Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Aperture Fever? 8" vs 10" or 12"

  • Please log in to reply
112 replies to this topic

#76 stargazer193857

stargazer193857

    Fly Me to the Moon

  • *****
  • Posts: 6756
  • Joined: 01 Dec 2013
  • Loc: Southern Idaho

Posted 02 February 2019 - 12:52 PM

12" is nicer if you like to stand. You don't have to stoop as low. But sitting is better, and the 12" will need an adjustable chair, tall if the observer is not tall.
  • DNA7744, Bonco2 and Earthbound1 like this

#77 Don H

Don H

    Viking 1

  • -----
  • Posts: 868
  • Joined: 28 Dec 2006
  • Loc: Desert SW

Posted 03 February 2019 - 11:38 PM

Well after much lively discussion, and with consultation with my finance minister (spouse)...I have decided that the ES 12" truss Dobson is in my future. Will be looking on CN and other dealers for a deal and hope to have finances in place within a couple of months! My 8" Sky-Watcher will be my quick set up scope and the ES 12 will be my detail scope when good stable weather prevails! Thanks for all the comments!

Good luck with your new 12 when you get it. FWIW, I have an 8, 10 and 12.5 (plus 6, 4.5 and 66mm). The 10 gets used the most by far. While I did build all 3 to be lightweight, the 10 inch f/6.3 sits a few feet from the patio door and gets carried out most clear nights when the moon is not involved. You could always get a ten in the future too, after you have used the 8 and 12 for a while. The 10 never fails to pIease, although the 12.5 will always do a little better side by side. The 12.5 is f/5.9 and is a bit much to carry out fully assembled, so using it means taking the time to put it together, although that only takes a few minutes. Actually, I hope to keep them all for a long time...

Attached Thumbnails

  • 10.jpg

  • Jon Isaacs, DNA7744 and 25585 like this

#78 iKMN

iKMN

    Viking 1

  • *****
  • Posts: 650
  • Joined: 03 Aug 2015
  • Loc: South Central Florida

Posted 04 February 2019 - 12:21 AM

Well after much lively discussion, and with consultation with my finance minister (spouse)...I have decided that the ES 12" truss Dobson is in my future. Will be looking on CN and other dealers for a deal and hope to have finances in place within a couple of months! My 8" Sky-Watcher will be my quick set up scope and the ES 12 will be my detail scope when good stable weather prevails! Thanks for all the comments!


Well I think that’s a great choice if you have the 8” the 12” is a nice bump. I recommend you get a coma corrector it really is a game changer. I would definitely budget for one. The Parcorr is #1 but the ES HRCC works flawlessly with the ES dobs. I can’t get over what a difference it makes in my 10”.

Good luck

K
  • Jon Isaacs, DNA7744 and 25585 like this

#79 stargazer193857

stargazer193857

    Fly Me to the Moon

  • *****
  • Posts: 6756
  • Joined: 01 Dec 2013
  • Loc: Southern Idaho

Posted 04 February 2019 - 12:11 PM

I have yet to understand why many move their Dobs in one piece. It just makes what could be an easy, relaxed job more awkward and difficult. There are unique situations like Gary's where he moves it frequently throughout the night and has quite a distance to go .

But for setup and tear down, it's just one more trip and takes but a minute or so.


But. . With a bit of thought and planning, working with the scope rather than fighting it (see above ) the difficulties associated with larger scopes can be reduced .

Jon

Most Meade 12" and Orion 10" do not have wheel barrow handles. How should that dodge trees? Lay the OTA in the dirt while you move the base? Balance the OTA on the variable height chair? Put it back in the car? Or wait an hour for the object to move out of the trees? I like bring able to just pick up and go look at what I want, when I want.

Edited by stargazer193857, 04 February 2019 - 12:13 PM.


#80 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 74368
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 05 February 2019 - 01:34 AM

Most Meade 12" and Orion 10" do not have wheel barrow handles. How should that dodge trees? Lay the OTA in the dirt while you move the base? Balance the OTA on the variable height chair? Put it back in the car? Or wait an hour for the object to move out of the trees? I like bring able to just pick up and go look at what I want, when I want.

 

Did you read my post? 

