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100 Brightest Planetary Nebulae (Spreadsheet)

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#1 rhymeswithorange

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Posted 18 March 2011 - 12:23 AM

They appear in the attached excel spreadsheet and are ordered according to:

1. Visual Magnitude (Brightest to Least Bright)
2. Stellar Magnitude (Brightest to Least Bright)
3. Angular Size in arcseconds (Smallest to Biggest)
4. Constellation (Alphabetical)

Along with their NGC and IC catalogue designations, the common names of the planetary nebula are also included (NOTE: Common names surrounded by ‘?’ question marks ‘?’ are names that I made up based on their appearance in photos and sketches). I also included an EXTRA section at the bottom of the spreadsheet which contains five planetaries that were not included in the major list (The Red Rectangle, Campbell's Hydrogen Star, Abell 12, Abell 50 and Abell 81)

This spreadsheet narrows down the easiest planetary nebulae that can be seen from an urban/suburban location. Where I live, light pollution tends to destroy my overall DSO viewing experience: Diffuse nebulae (aside from M42 and the major four in Sagittarius) are often invisible in the sky-glow. As are galaxies; the best looking like faint grey/white circular or pencil shaped smudges.
Planetary nebulae on the otherhand are bright, concentrated areas of light that are able to pierce through that urban/suburban skyglow. They also have color (green and blue being the easiest to see) and gaseous detail you can see when you view them through your telescope! And as an extra challenge they also have little jewels in their middles: central stars. For these reasons, planetary nebulae are the kings of the urban/suburban observing experience to me.

TIPS for you the Beginners:

-->Don't be scared of high visual magnitudes like 9,10,11,12 or even 13. Planetary nebula have relatively high surface brightnesses, unlike galaxies and diffuse nebulae, so they are easier to see (even with bad light pollution). For example, I have never been able to see the galaxy M51 (mag 8.4) or m78, the diffuse reflection nebula in Orion (mag 8.3), yet I have no problem seeing M76, the Little Dumbell (mag 11).

-->Get a GOOD OIII filter (ie. Lumicon), it is essential. Planetary nebulae will jump out at you with this little guy since they emit light strongly in the OIII wavelength. Surrounding stars will dim while the planetary nebulae will stick out like a sore thumb (see for yourself with NGC 2438 in the M46 cluster).

-->Don't be afraid to crank up the magnification to what you would usually call ludicrous (ie. 300x-600x). Planetaries are bright and can take the magnification abuse. Look for the central star and wisps of gas around it.

-->Sketch what you see. Viewing a Planetary Nebula is one thing, but actually sketching it allows you to appreciate its detail fully (ie. picking out minute details that you would have otherwise missed) and gives you the full feeling of 'bagging another one'. Sketching your observing sessions will also help you to catalogue everything you've viewed over time.

-->If you haven't gone planetary nebulae hunting yet, you've gotta start now!

To the experienced observers: If you know of any other bright planetary nebulae that were missed please share. Thanks

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#2 mak7

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Posted 18 March 2011 - 12:43 AM

What a great list, thanks for your time and effort.

I'll be using it to revisit lots of old friends, and probably make a few new ones as well.

Brad

#3 David Knisely

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Posted 18 March 2011 - 01:38 AM

It is an interesting listing. There is a little uncertainty on the exact visual magnitude of planetary nebulae, so ranking them accurately by apparent brightenss is difficult. However, a lot of those magnitude figures vary from what is commonly published for visual magnitudes (maybe photographic magnitudes?). According to Doug Snyder's Planetary nebula site's database (somewhat more accurate than just using the photographic magnitudes), the Helix's visual magnitude is around 7.1 and the Dumbell about 7.6 or so. NGC 7009 is listed at magnitude 7.8 (consistent with other figures I have seen for it) which would put it 4th brightest ahead of both the Cat's Eye (NGC 6543, visual mag. 8.2) and NGC 3918 (visual magnitude 8.2). Indeed, the "Eight Burst" nebula (NGC 3132) is listed by Snyder's database at a much fainter magnitude 9.7, which would move it down the list quite a bit. NGC 246 is much fainter than the spreadsheet's magnitude, as is verified by how difficult it is to actually see in the telescope. That object (the "Skull" nebula) is probably closer to magnitude 10.4 visually.

