140 replies to this topic

[CHASLX200]

Ever used a Goto 60 F20?   Mine was a doublet (visual) APO.  Yeah, it's a LONG tube.  TS-65P / 500 almost gets there, and is sharp at up to 120x / inch, too.

Them kind of scopes are never in FL. Only 60mm i would want is a older gray Tak as a finder or low power sweeper.

[Joe Cepleur]

I try to avoid Math, but to repeat myself...

Your View at the Eyepiece = Object + SEEING + Telescope SYSTEM + You!

With apologies for not avoiding math, and not to narc on you (this is nerdy), this good insight could be better conceptualized with multiplication:

Your View at the Eyepiece = Object x SEEING x Telescope SYSTEM x You!

This then means that there is an object to be seen. It is 100% out there in the sky.

If the seeing is 100% perfect, multiply by 1, meaning you see everything possible. If the seeing is imperfect (and it always is), multiply by less, with the result of degrading the 100% potential image.

Similarly with the telescope system. It either hypothetically shows you everything (no telescope actually does), or it degrades the view. Multiply by less than 1 to degrade the view. Smaller numbers degrade more.

Finally there is you. How skilled are you at observing? Multiply by 1 if you are good-like and see 100% of what there is to see. Multiply by less than 1 in proportion to how much your skills degrade the image.

In a perfect world with perfect optics and infallible astronomers, you see everything:

1 x 1 x 1 x 1 = 1

In the real world with its imperfections, you see less. As an example,

1 x 0.90 x 0.98 x 0.77 = 0.68

A good view, but less than 1; less than all of what we might have seen; less than perfect. The point is that we do not add and add and add to get our views; we avoid degrading the image that might be present, if only we did not diminish it through our best but imperfect efforts.

Edited by Joe Cepleur, 20 February 2024 - 07:11 PM.

[CHASLX200]

you would think at 120x a 60mm would not be able to gather enough light to see an image well enough to see detail.   I remember when I pushed an old 60mm to 400X on the moon it took me forever to even figure out what I was looking at.   I was looking at a crater on the moon, but it took me a while to realize I was in focus the image was that dim.   And even when I realized I was in focus it was not worth effort.  

 

You guys do know that stories begin in different ways.

 

A  war story starts off with  "this is no schiXXX

 

A fairy story  starts of whit  "once upon a time"

 

And then there is the astronomy story  "starts of with you wont believe the power I was using"  

120x is nothing for a 60mm. 

[Garyth64]

I was really referring to higher power than 50X per inch. Sorry I was not paying attention to detail.  Hard to do while in a meeting   I know when I first started out I tried the highest powers I could and that did not work out to well.   Learned very quickly to use the power that worked best for my seeing and mount and something I could find again with out too much effort.  without a drive higher powers was a strain on my patience.   Maybe if I would have polar aligned the scope it would not have been such an issue.   When I read Terra's post about  using 3500X with her questar I was impressed.   I had not idea she had such talent.

And just think what could have been done with all the money that was wasted on Hubble and the James Webb.  Shh, Nasa may start looking for answers here on CN.

[Rick-T137]

50x per inch is my answer.

 

Back in the early 2000's, I used my Meade 2120 Premier f/10 at 500x while viewing Jupiter. It was a night of exceptional seeing (at least for my area) and I haven't had a view to match it since.

 

Clear skies!

 

Rick

Edited by Rick-T137, 20 February 2024 - 07:29 PM.

[Terra Nova]

oh oh

I simplified my life two days ago by exercising both the ignore list and PM blocking. It's blissfully peaceful!

[CHASLX200]

oh oh

So you never used more than 120x in a 60mm?

[mdowns]

What is the most pow wow you ever used in your classic on a dead still nite?  I have had no trouble at 100x+ per inch on SOME OBJECTS.  This is just for kicks as it seems many take it the wrong way.

This is Charles opening post and is where the thread should stay.Though spoken in jest, mocking is seldom useful and more often a thread derailer. This is why some will notice their posts removed. Back on track please!

[Kasmos]

130x (f/910mm÷7mm EP), is about the max I'll do with a 60mm and prefer the views more closer to 100x. If you ever try one during the day it's shocking to see how quickly the image gets dim as the power goes up. Personally I like when a scope is just cruising along instead of straining to see something. Also, floaters can get to be more problematic for me when I use an EP 7mm or shorter so I prefer the views more with a 9mm. If floaters don't bother you now, enjoy the views while you can.

[starman876]

So you never used more than 120x in a 60mm?

120X per inch with a 60mm is what I meant. Tried it once and it was dismal.  

[Bomber Bob]

Well, as of right now, in the middle of Swamp Winter, my heart goes out to All Y'all who live in places with below-average planetary seeing...  Come May, and the start of our long Hot Box, Papua New Guinea, 8 month sweaty summers, I'll be less sympathetic.

 

Been here 30 years, and I've earned my couple a dozen or so near-perfect nights with no frying-size skeeters, no rabid racoons, and no prison-grade security lights going on & off all night with outdoor BBQ Party-Goers.

 

IF we lived under a jet stream, I wouldn't invest a plug-Nickle in Tak this or Questar that.  I'd want a couple of high-quality Newts - a small / g&g, and a larger Dob (yuck!).  And maybe my Jaegers 6" F5, for when that 150-knot jet pushes all the clouds out.

[CHASLX200]

120X per inch with a 60mm is what I meant. Tried it once and it was dismal.  

A good 60mm can do 200x on the moon without batting a eye.  I am sure Bomber Bob has use much higher in them.  

[CHASLX200]

Well, as of right now, in the middle of Swamp Winter, my heart goes out to All Y'all who live in places with below-average planetary seeing...  Come May, and the start of our long Hot Box, Papua New Guinea, 8 month sweaty summers, I'll be less sympathetic.

 

Been here 30 years, and I've earned my couple a dozen or so near-perfect nights with no frying-size skeeters, no rabid racoons, and no prison-grade security lights going on & off all night with outdoor BBQ Party-Goers.

 

IF we lived under a jet stream, I wouldn't invest a plug-Nickle in Tak this or Questar that.  I'd want a couple of high-quality Newts - a small / g&g, and a larger Dob (yuck!).  And maybe my Jaegers 6" F5, for when that 150-knot jet pushes all the clouds out.

Odd my seeing 90% of the time is bad in the summer after sun down. But a few hours before sunup i avg 8+ nites. I love seeing Jupiter up in the AM during the summer.  It is gonna get to low soon so looks like i will have to wait till next Sept in the AM for some real looking. Mars is up now but dim and tiny. Sat is done for a while.

Edited by CHASLX200, 21 February 2024 - 06:52 AM.

[Bomber Bob]

Best Planetary Seeing at The Swamp is usually from mid-FEB to mid-MARCH:  Daytime highs in the 60s, and nighttime lows in the 30s.  About a half-hour after sunset, the air can get very still, and that's when extreme magnifications are most useful.  (By Extreme, I mean 100x / inch or higher.)  IMO, one of my Very Best Jupiter photos with my RV-6 was at Sundown, in a large gap between Powder-Puff clouds - perfect focus, great resolution, and such natural belt colors -- EXACTLY the same as I saw in the eyepiece.  I still remember:  I was sweatin' it while recording, as a cloud's edge approached, and I wanted to hit 5000 frames... I beat the clock, but just barely!

 

About Photos:  As I've posted before, these pix are proof that my scopes can do what I claim.  Yes, they can be improved in post-processing, BUT only so much.  If the RAW data is blurry, then short of owning my own AI, they're not going to turn out sharp as a TAK [pun intended].  After I posted my famous Monolux 4380 Mars photo, a CNer PM'ed me, wanted to verify that the pix really was made with a rinky-dink Dept Store scope.  I assured him that this 4380 had a Hiyoshi objective, gave near-perfect star tests (no DPAC Rig back then), and made that image.

Edited by Bomber Bob, 21 February 2024 - 08:18 AM.

[Joe Cepleur]

No. What I look for is at what magnification I can no longer focus a planet's limb to a sharp edge. That could be 40x / inch, or 140x / inch. How do I know that I've gotten there? I start "chasing focus" without nailing it.

Now, on a near-perfect night, and with a high-quality scope, going that extra little bit of magnification may be useful for some features. For Jupiter, the GRS will fade at 312x with the TS-65S, but the Gap is easier to see: distinct interruption in the cloud belts, and that thin white arc between it & the GRS itself. Or, the thin "tails" that trail off & away from some festoons. IOW: Limited-purpose, but worth it to confirm / enhance something seen at a lower power. Tight constraints; which is another benefit to using a low to no visible CA scope.

This makes sense to me. The increase in power beyond the objective's capacity for resolution could allow the gap to become enlarged, becoming easier to see. This would not help with all details, but I can imagine how it may with a gap.

[fullthrottle_man]

The only classic I have is the ol' Dynamax 8. Doing visual, I can only get about 35x per inch (about 225x or so) before the image starts breaking down and going soft. I don't mind the lack of high power magnification at this point, mostly because most of what I hunt down at night can be seen with low to medium powers on the DX8.

[Bomber Bob]

This makes sense to me. The increase in power beyond the objective's capacity for resolution could allow the gap to become enlarged, becoming easier to see. This would not help with all details, but I can imagine how it may with a gap.

The Point I make (& maybe CHAS, too) is that the 50x / inch guideline is just that -- a Guide.  IMO, I'd write it as:  For an average (mass-produced) scope, in average seeing, & an inexperienced observer, about 50x per inch is a reasonable expectation for a Refractor.

 

IME, the average mag. / inch, and the max mag. / inch at The Swamp comes out to:

 

- Refractor (achromatic Doublet) F11 or higher:  60x / inch; 120x / inch.

- APO Refractor (ED Doublet):  75x / inch; 120x / inch.

- APO Refractor (Fluorite Doublet):  80x / inch; 140x / inch.

- Reflector (Newtonian) F6 or higher:  40x / inch; 60x / inch.

- Reflector (Cassegrain) F12 or higher:  50x / inch; 75x / inch.

- CAT (Mak-Cassegrain) F12 or higher:  50x / inch; 75x / inch.

- CAT (Schmidt-Cass) F10 or higher:  40x / inch; 60x / inch.

 

In down-sizing, I'm not keeping the Average scopes (unless they're antique).  My Keepers are dwindling down to the Exceptional of each type.  I expect each type to at least make it to Average; and, the closer an old scope gets to the Max, the more likely I am to add it to the Keeper set.

[starman876]

The Point I make (& maybe CHAS, too) is that the 50x / inch guideline is just that -- a Guide.  IMO, I'd write it as:  For an average (mass-produced) scope, in average seeing, & an inexperienced observer, about 50x per inch is a reasonable expectation for a Refractor.

 

IME, the average mag. / inch, and the max mag. / inch at The Swamp comes out to:

 

- Refractor (achromatic Doublet) F11 or higher:  60x / inch; 120x / inch.

- APO Refractor (ED Doublet):  75x / inch; 120x / inch.

- APO Refractor (Fluorite Doublet):  80x / inch; 140x / inch.

- Reflector (Newtonian) F6 or higher:  40x / inch; 60x / inch.

- Reflector (Cassegrain) F12 or higher:  50x / inch; 75x / inch.

- CAT (Mak-Cassegrain) F12 or higher:  50x / inch; 75x / inch.

- CAT (Schmidt-Cass) F10 or higher:  40x / inch; 60x / inch.

 

In down-sizing, I'm not keeping the Average scopes (unless they're antique).  My Keepers are dwindling down to the Exceptional of each type.  I expect each type to at least make it to Average; and, the closer an old scope gets to the Max, the more likely I am to add it to the Keeper set.

We are rewriting the guide lines for what power should be used for viewing.   The whole world needs to know.   

[Garyth64]

We are rewriting the guide lines for what power should be used for viewing.   The whole world needs to know.   

 

So the advertising on those scopes back in the 60's, claiming 600x, weren't really wrong.

Edited by Garyth64, 21 February 2024 - 12:08 PM.

[Bomber Bob]

We are rewriting the guide lines for what power should be used for viewing.   The whole world needs to know.   

The Whole World ain't The Swamp... and, be grateful for that reality.

[starman876]

So the advertising on those scope back in the 60's, claiming 600x weren't really wrong.

yes, you could go to 600X but you had no idea what you were looking at.  And 600X could only be used on the moon.  However, focusing was really hard.  Every time you touched the focusing knob the object would go out of view

[djgilley]

I've only had the 4 inch Edmund since late summer last year and haven't had too many viewing opportunities due to work related travel and weather, but I'm beginning to think my seeing here in the central part of FL isn't as good overall as it can get on the coast(s) or especially down in the Keys. It might be specific to my location , things such as the location of neighboring houses relative to the direction im viewing, or a large stand of trees to the SE that might be releasing heat late into the night perhaps? I do seem to recall last summer the seeing be pretty bad after sunset as well,  but early AM being better, something like a 7 on the Pickering scale occasionally. On the moon and Jupiter the most power I've used is ~235x. Still trying to get a session with good seeing with the 6 inch F10 to see what it's capable of. 

Odd my seeing 90% of the time is bad in the summer after sun down. But a few hours before sunup i avg 8+ nites. I love seeing Jupiter up in the AM during the summer.  It is gonna get to low soon so looks like i will have to wait till next Sept in the AM for some real looking. Mars is up now but dim and tiny. Sat is done for a while.

 

Edited by djgilley, 21 February 2024 - 10:01 AM.

[Bomber Bob]

50 years ago, I had 2 Sears branded 60mm refractors, 700mm & 900mm FLs.  I never tried 600x in either.  I did try about 300x with the F15 model, on Saturn, IIRC, and had to back-off because those lousy .965" bundled eyepieces wouldn't provide any kind of decent views that high -- even using the higher FL eyepieces with the 2x Barlow.

 

When I won my Tasco 15K (Towa 339) in 1978, that opened up my universe.  That 80mm refractor had an excellent lens -- got me buying quality 1.25" accessories, like my Research Grade eyepieces... 

[Terra Nova]

This is Charles opening post and is where the thread should stay.Though spoken in jest, mocking is seldom useful and more often a thread derailer. This is why some will notice their posts removed. Back on track please!

https://youtu.be/OCa...t6JVEdrNABuecu1

[deSitter]

yes, you could go to 600X but you had no idea what you were looking at.  And 600X could only be used on the moon.  However, focusing was really hard.  Every time you touched the focusing knob the object would go out of view

I quickly discovered that the 6mm and 4mm eyepieces were useless on my 76/1200mm scope. I'm sure I figured that a Unitron was much better It took a while until I understood that I was running up against hard limits, not optical quality.

 

-drl