Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 975
Loc: Florida
|
|
I truly figured that deep sky observing was a no-go for those of us living in a Bortle scale "white zone." I've been excited by my finding that this definitely isn't the case! Despite having skies where I sometimes struggle to see Alberio and using only 77mm aperture, I've been able to enjoy some great views of deep sky targets. Here are my latest sketches and some notes. I hope that these encourage other city-dwellers to get outside and see what can be seen.
M57 was my first deep sky target after successfully viewing and sketching M30 through a pale grey-white sky glow earlier this month. I knew M57 shone brightly and would resist light pollution quite well. I was still surprised with the view - using moderate power (139x) and swapping between a UHC and OIII filter, I was able to see considerable detail in the famed Ring Nebula. I was most excited to clearly observe that the "ring" is not uniform in brightness and appears to have a couple of breaks in it.
On another night, I enjoyed sweeping-up Collinder 399, "The Coathanger". The asterism was very apparent and resists light pollution quite well. One of the stars in the "hook" of the hanger appeared distinctly golden-orange to me.
The same evening that I viewed Cr 399, I also visited the nearby planetary nebula, M27. In spite of the background sky having a grey-blue cast with lower power (28x), the object clearly shone through. Using higher power and narrowband filters (UHC and OIII), I was able to clearly discern the "dumbbell" or "hour glass" shape to the brighter nebulosity, which was against a larger, dimmer, bulb of faint glowing gas. The southern lobe of the dumbbell structure seemed a bit brighter to me. These details were apparent without the filters, too. The filters merely enhanced the contrast.
By observing with a small scope from under bright sky glow, I've learned that it's possible to have great views of many deep sky objects from even severe light pollution. Experience in observing seems to be the greatest asset - more important than even a dark sky. I mention this as I remember not having views nearly as rewarding when I first began observing from a site with fairly dark skies. It takes time to train yourself in how to observe. Another great help to city deep sky observing is to have good star charts. Even if using a computerized scope, having charts to tell you precisely where to look for an object will be of immense help. Higher power is another plus for urban astronomy. When I pump my power up to 139x, I notice that the background sky glow diminishes and dimmer background stars begin to shimmer through noticeably. A final help, to me, is patience. Instead of hurrying through the objects I've observed this past week I've spent considerable time studying them through the eyepiece. On M57 and M27, I spent 1 to 2 hours on each object and it paid off. For instance, the break in M57's ring didn't appear to me until after I observed the object for at least half-an-hour.
Does anyone else have tips for the deep sky observer who chooses to observe from beneath city skies?
- Jay
South Florida
--------------------
Refractor manic. 
My Sketches
|
star drop
Guilty as Charged
Reged: 02/02/08
Posts: 16198
Loc: Snow Plop, WNY
|
|
Quote:
Does anyone else have tips for the deep sky observer who chooses to observe from beneath city skies?
- Jay
South Florida
Go big in aperture if you can. I went from 3" to 4.25" to 13.1" and finally to 25".
--------------------
Ted
|
JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 975
Loc: Florida
|
|
Aperture definitely is a boost for deep sky observing. I own some larger scopes, but they're presently in storage with some relatives since I don't have much space in my apartment.
One challenge for me is that I do not have a secure location to set-up equipment. Since I can only observe from public or community-owned locations, I am wary to leave anything unattended. This means that I need to be able to haul my telescope, accessories, charts, and observing stool in one trip and walk with it all 200 to 500 feet depending on what sprinkler systems are running!
- Jay
South Florida
--------------------
Refractor manic.
My Sketches
|
Dain
Carpal Tunnel
Reged: 03/24/05
Posts: 1596
Loc: N.Y. Adirondack Mnts. NGC 4565...
|
|
Jay,
Good eye my friend! Noticing you also use an 18MM SWA, that is one of my favorite eyepieces in my case and is used quite often. I think there are alot of small things one could do to bring out some details in objects beneath the city lights:
-Try to catch your target objects straight overhead. This is always the darkest part of the sky.