The "top 10" brightest planetary nebulae (visual magnitude) according to Snyder would be:

1. NGC 7293 (Helix Neb., mag. 7.1)
2. NGC 3242 ("Ghost of Jupiter", mag. 7.3)
3. M27 (Dumbell Neb., mag. 7.6)
4. NGC 7009 (Saturn Neb., mag. 7.8)
5. NGC 6572 (Blue Raquetball, mag. 8.0)
6. Tie: NGC 6543 (Cat's Eye, mag. 8.2) and NGC 3918 (Blue Planetary, mag. 8.2)
7. NGC 7662 (Blue Snowball, mag. 8.3)
8. NGC 7027 ("magic carpet"??, mag. 8.5)
9. NGC 6210 ("turtle"?, mag. 8.8)
10. NGC 6826 (Blinking Planetary, mag. 8.9)

However, again this ranking would depend on how accurate a figure can be given for the visual magnitude, which is uncertain at best. Below is a link to Doug Snyder's fine Planetary Nebula site:

Planetary Nebulae Observer's Home Page

Clear skies to you.

#4 Astrojensen

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Posted 18 March 2011 - 03:22 AM

Hi

Very nice list. Thanks for your hard work.

I am especially pleased to see your remark about using very high powers on the small, high-surface brightness planetaries. I have used this technique myself and it works really well. Interestingly, it seems to depend more on the actual surface brightness than the visual magnitude! Even a relatively faint planetary such as IC 2149 in Auriga could take 850x on my 4" f/15 Antares with great results. Tracking is a must!

I saw many objects on the list that I've observed in the past with my 63mm Zeiss Telemator, so I know from experience that most, if not all, objects on the list could be observed with that class telescope and certainly with an 80mm by a careful and skilled observer. A dark sky would probably be needed for some of them, however. The Fetus Nebula, NGC 7008, is pretty **** faint in the Telemator, even from my dark sky sites. IC 289 is also right on the limit. That was before I got a O-III filter, though! How they look through the filter I don't know, as I haven't observed them through it yet.

So, to anyone reading this: Go out and observe these interesting targets on this interesting list. There are many treats awaiting you, however small your telescope may be.


Clear skies!
Thomas, Denmark

#5 nytecam

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Posted 18 March 2011 - 03:50 AM

Many thanks for the excellent list :bow: is there any way to reformat it - it exceeds my screen size and appear jumbled :question:

#6 C_Moon

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Posted 18 March 2011 - 10:04 AM

Thanks for the list, I will be sure to put it to use.

How does a Narrowband Filter (e.g., Orion Ultrablock or Lumicon UHC) perform on these compared to the OIII? Also, does the filter still help at high powers?

Thanks

#7 tatarjj

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Posted 18 March 2011 - 10:28 AM

As a footnote:

I don't think that the brightest planetary nebula in the sky is not even on this list.

The brightest planetary nebula would likely be Sh2-216, which is the second closest or closest planetary nebula to earth (last I heard, astronomers hadn't figured out whether Sh2-216 or Hewett 1 was the closest PN to earth).

At 1.6 degrees across, Sh2-216 only needs an average surface brightness of 16.8 magnitudes per square arcminute (~25.7 magnitudes per square arc second) to beat out the Helix nebula. I believe Sh2-216 is probably above that threshold. I've seen Sh2-216 from a green zone without a filter (it has odd emission characteristics), meaning that it's not a very faint object. But even if it WASN'T above the 16.8 magnitudes per arcminute square threshold required to make it the brightest planetary nebula in the sky, then it cannot place any lower than seventh on that list David Knisely posted, because the faintest possible surface brightness that it is possible to perceive is about 18 magnitudes per square arc minute, and if it was that faint, then it would still have a total integrated magnitude of 8.3.

