OR: The Eyes of Texas

[Akarsh Simha]

I was at the Texas Star Party 2023 (or perhaps more appropriately the Texas Storm Party 2023) last week. I guess I have made a tradition of taking an annual pilgrimage to Jimi Lowrey's 48" telescope more-or-less around Texas Star Party, but this time was the first time in almost 7 years when I registered for TSP and therefore had access to the field.

I flew into El Paso airport and rented a car. Avis took 3.5 hours to get me a car, which they did by 11 PM on Monday, which was slated to be my first night. Thankfully it was cloudy in Fort Davis that night and I did not miss much despite arriving in the wee morning hours.

Clear nights were hard to come by at Texas Storm Party, but Tuesday night was one such night. The transparency was perhaps average at best, but the seeing was very steady. The best object of that night, also my favorite observation of the entire run, inspires the subject of this e-mail: NGC 4438 = Arp 120 = the southern member of "The Eyes" in the Markarian Chain, the one on the right in this image:

The tidal tails of NGC 4438 have been beautifully sketched by Howard Banich in his 28", see his Sky & Telescope April 2022 article on the Markarian Chain. I have picked up hints of one of the tails in my 18" from Bortle 2 conditions, and the DeepSkyForum thread on the object has a successful report of the tail through an 8” by Uwe Glahn!

Of course, in the 48", it was truly a sight. The tidal tails marked T₁ and T₂ jumped into view fairly quickly. The study of this galaxy was inspired by its presence on the Texas Star Party Advanced Observing Program of this year. Jimi noticed the tiny galaxy VCC 1040 on the photograph of NGC 4438 and wondered if anyone had seen it. Turns out that according to a 2005 study, VCC 1040 is a dwarf galaxy that had a recent encounter with NGC 4438 and is responsible for pulling out the tidal tail marked T₃ from the larger galaxy. Both T₃ and VCC 1040 were picked up without tremendous difficulty in Jimi Lowrey's 48".

As I was studying the field, I picked up the two dust lanes marked D₁ and D₂ in the below Hubble image, without knowing of their existence (indicative of great seeing):

D₁ appeared on the southern side of the galaxy's stellar nucleus, was marked and made a sharp curve towards the north. D₂ was much fainter and was picked up later while trying to observe D₁ at higher power. As for D₃, it was a low-contrast feature. I picked it up after going and looking at the image once again. We really managed to burst Arp 120 apart and see a number of its telltale features of interaction.

The forecast had called for dew, and although it did dew a bit, a breeze picked up and stopped the dew at the cost of destroying our incredible seeing. So whereas we were ready to wind down and go to bed after an hour's observing, we were lucky to get several more hours of distant photons. Of note is an attempt at a globular cluster 12 million light years away in the galaxy NGC 4449. While we were on this object, we lost our great seeing, so I had to be content with a marginal observation of a couple hints of "something there", rather than a concrete observation. In addition, we looked at NGC 4402, one of the flagship examples of a galaxy where the dust has been stripped due to ram pressure as the galaxy falls through the Virgo cluster's intra-cluster medium. This galaxy is one of the "nonet", the 9 galaxies near M 84 and M 86 in the Markarian chain that are seen readily in larger amateur telescopes, probably even visible in my binoculars. But the 48" can bring out much more: the dust lane was easily visible and was distinctly curved concave (north), a result of the ram pressure. Pretty cool to see astrophysics in (frozen) action. We also looked at NGC 4710, a barred spiral galaxy viewed edge on, with a prominent "boxy" bulge that is characteristic of barred spirals. Inspired by Howard Banich's recent S&T article on the Needle Galaxy where he picked up the boxy structure in the bulge of NGC 4565, I picked up this other galaxy where this feature is more prominent and could be detected, albeit with some difficulty, on the 48". It was nice to see the globular cluster Djorgovski 2 completely resolved! Dan Smiley and I had looked at it through Dan's 12" at GSSP last year, and I remembered the "Hercules Keystone" asterism that it nestles in, which is how we confirmed it in Jimi's scope. Paul Alsing recalls the placement of this object well too: "There's the cluster NGC 6520, and then the Inkspot Barnard 86, and then in a Hercules keystone lies Djorgovski 2", I'm paraphrasing him. So we also got to enjoy the Inkspot in a monster dob on the way there. But the real tough nut globular of the night was "PWM 2" or "Pfleiderer 2", which a 2009 study asserts is a globular cluster of our Milky Way. This heavily extincted globular was a difficult challenge in the 48", but we were also observing under sub-par conditions. (Thanks to Scott Harrington's post on CN for putting this on my radar.)

