Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

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

Equipment Discussions >> Reflectors

Pages: 1 | 2 | (show all)
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Obsession 15" in the red zone?
      #5664552 - 02/06/13 01:14 AM

OK, I am slowly developing a case of aperture fever. I've gone from 80mm to 127mm to 250mm in the past few years, and the craving to go up to 380mm+ is rising.

The issue is that in practice, I very rarely get out to my club's dark sky site (over an hour away), and I get to at most 1 - 2 star parties per year. So the question comes down to whether it's worth using the greater aperture at home, where 95%+ of my observing takes place. This means from the deck of my condo on the second story, under skies of about mag 4.5 that, in clear weather in summer/fall, show the Milky Way above 45 degrees. The 10" Dob sees a lot of use on that deck. Local lights are full-cutoff and glare is usually not a problem; local hills block the skyglow near the horizon. Views are good to the northwest, southwest, and overhead, and blocked to the east, which still lets me see something like 40% of the available sky.

I'd like to push to the next level, looking at structures of galaxies, detecting faint (but reasonably-high-surface-brightness) galaxies, breaking open compact globulars, looking at more detail in the Veil, locating more planetaries, etc. I have looked through several 15" and 16" scopes (plus some even larger that are absolutely NOT under consideration) at star parties and informal get-togethers, but always under relatively dark skies ("dark suburban" in some cases -- 15" and 16" scopes produced pretty amazing views of M81 under those conditions).

So, is it really worth the significant investment for a 15 - 16" quality Dobsonian that will live most of its life under Mag 4.5 skies, with very occasional trips to darker sites? Cooldown is probably not a major problem here in northern California, as the temperatures shifts are more moderate than in many other areas. An hour out on the deck with the fan running generally makes the 10" Zhumell happy.

Anything bigger than 16" is not under consideration. Too big, mirror box too heavy, ladder required, etc, etc. A 15 - 16" scope would likely be my lifetime aperture upper limit.

So is it worth it? Rationally, it feels as though it makes sense for me to wait a few years until I own a home with a yard, probably under darker skies, but I would almost certainly have left California by that time and have worse weather conditions!

I'm probably dreaming here, not because I can't afford the premium scope (I can, though getting spousal agreement may be fun ), but because it looks like it just doesn't fit my current lifestyle.

Opinions welcome...

Cathy

Edited by RocketScientist (02/06/13 11:22 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
deepskydarrell
member


Reged: 03/09/08

Loc: Abbotsford, BC Canada
Re: Obsession 15" in the red zone? new [Re: RocketScientist]
      #5664576 - 02/06/13 01:59 AM

I've found the bigger my scope, the farther and darker I want to take it. Farther as in deep sky objects and farther in distance driven. Darker as in fainter objects and darker in sky quality. I no longer observe from my red zone backyard. That's just how my interest has developed for me. I've always liked chasing fainter things.

DSD.


Post Extras: Print Post   Remind Me!   Notify Moderator  
nicknacknock
professor emeritus
*****

Reged: 02/20/12

Loc: In a galaxy far far away...
Re: Obsession 15" in the red zone? new [Re: deepskydarrell]
      #5664652 - 02/06/13 04:38 AM

I am getting my first Dob soon, but even with my refractors I will drive about an hour to observe as well. Last year was pretty good, averaging 3-5 trips a month to a dark site! Driving to a dark site is worth it as it offers so much more. Your eyes, your eyepieces and your telescope will work so much better under dark skies...

An hour's drive is practically next door! Just make sure that whatever telescope you buy is relatively friendly relative to your car's size. Obsession has the 15" ultralight which fits the bill at the aperture you want, but also in terms of ease of setup and total weight of the scope.

That is unless there is a specific reason you are against travelling to a dark site frequently...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Thomas Karpf
Carpal Tunnel


Reged: 02/09/09

Loc: Newington, CT
Re: Obsession 15" in the red zone? new [Re: nicknacknock]
      #5664677 - 02/06/13 06:03 AM

Keep the dob. Get the big scope.

Use the 'little' scope from home when time is tight or the weather is iffy.
Use the big scope from home for planets, clusters, and bright extended object.

Take BOTH scopes to a dark site whenever possible. Why both? That gives you OPTIONS if, after having driven several hours to get there you just don't have the energy to set up the BIG scope (or the weather is really iffy), but the little one sets up in just two minutes. Plus maybe there's someone else there with you?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Bob S.
Carpal Tunnel
*****

Reged: 07/14/05

Re: Obsession 15" in the red zone? new [Re: Thomas Karpf]
      #5664688 - 02/06/13 06:20 AM

+1 for what Tom said. 10" scopes frequently tend to beat the seeing on poorer nights. I have 10", 12.5" and 20" Newts and they all serve different purposes on different nights.