 

"I have yet to understand why many move their Dobs in one piece. It just makes what could be an easy, relaxed job more awkward and difficult. There are unique situations like Gary's where he moves it frequently throughout the night and has quite a distance to go .

 

But for setup and tear down, it's just one more trip and takes but a minute or so. "

 

 

 

Jon


  • spaceoddity, tommy10 and 25585 like this

#81 Biggen

Biggen

    Explorer 1

  • -----
  • Posts: 59
  • Joined: 04 Jan 2019

Posted 05 February 2019 - 06:54 AM

Did you read my post? 

 

"I have yet to understand why many move their Dobs in one piece. It just makes what could be an easy, relaxed job more awkward and difficult. There are unique situations like Gary's where he moves it frequently throughout the night and has quite a distance to go .

 

But for setup and tear down, it's just one more trip and takes but a minute or so. "

 

 

 

Jon

I move my 8” in one piece. It’s pretty easy for me to peak up a paltry ~45lbs.

 

Now when I move to a 12”, then it’s time to add the wheels or at least two a two trip move. But for an 8” it’s more work (for me) to do two trips than one.

 

But it’s different for everyone. Not everyone wants to lift and carry that weight at once. Just like not everyone wants to make more trips the necessary. I’m also the guy that refuses to make more than one trip from the car to the inside of the house when carrying groceries. I’ll give myself a near hernia hanging grocery bags all over me to make sure I can do it it one trip. My wife just watches and shakes her head...


Edited by Biggen, 05 February 2019 - 07:05 AM.

  • MSWcdavis likes this

#82 25585

25585

    Vanguard

  • *****
  • Posts: 2189
  • Joined: 29 Aug 2017
  • Loc: In a valley

Posted 06 February 2019 - 09:31 AM

Always 2 pieces for me. However many times. And then eyepieces case & chair, making 3. Same with tripod mounted scopes, OTA on its own, tripod & mount, eyepieces. Just a drill I do instinctively.



#83 Traveler

Traveler

    Mercury-Atlas

  • *****
  • Posts: 2727
  • Joined: 19 Aug 2007
  • Loc: The Netherlands

Posted 06 February 2019 - 12:38 PM

Just an observation..

When one ask in the SCT section which step to take from a C8, most of the time the advice and/or the decision of the one that ask the question is going to a C9.25 and just sometimes they go for a C11...



#84 stargazer193857

stargazer193857

    Fly Me to the Moon

  • *****
  • Posts: 6756
  • Joined: 01 Dec 2013
  • Loc: Southern Idaho

Posted 07 February 2019 - 12:18 AM

Just an observation..
When one ask in the SCT section which step to take from a C8, most of the time the advice and/or the decision of the one that ask the question is going to a C9.25 and just sometimes they go for a C11...

Because the mounts don't take extra weight well like a dob mount. Changes the equation. GEMs are heavy.

Also, SCT come with more native magnification. With a bigger fast newt of same focal length, you have to use a stronger eyepiece to get the extra mag. At equal magnification, more aperture is needed to wow.

Edited by stargazer193857, 07 February 2019 - 12:20 AM.

  • Traveler likes this

#85 Traveler

Traveler

    Mercury-Atlas

  • *****
  • Posts: 2727
  • Joined: 19 Aug 2007
  • Loc: The Netherlands

Posted 08 February 2019 - 12:49 AM

Of course, mainly because of the mounts, that make sense. Thanks stargazer.



#86 25585

25585

    Vanguard

  • *****
  • Posts: 2189
  • Joined: 29 Aug 2017
  • Loc: In a valley

Posted 08 February 2019 - 01:08 PM

Just an observation..

When one ask in the SCT section which step to take from a C8, most of the time the advice and/or the decision of the one that ask the question is going to a C9.25 and just sometimes they go for a C11...

There is the Meade 10" SCT as well to consider.



#87 JackBorden

JackBorden

    Lift Off

  • -----
  • Posts: 1
  • Joined: 08 Feb 2019

Posted 08 February 2019 - 07:53 PM

 

If a scope is too big or too awkward,  it's unlikely to get much use. 

Very true, but I find there can be creative ways to make them less awkward. A few years ago I was forced to move into a small apartment on the ground floor of a 3-story building, so I bought an Orion 70mm refractor so I could easily take up to the roof. But because of its small aperture and the light pollution of Los Angeles I usually only used it on the moon. I rarely used my Meade 8" SCT anymore because I figured it would be too much trouble, so for quite awhile it just sat in its case. But then I constructed a 3-wheeled dolly so I could easily roll it, already assembled on its tripod, down the hall to the parking lot, and I began using it again. But the parking lot has lots of traffic noise and no privacy, so a couple years ago I rigged up some 1.5 inch wide nylon straps to the tripod and optical tube to help me carry them to the roof. One at a time, of course, so it takes two trips, but it's worth it. I've used it up there many times now, and I again have enough aperture to observe more than just the moon.



#88 sickfish

sickfish

    Fly Me to the Moon

  • *****
  • Posts: 6210
  • Joined: 13 Jan 2009
  • Loc: Watertown Ma.

Posted 08 February 2019 - 08:45 PM

With my 8 I take it in 2 pieces from my shed to the patio where I set up.

Its 30 feet tops.

I can lift things,  carrying stuff doesn't bother me.

The tube and base is awkward and it finds a way to bump into things. Also carrying stuff across a lawn in the dark is tricky. You can screw up less with a lighter and smaller piece.

But everyone is different. 


Edited by sickfish, 08 February 2019 - 08:47 PM.

  • Jon Isaacs and tommy10 like this

#89 AnalogKid

AnalogKid

    Viking 1

  • *****
  • Posts: 527
  • Joined: 12 Dec 2017
  • Loc: North/West of Pittsburgh PA

Posted 15 February 2019 - 04:36 PM

Congrats on the 12"  IMO the Goldilocks scope...   I was convinced to go from my 8" to a 12" when I saw the Orion Nebula side by side at a star party.  Man that thing in the 12" just seemed to go on forever in the 12" with details galore... I USED to think it looked great in my 8". wink.gif    I revisited M42 this year with my own 12" and even side by side with the 8"  . Yes there still is that big of a difference.

But on some of the other objects, as others have mentioned, not so much of a difference.  Yes a difference, but not as jaw dropping as M42 and most globs.   I actually prefer the views of some of the larger open clusters with my 8" and its ~<1000mm FL. 

 

     A few weeks before I got the 12" an old friend and neighbor stopped over with her early 20 something daughter while I had the old Coulter 8" out.     At first they asked what I was doing with a canon in my yard.  No really, they did.   I showed them Jupiter in my 8" and planed on a few globs, and a few others objects I can't remember.   They though that Jupiter was cool and all, and were kind of meh on M13 so I didn't go to any more globs. Saturn wasn't up yet, at least not before they went to bed.   The daughter was more interested in the other assorted forgotten objects I showed that night, and mom kinda lost interest and started playing with her phone.  Yea, just the opposite of what you would expect.  

 

So when I got the 12" they stopped over. I didn't say anything to them about it other than "yep", when they asked if it was different from the one a week or so back.   They were howly cowing, and oohing and awing over Jupiter.  When I showed them M31 it elicited the biggest gasp.  They were basically fighting over the eyepiece.  OK, not really, but close.   The moon was just setting and we got a decent look at that too.  The mom was asking why I didn't show them the moon last time.  I asked if she remembered seeing it in the sky last time.  She said no, but still wanted to know why I didn't show them with the telescope....I let her daugher explain... 

 

So yes you will see the difference in the 8" and 12" scopes.  From my light polluted yard about 5 miles from Greater Pgh Airport, my neighbors did without being told it was all that different other than not being the same one,  and this was only the 1st and 2nd times they ever looked through a telescope... and a week or so before that I had to convince them my old Coulter 8" wasn't a cannon.


  • DNA7744 and 25585 like this

#90 DNA7744

DNA7744

    Explorer 1

  • -----
  • topic starter
  • Posts: 68
  • Joined: 02 Oct 2010
  • Loc: Big Bear Lake, CA

Posted 15 February 2019 - 07:52 PM

12" is nicer if you like to stand. You don't have to stoop as low. But sitting is better, and the 12" will need an adjustable chair, tall if the observer is not tall.

That put a thought in my head...maybe the 10" would be used more if I don't have to stand...I do like that about the current 8" I have!  The price is much more affordable too!  Thoughts?



#91 CHASLX200

CHASLX200

    Hubble

  • *****
  • Posts: 16034
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 15 February 2019 - 08:02 PM

Did you read my post? 

 

"I have yet to understand why many move their Dobs in one piece. It just makes what could be an easy, relaxed job more awkward and difficult. There are unique situations like Gary's where he moves it frequently throughout the night and has quite a distance to go .

 

But for setup and tear down, it's just one more trip and takes but a minute or so. "

 

 

 

Jon

That is the only way i would buy a Dob if it will fit thru the door all set up and get it out in one trip.  I rolled a complete 18"F/5 Tectron out the door, to bad the mirror was a flop or i would have kept it. If it is too much work i won't use it.



#92 Asbytec

Asbytec

    Guy in a furry hat

  • *****
  • Posts: 14355
  • Joined: 08 Aug 2007
  • Loc: Pampanga, PI

Posted 15 February 2019 - 09:16 PM

That put a thought in my head...maybe the 10" would be used more if I don't have to stand...I do like that about the current 8" I have!  The price is much more affordable too!  Thoughts?

Up to you, but I enjoy sitting, too. I am usually at the eyepiece for long periods of time. Price is another consideration. A 10" is a capable aperture in the right hands, a 12" even more so especially over the 8" you currently own. Tough choice, but weigh the benefits...there are other things to consider other than aperture. Comfort and ease of movement and set up are two of them. Cost is another, and so on. Strike that balance and you have a good scope you will use and enjoy using it. 


  • Jon Isaacs and AnalogKid like this

#93 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 74368
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 16 February 2019 - 07:06 AM

That put a thought in my head...maybe the 10" would be used more if I don't have to stand...I do like that about the current 8" I have!  The price is much more affordable too!  Thoughts?

 

I really don't see any difference in terms of sitting versus standing between a 10 inch F/5 versus a 12 inch F/5.  Both are too short to allow standing and both are best when the observer sits on an adjustable chair such as the Starbound.

 

Jon


  • Asbytec likes this

#94 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 74368
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 16 February 2019 - 07:08 AM

That is the only way i would buy a Dob if it will fit thru the door all set up and get it out in one trip.  I rolled a complete 18"F/5 Tectron out the door, to bad the mirror was a flop or i would have kept it. If it is too much work i won't use it.

 

This thread is about 8, 10 inch and 12 inch Tube Dobs...  For large Dobs, moving them in 2 pieces is difficult..  

 

Jon



#95 Asbytec

Asbytec

    Guy in a furry hat

  • *****
  • Posts: 14355
  • Joined: 08 Aug 2007
  • Loc: Pampanga, PI

Posted 16 February 2019 - 08:39 AM

I really don't see any difference in terms of sitting versus standing between a 10 inch F/5 versus a 12 inch F/5.  Both are too short to allow standing and both are best when the observer sits on an adjustable chair such as the Starbound.

 

Jon

That's true, too...thinking out of the box - (that your Starbound chair was shipped in.) :) 

 

I just use a simple plastic chair that happens to be a good height for an 8" and maybe a 10". They are cheap and shipping is expensive here. 


  • Jon Isaacs likes this

#96 WyattDavis

WyattDavis

    Viking 1

  • *****
  • Posts: 751
  • Joined: 25 Dec 2013
  • Loc: Rye, NH

Posted 16 February 2019 - 09:28 AM

So far, my experiments buying an ultralight 8” scopes or lightening an 8” factory scope haven’t turned out well. I found that reducing the weight of a scope is EASY, but doing so without introducing other serious problems is difficult, which is one reason mainstream scopes weigh what they do.

 

So, if someone offered me a 30# 10” Dob, I would be more than a little skeptical about its performance, and wouldn’t consider buying it without doing a thorough hands-on evaluation first. 

 

Nice to know. What sort of problems did the light weight ones have? Would you need to inspect it yourself if a big name poster did so first?

Good point/good question:

 

I initially went with a lightweight strut setup when I moved from the solid-tube structure on my XT10. The new strut structure was very well constructed, but I found that mounting equipment to the structure was a weak point. For example, rather than having a full upper tube assembly (UTA), the "UTA" was a single wooden ring. The focuser installed to a metal plate that was attached on its top edge by two bolts to the bottom of the wooden ring. With larger eyepieces and/or when using an eyepiece plus a Barlow, I got focuser flex. I also found that the lack of UTA surface made mounting/aligning finder scope challenging. Also, getting a full shroud on the strut OTA was challenging. 

