Object of the Week September 27th, 2020 – IC 289 (Hubble 1)

[Dragan]

IC289
Hubble 1
PK 138+2.1

Cassiopeia

Planetary Nebula

RA 03h 10m 19.7s
DEC +61 19 01

Magnitude 13.2
Central Star Mag 15.9
Size 33.0”

When Jimi and I first discussed the requirements of an object to be selected as an OOTW, it became quite apparent early-on that an object had to fit certain criteria. Some rules are subjective. Others are required. In no particular order, an OOTW had to be:

• Visible - and no, I don’t mean “only visible in Jimi’s 48”. An OOTW had to be bright enough to be ideally seen in scopes around the 15-18” range. Anything dimmer would be more appropriate in the “Off the Beaten Path” forum. Although we encourage dim, challenging objects - after all, we want to push people limits - it doesn’t need to be M31. But it also can’t be G1.
• An object should be interesting. It should provide the reader with something of some intellectual value to be gleaned in the forum.
• An object had to be “in season”. No springtime galaxies in November posts for example. An object has to be up and visible during the week it is posted.
• An OOTW should be, but again doesn’t need to be, visually interesting. Again, we didn’t want every OOTW to be a bright Messier object. We wanted this forum to be a way to share new and unique objects that readers may have never heard about. A resource that observers can come to while compiling an observing list.

I hope my object this week checks off some of these boxes.

Located in Cassiopeia, IC 289 is a faint planetary nebula first discovered by Lewis Swift in 1888. IC 289 is a very challenging object. Although visible in scopes as small as 8”, you really need a good combination of dark skies, filters and bigger aperture to appreciate this object. Either way, this OOTW is a good challenge for anybody.

IC289 is best seen with filters, namely OIII, NPB or UHC. Be on the lookout for a slightly elongated but round 30” disk with brightening near its northwestern edge. The central star and the nebula’s ring structure can be seen but you’ll need a scope greater than 20” to see them with any certainty. As I mentioned, filters help with contrast but no matter the scope, this object will benefit greatly with averted vision.

One thing I couldn’t exactly ascertain was how IC 289 earned the moniker of Hubble 1. Nowhere was I able to find a concrete connection of this object with Hubble. Steve Gottlieb’s website “Astronomy Mall” implies that the Hubble may have claimed discovery of IC289 in error. Other than this, I wasn’t able to find anything else out. Does anyone have additional information?

So next time you’re out, give this object shot. It will definitely be a challenge but I urge you to

“Give it a go!”

IC289_Jacobs.jpeg
©Jacobs

IC289_Block.jpg
©Block


IC289_HST.jpg

©HST

[wvreeven]

This planetary nebula certainly ticks of the first three boxes for me, and possibly the fourth now as well since I observed it with my 20" from poor conditions. SQM 20.5 and not a great seeing in Spain. My notes from November 11, 2015, read

"At 320x with UHC visible as a large, round, faint disk. Without UHC I suspect some nebulosity but I am not sure. There are two faint stars close by and a brighter one."

Time for a revisit though that may be hard from Chile...

[lamperti]

With a 20" in 2006 at 272x and a UHC filter: "No central star but it seems to be slightly brighter in the center. No color. Easy to see."
Worth a re-look.
Al

[Raul Leon]

Hi, here's my observation from 9/26/2008: IC 289 is a planetary nebula in Cassiopeia; magnitude: 13.2 size: 33" ; roundish, uniform in brightness, UHC filter works well on it ; no central star observed, I used a 10mm Radianat 158x with my 14.5 Starstructure dobsonian f/4.3ic 289.jpg

[Bill Weir]

First let me say why not G1? I’ve picked it out more than a few times with my 6” dob as a Mickey Mouse head.

IC 289 nice choice This is an object that when I was first teaching myself to observe almost 20 yrs ago was my toughest nut to crack. I’d earned my RASC Messier Certificate with my 6” and was then working my way though it’s Finest NGC list. I have no idea how many times I tried at IC 289 with no results. Probably dozens. I knew the location but had no success. I even once at a star party went to someone with a GOTO 12” SCT with an eyepiece and filter and asked them to punch in the object just so I could give myself an idea of what to expect. I didn’t count that as my observation for the certificate but just wanted to prove to myself the object actually existed. I’m on a road trip so can’t recall when I logged it but I believe it was late 2002 on a night of near perfect transparency. It would have been with a 22mm SW Lanthanum eyepiece and an ultra block. It was like magic. I star hopped to the correct location with low expectations. I added the filter and as soon as I looked in the eyepiece a small round soft glow appeared. It was an amazing feeling as a learning observer and knew at that moment I had taken a step forward in my quest to be a good observer. A couple of years after this I was at a dinner with Alan Dyer (co-creator of the list) and sitting at a table with him. I mentioned to him how I’d really enjoyed working though the list and had accomplished it with my 6” and how IC 289 had been my nemesis. He seemed a bit surprised I managed it with my little dob.

