Object of the Week, February 16, 2014 – Howell-Crisp 1 - a recently discovered PN

[Steve Gottlieb]

Howell-Crisp 1 (HoCr 1)

RA: 06 21 41.0
Dec: +23 35 13

Type: PN candidate (likely)
Size: 50"
Mag: ~15V

Michael Howell "discovered" HoCr 1 in early 2006 as a possible planetary nebula on an image he made of the region surrounding IC 443 and IC 444. Howell's web page has a number of images of this object. At the same time Richard Crisp, a California amateur, also provided an image. This object is clearly visible on the DSS, though it had not been analyzed, except for an earlier IRAS detection (IRAS 06185+2336). You'll find it 11' SSW of 7.4-magnitude HD 44251 and 37' ENE of the reflection nebula IC 444.

HoCr 1_wikisky.jpg

Dr. George Jacoby, Director of the WIYN Observatory 3.5 meter Telescope at Kitt Peak, Tucson, AZ provided a high-resolution image and it was announced as a possible planetary nebula.

HoCr 1.jpg

Finally, it was included in the 2010 paper "Searching for Faint Planetary Nebulae Using the Digital Sky Survey" in Publications of the Astronomical Society of Australia as a probable or confirmed planetary.

I first viewed this object back in November 2006, along with Mark Wagner and Ray Cash. I'm sure this was among the very first visual sightings. Ray first took a stab at it with his 13-inch using a UHC filter and it was marginal in partially cloudy conditions. I later took a look in my 18" Starmaster when the sky was clear and it was definitely visible, though only seen part of the time at 115x using a DGM Optics NPB filter. It appeared as an extremely low surface brightness hazy spot, perhaps 30" in diameter. A trio of faint stars 1' west pinpointed the location. Mark felt the object had an irregularly round shape with an occasional sharp edge on its SW perimeter.

A couple of weeks ago, I picked up HoCr 1 unfiltered as 200x in my 24-inch f/3.7 Starstructure, though it required knowing the exact location. Adding a NPB filter, it was visible continuously, though very faint, roundish, 30" diameter, low surface brightness. A mag 15 star is at the NE edge.

HoCr 1_widefield.jpg

I'm guessing a 10" to 12" is the minimum aperture to pick up this new planetary, but who knows unless you take a look.

"GIVE IT A GO AND LET US KNOW"

[Uwe Glahn]

Hey Steve,

OOTW starts as quick as your First Light on new discovered objects

When my notes are right Michael Howell und Richard Crisp discovered the new PN on 4 November 2006. Afters this Matthias Kronberger gave me the information on 7 November 2006 so that Friedl L. and I could use the first possible weather window on 16 November 2006 with our 16" telescopes. We both could see a very faint round disk with 129x/225x + [OIII] with 1' diameter. Edges were sharp defined with no other details. Under a good NELM 6,8mag sky we could not hold the glow steadily but it pops each for several seconds.

16", 225x, [OIII], NELM 6,8mag

[Steve Gottlieb]

I just checked my calendar and my observation was made on Saturday night, November 18, 2006 --- so you guys beat me by two days!!

[Howard B]

I was a real laggard, you guys beat me by nearly two months! My observation is from January 12, 2007 with my 28 inch:

"By golly, there it is! Easy to locate and almost as easy to see, this relatively small nebula shows best at 167x and the UHC filter. It comes across as a faint, round fuzzy with no further detail. It's in a nice star field about 3 degrees from M35. The OIII shows it about half as well as the UHC, and Howell-Crisp is invisible with the h-beta filter and no filter."

No SQM reading but limiting magnitude was estimated at 6.3, which is below average for my usual observing location.

HowellCrispNebula_crop.jpg HowellCrispNebula_crop_invert.jpg

[reiner]

I had observed this PN a few weeks after Uwe had posted his observation in a German astronomy forum.

With my 22" at 300x the PN was very faint, but well visible with UHC filter. The disk was about 1' diameter and uniform without internal structure, yet with well defined edges. With OIII filter, the visibility decreased somewhat, and without filter it was no longer visible.

[RolandosCY]

Megastar charts prepared, waiting for the moon to get out of the sky....

[Steve Gottlieb]

Megastar charts prepared, waiting for the moon to get out of the sky....

Let us know how it goes. An 18" scope should do the trick, but I highly recommend using either a narrow bandpass filter such as a Lumicon UHC filter or a DGM Optics NPB filter.