Mta472
member
Reged: 02/28/06
Posts: 83
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I live in a rural area of CT on a dead end street where there are no street lights, so nights get pretty dark here.
I currently have an 8 inch LX90 with UHTC.
My passion, if you will, is for galaxies, but I find that the 8 inch appears to be just too small to see much more than the faintest details in any of the galaxies.
Would a 12 inch LX90 with UHTC make much of a difference in seeing galaxy details vs the 8 inch?
How much details on a dark night could I expect to see, for example, on M31, M51, M65, M66 and/or M81 with a 12 inch?
Thanks.....Mike
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Bonco
Carpal Tunnel
Reged: 04/17/06
Posts: 1979
Loc: Florida
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In my humble opinion, scopes under 10 inch are galaxy detectors and thousands are viewable. But detail is hard to see. There are exceptions like M31 which is way more interesting in a wide field scope. My 4 inch f/5 refractor is superior to views with larger scopes because they can only see parts of it at one time while the 4 inch shows the dark lanes all the way to the edge of the galaxy and shows its companion galaxies all in one view. Viewed M33 thru a Celestron 14 and was very dissapointed, I've had better views with my 10 inch F/6 Newt as I could easly frame the entire object and get a more contrasty view of its spiral arms.
For the more numerous "concentrated" galaxies like M104, aperature will win every time. Did a side by side comparison of 104 recently with a 10 and 12 Dob. The 12 Dob won by a wide margin all tho it was a nice view in the 10. M51 is awesome in a 12, same for M81/82. As you probably know MOST galaxies visually only look like like smudges even in larger scopes.
Bonco
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novbabies
Postmaster
Reged: 06/05/05
Posts: 15678
Loc: Northern Georgia!
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I have just moved to rural E CT and also have dark skies now. I do see detail in M51 with my 12", and some other galaxies also (sorry, don't remember which ones now that I amflying around the skies again).
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Good Seeing!
Mark
Orion 12" XTi f/4.9
VERY old Edmund 6" f/8 reflector
Assorted binoculars
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Achernar
Post Laureate
Reged: 02/25/06
Posts: 3720
Loc: Alabama, USA
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There is no contest between an 8 and a 12-inch. You'll see dustlanes, a massive star cloud and globular clusters easily in M-31. The others will show spiral arms and dustlanes to varying degrees, M-81 is fairly amorphous but M-82 will show the dark lanes bisecting it with ease. Four galaxies that will show amazing detail through a 12-inch are NGC-4565, NGC-253, M-64 and NGC-3079. They look great in even a small scope, but a 12-inch begins to show a view that begins to look like black and white photographs from very dark sites.
Taras
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10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
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Bonco
Carpal Tunnel
Reged: 04/17/06
Posts: 1979
Loc: Florida
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Taras,
I have often wondered why NGC 253 doesn't get more attention. It's a galaxy show piece even in moderate sized scopes.
Bonco
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RV6
Meade 2045
6 inch f/4 RFT R. Fagin Optics
TV Genesis
2.4 inch Lafayette Equitorial
3 inch Polarex/Unitron Equitorial
10 inch Zhumell
PST 40mm Solar scope
4 inch F/15 Antares
2.4 inch Unitron Equitorial
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novbabies
Postmaster
Reged: 06/05/05
Posts: 15678
Loc: Northern Georgia!
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Quote:
Taras,
I have often wondered why NGC 253 doesn't get more attention. It's a galaxy show piece even in moderate sized scopes.
Bonco
Yippee - culmination here at (3:43 AM 8-20-06 - 2hrs/month x 3 months) 9:43PM on 11-20-06 at 23 degrees altitude!!! And the southern horizon is clear! Prior to now, I've seen it only twice, both time very low on the SE horizon from LP skies...
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Good Seeing!
Mark
Orion 12" XTi f/4.9
VERY old Edmund 6" f/8 reflector
Assorted binoculars
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Lucifigus
super member
Reged: 05/10/03
Posts: 235
Loc: Halifax, Nova Scotia
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Bigger will always get you more, but it's always a trick to find your personal sweet spot for size, cost, cool down time and potability etc.
A 12" scope will dig about a magnitude deeper than an 8". This is a substantial increase in detection and detail. You have to move to 20 inches to get another magnitude.
Under dark skies (LVM >6.0), bright galaxies begin to show real detail as opposed to just shape. M51 & M33 have real and distinct spiral structure; dust lanes, shape and extension are easy in edge on galaxies like NGC 4565, NGC 3628 (the "third" in the Leo triplet). Keep in mind that your experience and patience in the EP also plays a great part in what you can discern. I have seen situations where an experienced person can see the same detail in an 8" that a less experienced person would see in a 12".