-Select the right objects to observe. Magnitude is not everything. A bright galaxy may be invisible, whereas a dim planetary may be easily seen. Small, high surface brightness and stellar objects are easier to observe than large, diffuse objects.
-Pay close attention to the weather. Cool, dry nights are best at any location, but are more pronounced in the city.
-Observe after 10:00PM. This gives the dust and water in the air a chance to settle. Dust and water reflect light which can turn a good night into a bad one.
-Observe after 11:00PM. Many stores have closed by this time, and because they turn off their lights, a city's light glow is reduced considerably.
-Observe after 1:00AM. After the stores have closed, most shoppers and workers have gone home which means that there is a lot less traffic on the streets and freeways, and light pollution is reduced.
-Learn to read the quality of the sky by the observing of stars with the naked eye. A clear night might seem perfect for observing, but may in fact be bad for viewing if the seeing is not good.
-Observe after a rain storm. The skies appear darker as light is no longer reflected off of dust particles in the air.
-Observe after a cold front has come through. The air is more stable and the air pollution has been blown out.
-Use a dark cloth to cover your head and eyepiece to shield them from stray light.
-Use a dew shield on your telescope to shade it from stray light.
-Clean and collimate all optics. Dirty optics scatter light. Light pollution and O-III filters are good for planetary and emission nebulae.
-Use a pirate's eyepatch to keep out stray light.
-A right-angle finder with amici prism under a dark cloth
is helpful for finding objects.
-Setting circles are a great aid for finding difficult objects, especially when those objects are quite some distance from a naked eye star.
-A good star atlas, a pair of binoculars, and a one power finder (e.g. Telrad) with a template for that finder, are inportant for finding objects in bright, non-contrasty skies. Telrad-hopping can sometimes be easier and just as useful as star-hopping with a finder. Viewing the sky through your Telrad with binoculars is also a nice trick.
--------------------
Best,
Dain
Adirondack Mountains (my true dark sky site)
@ Cedar River Flow
Local Site
Clear Skies?
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Quote:
-Try to catch your target objects straight overhead. This is always the darkest part of the sky.
-Select the right objects to observe. Magnitude is not everything. A bright galaxy may be invisible, whereas a dim planetary may be easily seen. Small, high surface brightness and stellar objects are easier to observe than large, diffuse objects.
-Pay close attention to the weather. Cool, dry nights are best at any location, but are more pronounced in the city.
-Observe after 10:00PM. This gives the dust and water in the air a chance to settle. Dust and water reflect light which can turn a good night into a bad one.
-Observe after 11:00PM. Many stores have closed by this time, and because they turn off their lights, a city's light glow is reduced considerably.
-Observe after 1:00AM. After the stores have closed, most shoppers and workers have gone home which means that there is a lot less traffic on the streets and freeways, and light pollution is reduced.
-Learn to read the quality of the sky by the observing of stars with the naked eye. A clear night might seem perfect for observing, but may in fact be bad for viewing if the seeing is not good.
-Observe after a rain storm. The skies appear darker as light is no longer reflected off of dust particles in the air.
-Observe after a cold front has come through. The air is more stable and the air pollution has been blown out.
-Use a dark cloth to cover your head and eyepiece to shield them from stray light.
-Use a dew shield on your telescope to shade it from stray light.
-Clean and collimate all optics. Dirty optics scatter light. Light pollution and O-III filters are good for planetary and emission nebulae.
-Use a pirate's eyepatch to keep out stray light.
-A right-angle finder with amici prism under a dark cloth
is helpful for finding objects.
-Setting circles are a great aid for finding difficult objects, especially when those objects are quite some distance from a naked eye star.
-A good star atlas, a pair of binoculars, and a one power finder (e.g. Telrad) with a template for that finder, are inportant for finding objects in bright, non-contrasty skies. Telrad-hopping can sometimes be easier and just as useful as star-hopping with a finder. Viewing the sky through your Telrad with binoculars is also a nice trick.
