27 replies to this topic

[Charlie Hein]

If you have ever glanced at a compendium of images taken with the Hubble Space Telescope, then chances are you have seen this next challenge. You may not know it by its catalog number, IC 418, but instead may recognize it by its nickname, the Spirograph Nebula. That nickname came about because the Hubble images show an amazingly complex cloud of entangled filaments that create a strange, oval cloud that looks like it could have been drawn using a child's Spirograph toy. Remember those? You would trace intertwining arcs by rolling a color pen in a circle along the inside or outside of another circle.

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[Dave Mitsky]

IC 418 will always be the Raspberry Nebula to me.  My first view of this interesting planetary nebula was through a 25" Dob at the 1995 Winter Star Party.  IC 418's peculiar color was clearly evident.

 

Since then, I've observed IC 418 a number of times through various apertures.  Sometimes I've seen the pinkish/reddish/purplish color.  Other times I haven't.  Aperture and the quality of the observing conditions certainly seem to play a role in being able to perceive it.

[Dave Mitsky]

https://www.lcas-ast...egory=observing

[David Knisely]

Yup, it has always been "The Pink Planetary" or "The Raspberry Nebula" to me long long before some "person" took a look at the first HST image of it and gave it the name of a somewhat obscure toy.  I first saw the nebula in the mid to late 1980's in a 10 inch, and I was shocked at the time with the distinct reddish hue found along its outer edge at low to moderate power.  Clear skies to you.

[dave253]

I only discovered this nebula was visible late last summer, when it was sinking in the west.

 

Now if we can have some clear nights, I’ll search it when it’s high overhead.

 

Thanks for the article Charlie, and of course Phil.

Edited by dave253, 02 January 2023 - 11:19 PM.

[RyzenAMD]

I have a few pics of this planetary I will post.

 

This was taken using Firecapture 2.4 back in 2015, just when I was getting my feet wet in astro-imaging.

 

 

Taken with my new Evolution 6 and ASI533MC camera, post processing into mono.

Edited by RyzenAMD, 03 January 2023 - 10:54 AM.

[UnityLover]

Do any of you think I could see this through a 5 inch reflector?

[TienTran@134]

Do any of you think I could see this through a 5 inch reflector?

Absolutely you can. I have seen this nebula multiple time before with my 6 inch dob under the murky city sky (1 inch bigger than your scope but you should be able to bag it as well). It's very bright but also tiny in size so throw as much magnification as seeing condition allow. Just be careful when searching for it, it looked pretty much like a star at low magnification. 

[PhilH]

Do any of you think I could see this through a 5 inch reflector?

Only one way to find out! But as TienTran@134 also advised, use moderately high magnification to make it out from surrounding stars.

[UnityLover]

Only one way to find out! But as TienTran@134 also advised, use moderately high magnification to make it out from surrounding stars.

Would around 50 - 70x be good? or do I need 120x?

[UnityLover]

Absolutely you can. I have seen this nebula multiple time before with my 6 inch dob under the murky city sky (1 inch bigger than your scope but you should be able to bag it as well). It's very bright but also tiny in size so throw as much magnification as seeing condition allow. Just be careful when searching for it, it looked pretty much like a star at low magnification. 

Thats good, my skies are more suburban, still polluted, but my skies should make up for the 1 inch aperture. 

[TienTran@134]

Would around 50 - 70x be good? or do I need 120x?

To me, 75x with my 6 inch was enough to distinguish it from the surrounding stars; higher power can be use to make it look bigger.  These tiny PNs usually have very noticeable bluish color which stands out in the FOV. So be careful when star hopping, you may mistake the nebula for a star. And just as PhilH said earlier the only way to find out is give it a try. Good luck  !!!

[UnityLover]

To me, 75x with my 6 inch was enough to distinguish it from the surrounding stars; higher power can be use to make it look bigger.  These tiny PNs usually have very noticeable bluish color which stands out in the FOV. So be careful when star hopping, you may mistake the nebula for a star. And just as PhilH said earlier the only way to find out is give it a try. Good luck  !!!