For those interested:
http://www.astronomy...pace/sh2216.htm


There's also the possibility that Hewett 1 is the brightest planetary nebula in the sky. It might belong on this list somewhere. Despite a few positive observing reports, there was still some debate last I checked as to whether Hewett 1 is visually observable at all. It is certainly not visually observable for most people.

BUT- For planetary nebulae that are bright AND easily observable, all these are good lists. It's just that technically, using the integrated brigthness method, these lists are not correct, and they miss at least one object that is in the top ten, and most likely, #1.



#8 rhymeswithorange

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Posted 18 March 2011 - 12:21 PM

David Knisely - my list was based off of the figures presented here:
http://www.atlasofth...m/plannebs.html

I agree that some of the magnitudes may be off a little bit, but in general they work pretty well. Most of the top 30 are easily observable from my location with the exception of NGC 246 (Skull Nebula), NGC 1360 (Robins Egg Nebula) and NGC 4361 (Raven's Eye Nebula) which are all very faint from my suburban location. This isn't really surprising since they rank among the largest nebula in terms of angular size (thus having more of their light spread out, decreasing their apparent surface brightness). I should also mention that the nebulosity surrounding the central star of NGC 40 (Bow Tie Nebula) and NGC 1514 (Crystal Ball Nebula) is also quite hard to see from my location.
Your list is pretty consistent in terms of what I would rank as the top 10, however I may have thrown in M57 (Ring Nebula), NGC 2392 (Eskimo Nebula) and NGC 1535 (Cleopatra's Eye Nebula) there as well (maybe even IC 418 [Spirograph Nebula] for the Blinking Planetary :p ).

C_Moon - In my personal experience I have found that the OIII filter is the more useful of the two (OIII vs UHC) for all DSOs. I have found this is especially true for planetary nebulae. Keep in mind that I am using a 12" dobsonian and that I am viewing from a suburban, light-polluted area. To answer your other question: I do find the OIII filter useful at high magnifications for most planetary nebulae.

tatarjj - Thanks for the info. I had never even heard of Sh2-216 or Hewett 1 until now. However, upon looking online I have found that Sh2-216 is at the very limit of visual seeing, even under dark skies and with large aperture. Hewett 1 is even harder apparently. My goal with this list was to help people with modest aperture and who are observing from a suburban/urban light polluted area, narrow down the best planetary nebulae for their viewing sessions.

#9 rhymeswithorange

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Posted 18 March 2011 - 12:56 PM

nytecam - I attached an excel spreadsheet to this reply that organizes the lists vertically rather then horizontally. Hope that helps.

Attached Files



#10 uniondrone

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Posted 18 March 2011 - 02:22 PM

Nice list! I will have to look through it to see if there are any that I need to check out.

One criticism, however: I find that the surface brightness is a much more useful metric for planetary nebulae than visual magnitude. There are many PNs that are bright by visual magnitude, but are exceptionally hard to see. On the other hand, there are quite many that are dim in terms of magnitude, but are very bright and easy due to the high surface brightness. From the magnitude and area, it should be fairly strightforward to determine surface brightness, which is how I would rank the PNs.

By the way, a tool like the DSO Browser is incredibly useful in helping to make observing lists.