On Wednesday night, Jimi and I were joined by Steve Gottlieb. Looking at the sucker-holed skies, I drove down to the Prude Ranch to socialize and meet some people.  Amongst the people I met were Jonathan Kissner, inventor of the 3D-printed budget beginner scope called "The Hadley" and Chris Hildreth who is making a low-cost Alt-Az goto version of it. (I knew of them through a Discord server called Observational Astronomy, mostly comprised by a younger generation of astronomers although Mel Bartels made a presence too!) I enjoyed some NV views through Jonathan's DIY 16" which won the TSP ATM award for its innovative hexapod truss-pole collimation system and wire suspended secondary, and also through Chris' 8" goto which won a runner up prize. I also looked through Mark Ferraz's 25" Obsession. But these social visits came at a cost: Steve Gottlieb and Jimi Lowrey were looking at some objects, and the one I missed the most was NGC 3432, which Steve talked about on Dan Smiley's OR. Just as I returned to Jimi's observatory, the clouds came in and skunked us out for the night.

Thursday was another night that we stole from the weather devil. We started out by observing the Antennae Galaxies and the tidal tail of NGC 4038. Despite the subpar transparency, the 48" pulled out the southern tidal tail. The purpose of our pursuit of this object was the tidal dwarf galaxy at the end of the southern tail whose brightest part (comprising the HII regions described in the paper) was detected as a dim brightening in the 48" using a 17mm Ethos. One of my favorite observations from this night was a chain of 5 galaxies near the beautiful merger IC 883 that I wish to nickname the "Gottlieb Chain". All five galaxies seen in the DSS2 image below were held continuously with averted vision and were bright:

It turns out that not all members of the chain are physically related. As for IC 883, although I seemingly picked up the tidal tail seen going to the 11 o'clock in the above pic, I could not really confirm it before clouds engulfed the view.

Above photo shows Steve Gottlieb on the 14-foot ladder to the eyepiece of the monster dob that let us peer into ancient light. The Coma Berencies star cluster (Melotte 111) is seen just above the silhouette of the telescope.

We were out of luck on Friday, my last night, although there were brief sucker-holes and regions of poor transparency that someone more dogged than me could have utilized. Instead I enjoyed being on the field and seeing all our friends once again, bidding goodbyes until soon. I happened to win something at the raffle that was completely useless to me -- a master-class on Pixinsight -- which I promptly donated to an astrophotographer.

In anticipation of clear skies at GSSP,

Akarsh

[Jamie Dillon, DDK]

You are just the social butterfly, Akarsh. 

Meanwhile, we might have to start using the nickname Tidal Tail Man.

[Akarsh Simha]

On Sat, May 27, 2023 at 21:45 Jamie Dillon, DDK <ngc1...@gmail.com> wrote:

You are just the social butterfly, Akarsh. 

Meanwhile, we might have to start using the nickname Tidal Tail Man.

Jamie I do have a fascination for tidal tails!

--
TAC Astro-Classifieds: https://groups.google.com/forum/#!topic/sf-bay-tac/extFBoHlCe4
 
Observing Sites, Observing Reports, About TAC linked at top of:
 
https://groups.google.com/forum/#!forum/sf-bay-tac
 
Subscribers post to the mailing list at:
 
sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sf-bay-tac/96e5189f-124e-43cc-9ff5-6710d94d2301n%40googlegroups.com.