I could not agree more. He stole my thunder, but probably better said. For example I can see Planetary nebulas, Open clusters and Globular clusters from a white zone in town but Galaxies are a horse of another color. Tonight I can see NGC 404 (Mirach's Ghost)on the zenith but NGC 253, a bright galixy I have seen in binoculars from a darker sky, could not be seen in my 10" dob at an altitude of 30 deg. Go figure, galaxies do not make any since to me, they are so sentivie to light pullution.
Any way good luck and keep looking. Buddy
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
|
Ptarmigan
Carpal Tunnel
Reged: 09/23/04
Posts: 2351
Loc: Arctic
|
|
Good observing session. A fellow CN'er, YankeeJeff, saw M74 in Brooklyn. M74 is the most difficult Messier object.  
--------------------
Ptarmigans=Cute and Cuddly
Meade Starfinder 8
Nikon 10x50
Rebel XT
Edited by Ptarmigan (10/19/09 11:54 PM)
|
Ptarmigan
Carpal Tunnel
Reged: 09/23/04
Posts: 2351
Loc: Arctic
|
|
I could never see NGC 404 in a light polluted sky. I did once see M79 in Lepus, which is closer the to the horizon, which is more light polluted than at the zenith. M79 is one of the more fainter globular clusters.
--------------------
Ptarmigans=Cute and Cuddly
Meade Starfinder 8
Nikon 10x50
Rebel XT
|
JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 975
Loc: Florida
|
|
Dain - those are excellent tips. I recalled the late night observing one, though have yet to stay out much past midnight. I have noticed, though, that observing around 8 or 9PM renders the sky an odd twilight color here while later it appears much darker. I'm unsure if it's an effect of actual twilight, light pollution, or a combo. The zenith viewing is a good pointer to keep in mind, too. I was last observing the Vulpecula region as it sunk lower into the west, right in the midst of some nasty sky glow. This reminds me that in one way I'm fortunate. I live close enough to the Atlantic ocean that my entire eastern sky is just about as dark as the zenith.
The old Meade 18mm SWA series 4K is a great eyepiece, I agree. It's long become my single most-used eyepiece.
Blb - How severe is the light pollution you contend with? I'm interested, as I'd like to try to nab some galaxies (especially during the spring), as folly that may seem given my light polluted skies and a mere 77mm aperture! Many thanks for the well-wishes.
Ptarmigans - seeing M74 from Brooklyn gives me hope! Thanks for reporting that.
- Jay
South Florida
--------------------
Refractor manic.
My Sketches
|
starbux
sage
Reged: 02/08/06
Posts: 289
Loc: Silicon Valley, CA
|
|
Quote:
....
Does anyone else have tips for the deep sky observer who chooses to observe from beneath city skies?
- Jay
South Florida
If you don't already own a copy, Rod Mollise's book The Urban Astronomer's Guide is a must-have. The only book dedicated to observing deep sky objects from city skies.
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Quote:
Blb - How severe is the light pollution you contend with? I'm interested, as I'd like to try to nab some galaxies (especially during the spring), as folly that may seem given my light polluted skies and a mere 77mm aperture! Many thanks for the well-wishes.
If you go to the light pollution map, I am just in the edge of the white zone, thats about as bad as it gets. On a good night, maybe once a month, I can see stars to 4th mag with the naked eye, with the usual being about 3rd mag. I live only a mile from the downtown central business district and a quarter mile from a shopping center, restaurants, used and new car lots, plus 4 street lights on the two block long street I live on. So you can see for me to see anything I have had to learn all the tricks. Galaxies are realy tough for me, with only the brightest Messier objects usualy visible and then nothing below about 40 deg above the horizon. The late night and near the zenuth or as it crosses your meridian are the best tips though, along with the dark cloth over your head and a lot of time learning to see because your eyes never realy get dark adapted. 