Edited by Bob S. (02/06/13 06:22 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Obsession 15" in the red zone? new [Re: RocketScientist]
      #5664849 - 02/06/13 09:21 AM

I use all three of my telescopes from my red zone driveway, and even there the 15-inch does a lot more than the smaller telescopes. That said, I built mine for the same reason you are considering acquiring a 15-inch, hunting galaxies and nebulae from darker sites. However, surprising numbers of DSO's are easily visible though from my house through all three telescopes, despite a streetlight right across the street. I was shocked at how many galaxies I was able to see at home. I have decided like you that a 16-inch class Dob is the largest telescope I'll ever want due to cost, weight and bulk considerations. Avoiding the need for a ladder also entered into the equation. Yes, I would say it's worthwhile even if you can go to dark sites only on ocassion. Most people do not have the time and opportunity to do that as often as they like. A 15-inch with good optics will also be a very good planetary telescope as well. I had my best views of Mars, Jupiter and Saturn yet with the 15-inch I built.

Taras

Edited by Achernar (02/06/13 09:22 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
aatt
sage


Reged: 07/26/12

Loc: CT
Re: Obsession 15" in the red zone? new [Re: Achernar]
      #5665195 - 02/06/13 12:51 PM

I have a 15" and I live in an orange to red zone transition area. I am so glad I got this scope! Everything is more detailed, I am seeing huge numbers of galaxies all over Ursa major, Leo and Virgo. The moon, open clusters, Jupiter and globs are just wonderful and bright.I have yet to get it to a dark site and I can't wait to do so. I say if you can afford it, get the 15". You will probably be veery glad you did.

Post Extras: Print Post   Remind Me!   Notify Moderator  
pdfermat
scholastic sledgehammer
*****

Reged: 11/12/07

Loc: Wisconsin
Re: Obsession 15" in the red zone? new [Re: RocketScientist]
      #5665443 - 02/06/13 02:52 PM

I'd say consider this: have you attempted and (for the most part succeeded) to observe those objects through your 10" at your home site? Have you found that enjoyable? If you answered yes to both, then I think the 15" to 16" jump might be ideal for you.

Something like an Obsession 15" is quite portable (IMHO), and fairly easy to set up. That means you most likely wouldn't feel its too much trouble to set up and observe with it from your home site on a regular basis, and it would be transport friendly for those rare dark sky trips.

In a red zone, things will definitely be brighter in the 15" vs. a 10", and (depending upon the object) show a bit more detail (but this is the tough one - especially for galaxies).

I live on a red/orange border zone, and here's what I can see with my 12" in response to some of your specific targets:

Quote:

...looking at structures of galaxies...




A little bit, with select targets and a lot of practice.

Quote:

...detecting faint (but reasonably-high-surface-brightness) galaxies...




Most definitely.

Quote:

...breaking own compact globulars...




Fairly often, again - depending upon the target.

Quote:

...looking at more detail in the Veil...




Yes - with a UHC filter.

Quote:

...locating more planetaries...




Yes, and not only that, but pumping up the magnification and seeing some structure every now and again.

Clear skies!!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Obsession 15" in the red zone? new [Re: pdfermat]
      #5665740 - 02/06/13 05:54 PM

I, too, would say *yes*- go for it! The additional light-grasp equates to seeing deeper, sure, but it'll equate to MORE than that:
1) likely better, brighter, & more detailed planetary+Lunar
2) increased resolution of globulars
3) increased grasp of detail in nebulae

.. from where EVER the scope is used!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Markovich
professor emeritus
*****

Reged: 05/22/07

Loc: Central Ohio
Re: Obsession 15" in the red zone? new [Re: Mike B]
      #5665890 - 02/06/13 07:28 PM

I have a 15" Obsession in the red-orange zone, just south of Columbus, Ohio. Due to family duties, I do most of my observing from my backyard. The 15" always does better than my C8, and smaller scopes. I stick with higher surface brighten DSO's like globulars, compact open clusters, some galaxies and of course the planets. It's never a waste of my time to set it up and observe.
All things being equal, aperture always rules!


