Object of the Week June 26, 2016- Edward's Galaxy NGC 6621

[Jimi Lowrey]

NGC 6621 AKA Arp 81

RA
18 12 55
DEC
+68 21 48

Mag 13.6

Type SB Pec

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On the night of June 2, 1885 14 year old Edward Swift swept up 6621 with his famous father's (Lewis Swift) 16" Clark refactor. I have read that he would look for new nebula with the 16" while his father would be looking for comets with his 5 1/2" refactor. I am pretty sure Edward Swift is the youngest contributor to the NGC and IC catalog. They reported that the nebula was pretty faint,pretty small,little brighter in the middle,round,North of 2"

Edward his mother and Lewis Swift
2171

They swept up the nebula again on August 11, 1885 and thought that it was new. Lewis noted the companion 6622 this time.

2172

During the Texas star party we had a memorable view of this fantastic galaxy with my 48" reflector. Observing with me were Steve Gottlieb,Larry Mitchel and Howard Banich and a host of others. The best view that night was with a 7MM Tak UW @ 697X. The full tidal tail was visible with lots of star forming regions as brighter knots. Howard did a nice drawing of 6621/2 and I hope he will post it.

Next warm summer night you are out be sure to check out young Edward's Galaxy 6621/2 and as usual,

GIVE IT A GO AND LET US KNOW!

[lamperti]

Did see this in 2013 with a 22" U.C. at 337x with a Galaxy Contrast Enhancement filter. "Can see two globs, one is the galaxy and the other is its companion, NGC-6622. The GCE filter shows the glow surrounding them." Looking at the image posted, the glow may have been the tail.
Al

[kisspeter]

I drew NGC 6621-22 in August 2014 using a 16" Newtonian. I was pretty surprised to see the tidal tail. A friend of mine confirmed the observation (spotted the tidal tail without any information - he didn't even know what he was taking a look at).

My drawing from 2014 (16", f/4.4, 220x - 294x):
21732174

[Uwe Glahn]

Nice object Jimi and interesting story behind the discovery.

I catch the galaxy several years ago under bad seeing but good transparency. I noted roughly: main body 4:1 elongated, 4 knots along the main axle (SE knot = NGC 6622), extensions along the long axle to the NE, first view looks not as the thin arm itself but like not so difficult extensions which is divided through a dark lane directly NE of NGC 6621, more intensive views shows the arm directly with a knot at the curve at the NW end

27", 293x-419x, NELM 6m5+, Seeing V
2176

[Ivan Maly]

I like this Arp (also one of the original VVs) but did not know it was discovered by E. Swift. Here is what I have on it so far (2014, 16", SQM 21.6 - and thanks for the ultra-hi-res photo, the "possible superimposed star" was undoubtedly the massive star-forming region):

Arp 81 (NGC 6621-2, VV 247, KPG 534, 275 Mly) is seen vaguely in the finder eyepiece as a strongly elongated patch. At 330x, the view is very detailed. The companion is elongated roughly EW, pointing at the nearest star. There is an enhancement between it and the core that occasionally exhibits a sharp center, possibly a superimposed star. On the opposite side of the core is another bright enhancement that at the first glance makes the galaxies look like a triple system. The main part of the galaxy extends farther NNW and then curves sharply into an arm that runs almost as far SSE as the mentioned nearest field star. There is a broad proximal and a very thin, sharp distal enhancement in this arm.

[akarsh]

Peter, it is very inspiring that you could see the tidal tail in a 16"! I should give it a go in my 18", but probably after I get new coatings. It's unfortunate that very few tidal tails are accessible in 16"~18" scopes.

Here is an observation of the object from the Leviathan of Fort Davis (Jimi's telescope) with a 7mm Takahashi eyepiece on the same night (TSP 2016) that Jimi described in the post:

2185

a, d: very easy
g: The upper part of the tidal tail is the most evident and thick
b: Much fainter than appears in the image. Somewhat stellar. (Someone in the group told me it's probably a stellar association whose formation was triggered by collision.)
e: Spiral arm evident.
f: Easier knot
c: Harder knot
h: Knot in the tidal tail, hardest.

Ease: a ~ d > g > f > e > c > b > h. During moments of great seeing, one could see mottling of the tidal tail! Photographic!!!

We also took a look at this object in Bob Douglas' 28" at GSSP a few weeks ago -- the tidal tail was not difficult to see.

Clear Skies

Regards
Akarsh

[Howard B]

I've finally scanned my notes since last April, and here's my observation of 6621 with Jimi's 48 inch from May 5:

"Nice tidal tail - it curves around like a safety pin. Two nuclei, several knots and its highly curved shape make this a fascinating object. 690x, 21.67 SQM."

2278 2279

This is just a quick sketch - more of an impression really - of what I saw because we had 10 people observing that night. But then the 48 inch mirror was freshly washed and it was remarkable how much cleaner the images looked from the night before. It was the first time I've crawled inside a scope to clean the mirror, and what a great experience. Jimi had thought through the process so well that we had no trouble at all.

[Jimi Lowrey]

Awesome drawing Howard. The view that night of 6621 with the newly cleaned mirror is burnt into my mind. What a view!

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Thanks Howard for the help cleaning the mirror.