140 replies to this topic

[CHASLX200]

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.

[clamchip]

I've always been mad as a hatter. Here I'm bird watching with my ex C14 at 1600X.

I like to know my limitations at both ends, maximum available power and also minimum power with

an obstructed telescope.

I suppose as a 'general rule' 60X per inch. Sometimes there is more to gain with higher power, it

depends on the target. 60X per inch in a C14 is 840X.

Robert

 

Edited by clamchip, 18 February 2024 - 11:30 AM.

[CHASLX200]

I've always been mad as a hatter. Here I'm bird watching with my ex C14 at 1600X.

I like to know my limitations at both ends, maximum available power and also minimum power with

an obstructed telescope.

I suppose as a 'general rule' 60X per inch. Sometimes there is more to gain with higher power, it

depends on the target. 60X per inch in a C14 is 840X.

Robert

 

post-50896-0-94022000-1571962429.jpg

SCT's never take very high power well vs a Newt of Fract.

Edited by CHASLX200, 18 February 2024 - 11:42 AM.

[Astro-Master]

I once used 500x on the double star Izar (Epsilon Bootes) in my 105mm APO on a perfect night of seeing, that was 121x per inch using a TV 3-6 zoom and a 2x barlow.

 

With my 18" Obsession Classic I once used 1,300x on the Eskimo Neb on a night with perfect seeing in the Anza Borrego Desert, that was only 72x per inch.

[starman876]

not sure what the benefit is of using higher powers than needed for obtaining a good view of an object.   I view to see as much detail as possible.  I will keep increasing the power until the detail of the object starts to vanish. Viewing blobs of light has never been the goal of my viewing unless I am aligning a SCT.     I love it when the scope I am using starts to reveal more detail as I increase the power.   Around here using empty magnification is always useless.  Not saying that some do not enjoy this.  Just saying for me it is useless.  

[Joe Cepleur]

I'm lucky! Where I live, the seeing is lousy, so experiments with ultra high powers are futile!

[starman876]

I'm lucky! Where I live, the seeing is lousy, so experiments with ultra high powers are futile!

yes, when things are futile it is time for a new scope

[CHASLX200]

yes, when things are futile it is time for a new scope

That TMB 100/800 you have would be a easy 100x per inch scope if it is like the same run i used back around 1999.  It was over built and gray like my  TMB 105/650.

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[CHASLX200]

not sure what the benefit is of using higher powers than needed for obtaining a good view of an object.   I view to see as much detail as possible.  I will keep increasing the power until the detail of the object starts to vanish. Viewing blobs of light has never been the goal of my viewing unless I am aligning a SCT.     I love it when the scope I am using starts to reveal more detail as I increase the power.   Around here using empty magnification is always useless.  Not saying that some do not enjoy this.  Just saying for me it is useless.  

No one is forced to use crazy power. Just something to do for fun if the seeing is good.

[Kasmos]

I usually don't go past 50x per inch and find 40x is a more pleasing limit with my skies and old eyes . The one good thing about higher power is sometimes objects like Jupiter need to be dimmer to reduce the glare (again) in my old eyes. Also, the seeing here seems to have gone way down in the last 10-15 years so it's not worth trying higher. I honestly can't remember the last really good steady night.

Edited by Kasmos, 18 February 2024 - 04:00 PM.

[CHASLX200]

I usually don't go past 50x per inch and find 40x is a more pleasing limit with my skies and old eyes . The one good thing about higher power is sometimes objects like Jupiter need to be dimmer to reduce the glare (again) in my old eyes. Also, the seeing here seems to have gone way down in the last 10-15 years so it's not worth trying higher. I honestly can't remember the last really good steady night.

Most times i don't go past 60x per inch.

[ccwemyss]

I've had my AP 6" f9 up to 600X in good seeing on bright objects, but it doesn't offer more detail above 75X per inch (456X). The Pentax 85 can also do 75X per inch on Venus and the moon (about 260X) without breaking down. I haven't had good enough seeing yet to try the Pentax 100 beyond 50X per inch. These are the only ones that give perfect star tests. 

 

None of my other refractors have been able to go that high. The Meade 152ED topped out at a bit over 50X per inch, and that's about the limit for the Edmund 4" (200X), and the Jaegers 80mm f15 (160X). I haven't taken the time to go through the loaner refractors to see if any of them go higher -- the students wouldn't know how to find or track anything at more than about 120X. The 11 and 14 inch SCTs I've used generally max out at about 40X per inch. 

 

Chip W. 

[starman876]

No one is forced to use crazy power. Just something to do for fun if the seeing is good.

Yes, for fun I have tried insane powers only to realize that this is not fun, but frustrating in the fact all I see is something  that would be useful if I want to observe tube currents.  

[clamchip]

I love high power, and its mostly during daytime just seeing what my telescopes can do.

Reading signs across the valley, license plate tabs, that sorta thing. I have so much fun.

Over the years my Maksutovs have been my favorite for high power. 

 

Robert 

[luxo II]

In excellent seeing I’ve had my 10” f/12 mak at 75X per inch on the planets - notably Saturn and Mars, and the moon… it handles a 4mm eyepiece quite well.

Doubt many SCT owners would go near a 4mm, ever.

Edited by luxo II, 18 February 2024 - 10:00 PM.

[CHASLX200]

In excellent seeing I’ve had my 10” f/12 mak at 75X per inch on the planets - notably Saturn and Mars, and the moon… it handles a 4mm eyepiece quite well.

Doubt many SCT owners would go near a 4mm, ever.