Since then I observed it many times and have with my 20” seen it as a ring and on a couple of occasions detected the central star. Thanks for stimulating this memory.

Bill

[Steve Gottlieb]

Like Bill, IC 289 was also a popular challenge object for me, though going back 40 years ago to 1980. I was observing with a C-8 and just starting to venture out to dark sites in California. Most of my observing was done right on my light-polluted front lawn near Berkeley, with nearby street lights, neighbor porch lights and no sign of the Milky Way (well, sometimes a hint around 2:00 AM). I believe the naked-eye limit was typically about 4.5.

Under these conditions, IC 289 was not an easy target in an 8", so I was thrilled when I was able to track it down and catch its faint glow using the new UHC filter. I logged several successful observations in relatively miserable conditions.

I've now observed IC 289 in a variety of apertures, but first noticed the outer halo in Jimi's 48". It has a low surface brightness, is pretty thin and more elongated along the minor axis, creating an overall roughly circular outline to the planetary (see Adam Block's image in Dragan's post).

Hubble announced it as a new planetary nebula in a 1921 paper titled "Twelve New Planetary Nebulae" The classification was based on the emission lines recorded on objective prism plates. His dozen objects included several known nebulae -- IC 289 (the first object in the table), NGC 2818, NGC 6072, NGC 7048, IC 1470 and IC 4670. But five more were actually new discoveries -- Hb 4, Hb 5, Hb 7, Hb, 8 and Hb 12.

[Don Pensack]

I just looked at the spectrum of this object.
The H-ß line is very weak, so the best filter for it would be a dual-line O-III, rather than a UHC, in case anyone is tempted to try to see it in a small aperture, or for identification purposes at low power.
I recorded it in my 12.5", and it wasn't as hard as some of the Abells.
"slightly faint,roundish-oval,fairly lrg for plan., near moderately bright star (m.10), diffuse outer edge, best eyepiece 6mm (304x), no filter."
Note: I don't use a filter above 130x in the scope, so an O-III filter would only be used for a positive ID.

I see a V magnitude of 13.2, and a size of 0.58', which would give this a fairly high surface brightness of 11.8.

Now I need to revisit this object to see how it looks at 400 or 500x.

[Steve Gottlieb]

In 1985, I was using an O-III filter at low power to view IC 289, but I don't believe the filter was introduced by 1980 when I made observations with a UHC. In fact, the first year I could find notes with an O-III filter was back in 1982. Anyone know if that was the first year Lumicon offered the filter?

[Uwe Glahn]

Nice OOTW Dragan. Interesting for almost every aperture.

With 27-inch I wrote: relative large PN, laminar even in the searching eyepiece, knotty oval, bad reaction to [OIII], filled with nebula, very faint ears (once thought it is a shell structure but Corradi also stated it as a halo)CS faint but steadily with averted vision

sketch: 27", 586x, Seeing III, NELM 6m5+, no filter
IC289.jpg

[Don Pensack]

Uwe,
You remarked "bad reaction to O-III (filter)"
I include the spectrum of the object, which shows a very strong O-III output.
IC289r.jpg
Were you referring to how it reacted at high power?

[oliva]

Hi,

With 14” I gave it a try and was surprised how bright this nebula really is:

“Oval, quite bright nebula, which can already be seen at 65x. At 430x an oval nebula appears, which with patient, turns into a ring, filled with nebula inside. Three knots are visible on the edge and I can hardly spot a very, very weak central star. OIII filter does not work.”

6F9EC356-D395-4093-99D6-A827C30FECEE.jpeg

I also noticed bad OIII reaction.

CS
Oliver

[Don Pensack]

Bear in mind that filters such as the O-III filters are designed to work at low powers, say, < 10x/inch of aperture.
At high powers, the contrast enhancement is pretty much gone and the dimming, even though only about 0.1 magnitude, becomes the predominant issue.
It's why I do not view planetaries at high power with a filter.

[wvreeven]

Added to what Don says: if there are bright stars or if there is glare then using a filter at high magnification may help.