mdebellis
super member
Reged: 12/22/08
Posts: 171
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Hello all, Figured I'd ask the experts in this forum a question that has been bugging me. I have a Celextron 8SE and mainly do planetary and lunar stuff, but of course I'd like to see some deep space stuff too. Tried looking at M51 the other night from a moderately light polluted area and could only make out the faint fuzzy cores. Tell me, what can you expect to see with a C8 when it comes to DSO's? Of course, I do not expect to see the detail present in astrophotos, but can you expect to see any structure at all via direct viewing? I assume very dark skies are prerequisite. I also assume a field reducer is also a must but I thought decent results may be attained at f/10 with a 40 mm EP.
Please give me some guidance on how to maximize the viewing capability of my scope for DSO's. Many thanks in advance.
Best,
Mark
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Nexstar 8SE
40mm, 25mm, 15mm, 9mm EP's
Celestron Ultima 2x barlow
Astrozap Dew Shield
Celestron Power Tank
Westchester County, NY USA
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Steven Aggas
sage
Reged: 04/15/08
Posts: 463
Loc: Arizona
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Hi Mark, I'll chime in that having used an 8"f6 for 15 years and occasionally peeking in my wife's 8"f10 as well, the wider field provided by ~f6 is nice, though not expressly required for some DSO's. Darker skies, however, are, as you've already stated, and you may find yourself on DSO observing runs to glimpse the lower surface brightness objects that are visible in an 8". I remember some really awesome DSO views and some disappointing ones too all related to having darker skies, or not.
Steven
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Mr. Wizard
Walking on a Dob: http://darkskyobserving.com/MtGraham.html
Elements in Harmony I, an 8"f6 German Equatorial - Stellafane Winner,
II a 20"f4.2 Newt-Dob - Astrofest Winner,
III a 6"f3.5 Finder/Newt-Dob, and
IV a 36"f4.5 Newt-Dob - "If it's up there, it's in here."
Apache-Sitgreaves Center for Astrophysics
www.DarkSkyObserving.com
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TenthEnemy
sage
Reged: 01/21/08
Posts: 428
Loc: Maryland
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You have enough aperture to see structure in M51 and many other galaxies as well. Many DSOs like low power which might be a problem with that scope. Galaxies are generally more affected by LP than other objects but it's still possible to observe them.
I'd recommend globular clusters and planetary nebulae for you. Both look very good at high power, FOV is irrelevant, and most show through light pollution very well. A nebula filter like a UHC can provide good views of nebulae from a bright sky, but you'll need a dark sky to really bring out details in galaxies.
Another thing that you'll need is experience, your eye isn't used to looking at galaxies. Try to see the dust lanes in M82, M64, and M104. That will help with seeing details with averted vision.
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Orion XT10
70mm refractor
12x50 binoculars
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 10488
Loc: PA, USA, Planet Earth
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You may find the aperture comparison at http://www.clarkvision.com/visastro/m51-apert/index.html helpful.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3468
Loc: Cambridge, MA, USA
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Quote:
I have a Celextron 8SE and mainly do planetary and lunar stuff, but of course I'd like to see some deep space stuff too. Tried looking at M51 the other night from a moderately light polluted area and could only make out the faint fuzzy cores. Tell me, what can you expect to see with a C8 when it comes to DSO's?
It depends on the level of light pollution. When you say that yours is "moderate," what does that mean? How easy is it to see the Milky Way on a moonless night, for instance? Is it completely invisible, just a vague swath of light, or can you see structure inside it?
Seeing only the cores implies pretty heavy light pollution to me. Anywhere where the Milky Way is visible, I would expect the disks of the two galaxies to overlap, or nearly so.
Eight inches is ample to see the spiral arms, but that requires at least modestly dark skies (yellow zone or better) and a fair amount of practice. It took me quite a while before I could decipher the arms with my 7-incher, but now they're quite apparent to me. Deep-sky observing is like planetary observing; it takes a lot of time to develop the necessary skills.
Quote:
I also assume a field reducer is also a must ...
Certainly not! In general, my best galaxy views are at exit pupils of 2 mm or less. That would mean a 20-mm eyepiece and no focal reducer in your scope -- and 15 mm might well be better. Using too little power may be part of your problem.
And remember -- anything you can see with direct vision isn't worth seeing. Scan the bigger disk with averted vision and see if you can make out darker areas in it. Those are the dark lanes between the spiral arms.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Carol L
Reged: 07/05/04
Posts: 6034
Loc: Tomahawk, WI 45N//89W
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Quote:
Tell me, what can you expect to see with a C8 when it comes to DSO's?
Hi Mark, this is the best I've ever been able to squeeze out of M51 from my rural location using a Meade 13.8 SWA ep... hope it helps give you an idea regarding what to expect. 
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 Authoring the monthly AstroSketch page in "Sky at Night" magazine
Lunar Sketch Tutorial
CN Gallery
Photo Gallery
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 10488
Loc: PA, USA, Planet Earth
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The effects of magnification on seeing detail:
http://www.clarkvision.com/visastro/m51-mag/index.html
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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rocco13
Got Milk?