Did you use a nebula filter? 

[TienTran@134]

Did you use a nebula filter? 

No, it was already bright enough. Although an UHC can be used to dim the stars down and makes the nebula stands out better; I haven't tried my OIII yet. But after all I preferred the unfiltered view most. 

[David Knisely]

No, it was already bright enough. Although an UHC can be used to dim the stars down and makes the nebula stands out better; I haven't tried my OIII yet. But after all I preferred the unfiltered view most. 

An OIII makes it stand out even better than a narrow-band "UHC-like" filter, but unless it has one of those broad "red leak" secondary passbands like the old Lumicon OIII once did, you won't see the reddish fringe around the edge of the disk.  Clear skies to you.

[thetechguy]

Can I see this in a short tube 120 achro refractor? 

[RyzenAMD]

Yes you can, but it wont be a large object in your field of view.

[Pete W]

This guy was quite obvious in my old Tasco 3" f/15 refractor from the suburban backyard - no filter required.   Stellar at less than 100x but definitely non-stellar at 160x and above.  Surprisingly bright, no central star.

[Alex Swartzinski]

I took a shot at this one tonight with the 15". 

 

To me, the nebula had a light blue color, but I did not see any red. With a UHC it stood out like a sore thumb, but it was pretty obvious without it too.

 

Thank you for continuing to post these challenges every month Phil! 

[JoshUrban]

Bagged this last night for the first time in a 12.5" dob.  Thanks for the article!  What a nifty little gem.

[John Huntley]

I got IC 418 tonight with my 130mm refractor. Very nice little planetary nebula and a new one for me 

 

I found 240x worked quite well on it and the central star showed up very nicely.

 

Many thanks Phil 

[alder1]

I captured this image with my eQuinox. There’s no structure visible, but it was a short exposure, and quite low in the sky. It was one of the objects on the AL’s PN list, which I completed last year. I wasn’t sure if the pink color was due to it’s being in the murk near the horizon but I guess that’s its natural hue. It’s a cool target. 

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[Jon Isaacs]

I've seen this nebula numerous times in scopes of a great variety of apertures. I decided to take a look last night from the high desert in my 16 inch.  

 

I was cranking up the magnification to see if I could see more detail. I was at 590x and to my surprise, I noticed a thin reddish-purple fringe around the outer edge.. I'd never seen it before, I wasn't looking for because of the small exit pupil but there it was..

 

Jon

[Alex Swartzinski]

I've seen this nebula numerous times in scopes of a great variety of apertures. I decided to take a look last night from the high desert in my 16 inch.  

 

I was cranking up the magnification to see if I could see more detail. I was at 590x and to my surprise, I noticed a thin reddish-purple fringe around the outer edge.. I'd never seen it before, I wasn't looking for because of the small exit pupil but there it was..

 

Jon

Wow, I would expect color to be gone at a small exit pupil. That's cool! 

[Dave Mitsky]

I was at the Naylor Observatory on Tuesday night.  After a quick look at M42 through the observatory's 17" f/15 classical Cassegrain, I located IC 418.  I observed the Raspberry Nebula or the Spirograph Nebula for HST fans at 116, 170, 216, 259, 324, and 462x.  The seeing wasn't all that great and neither was the transparency but IC 418's central star was easily visible.  However, I didn't notice any color this time around.

 

A bit later while I was talking with a fellow ASH member who was observing with a 8" f/10 Celestron NexStar 8SE SCT that he purchased recently, I mentioned IC 418 and Phil's observing challenge.  He wasn't familiar with the curious planetary nebula so he put it into view.  The central star was visible and both he and I thought we could see the slightest hint of blue in the interior of the nebula but not the odd color around the perimeter that IC 418 is known for.

 

I had hoped to observe Comet C/2022 E3 (ZTF) when it rose a bit higher but clouds covered the sky earlier than I had expected and eventually I drove home.

 

I've included an iPhone Night mode photo of the 17" f/15 classical Cassegrain and a screen capture from SkySafari.

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