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
Edited by blb (10/20/09 01:34 PM)
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Oh Yes! NGC404 was a really good catch for me. Its rare that I can see any thing that faint but it was within 10 degrees of the zenith when I saw it, That wonderful dark spot overhead. My northeastern to southwestern skies are hopeless though as evidenced by my being unable to see NGC253 with my 10" dob, this is a binocular object for me from darker skies. But later last night I too was able to see M79 with the same telescope, It was only a small gray blob that was brighter in the center but I could not resolve any stars. Go figure. Hey don't get me wrong, there is a big differance in being able to barely see something and being able to observe it. I saw NGC404 as a small dim blob, no detail.
Anyway clear skies, Buddy
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
Edited by blb (10/20/09 01:22 PM)
|
Tim L
professor emeritus
Reged: 12/17/08
Posts: 556
Loc: Austin, TX
|
|
Jay,
Great report and wonderful sketches!
You're actually working against two prejudices that crop up here every so often: First, that you can't see DSO's under light pollution; and second, that you can't see DSO's with smaller aperture.
We all know that more aperture will help, and we all know that darker skies will help, but that doesn't mean DSO hunting CAN'T be done without these. I hope your experience inspires many others to see just how much they can observe, even with other limiting factors.
And Dain--That is a great comprehensive list! Well done!
--------------------
Tim
Zhumell Z10 dob
Meade 60mm refractor
Zhumell 1.25" eyepiece and filter kit
Zhumell sky-glow, UHC, and OIII filters
|
JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 975
Loc: Florida
|
|
Many thanks for the compliment, Tim. I find that sketching objects forces me to slow-down and really study what I'm looking at. Since I started sketching a decade ago, I dare say that I now see more detail in objects with a 77mm scope from the city than I did with a 200mm scope from the rural suburbs! Experience plays a role, but the slowed pace of observing must as well.
I definitely hope to add additional observing notes here in the CN forums to encourage other urban astronomers who might also need to sacrifice aperture for portability.
Starbux - Rod Mollise's The Urban Astronomer's Guide is definitely on my list of future purchases! Thank you for the recommendation.
Blb - Your skies and mine are quite similar, then. I live within a couple miles of my city's two downtowns (weirdly there are two!) and the city airport. The more I read-up on light pollution versus deep sky objects, the more I'm finding that galaxy cores tend to remain intact assuming that they're not diffuse. This opens up most of the Messier galaxies and many of the brighter NGC's... I wonder how many of them I could nab with 77mm aperture? 
Thanks once more for the comments and suggestions on urban observing techniques!
- Jay
South Florida
--------------------
Refractor manic.
My Sketches
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Hi Jay, I wish I could remember where I found the story about "Refractor Red" but I can't. Anyway J. R. Freeman living in Palo Alto, Ca. wrote a wright up about using a 55mm f/8 Vixen refractor to find and observe the Astronomical League's Herschel 400. This was done from his front yard with ocasional trips to darker skies.
Steve O'Meara wrote his "Herschel 400 Observing Guide" using only a 4 inch refractor from pristeen skies. So you tell me what we can see from our sites. I say lets keep trying and never give up the effort. I look forward to more of your sketches from our light polluted skies. Keep challenging us to see more!
Clear skies, Buddy
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
|
JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 975
Loc: Florida
|
|
Hi Blb. I didn't know of Freeman's "Refractor Red," but a quick Google search led to Freeman's "Refractor Red" in pdf form.. I can't believe that Freeman was able to observe the Herschel 400 mostly from his suburban skies with only a 55mm apo. I particularly like this quote: "Much small equipment lies unused because its owners think it takes a six-inch aperture even to see the Messier objects. It isn't so. It never was."
Thanks for mentioning this write-up; it's given me tremendous hope considering that while my skies are a notch worse than what Freeman encountered, I am working with a scope that's a full 22mm larger! (How's that for big aperture?)
I'll keep updating as the autumn progresses and as I get clearer skies. Gauging from the present forecasts, though, it looks like I won't have much for sky clarity until sometime next week.
