close to each other" is obvious, but it takes a while for the "perterbation" to become obvious. The extensive dust clouds connecting these galaxies are much lower brightness and took a while to become evident. Luckily it was a clear, dark night and I was able to continue integration until I judged minimal additional detail was forthcoming, after about half an hour. Very peculiar! |
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Arp 124 / NGC 6361 | Elliptical galaxies close to and perturbing spiral galaxies | 2024-06-13 23:45:00 | NGC 6361 is a straightforward target, but the tiny galaxy on its tail, MCG +10-25-3 is magnitude 15.8 and another story altogether. And, of course, the connecting dust lanes are even more obscure. BTW, the MCG catalog was based on the Palomar Sky Survey, and contains only a few galaxies above magnitude 15. Presumably this galaxy is cataloged in MCG because of its importance to Arp. Unfortunately, the evening's transparency, never very good, took a big hit after 20 minutes of integration, with a now thickened layer of high clouds shutting me down. It was tough to distinguish any connecting lane from general noise in the SharpCap capture... I processed it heavily in Affinity Photo and just managed to bring it out (note it's not terribly evident in the Palomar capture either). |
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Arp 130 / IC 5378 | Elliptical galaxies close to and perturbing spiral galaxies | 2024-11-03 20:23:00 | Based on Arp's category description, it's clear that Arp felt IC 5738 is actually two galaxies: an elliptical galaxy (left/lower) perturbing a spiral galaxy (right/upper). It seems likely that when initially observed as an entry in the IC, the spiral component of the pair was not resolved. Even with the benefit of CMOS cameras and stacking, distinguishing an elliptical and spiral component is tough. Arp's image, benefiting from the resolution supported by a 200" aperture plus a photographic plate does support that distinction. Of course, it seems highly likely that we're observing a merger in mid-process. |
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Arp 135 / NGC 1023 | Galaxies with nearby fragments | 2024-03-13 11:09:27 | First observation of the evening starting with Astronomical Dusk. Altitude just under 40° at start. This is a relatively large and bright object that appeared almost immediately in SharpCap. I stayed on it as long as needed to clearly see the bulge at the bottom which is NGC 1023A merging into it; the enhanced version of the image makes this obvious, though increases noise. Note Arp comparison is rotate 180° to match Arp's original image. |
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Arp 141 | Material emanating from elliptical galaxies | 2024-03-24 23:22:32 | A clear night, but a full moon. I searched for Arp targets that would be as far from the moon as possible, and this was the first I came up with... The two nucleii came up almost immediately. The bulbous end next. Eventually the loop structure began to fill in. |
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Arp 145 / UGC 1840 | Material emanating from elliptical galaxies | 2024-02-29 20:00:01 | Despite an 88% moon, I was determined to capture a number of Arp galaxies in Andromeda, recognizing the window of opportunity this year was short. This was the second observation of the evening, and the target was fairly low in the west. I captured as much data as I could until I judged the thicker atmosphere and glow at the horizon would render further integration useless. SharpCap had some issue subtracting darks, so the full image exhibits what I take to be amp glow from the 294mc-pro camera. Nevertheless, while it won't win "Astrophoto of the Month", it does show Arp 145 clearly, with it's two bright centers and partially merged eliptical galaxies. |
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Arp 150 / NGC 7609 | Galaxies with jets | 2024-11-03 21:36:00 | It's unclear to me whether Arp 150 and NGC 7609 are synonymous or whether the former refers to the entire cluster. "Galaxies with jets" isn't terribly helpful, though I imagine it refers to the direct connection between galactic centers at either end of the "jet". These bright sots are also connected by the curved arc. The image suggests that NGC 7609 is in fact two galaxies, a larger one (left) absorbing the smaller one. |
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Arp 152 / Virgo A / M87 | Galaxies with jets | 2024-03-13 00:42:00 | As expected for a large Messier object, this is an extremely bright target. The toughest aspect was to set the black level appropriately to show the diffuse outer ring of this nebulous, elliptical galaxy... It's so large, I thought for a while my dark-subtraction in SharpCap was failing, and I was seeing amp glow! However, I was able to identify that the diffusion wasn't quite round, and not "quite" as large as uncontrolled amp-glow with my 294 sensor. This became obvious after about 15m of integration. The S/N ratio was so high, and since there is no structure to speak of in the outer disc, there seemed no advantage to continuing integration longer than the 25m once the two tiny galaxies, LEDA 139919 and UGC 7652, were clear. At first, I thought the dust lane connecting these small galaxies to the galactic center were the "jets" referenced in the Arp Category text. Then a friend pointed out that it's actually a tiny bump on the edge of the galactic core. You can see it if you enlarge the featured image, and an enlarged closeup is in the gallery. It is barely visible in the Arp photograph; note the Arp comparison is rotated 180° relative to the original capture, featured image, and jet enlargement. |
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Arp 155 / NGC 3656 | Galaxies disturbed by interior absorption | 2024-03-12 13:38:32 | This was the third Arp observation of the evening. Having switched to Ursa Major, mid evening the target was rising. I judged 53m of integration time was sufficient. |
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Arp 158 / NGC 537 | Galaxies disturbed by interior absorption | 2024-02-29 19:39:57 | Another of the targets in Andromeda captured on this night with 88% moon. Time was limited because it was descending towards the horizon; capture started at approximately 40° altitude. Despite moonglow and a relatively dim target, the extensions both above and below were evident in real time and enhanced in Affinity Photo working on SharpCaps "as adjusted" .png file. |