I did with my new C8 with a 4mm Radian on Jup and it was ok. Not Zambuto ok for sure. 

[steve t]

You folks have some excellent scopes. I've got the early onset of cataracts that normally limits me to larger, 1mm, exit pupal (31x/inch).

With my modest little 4" F/10 Newtonian that turns out to be 125X. Last night, for fun, while observing Jupiter, I kicked it up a bit to 156x (.6mm exit pupil) using an 8mm + 1.25X Barlow + Neodymium type filter. Since I don't have slow motion controls on my mount, tracking was a bit more of a challenge, but Jupiter still looked good.

 

Steve T

 

Apologies, I couldn't get the image to rotate.

ST

 

 

 

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[starman876]

You folks have some excellent scopes. I've got the early onset of cataracts that normally limits me to larger, 1mm, exit pupal (31x/inch).

With my modest little 4" F/10 Newtonian that turns out to be 125X. Last night, for fun, while observing Jupiter, I kicked it up a bit to 156x (.6mm exit pupil) using an 8mm + 1.25X Barlow + Neodymium type filter. Since I don't have slow motion controls on my mount, tracking was a bit more of a challenge, but Jupiter still looked good.

 

Steve T

 

Apologies, I couldn't get the image to rotate.

ST

Is that a Takahashi?

[steve t]

Is that a Takahashi?

LOL, it's not a Takahashi.

 

It an ATM Newtonian that started life back in 1973.

 

During Covid lockdown I did a major restoration on the old scope and replace a few OTA components to make it more usable.

 

Being a retired engineer, I can't resist playing with number to satisfy my nerd instincts

 

I had the original mirror tested and it turned out to have a Strehl Ratio (SR) of .5, so I replaced it with another mirror I had the tested out as SR .967.

 

The secondary mirror tested out to have an SR of .987 (taking in to account it is at 45-degree angle).

 

The effect of a 28 % central obstruction reduces the system SR by .869.

 

The bottom line is taking the (Primary Mirror SR) x (Secondary Mirror SR) x (Effect of the central obstruction on the SR) I ended up with a system that has a total SR of .84 (~1/4 wavefront).

 

So, it's not Takahashi quality, but still a fun little scope

[Joe Cepleur]

Best pipe mount ever!

[starman876]

LOL, it's not a Takahashi.

 

It an ATM Newtonian that started life back in 1973.

 

During Covid lockdown I did a major restoration on the old scope and replace a few OTA components to make it more usable.

 

Being a retired engineer, I can't resist playing with number to satisfy my nerd instincts

 

I had the original mirror tested and it turned out to have a Strehl Ratio (SR) of .5, so I replaced it with another mirror I had the tested out as SR .967.

 

The secondary mirror tested out to have an SR of .987 (taking in to account it is at 45-degree angle).

 

The effect of a 28 % central obstruction reduces the system SR by .869.

 

The bottom line is taking the (Primary Mirror SR) x (Secondary Mirror SR) x (Effect of the central obstruction on the SR) I ended up with a system that has a total SR of .84 (~1/4 wavefront).

 

So, it's not Takahashi quality, but still a fun little scope

funny, I have a Tak that looks like that OTA

[steve t]

Best pipe mount ever!

Thanks, I don't deserve credit for the mount. A friend of my grandfather was a hobby machinist and made the mount for me per Allyn Thompson's book "Making Your Own Telescope." He had made a few scopes for other teenagers in the area. 

 

funny, I have a Tak that looks like that OTA

Would you post a picture of your Tak? I bet it's a killer on planets.

 

When I started the restoration back in 2020 the original cardboard tube had started to turn to mulch, so it was replaced with an aluminum tube lined with 1/8" cork.

 

Where I could find them, I replaced other parts with original NOS.

 

The original focuser / single stalk diagonal holder was junk and wouldn't hold collimation, so it was replaced with a three-vane spider and diagonal mount and a single speed, 1.25", focuser. Initially I had a problem with the single speed being too course, so I replaced the pinion assembly with a dual speed one. 

 

Take Care

ST

Edited by steve t, 19 February 2024 - 05:01 PM.

[bjkaras]

I’ve gotten my 10” f/5 up to 650x. Under good conditions I saw the central star in M-57. From my back yard I’ve observed Jupiter at 400x with a 6” f/8 newt. On normal nights from there 240-300x is more typical.

[CHASLX200]

I’ve gotten my 10” f/5 up to 650x. Under good conditions I saw the central star in M-57. From my back yard I’ve observed Jupiter at 400x with a 6” f/8 newt. On normal nights from there 240-300x is more typical.

Just proves how wrong some are on here about going by a book on pow wow. I started at age 13 using a 4mm and 2x barlow on my Sears 60mm and never stopped yet.  If ya got bad optics and seeing then ya go by the wrong book and use it's rules.

[Joe Cepleur]

With my Towa Jason 313 60mm refractor:

Today, while testing how well I could see the Moon during daylight, I decided also to test the idea of stacking Barlow lenses. I'd never heard of that until a few days ago on this forum! Hard to know the exact power when stacking Barlows that vary in power depending where they are in the optical train. Two 2x Barlows and one 17mm Plossl in a 60mm refractor of 910mm focal length for about 200x. But, as expected, resolution maxed out at about half of that.

The value here was in using an available, small telescope to test how much power would be needed at a star party focused on the Moon. More aperture would, of course, be needed to see details well.

Edited by Joe Cepleur, 19 February 2024 - 09:55 PM.