Nevertheless, it's often said (and I believe true for most people) that going to a 10" from an 8" will show noticeable improvement, but moving from an 8" to a 12" will provide enough of a change to experience an emotional "WOW" factor"
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Gary Weber
12.5" f/6 & 8" f/8 dobs - EQ Platform
102mm f/6 refractor - EQ Mount
Edited by Lucifigus (08/20/06 09:50 AM)
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novbabies
Postmaster
Reged: 06/05/05
Posts: 15678
Loc: Northern Georgia!
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Quote:
M51 & M33 have real and distinct spiral structure; dust lanes, shape and extension are easy in edge on galaxies like NGC 6545...
No offense, but did you mean NGC 4565?
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Good Seeing!
Mark
Orion 12" XTi f/4.9
VERY old Edmund 6" f/8 reflector
Assorted binoculars
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Lucifigus
super member
Reged: 05/10/03
Posts: 235
Loc: Halifax, Nova Scotia
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Quote:
No offense, but did you mean NGC 4565?
Yes, thanks. I have made the appropriate change to the post.
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Gary Weber
12.5" f/6 & 8" f/8 dobs - EQ Platform
102mm f/6 refractor - EQ Mount
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Stephonon
Carpal Tunnel
Reged: 07/28/05
Posts: 1873
Loc: Melbourne, Australia
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Don't expect too much in going from 8 to 12 inches. Yes there is a difference, and you will clearly see more in the 12 inch, but it won't be a night and day diff. Things like spiral arms or dust lanes, if seen at all, are usually there in either scope, just little easier to see in the 12". (I do own both 8" and 12" scopes.)
Those galaxies you mention should show quite a bit of detail in an 8" scope. Either you need to spend more time getting accustomed to seeing subtle detail and/or your skies are not as dark as you think. Try going for a drive somewhere more remote. Check out the light pollution charts on this]http://www.inquinamentoluminoso.it/dmsp/index.html]this site[/url] for some ideas.
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Steve H --- Dobs: Saxon/SW 10" f/4.7, GSO 8" f/6, custom truss 8" f/4 | Intes MK-65 (6" Mak) + EQ | binos: Pentax PCF 8x40, AOE 10x50MX Ultra, AOE 12x60.
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Tony Flanders
Carpal Tunnel
Reged: 05/18/06
Posts: 2096
Loc: Cambridge, MA, USA
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Quote:
Don't expect too much in going from 8 to 12 inches. Yes there is a difference, and you will clearly see more in the 12 inch, but it won't be a night and day diff. Things like spiral arms or dust lanes, if seen at all, are usually there in either scope, just little easier to see in the 12". (I do own both 8" and 12" scopes.)
I sort of agree and sort of disagree. I own a 7" and a 12.5" -- granted, a slightly bigger difference than 8" vs. 12" -- and I would say the difference between them is pretty big. For instance, I've tracked down 15 emission areas in M33 using the 12.5" scope, but I can see only a half dozen with the 7". The spiral arms of M51 pop out with the 12.5", whereas they require a bit of skill with the 7". And so on.
Having said that, the difference still isn't as big as the difference between a novice and a skilled galaxy observer, or the difference between genuinely dark skies and good suburban skies.
I'm not sure where the original poster lives. Nowhere in Connecticut is really dark, but the far northwest corner isn't half bad, and there are some darkish enclaves near the Rhode Island border.
In an area that's yellow on the Light Pollution Atlas, an 8" scope should show the spiral arms of M51 and M33 and the dust lanes of M31 with a little persistence.
- Tony Flanders
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Tony Flanders
eyeglasses
6x15 and 8x32 monoculars
8x25, 7x35, 10x30 IS, 10x50, and 15x70 binoculars
70mm and 100mm achromatic refractors
4.5", 7", and 12.5" Dobs
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NewAstronomer
Carpal Tunnel
Reged: 09/03/04
Posts: 2690
Loc: Scranton, PA U.S.A
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This is roughly (and I mean roughly) what I see in a 10" of M51 in my dark site (which is best guesstimate mag 5.5 or slightly better). A 12" should show you more structure and backround stars (which I skipped a few), and I drew this quickly as I was packing it in after a night of glob hunting AND my cell phone rang, blinding me when I opened it, just before I drew it (note to self, don't do that again).
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Chris
AT66ED f/6
C80ED f/7.5
10" GSO Dob f/5
SVP w/ autoguide mod
Oly E-500 DSLR, DSI-P, DSI-C, NexImage
Edited by NewAstronomer (08/21/06 05:58 PM)
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NewAstronomer
Carpal Tunnel
Reged: 09/03/04
Posts: 2690
Loc: Scranton, PA U.S.A
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Quote:
I live in a rural area of CT on a dead end street where there are no street lights, so nights get pretty dark here.
I currently have an 8 inch LX90 with UHTC.
My passion, if you will, is for galaxies, but I find that the 8 inch appears to be just too small to see much more than the faintest details in any of the galaxies.
Would a 12 inch LX90 with UHTC make much of a difference in seeing galaxy details vs the 8 inch?
How much details on a dark night could I expect to see, for example, on M31, M51, M65, M66 and/or M81 with a 12 inch?
Thanks.....Mike
Now that I re-read your question. My question is this, if you really want galaxy detail, you want the biggest scope you can afford. Have you thought about a 16" or 18" Truss Dob ? In addition, you say your skies are dark, what s the faintest naked eye star you can see directly above? Did you travel to a darker site with your current scope? That is like a 2-4" jump in scope size.
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Chris
AT66ED f/6
C80ED f/7.5
10" GSO Dob f/5
SVP w/ autoguide mod
Oly E-500 DSLR, DSI-P, DSI-C, NexImage
Edited by NewAstronomer (08/21/06 06:03 PM)
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Silicon Owl
scholastic sledgehammer
Reged: 11/25/05
Posts: 943
Loc: Waimea, Hawaii
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I was always somewhat dissapointed by the 8" when it came to galaxies. No problem with good dark skies around Tucson, I just didn't see much galaxy detail. Thus the 18" was built...
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Andrew Cooper
Personal Website and CN Gallery
Handmade 18" Dob / NS11GPS / 6" RFT / 90mm APO / TV-76 ...and a twin 10m
"I have loved the stars too fondly to be fearful of the night." --Sarah Williams
Edited by Silicon Owl (08/21/06 10:58 PM)
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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You really should consider spending ~$120 and getting a Sky Quality Meter. That takes much of the guesswork out of evealuating your site.
To get back to the original question, yes a 12" will show more detail than a 8" IF it is of equivalent optical quality and basic design. I have both an 8" APO refractor and a 12.5" Dob, and in this case the difference is not real extreme, but it is still very noticable: more like comparing a 10" Dob to a 12" Dob. The 8" APO definitely outperforms a 9.25" SCT (Celestron)and a 10" SCT (Meade), but the overall brightness of the 12.5" Discovery Dob is ahead of the refractor (as it should be). My former Meade SN-10 also did better on DSOs w/r brightness, but not in image sharpness or contrast.
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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RRaubach
AstroCowboy
Reged: 01/26/05
Posts: 2173
Loc: Douglas (Converse County),WY
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Great sketch! I'm envious! 
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Rodger
Meade SN-10 (UHTC) on Tak EM-200 mount/Antares rotating rings. Moonlite focuser.
Parallax 14.5" Newtonian on HD 200 mount (arriving soon!) w/ conical Royce mirror.
TMB 203 f/7 APO refractor on Tak NJP-160 mount.
Discovery 12.5" PDHQ
Schneider 18x80 "Flakfernrohr" binoculars/tripod mounted. Canon 15x50 IS binoculars
Unihedron Sky Quality Meter
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Dain
professor emeritus
Reged: 03/24/05
Posts: 590
Loc: Upstate New York
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Quote:
My passion, if you will, is for galaxies, but I find that the 8 inch appears to be just too small to see much more than the faintest details in any of the galaxies.
We all know getting to the dark skies is a requirement for seeing fine details in objects ( along with dark adaption,collimation,etc). It's a given. I believe the most important thing is getting those eyes trained to know what to look for. Perhaps you've seen an object before in a nice 18"+ dob. You've seen the fine detail those babies can pull in. Well if you've took some time to observe the objects(s) and have carefully studied the details, your chances of seeing those details in an 8" dob are pretty good because you know what to look for. It may not be as bright of an image hence aperture difference but it's there with a good trained eye and dark skies. I've pulled in quite a bit of detail on some of the brighter galaxies in a few of my 8" dobs. I'm extremely persistent in trying to make it happen and if it takes me all night to do so,even on one object, then so it be. It's the challenge I love in doing it and using my gear for everything it has.
regards,
Dain
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Regards,
Your CN Friend-
Dain
You can't reach for the stars.....if you can't see them. Fight Light Pollution.
Adirondack Public Observatory
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6778
Loc: Beatrice, Nebraska
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Here is what M51 looks like to me in a good 10 or 12 inch at between 178x and 220x. The details are not visible with direct vision, but with averted vision, most of what is shown here is at least detectable. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
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Bonco
Carpal Tunnel
Reged: 04/17/06
Posts: 1979
Loc: Florida
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David..That is an excellent rendition of a visual view in a 10-12 inch scope of M51 observed in a dark sky. I like how you showed the foreground stars too. Perfecto...Thanks for posting it.
Bonco
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RV6
Meade 2045
6 inch f/4 RFT R. Fagin Optics
TV Genesis
2.4 inch Lafayette Equitorial
3 inch Polarex/Unitron Equitorial
10 inch Zhumell
PST 40mm Solar scope
4 inch F/15 Antares
2.4 inch Unitron Equitorial
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kfred
Carpal Tunnel
Reged: 11/11/03
Posts: 2001
Loc: Dayton, Ohio
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David - Is that a picture or sketch?
Fred
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River Cam - Cambridge England
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