- Jay
South Florida
--------------------
Refractor manic.
My Sketches
|
coutleef
Carpal Tunnel
Reged: 02/21/08
Posts: 1706
Loc: Montréal and Saint-Donat, Québ...
|
|
Quote:
-Observe after a rain storm. The skies appear darker as light is no longer reflected off of dust particles in the air.
-Observe after a cold front has come through. The air is more stable and the air pollution has been blown out.
I was unaware of these two tips. Great , thanks a lot, i'll use them.
In fact, i have been observing for two years with a 8" scope from the city (white zone) and a dark site in the mountains (green zone). The galaxies are superb from the green site, but there is plenty to look at for years in terms of open clusters, planetary nebula, double stars. With UHC or OIII filters you can catch some emission nebulas that still look interesting despite the heavy LP.
Observing with a 8" from the city will keep me busy for years.
Most importantly, it is challenging to star hop from the city, but it gets so easier from a dark site. Great way to learn the sky and it makes hunting after faint DSOs easier once you trained from the city.
--------------------
François
Scopes: Nexstar 8 SE with Ron's rail and Denk S1 Powerswitch. EPs list is on my Bio.
|
Carl Kolchak
professor emeritus
Reged: 08/02/06
Posts: 546
Loc: Northeast, Florida
|
|
Hi all
Great post, Jay!
I observe from my driveway on the Southside of Jacksonville. I have the city lights to my west, a large shopping mall to the south, and the north has downtown Jacksonville, fortunately the east is not to bad with the beaches. I primarily use my 80mm or 102mm refractor to view DSOs.
@Dain - Thanks for the tips, very nice.
If you would like to read more about Refractor Red, this site, TAC, has a search function that will pull up quite a few adventures with Refractor Red.
peace & clear skies,
--------------------
Richard H.
Antares 105mm f/9.5 Elite Series Refractor
AstroTelescopes 102mm f/7 Refractor
Orion ShortTube 90mm f/5.6 Refractor
Meade Model 300 80mm f/15 Refractor
Tasco Cosmic 6TE-5 50mm f/12 Refractor
Orion SkyView Pro 8" Intelliscope
Orion Scenix 10x50 Binoculars
Zhumell SuperGiant 20x80 binoculars
NightSky Journal
Edited by Carl Kolchak (10/21/09 01:47 PM)
|
Jack Tripper
sage
Reged: 05/10/09
Posts: 339
Loc: Canada
|
|
In my case, the only galaxies I have been able to spot from my severely light polluted backyard are M31, M32, M81/M82. That was with my 8" SCT. Observing from an Orange Zone revealed at least a dozen more galaxies to me. My best estimate is that you would need a 14" scope from a white zone to equal an 8" scope from a Orange Zone. It's unfortunate for me. It seems that galaxies are most affected by severe light pollution.
--------------------
Celestron CPC 1100 
Denkmeier S2 Power Filter Switch Diagonal (.66x Reducer, 2x Barlow)
Ethos 17mm, Baader Scopos 30mm
Lunt 60mm Hydrogen-Alpha Solar Scope, Lunt Zoom
|
Tim L
professor emeritus
Reged: 12/17/08
Posts: 556
Loc: Austin, TX
|
|
Hey Jack,
If you can get M81/82, there's several more in the springtime bunch I would think you could also see. Most of the Messier edge-on galaxies are probably potentials for you.
I wish I could comment about Autumn/winter galaxies, but I haven't had my scope long enough!
--------------------
Tim
Zhumell Z10 dob
Meade 60mm refractor
Zhumell 1.25" eyepiece and filter kit
Zhumell sky-glow, UHC, and OIII filters
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Hi Richard,
Thanks for the link to "Refractor Red". I really enjoyed reading them and it motivates me to using mine more often. If only the clouds will cooperate.
Clear skies, Buddy
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
|
|
4 registered and 3 anonymous users are browsing this forum.
Moderator: Olivier Biot
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 632
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 