Reged: 07/29/06
Posts: 2646
Loc: Phoenix, Arizona
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Carol, that sketch looks very similar to what i saw through my C8 last night in southern Arizona. The nebulosity surrounding the nuclei was maybe just a tad brighter viewing with a 22 Panoptic, but the detail level is spot on. Great sketch!
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Rocco
Zhumell Z12
Super C8 (1984 vintage)
Celestron 102 f/5
and a cheap pair of binoculars
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John Kocijanski
Carpal Tunnel
Reged: 08/22/03
Posts: 1662
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Quote:
Quote:
Tell me, what can you expect to see with a C8 when it comes to DSO's?
Hi Mark, this is the best I've ever been able to squeeze out of M51 from my rural location using a Meade 13.8 SWA ep... hope it helps give you an idea regarding what to expect.
That's about how I see M51 through my C8 on a good night. Nice sketch Carol.
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Deep Space Observer 10 * SPC-8 * C102 HD f/10 * XT 4.5 * Orion/Moonlite 80ED * PST *
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Carol L
Reged: 07/05/04
Posts: 6034
Loc: Tomahawk, WI 45N//89W
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Thanks, Rocco and John.
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Authoring the monthly AstroSketch page in "Sky at Night" magazine
Lunar Sketch Tutorial
CN Gallery
Photo Gallery
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droid
rocketman
Reged: 08/29/04
Posts: 4034
Loc: ohio
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Thats a sweet drawing Carol.Ive never seen any hint of the arms in my 8 inch ,maybe I need ot get out of town.
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102mm Celestron C102HD
Tasco 7TE5 60mm Classic
Tasco 9TE5 60mm Classic
Celestron Ultima 2000 SCT
Remains of an 8 inch dob
Celestron Comet catcher(orange tube)
1960 Edscorp Space Conquerer 6inch f/8
10x50 Bushnell Binoculars.
11T 4.5 inch Tasco reflector Lunograsso?
60mm Telescope Club
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freky1
member
Reged: 12/14/08
Posts: 55
Loc: Las Vegas NV
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m51 for me is invisable in the light polution of the city but last weekend from a site with in the blue zone i was able to see bright cores and faint spiral arms with my 8se. i csnt wait to get to a truly dark sky this summer.
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nexstar 8se
celestron 114gt
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coutleef
Carpal Tunnel
Reged: 02/21/08
Posts: 1713
Loc: Montréal and Saint-Donat, Québ...
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Quote:
m51 for me is invisable in the light polution of the city but last weekend from a site with in the blue zone i was able to see bright cores and faint spiral arms with my 8se. i csnt wait to get to a truly dark sky this summer.
Wow, i would say that a blue zone is a truly dark site. The best i can have is green and it makes quite a difference. In ablue zone, your 8SE gains several inches in aperture.
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François
Scopes: Nexstar 8 SE with Ron's rail and Denk S1 Powerswitch. EPs list is on my Bio.
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Mta472
member
Reged: 02/28/06
Posts: 94
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Nice reply Tony....I have a 12 inch Meade and live in orange zone in CT......for M51 I find best views are with an 18 mm U.O. ortho which gives me 170X and a field of view of ca 17 arc minutes
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coutleef
Carpal Tunnel
Reged: 02/21/08
Posts: 1713
Loc: Montréal and Saint-Donat, Québ...
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I would also add that from a green zone, M51 was clearly visible in my SV50 finderscope using a 9T6 (22x). I have difficulty seeing it from the city with a 8"
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François
Scopes: Nexstar 8 SE with Ron's rail and Denk S1 Powerswitch. EPs list is on my Bio.
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freky1
member
Reged: 12/14/08
Posts: 55
Loc: Las Vegas NV
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i sometimes for get how bad you eastern guys have it. not to brag but its only a 45 min drive to a blue zone and only anlther 30-40 min further to a legitemate black zone. i havent been able to get to a black zone since i entered this hobbie around 6 months ago and i ame having serious black zone cravings.
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nexstar 8se
celestron 114gt
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Dain
Carpal Tunnel
Reged: 03/24/05
Posts: 1596
Loc: N.Y. Adirondack Mnts. NGC 4565...
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Freky1,
We do have it pretty bad over here on the east coast but there are locations that are readily accessible that are within the blue/grey zone. As I previously mentioned in another thread, a grey zone for me is a 91 mile drive which isn't bad considering I live in NY state.
Clear Skies to All!
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Best,
Dain
Adirondack Mountains (my true dark sky site)
@ Cedar River Flow
Local Site
Clear Skies?
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contrailmaker
sage
Reged: 01/02/09
Posts: 251
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From a dark location 1 hour south of Phoenix I could make out spiral structure as well as the "bridge" connecting the galaxies and also a few bright knots on M51. That was with my Nexstar 8. Fairly decent view. Its about the only galaxy where I can clearly see spiral arms with an 8".
cm
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Dain
Carpal Tunnel
Reged: 03/24/05
Posts: 1596
Loc: N.Y. Adirondack Mnts. NGC 4565...
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...Again, just about at zenith tonight, I was able to detect the spiral structure of M51 with no problem in my 8" along with it's companion w/ AV.
Clear Skies to All!
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Best,
Dain
Adirondack Mountains (my true dark sky site)
@ Cedar River Flow
Local Site
Clear Skies?
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