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

Want a Planet killer-suggest some

  • Please log in to reply
178 replies to this topic

#51 stubeeef

stubeeef

    Viking 1

  • *****
  • topic starter
  • Posts: 703
  • Joined: 06 Aug 2012
  • Loc: NW NC

Posted 20 January 2020 - 05:48 PM

its not, doesn't do much for me, but its a target of opportunity.

 

Not sure about the possibilities for Mars in the morning, but hey-I'll just mix my scotch with coffee


Edited by stubeeef, 20 January 2020 - 05:50 PM.


#52 starzonesteve

starzonesteve

    Viking 1

  • *****
  • Posts: 699
  • Joined: 17 May 2014
  • Loc: Central Alabama

Posted 20 January 2020 - 05:49 PM

That's the big issue. It's a 20mm thick 12.5", so it's going to push the bounds of what can be done. My 8" F7 is siliconed to an Aurora Precision cell and I've had it beyond 400x and it shows no evidence of astigmatism.

 

My current structure is a 12.5" Portaball circa 2003. The original cell is wooden, and has 8 stainless L-brackets that are siliconed to the edges of the mirror (current mirror is 1.625"). And the cell has 6 points, also siliconed. I've found that can give me some issues with astigmatism, so I'm sure it will with the thinner quartz.

 

I've also got the cell from the recent generation, which appears to be made by Aurora Precision. That one is also 6 points, but has no edge supports.

 

My plan at the moment is to use the original cell with no silicone, and to cut vertical slots into the L-brackets. I will then be able to screw in stainless bolts with nylon tips that can be placed to just touch the edge of the mirror. The slot would allow those to be positioned right on the center of gravity, and the nylon (I hope!) will have sufficiently little friction that it will not induce any astigmatism.

 

If that doesn't work, I'm thinking of looking into putting two whiffle-tree supports on the Aurora cell. Mike Lockwood's site on edge support is helpful, but hasn't been applied to super thin mirrors in a Portaball structure. But he seems convinced by the whiffle trees.

 

If all of that fails, I will sell the Portaball with original mirror, and find a more standard Dob structure with a modern cell from someplace.

Mike L felt very strongly when he sold me my 14.7" thin quartz (20mm) mirror that it would benefit from/require the whiffletree support. I had to twist Nate at Aurora's arm a bit but he built me a nice custom cell for it.


  • areyoukiddingme likes this

#53 starzonesteve

starzonesteve

    Viking 1

  • *****
  • Posts: 699
  • Joined: 17 May 2014
  • Loc: Central Alabama

Posted 20 January 2020 - 05:50 PM

its not, doesn't do much for me, but its a target of opportunity.

Opportunity for disappointment... hardly the target that shows off what a high end scope can do, imo.



#54 stubeeef

stubeeef

    Viking 1

  • *****
  • topic starter
  • Posts: 703
  • Joined: 06 Aug 2012
  • Loc: NW NC

Posted 20 January 2020 - 05:52 PM

So don't even look you say? Heresy I say, you may lose some rations with that gosh darn negativity!



#55 areyoukiddingme

areyoukiddingme

    Fly Me to the Moon

  • *****
  • Posts: 5,063
  • Joined: 18 Nov 2012

Posted 20 January 2020 - 05:57 PM

Mike L felt very strongly when he sold me my 14.7" thin quartz (20mm) mirror that it would benefit from/require the whiffletree support. I had to twist Nate at Aurora's arm a bit but he built me a nice custom cell for it.

Now that's interesting to hear. Thanks for chiming in!



#56 CHASLX200

CHASLX200

    Hubble

  • *****
  • Posts: 19,544
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 20 January 2020 - 07:36 PM

This will probably sound like heresy, but Venus just doesn't get it for me. No contrast. If I'm doing something wrong I'd be happy to hear what works for others.

I only like Venus when it is close and a thinner cresent. I can jack up the power to 800x and get a very big disk before dark But i have never seen detail.