 

For these reasons I decided to move on to a heavier truss design with a full-sized UTA to allow more solid mounting of focuser and finders. I also wanted a more robust mirror-box-installed primary cooling solution than what was practical on the ultralight structure and wanted a cleaner implementation for an OTA light shroud and for installed power and dew control. The heavier structure made all of this easier.

 

Even so, I am a believer in the connection between scope ease of use and frequency of use. I also agree that there is probably no cure to aperture fever if WOW is the only objective and that working to make the greatest use of available aperture is the most sustainable and rewarding long-term pursuit. These considerations (plus the fact that I knew the 10" primary I already had was well-figured) led me to stay with a 10" aperture rather than moving to 12.5" or making the next "one magnitude jump" up to something like a 16".



#97 stargazer193857

stargazer193857

    Fly Me to the Moon

  • *****
  • Posts: 6756
  • Joined: 01 Dec 2013
  • Loc: Southern Idaho

Posted 16 February 2019 - 11:58 AM

My cure for aperture feaver is wanting to fit some common sized objects in an 82 deg fov at a magnification that is unlikely to be affected by the atmosphere and with an exit pupil that is not likely to be vignetted, say 6mm.

So 80x and 6mm is 480mm of aperture, or 19". So 20" is as big as I'd want, if transportation and viewing comfort were not issues. Although, there are many more smaller galaxies half the size that would benefit from 40", and a 100 deg eyepiece can help find them.

However, 8-12" frames 1.25 ish deg with a 4-5mm exit pupil, and is very comfy to sit by and easy to transport. And as Jon points out often, big fast scopes have big sevondaries. They get thicker, too.

Edited by stargazer193857, 16 February 2019 - 12:01 PM.


#98 sunnynights

sunnynights

    Sputnik

  • *****
  • Posts: 28
  • Joined: 26 Aug 2006

Posted 17 February 2019 - 12:38 AM

Good luck on your decision. You are not alone here. It's hard to go wrong, in general.

One other factor may be the seeing and transparency where you live. Atmospheric conditions are not to be sneezed at. If you experience regular atmospheric turbulence, you may want to stay with the 8" to reduce the effects of turbulence (good links are cleardarksky.com for a forecasted observing chart for your area, courtesy of the Canadian Meteorological Center, and arksky.org for explanations of atmospheric effects on observing).

I suggest mirror quality is important too, and a mediocre 12" may disappoint (I was unable to split the double-double, or Polaris, at 170X in a scope made by a popular manufacturer). ES quality may vary a bit more than you might expect with advertising -- you may get a great mirror or a not-so-great one. This is likely shared with most other mirrors made in the People's Republic. Many custom mirror makers can possibly test and refigure your mirror, though.

A 12" will not only be clumsier and generate more cuss words as you move it, it will also be more subject to winds.


  • DNA7744 likes this

#99 stargazer193857

stargazer193857

    Fly Me to the Moon

  • *****
  • Posts: 6756
  • Joined: 01 Dec 2013
  • Loc: Southern Idaho

Posted 17 February 2019 - 11:40 AM

As for standing to view in a 12", it still is a stopping contest at 45 deg. I even bent my knees to look in 18" f4.3.

My best view ever of M82/M81 was through a 10" f5, seemed comfortably.

I sit in an adjustable office chair at all day. The high position becomes uncomfortable after 30 minutes tops. And that chair is padded. That's why I keep declining Jon's offer to get a 16" and a cat's perch.

#100 Earthbound1

Earthbound1

    Ranger 4

  • -----
  • Posts: 326
  • Joined: 19 Sep 2018
  • Loc: Gordo, Alabama

Posted 17 February 2019 - 12:39 PM

Here's a screenshot of Astrojensen's Meade dob with pneumatic wheels and wood handles. I would've made it a single axel with "notches" on top of the handles instead of bolting through them, so I could drop them and the scope and then move the handles out of the way... I really like his design and it has inspired me to "improve" upon it by thinking of how the handles could be made to be removable. I dig those yellow easy to see tires!!!

Attached Thumbnails

  • image.jpeg

Edited by Earthbound1, 17 February 2019 - 12:48 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics