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9.25 SCT, it ain't no planet scope

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#301 punk35

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Posted 09 November 2018 - 06:14 PM

One night while viewing Jupiter with the C11 is getting decent views and was satisfied. Then I wondered about my collimation. I went to one of Jupiters moons and defocused enough to see that the Poisson spot wasn’t perfectly centered in the rings. I tweaked collimation a bit and got the point more centered but maybe still not perfect. The result was a noticeably better image of Jupiter. Small adjustments can make a big difference.


 

#302 Asbytec

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Posted 09 November 2018 - 06:22 PM

Every kind of scope has it good and bad points. APO's cost too much per inch, get heavy in the bigger sizes 7" and up and need a monster pricey mount.  Bigger EQ Newts are heavy in the 10" sizes and up. They need more collimation than SCT's and APO's.  But price per inch they can't be beat for planet work if you got the seeing.  SCT's are great for being smaller and lighter vs the same size APO and Newts.  So no matter what scope you pick other kinds of scopes do some things better.

Every scope presents the image a little differently, too. Smaller APOs are sharper with less resolution. Larger CATs are less sharp, but with more resolution. Some have better throughput and glare control than others. Some are just better than others. Every scope obeys the laws of physics (collimation, diffraction, and aberration) and each is beholden to the atmosphere and climate. Consequently, each will present the image somewhat differently. 


 

#303 Ron359

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Posted 09 November 2018 - 06:28 PM

And here you are saying i said they are all bad when i just said 5 i owned were super. Mos really don't know better until you have owned the scopes i have and have my kind of seeing.

Didn't say you said that.  It was another 'naysayer' that claims to have "stacks of interferometer data."  You'll have to read the thread if you want to find out who and when it was said.  I'm past done wasting my time on this.  To paraphrase Carl Sagan;  'ordinary claims have to produce ordinary evidence.' Or, as we SHOULD all know since Galileo, you have to produce your data and references for all your claims or you are just producing hot air.  


 

#304 CHASLX200

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Posted 09 November 2018 - 06:28 PM

Every scope presents the image a little differently, too. Smaller APOs are sharper with less resolution. Larger CATs are less sharp, but with more resolution. Some have better throughput and glare control than others. Some are just better than others. Every scope obeys the laws of physics (collimation, diffraction, and aberration) and each is beholden to the atmosphere and climate. Consequently, each will present the image somewhat differently. 

There is no one perfect scope.


 

#305 CHASLX200

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Posted 09 November 2018 - 06:30 PM

Didn't say you said that.  It was another 'naysayer' that claims to have "stacks of interferometer data."  You'll have to read the thread if you want to find out who and when it was said.  I'm past done wasting my time on this.  To paraphrase Carl Sagan;  'ordinary claims have to produce ordinary evidence.' Or, as we SHOULD all know since Galileo, you have to produce your data and references for all your claims or you are just producing hot air.  

Well i don't need to prove anything. But do a side by side with a Zambuto Newt and the same size SCT and guess what scope will show a better image of Jupiter.  That being both scopes are cooled and collimated.


 

#306 Jaimo!

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Posted 09 November 2018 - 06:33 PM

Didn't say you said that.  It was another 'naysayer' that claims to have "stacks of interferometer data."  You'll have to read the thread if you want to find out who and when it was said.  I'm past done wasting my time on this.  To paraphrase Carl Sagan;  'ordinary claims have to produce ordinary evidence.' Or, as we SHOULD all know since Galileo, you have to produce your data and references for all your claims or you are just producing hot air.  

That was Eddgie, at the beginning of this thread on 20-Oct-2018.


 

#307 earlyriser

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Posted 09 November 2018 - 07:07 PM

A well built Newt does all i need it to do.

The twelve step recovering telescope addict group must be helping. smile.gif


 

#308 Bomber Bob

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Posted 09 November 2018 - 07:33 PM

Back On Topic (I hope!):  No Way would I say "scope X ain't no lunar / planetary / stellar / deep sky scope" without first making sure I did my part -- clean & collimated optics, acclimated, and multiple sessions on nights of good or better seeing.

 

I don't own a C9.25, but I'm pretty certain it holds collimation at least as well as my 40+ year old C5.

 

SCTs are compact, lighter, and cheaper than same aperture & F-ratio refractors & reflectors -- on EQ mounts that carry them stably & smoothly.  That flexibility & lower cost of ownership means compromise, but it doesn't mean the SCT can't deliver fine views.  Decades of owner reports support that.

 

If you're not happy with your SCT, sell it.  Someone will put it to good use.


 

#309 barbie

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Posted 09 November 2018 - 09:37 PM

Well i don't need to prove anything. But do a side by side with a Zambuto Newt and the same size SCT and guess what scope will show a better image of Jupiter.  That being both scopes are cooled and collimated.

Then how come you've had so many Zambutos?  Sounds like you couldn't find a keeper in the lot of them so they couldn't have been all that good!!lol.gif


 

#310 Deep13

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Posted 09 November 2018 - 11:29 PM

Back On Topic (I hope!):  No Way would I say "scope X ain't no lunar / planetary / stellar / deep sky scope" without first making sure I did my part -- clean & collimated optics, acclimated, and multiple sessions on nights of good or better seeing.

Really? This again?

The corrector was clean. So was the primary, not that there would be anyway to clean it if it wasn't. Already explained the collimation several times at this point. Seeing ranges from good to godawful, so I throw the dice. There is no way to know in advance. If it's clear and I'm available, I set up. If I don't, I might not get another clear sky for weeks, or months in winter.


 

#311 Deep13

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Posted 09 November 2018 - 11:30 PM

All right, I'm done with this endless thread. Since I can't drive a stake through it, I'll just go away.


 

#312 Magnetic Field

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Posted 10 November 2018 - 03:39 AM

All right, I'm done with this endless thread. Since I can't drive a stake through it, I'll just go away.

1. Just collimate your scope and report back (good or bad).

 

2. Or you could just say: ,,I don't wanna collimate my 9.25SCT."

 

But then it is not clear to me what you think should happen.


Edited by Magnetic Field, 10 November 2018 - 03:39 AM.

 

#313 Asbytec

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Posted 10 November 2018 - 06:05 AM

We do try to be helpful. Maybe we should just speak once then forget it. Tired of these threads, too. Endless.

Collimate and cool the scope, if not happy...sell it. That simple.

During observing season I'll be in the observing forums where we don't complain about our optics. Only discuss the amazing things we do see with them.

When it boils down to it, it is about what we do see in the sky, not propped up by the fireplace.

Good luck.

Edited by Asbytec, 10 November 2018 - 06:14 AM.

 

#314 CHASLX200

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Posted 10 November 2018 - 06:59 AM

Then how come you've had so many Zambutos?  Sounds like you couldn't find a keeper in the lot of them so they couldn't have been all that good!!lol.gif

I just like buying scopes. Did the same with speakers.


 

#315 Bomber Bob

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Posted 10 November 2018 - 08:03 AM

Really? This again?

 

Yeah... your thread, but my post is not just for you, but for new CN members, lurkers, and the search engine caches.

 

It's to balance Vendor Claims, which fuel unreasonable expectations; as well as the folks who really don't care for a particular scope type -- for whatever reasons.

 

If I only got 1 decent night a month or more, I wouldn't rely on an SCT as my big scope -- that's what I mean about expectations (and why I agreed with BillP earlier in this thread).


 

#316 Magnetic Field

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Posted 10 November 2018 - 08:37 AM

We do try to be helpful. Maybe we should just speak once then forget it. Tired of these threads, too. Endless.

Collimate and cool the scope, if not happy...sell it. That simple.

During observing season I'll be in the observing forums where we don't complain about our optics. Only discuss the amazing things we do see with them.

When it boils down to it, it is about what we do see in the sky, not propped up by the fireplace.

Good luck.

Maybe I missed it after 13 pages.

 

But has the OP indicated was is preventing him from attempting to collimate his 9.25" SCT?


 

#317 dustyc

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Posted 10 November 2018 - 01:45 PM

I just like buying scopes. Did the same with speakers.

You have my sympathy. I'm REALLY trying to avoid the same habit in astronomy as I did in high end audio!


 

#318 SandyHouTex

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Posted 10 November 2018 - 02:28 PM

We have a few here that can't get it in their head that not all SCT's are perfect

I would reply that we also have a few here who have it in their head that all SCTs suck.


 

#319 CHASLX200

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Posted 10 November 2018 - 03:52 PM

You have my sympathy. I'm REALLY trying to avoid the same habit in astronomy as I did in high end audio!

Hi end audio broke me over time. Over 450k in speakers in around 30 years time.  You peeps think scopes cost a lot then try Speakers at 50k a pop


 

#320 CHASLX200

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Posted 10 November 2018 - 04:00 PM

I would reply that we also have a few here who have it in their head that all SCTs suck.

And again you say i said ALL SCT's SUCK?  Did i not post more than a 100 times over the years i had 5 super SCT's out of around 60.  So it is clear that not all SCT's SUCK buck. I know there are some that slipped out of the factory that are killers.   I also had a so called high end Newt mirror that was very bad, a 18" Nova in a Tectron Dob bob.

 

I also had a 7" Meade ED that was total junk and made 6 trips back to Meade and it was never right. I call it as i see it. If a scope is bad i tell everyone and if a scope is great i tell everyone.  And my freaky super sharp 1984 Black C8 was one i should have never sold.

 

So it is clear not ALL SCT's are bad in my eyes.  But when doing a side by side with the same size Newt well then i am gonna pick the Newt everytime.


Edited by CHASLX200, 10 November 2018 - 04:01 PM.

 

#321 SandyHouTex

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Posted 10 November 2018 - 05:24 PM

And again you say i said ALL SCT's SUCK?  Did i not post more than a 100 times over the years i had 5 super SCT's out of around 60.  So it is clear that not all SCT's SUCK buck. I know there are some that slipped out of the factory that are killers.   I also had a so called high end Newt mirror that was very bad, a 18" Nova in a Tectron Dob bob.

 

I also had a 7" Meade ED that was total junk and made 6 trips back to Meade and it was never right. I call it as i see it. If a scope is bad i tell everyone and if a scope is great i tell everyone.  And my freaky super sharp 1984 Black C8 was one i should have never sold.

 

So it is clear not ALL SCT's are bad in my eyes.  But when doing a side by side with the same size Newt well then i am gonna pick the Newt everytime.

Before they lock the thread I would reply that if you bought 60 SCTs and you only thought 5 were any good, then you clearly have an issue with SCTs.

 

I bought 7.  The Meade has pinched optics but I wasn’t smart enough back then to send it back and get a replacement.  I still need to fix it.  Of the 6 Celestrons I’ve bought in the last 9 years, I only exchanged the C14 because there was a thumbprint on the primary.  Optically, ALL of the Celestrons I currently have are 1/6 wave or better.  It is beyond me how you got so many “supposedly” bad SCTs.


Edited by SandyHouTex, 10 November 2018 - 05:29 PM.

 

#322 CHASLX200

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Posted 10 November 2018 - 05:42 PM

Before they lock the thread I would reply that if you bought 60 SCTs and you only thought 5 were any good, then you clearly have an issue with SCTs.

 

I bought 7.  The Meade has pinched optics but I wasn’t smart enough back then to send it back and get a replacement.  I still need to fix it.  Of the 6 Celestrons I’ve bought in the last 9 years, I only exchanged the C14 because there was a thumbprint on the primary.  Optically, ALL of the Celestrons I currently have are 1/6 wave or better.  It is beyond me how you got so many “supposedly” bad SCTs.

After you use the best scopes it is easy to see why and that is all i can say.  But it is clear there are some super good SCT's out there.  


Edited by CHASLX200, 10 November 2018 - 05:43 PM.

 

#323 Jaimo!

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Posted 10 November 2018 - 06:04 PM

This thread has gone off the rails...  Locked pending moderator review.

 

lock.gif


 


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