Edited by CHASLX200, 20 January 2020 - 07:36 PM.


#57 starzonesteve

starzonesteve

    Viking 1

  • *****
  • Posts: 699
  • Joined: 17 May 2014
  • Loc: Central Alabama

Posted 20 January 2020 - 09:42 PM

So don't even look you say? Heresy I say, you may lose some rations with that gosh darn negativity!

No, it is fine to look. Just don't expect even the best corrected optics to pierce through those thick clouds...


  • MDavid and stubeeef like this

#58 Galicapernistein

Galicapernistein

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Sep 2007

Posted 20 January 2020 - 10:03 PM

Traditionally, aren’t planet killers considered to be slow Newtonians, around F7 or slower? And usually 8” or up in size? 


Edited by Galicapernistein, 20 January 2020 - 10:08 PM.


#59 stubeeef

stubeeef

    Viking 1

  • *****
  • topic starter
  • Posts: 703
  • Joined: 06 Aug 2012
  • Loc: NW NC

Posted 20 January 2020 - 10:10 PM

I did reach out to Ryan at NMT about a planet killer, he's making a fast 10" for me now.

My 10" f/3.5 NMT has a Pegasus Optic in it, Ostahowski did a double pass on it for me and had very nice compliments about how well they made it. 

I had him coat it, and pick a secondary for me.

 

Pegasus was super reasonably priced and had 3rd party testing to prove the makers claim.

 

I highly recommend Terry Ostahowski, would also love a Zambuto, and Pegasus did a great job for me as per the testing-haven't had the chance to have first light with it yet-but have great expectations. I'm sure there are some other makers to check, like Fullum that makes very large aperture optics too. Many people make good optics, there is a wide choice and nearly all are great to work with too.

 

The MAKs I spoke about earlier, seems that folks have found a way to mitigate the thermal issues, but I will probably look at just being a DOB guy.


Edited by stubeeef, 20 January 2020 - 11:04 PM.


#60 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 5,434
  • Joined: 09 Oct 2006

Posted 20 January 2020 - 10:38 PM

Any well built Newt is a brute for planets in my super steady seeing.  Fast or slow is fine.  Old school 8" F/8 Cave or other makes also make great planet scopes as well as used Starmaster Dobs at around F/4.3. 

 

Most mass made Newts the last 20 years just don't do it for me.

+1  I have a 12.5” and an 18” Starmaster, both with Zambuto mirrors, and on the best nights they are planet destroyers. :grin:


  • stubeeef and JoshUrban like this

#61 a__l

a__l

    Surveyor 1

  • -----
  • Posts: 1,727
  • Joined: 24 Nov 2007

Posted 20 January 2020 - 10:42 PM

turtle86, I would like to see the StarTest video of your telescopes "destroyers".

 

There are many such posts on CN. There must be a many of StarTest videos confirming these words. But I have never seen this, although it is easy to do. Even if it’s not a perfect atmosphere. There are programs (the planetaries know them) for processing such images.

For example this (in, 33% of obstruction): https://drive.google...1XTpzocFjV/view


Edited by a__l, 20 January 2020 - 11:49 PM.

  • ryderc1 likes this

#62 GShaffer

GShaffer

    Knight of Ni

  • *****
  • Moderators
  • Posts: 6,842
  • Joined: 28 Feb 2009
  • Loc: Winder, Ga USA

Posted 21 January 2020 - 01:08 AM

Get back to the topic and without the grousing or we can shut this one down folks. lock.gif


  • stubeeef likes this

#63 CHASLX200

CHASLX200

    Hubble

  • *****
  • Posts: 19,544
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 21 January 2020 - 06:44 AM

Traditionally, aren’t planet killers considered to be slow Newtonians, around F7 or slower? And usually 8” or up in size? 

Not really. I had six Zambuto and two OMI mirrors F/5 and faster that gave me the best images of planets ever at 700 to 1150x. Helps that i have very good seeing here and there.


  • turtle86 likes this

#64 Galicapernistein

Galicapernistein

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Sep 2007

Posted 21 January 2020 - 08:24 AM

Not really. I had six Zambuto and two OMI mirrors F/5 and faster that gave me the best images of planets ever at 700 to 1150x. Helps that i have very good seeing here and there.

I’m talking about the name “planet killer.” Hasn’t that always meant a slow Newtonian? Just like a rich field scope is a fast Newtonian, even though other scopes can obviously provide rich field views. A scope can give great planetary views and still not be called a planet killer. Maybe the term itself should be killed, and we should specify if we’re talking about slow Newtonians, or just any scope with good optics.



#65 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 84,162
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 21 January 2020 - 08:42 AM

I’m talking about the name “planet killer.” Hasn’t that always meant a slow Newtonian? Just like a rich field scope is a fast Newtonian, even though other scopes can obviously provide rich field views. A scope can give great planetary views and still not be called a planet killer. Maybe the term itself should be killed, and we should specify if we’re talking about slow Newtonians, or just any scope with good optics.

 

I think any scope that provides excellent planetary views can be called a planet killer, whether it's a refractor, Cat or Newt, it doesn't matter.

 

Jon


  • turtle86 and scooke like this

#66 Galicapernistein

Galicapernistein

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Sep 2007

Posted 21 January 2020 - 09:01 AM

I think any scope that provides excellent planetary views can be called a planet killer, whether it's a refractor, Cat or Newt, it doesn't matter.

 

Jon

So the terms “planet killer” and “good optics” are basically interchangeable. 



#67 Asbytec

Asbytec

    Guy in a furry hat

  • *****
  • Posts: 16,959
  • Joined: 08 Aug 2007
  • Loc: Pampanga, PI

Posted 21 January 2020 - 09:11 AM

I think any scope that provides excellent planetary views can be called a planet killer, whether it's a refractor, Cat or Newt, it doesn't matter.

Jon

To my way of thinking, planet killing requires more than a good scope. Our observing conditions, scope preparation, personal acuity, and experiences matter. A good scope with a modest or no obstruction and some aperture certainly helps when everything, including a good eyepeice, the right magnification relative to the aperture, thermal stability, and near perfect collimation is coupled with good seeing and an observer intent on observing. The wobbly stack needs to be less wobbly across the board. When it all comes together we can kill planets in most descent scopes, even in mass produced obstructed ones so long as the observer is on his or her game. Observing planets is the sum of all its parts. When it all comes together, we're killing planets, in my view, and not before the wobbly stack is shored up and we trust what we see.

Edited by Asbytec, 21 January 2020 - 09:18 AM.

  • turtle86 and tommy10 like this

#68 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 84,162
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 21 January 2020 - 09:16 AM

So the terms “planet killer” and “good optics” are basically interchangeable. 

Not necessarily.

 

A 60 mm can have excellent optics but not enough firepower to do much damage.

 

Mike Lockwood wrote:

 

"Any telescope with good optics, good optical support, good thermal management, good collimation, and a patient owner is a "planet killer".  Smaller, slower telescopes are often mistakenly lauded as such, when in reality they are just easier to equilibrate and collimate."

 

I would add sufficient aperture.. 

 

I've been following threads like this from the days of science.astro.amateur in the mid 90s. The idea of what a planet killer is seems to primarily depend on where one is located.

 

A planet killed can be a small scope that generally makes the best of a bad situation or it can be a larger scope that can take advantage of a very good situation.. 


  • turtle86, Asbytec, scooke and 1 other like this

#69 Galicapernistein

Galicapernistein

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Sep 2007

Posted 21 January 2020 - 09:26 AM

Not necessarily.

 

A 60 mm can have excellent optics but not enough firepower to do much damage.

 

Mike Lockwood wrote:

 

"Any telescope with good optics, good optical support, good thermal management, good collimation, and a patient owner is a "planet killer".  Smaller, slower telescopes are often mistakenly lauded as such, when in reality they are just easier to equilibrate and collimate."

 

I would add sufficient aperture.. 

 

I've been following threads like this from the days of science.astro.amateur in the mid 90s. The idea of what a planet killer is seems to primarily depend on where one is located.

 

A planet killed can be a small scope that generally makes the best of a bad situation or it can be a larger scope that can take advantage of a very good situation.. 

So in other words, it’s a term that means whatever someone wants it to mean. It really should be banned from this site as being useless. 



#70 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 5,434
  • Joined: 09 Oct 2006

Posted 21 January 2020 - 09:48 AM

Not really. I had six Zambuto and two OMI mirrors F/5 and faster that gave me the best images of planets ever at 700 to 1150x. Helps that i have very good seeing here and there.


No reason that a faster mirror can't be a planet killer if it's well-figured and well-collimated. In Florida it helps that the seeing is usually quite good and that we don't usually experience big temperature drops due to the high humidity.

Edited by turtle86, 21 January 2020 - 10:53 AM.


#71 Galicapernistein

Galicapernistein

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Sep 2007

Posted 21 January 2020 - 09:56 AM

No reason that a faster mirror can be a planet killer if it's well-figured and well-collimated. In Florida it helps that the seeing is usually quite good and that we don't usually experience big temperature drops due to the high humidity.

Slightly off topic, but is there a certain time of year when the atmosphere is the most stable in Florida?



#72 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 5,434
  • Joined: 09 Oct 2006

Posted 21 January 2020 - 10:03 AM

turtle86, I would like to see the StarTest video of your telescopes "destroyers".
 
There are many such posts on CN. There must be a many of StarTest videos confirming these words. But I have never seen this, although it is easy to do. Even if it’s not a perfect atmosphere. There are programs (the planetaries know them) for processing such images.
For example this (in, 33% of obstruction): https://drive.google...1XTpzocFjV/view



Not going to happen. I do this hobby for fun, and that sounds like work. grin.gif
  • Galicapernistein likes this

#73 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 5,434
  • Joined: 09 Oct 2006

Posted 21 January 2020 - 10:11 AM

Slightly off topic, but is there a certain time of year when the atmosphere is the most stable in Florida?


It's possible to have good seeing any time throughout the year, but summer generally has the steadiest skies. I've had some great planetary views on those still muggy nights with a light haze...

Right now as I write the seeing is actually bad because a front just came in. However, the transparency tonight will be excellent. It often seems to be the case that there's an inverse relationship between good seeing and good transparency...
  • Galicapernistein likes this

#74 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 84,162
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 21 January 2020 - 10:19 AM

So in other words, it’s a term that means whatever someone wants it to mean. It really should be banned from this site as being useless. 

 

No, no, no..

 

A planet killer is a scope that provides killer views of the planets..

 

Trying to pigeon hole it and saying only a traditional slow Newtonian can be a planet killer when a modern faster Newtonian with a thin mirror and near perfect optics may provide a better view doesn't make sense.

 

Jon


  • Mike Lockwood, Mike Spooner and Dougeo like this

#75 Galicapernistein

Galicapernistein

    Viking 1

  • *****
  • Posts: 591
  • Joined: 24 Sep 2007

Posted 21 January 2020 - 11:12 AM

No, no, no..

 

A planet killer is a scope that provides killer views of the planets..

 

Trying to pigeon hole it and saying only a traditional slow Newtonian can be a planet killer when a modern faster Newtonian with a thin mirror and near perfect optics may provide a better view doesn't make sense.

 

Jon

The point of calling slow newts planet killers is that they give killer views of planets. A high F ratio is inherently better for high power views. A slow scope with excellent optics will give better views of planets than a fast scope with equivalent optics. This is a fact that owners of fast scopes need to accept.


Edited by Galicapernistein, 21 January 2020 - 11:14 AM.

  • Spacedude4040 likes this


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