#11 rhymeswithorange

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Posted 18 March 2011 - 02:53 PM

uniondrone - I agree that surface brightness should, in theory, be a good indicator, however, have you looked at the top objects for surface brightness in that 'DSO Browser'? Pretty much all of them are Abell planetaries which are notoriously hard to see, especially in a light-polluted area. The Saturn Nebula doesn't even appear until page 21/30 and is ranked ~400th out of 600 in terms of surface brightness (that doesn't seem right :p)

#12 uniondrone

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Posted 18 March 2011 - 04:34 PM

uniondrone - I agree that surface brightness should, in theory, be a good indicator, however, have you looked at the top objects for surface brightness in that 'DSO Browser'? Pretty much all of them are Abell planetaries which are notoriously hard to see, especially in a light-polluted area. The Saturn Nebula doesn't even appear until page 21/30 and is ranked ~400th out of 600 in terms of surface brightness (that doesn't seem right :p)


Try putting a lower size limit of 10" into the DSO browser and you'll see things change drastically. :p

Also, you can limit searches to the IC and NGC catalogs on the browser pretty easily too.

My point was not that the DSO Browser is the answer to all observing lists. My point was that surface brightness is more useful than magnitude and that the DSO broswer can be helpful.

#13 Carol L

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Posted 18 March 2011 - 06:14 PM

Thanks!! :bow: :grin:

#14 thordraco

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Posted 18 March 2011 - 08:17 PM

Sweet! Thank you for sharing.
:)

#15 rhymeswithorange

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Posted 18 March 2011 - 11:24 PM

uniondrone - The DSO Browser is actually an awesome resource however in terms of surface brightness, the numbers still appear to be incorrect (even after I set the apparent size lower limit to 10 arcseconds). For example, NGC 6572 (Blue Racquetball Nebula) has the lowest surface brightness on the list at 45.11,

http://i.imgur.com/HjVvF.png

while Abell 7 has the highest at 190.21.

http://i.imgur.com/7XKRw.png

Again if I'm doing something wrong correct me. If I'm not, what other source of data do you use that gives accurate surface brightness measurements? Thanks again for your help uniondrone.

#16 David Knisely

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Posted 19 March 2011 - 02:38 AM

uniondrone - The DSO Browser is actually an awesome resource however in terms of surface brightness, the numbers still appear to be incorrect (even after I set the apparent size lower limit to 10 arcseconds). For example, NGC 6572 (Blue Racquetball Nebula) has the lowest surface brightness on the list at 45.11,

http://i.imgur.com/HjVvF.png

while Abell 7 has the highest at 190.21.

http://i.imgur.com/7XKRw.png

Again if I'm doing something wrong correct me. If I'm not, what other source of data do you use that gives accurate surface brightness measurements? Thanks again for your help uniondrone.


Again, Doug Snyder's database seems to be a fairly decent and useful source of information, as it also provides the surface brightness of many planetaries (in magnitudes per square arc minute). NGC 6572 comes in with a surface brightness of a whopping 4.90 mag/square-arcminute, which is a pretty high level. While the Helix may be big and possibly the brightest, it is way down in surface brightness at about 13.22 mag/square arcmin. Tiny IC 4997 (diameter of two arcseconds) has a very high 3.41 magnitudes per square arc minute, so many of the tiny nearly stellar ones will lead the pack here. NGC 6543 sits at 5.76 mag/s.a.m, NGC 6210 is 5.94 mag/s.a.m., NGC 7009 is at 6.14 mag/s.a.m., the "Ghost of Jupiter", NGC 3242 has a 6.72 mag/s.q.m. surface brightness, while NGC 7662 has a 6.79 mag/s.a.m. surface brightness figure. M57 sits at 9.24 mag/s.a.m. M27 comes in back of the pack at a measly 11.25 mag/s.a.m. so while it is easy to see, it doesn't have all that high of a surface brightness. Clear skies to you.

#17 Starman1

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Posted 19 March 2011 - 09:51 AM

Both total integrated magnitude AND surface brightness have to be taken into account.
NGC7293 is very bright, but its large size makes it harder to see than M57, which has a lower integrated magnitude but a much higher surface brightness.
I've found that, regardless of calculation of SB, the brightest planetaries are all listed in the Saguaro Astronomy Club's database that you can download for free.
Since it's an Excel spreadsheet, it's sortable any way you choose. And most objects have both TIM and SB figures listed.

#18 Arizona-Ken

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Posted 19 March 2011 - 05:53 PM

Thank you for making this available!

Arizona Ken

#19 rhymeswithorange

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Posted 19 March 2011 - 10:02 PM

David Knisely - Can you directly link me to Doug Snyder's Database/list?

Starman1 - Can you directly link me to Saguaro Astronomy Club's database/list?

Thanks again for the contribution guys

#20 Starman1

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Posted 20 March 2011 - 12:34 AM

David Knisely - Can you directly link me to Doug Snyder's Database/list?

Starman1 - Can you directly link me to Saguaro Astronomy Club's database/list?

Thanks again for the contribution guys

SAC downloads
Doug Snyder's site

#21 David Knisely

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Posted 20 March 2011 - 01:11 AM

Thanks for the list, I will be sure to put it to use.

How does a Narrowband Filter (e.g., Orion Ultrablock or Lumicon UHC) perform on these compared to the OIII? Also, does the filter still help at high powers?

Thanks


The OIII tends to be the filter most used for planetary nebulae, as the two Oxygen III lines tend to be somewhat stronger than the other lines. The OIII tends to be best for locating small planetaries using the "blinking" technique, where the filter dims all the stars but not the planetary. The narrow-band filters can help as well, especially under darker skies where fainter contributions from the H-Beta line tend to be more visible. For example, my favorite filter for M27 is the narrow-band DGM Optics NPB. It shows the faint outer "wings" off the side of the dumbell better than the OIII does. However, under moon light or in town, I often will go with the OIII filter for M27. Another couple of odd-ball planetaries are NGC 40 and Campbell's Hydrogen star, both of which respond to the H-Beta filter. For NGC 40 however, I still like a narrow-band nebula filter rather than the OIII, although the OIII does help a little on that object. With Campbell's Hydrogen star, I like not using a filter, as the object has a nice reddish hue in moderate to large apertures. However, with some planetaries that have brighter central stars, an OIII filter can be helpful in toning down the brightness of the stars and making the inner nebulosity easier to see at high power. Some planetaries that have fairly high surface brightness are still helped by the OIII filter when viewed at high power, while other more diffuse planetaries may not be (M76 is one example). You just have to play around with the filters on the planetaries and see which filters work at which magnifications. Clear skies to you.

Attached Thumbnails

  • 4461132-PlanetaryHuntingwithOIIIsmall.jpg


#22 Astrojensen

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Posted 20 March 2011 - 03:29 AM

I like that illustration! I only recently (relatively) got an O-III filter, but the difference on some planetaries is remarkable. NGC 1514 in Taurus comes to mind.


Clear skies!
Thomas, Denmark

#23 Starman1

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Posted 20 March 2011 - 10:02 AM

You can be scientific about which filter to use for each nebula.
Here is a link to a site with spectra for a lot of planetary nebulae:
http://web.williams....al=-1&search=Go
If you look at the spectra, you will see emission of high intensities at:
486nm--Hydrogen Beta
496nm--Oxygen III
501nm--Oxygen III
686nm--Hydrogen Alpha
Unfortunately, our eye is very insensitive to the light of H-alpha (686nm) at night, so it is the other 3 lines to which you should pay attention.

Now if the nebula has a very strong emission at 686nm (Ha), then it also will have a decent amount of emission at 486nm (Hb). If the nebula also shows strong emission at the O-III lines, then the UHC filter will probably show the nebula off to its best.

But if the Ha transmission is low, then the Hb transmission will be very low. In that case, if the O-III lines show prominently, the O-III filter will show the nebula to its best.

And, if the O-III transmissions are very weak and the nebula displays most of its emission power at Ha and Hb, then an H-Beta filter will show off the nebula to its best (though a UHC will still show the nebula well, the contrast would be slightly heightened by the H-Beta filter).

So you can be aware, in advance, which filter will work best on the nebula in question.

And you can also (I recommend it) look for David Knisely's list of filter comparisons for more "hands-on" recommendations.

#24 uniondrone

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Posted 21 March 2011 - 02:47 PM

uniondrone - The DSO Browser is actually an awesome resource however in terms of surface brightness, the numbers still appear to be incorrect (even after I set the apparent size lower limit to 10 arcseconds). For example, NGC 6572 (Blue Racquetball Nebula) has the lowest surface brightness on the list at 45.11,

http://i.imgur.com/HjVvF.png

while Abell 7 has the highest at 190.21.

http://i.imgur.com/7XKRw.png

Again if I'm doing something wrong correct me. If I'm not, what other source of data do you use that gives accurate surface brightness measurements? Thanks again for your help uniondrone.


To answer your questions:

1) although I am not sure what method or units are used for calculating the surface brightness values reported in the DSO Browser, a low number equals high surface brightness and a high number equals low surface brightness. So the Owl nebula (146) is dimmer than the Little Dumbell (107), both of which are dimmer than the Ring Nebula (87). By this measure, the blue raquetball (45) is one of the brightest PNs in the sky, whereas Abell 7 (190) would be extremely dim.

2) According to the author of the DSO Browser, the source of most of the data is the Saguaro Astronomy Club, Database version 8.1 spreadsheet. Although this source is generally considered reputable, the possibility of mistakes does exist. If you find one, you might want to report it to someone at Saguaro or to the guy who maintains the DSO browser for a correction.

Ultimately, when considering a PN for adding to my observing list, I always ask myself: a) is it big enough that it doesn't just look like a star, i.e. size >10", and b) is it bright enough to stand out against the skyglow at my observing site, i.e. surface brightness similar or better than others that I have been able to observe from that particular site.

Again, thanks for the Planetary Nebula list! :jump:

#25 tatarjj

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Posted 21 March 2011 - 04:00 PM

Nice list! I will have to look through it to see if there are any that I need to check out.

One criticism, however: I find that the surface brightness is a much more useful metric for planetary nebulae than visual magnitude. There are many PNs that are bright by visual magnitude, but are exceptionally hard to see. On the other hand, there are quite many that are dim in terms of magnitude, but are very bright and easy due to the high surface brightness. From the magnitude and area, it should be fairly strightforward to determine surface brightness, which is how I would rank the PNs.

By the way, a tool like the DSO Browser is incredibly useful in helping to make observing lists.


Yup, both surface brightness and total integrated magnitude has to be taken into account, otherwise, you get really absurd results such as Sh2-216 and Hewett 1 being in this list of objects intended to be a list of showpieces, near or at the top.:grin: Really, a scoring system that gives a score to an object based off of some product of its surface brightness and total integrated magnitude is the best.

tatarjj - Thanks for the info. I had never even heard of Sh2-216 or Hewett 1 until now. However, upon looking online I have found that Sh2-216 is at the very limit of visual seeing, even under dark skies and with large aperture. Hewett 1 is even harder apparently. My goal with this list was to help people with modest aperture and who are observing from a suburban/urban light polluted area, narrow down the best planetary nebulae for their viewing sessions.


Negative on the large aperture part. I've seen Sh2-216 with nothing more than a 4" refractor, from a West Texas mountaintop. I don't think it's beyond the realm of possibility for some really eagle-eyed observer to detect it naked eye from such a location (I sure can't)... I could probably spot it with binoculars. I've also seen Sh2-216 from a green zone with a 18" scope, and I bet a 8" scope in a green zone could see it too, if the observer had good eyesight and new exactly what to look for. So it's not a large aperture object, and not a particularly dark-sky object either. Would I class it as an easy object though? No, it's probably about the same difficulty as Banard's Loop.

The only positive/probable/possible report of Hewett 1 that I know of was with a 4" refractor from the TSP. Assuming that those probable observations were in fact true detections of the object, I think that you really need a site that is as close to "dark as space" as possible, and ridiculously good night vision that the majority of folks never even had as kids.


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