Post Extras: Print Post   Remind Me!   Notify Moderator  
John K
Carpal Tunnel


Reged: 12/26/05

Loc: Vernon BC Canada
Re: Obsession 15" in the red zone? new [Re: Markovich]
      #5666230 - 02/06/13 11:17 PM Attachment (28 downloads)

When you get to a dark sight bright Messier objects start to really show there stuff with the 15". I use it for DSO sketching all the time.
Here is an example of what I have observed in my 15 at a dark sky location.
Mag 6.5+


Post Extras: Print Post   Remind Me!   Notify Moderator  
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Re: Obsession 15" in the red zone? new [Re: deepskydarrell]
      #5666238 - 02/06/13 11:29 PM

Quote:

I've found the bigger my scope, the farther and darker I want to take it. Farther as in deep sky objects and farther in distance driven. Darker as in fainter objects and darker in sky quality. I no longer observe from my red zone backyard.




Quote:

Driving to a dark site is worth it as it offers so much more. Your eyes, your eyepieces and your telescope will work so much better under dark skies...An hour's drive is practically next door!




I understand everyone is different, but the two posters above must be living a different lifestyle from my own. I work at a full time job, spend an hour working out 2 - 3 evenings per week at the gym, volunteer at several different activities, and do a lot of hiking, camping, etc. with my husband. This doesn't leave a whole lot of time for observing, and my typical observing session is no more than one hour per night (but I observe on many nights). If I'm not in bed by 11 PM, I have trouble getting up for work the next day.

I recently bought an ETX-80 to have a scope that can easily go on a camping trip that is not primarily an astronomy trip, and it's worked out very well for a low-effort look at dark skies. But that's not what I'm discussing here. I simply don't have the time and energy to drive an hour plus each way, set up, collimate, spend 2+ hours observing, and return, except at very rare intervals.

Edited by RocketScientist (02/06/13 11:56 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Re: Obsession 15" in the red zone? new [Re: Thomas Karpf]
      #5666240 - 02/06/13 11:31 PM

Quote:

Keep the dob. Get the big scope.

Use the 'little' scope from home when time is tight or the weather is iffy.
Use the big scope from home for planets, clusters, and bright extended object.

Take BOTH scopes to a dark site whenever possible. Why both? That gives you OPTIONS if, after having driven several hours to get there you just don't have the energy to set up the BIG scope (or the weather is really iffy), but the little one sets up in just two minutes. Plus maybe there's someone else there with you?




All good advice. I have no intention of letting go of the 10" scope, which is a great compromise for me in many ways and sees a lot of use. I may get a 100EQ refractor one of these days to replace or supplement the C5. And I just sold the short tube 80 because I found I never used it.


Post Extras: Print Post   Remind Me!   Notify Moderator  
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Re: Obsession 15" in the red zone? new [Re: Bob S.]
      #5666241 - 02/06/13 11:32 PM

Quote:

+1 for what Tom said. 10" scopes frequently tend to beat the seeing on poorer nights. I have 10", 12.5" and 20" Newts and they all serve different purposes on different nights.




Can you tell me more about how you use each scope?


Post Extras: Print Post   Remind Me!   Notify Moderator  
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Re: Obsession 15" in the red zone? new [Re: aatt]
      #5666257 - 02/06/13 11:40 PM

Quote:

I have a 15" and I live in an orange to red zone transition area.




I would describe my home location about the same way. I can easily see M81 and M82 from home in an 80mm refractor. I've given up on seeing M74 even in the 10", though I know it will be trivial at a dark site.

Quote:

I am so glad I got this scope! Everything is more detailed, I am seeing huge numbers of galaxies all over Ursa major, Leo and Virgo.




That also sounds very encouraging. I have struggled to knock off all the main members of the Virgo cluster, much less the fainter ones. I've started working through the Herschel 400 list, but I think that while the globulars can be done from home, most of this is galaxies that really want dark skies, even with 10".

Quote:

The moon, open clusters, Jupiter and globs are just wonderful and bright.




I've seen several posters here say that the larger aperture is great on planets, and you mention the Moon as well. I am a major lunar observer, not just because of light pollution but because I have a long-term, deep interest in lunar geology (complete with requisite shelf of books, atlases, etc.) I had assumed that I wouldn't get much boost in resolution from 16" on the Moon most nights, but perhaps I'm being unduly pessimistic. It probably does need above-average seeing to get the benefit, but as often as I look at the Moon, there will always be nights of good seeing in there.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Obsession 15" in the red zone? new [Re: RocketScientist]
      #5666266 - 02/06/13 11:46 PM

I always used my 5" Mak to view the Moon. But one night at a star party, I viewed the crescent Moon with my 12.5". OMG. I had forgotten about the difference in resolution. The 12.5" showed details so much smaller than the 5" and ALL details so much more sharply, I realized that, just as with DSOs and planets, the Moon too was better with a larger aperture.
It does depend a little on seeing conditions, obviously, but the larger aperture will become a fantastic Lunar telescope.
Just remember:
--Cooling of the optics
--Collimation of the telescope
--Conditions of the sky
When all 3 are optimum: MAGIC!


Post Extras: Print Post   Remind Me!   Notify Moderator  
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Re: Obsession 15" in the red zone? new [Re: pdfermat]
      #5666278 - 02/06/13 11:52 PM

Quote:

I'd say consider this: have you attempted and (for the most part succeeded) to observe those objects through your 10" at your home site?




Globulars, open clusters, nebulae, yes. Galaxies, mostly failure, except for the easy Messiers (M31, M32, M51, M110, M81, M82, etc.) Even M109 is problematic. And of course the 10" won't show structure in any of these.

I can detect planetaries (typically using UHC or OIII filter), such as M97 and many very small ones, but except for M27 there's little detail. I can't see M101 from home with 10", and I can barely detect it from the high sierra with 80mm. I haven't taken the 10" up in the mountains, as it doesn't fit well in the car with a full load of camping gear.

Quote:

Have you found that enjoyable?




Yes, except galaxies. I probably need to create my own observer's list with only high-surface-brightness galaxies on it and focus on those. I would very much like to look at structure in the brighter galaxies, which I've done in other people's 15 - 16" scopes from moderately dark sites.

Quote:

Something like an Obsession 15" is quite portable (IMHO), and fairly easy to set up. That means you most likely wouldn't feel its too much trouble to set up and observe with it from your home site on a regular basis, and it would be transport friendly for those rare dark sky trips.




Thanks, that's about what I was hoping. 18"+ sounds cool, but I know that I would hardly ever use it.

Quote:

Quote:

...looking at structures of galaxies...




A little bit, with select targets and a lot of practice.




I find galaxies to be the objects that benefit most from going up from 10-12" to 16"+. Unfortunately, until someone invents the mythical "galaxy filter", these are the objects that are hardest to address from bright skies even with more aperture.


Post Extras: Print Post   Remind Me!   Notify Moderator  
RocketScientist
super member


Reged: 08/28/08

Loc: California (East Bay area)
Re: Obsession 15" in the red zone? new [Re: Mike B]
      #5666281 - 02/06/13 11:54 PM

Quote:

I, too, would say *yes*- go for it! The additional light-grasp equates to seeing deeper, sure, but it'll equate to MORE than that:
1) likely better, brighter, & more detailed planetary+Lunar
2) increased resolution of globulars
3) increased grasp of detail in nebulae

.. from where EVER the scope is used!





This is really good news, because it means that even if galaxies are a bomb, the scope would still see a lot of use and provide a lot of satisfaction.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Obsession 15" in the red zone? new [Re: RocketScientist]
      #5666382 - 02/07/13 01:46 AM

Quote:

I understand everyone is different, but the two posters above must be living a different lifestyle from my own. I work at a full time job, spend an hour working out 2 - 3 evenings per week at the gym, volunteer at several different activities, and do a lot of hiking, camping, etc. with my husband. This doesn't leave a whole lot of time for observing, and my typical observing session is no more than one hour per night (but I observe on many nights). If I'm not in bed by 11 PM, I have trouble getting up for work the next day.



I totally get this! Did this for a couple of decades. While our kids are now all grown, and work has slowed waay down... many additional activities remain, plus a new PT career is firin' up. I have to pick observing opportunities wisely, because they're fleeting, and quite weather-dependent.

For *me*, a big part of the "solution" has become a "Telegizmos" cover- i can keep the 15" Dob set up on the rear patio for days at a stretch, which opens up the opportunities notably. Unfortunately, i do *not* have a roll-out deployment situation. Maybe the next place?

Having stated all this, i made the jump to this 15" Dob from a 10" SCT about 5 years ago, and EVERY TIME I USE IT i am soooo thankful i made the choice! Maybe i could liken the experience to bathwater temperature? Dropping the temp 10% doesn't result in a 10% less enjoyable experience... prob'ly makes one feel downright uncomfortable! When i'm out in the yard viewing with the Dob, i'm still sayin' "Ahhhh" quite often. Not an exaggeration!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Obsession 15" in the red zone? new [Re: RocketScientist]
      #5666666 - 02/07/13 09:03 AM

I quite understand your situation there. Even so, I would say you'll find a lot of things well worth observing from home with a 15-inch. On most nights in my area, I'm better off just observing from the driveway than driving 45 minutes or longer before I can even unload my telescope and set it up. Even from the red zone, aperture wins. While I do go to very dark sites whenever I can, most of the time, I make the best of whatever comes my way.

Taras


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
20 registered and 24 anonymous users are browsing this forum.

Moderator:  ausastronomer, Phillip Creed, JayinUT, okieav8r 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1465

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics