150pl - is it really an apo killer?

[Mr Spock]

22 minutes ago, alacant said:

I'm more confused now over the label apo. All Newtonian reflectors are apo; the mirrors bring all light to a pinpoint focus. As soon as the light passes through glass, it's not any longer. Pay as much as you like, some wavelengths will always be brought to a distinct focus, hence what I label FWOABW refractor stars; blobs with coloured halos and dispersed light around them, rather than points. Hence, I would argue, '...my Newtonian reflector is an apo killer', doesn't make sense. Surely that should read, 'my apo x is better that your apo y'. Please correct me... 

The term 'apo' refers to an 'apochromatic refractor'. It's just an abbreviation or shortening of the name 'apochromatic refractor' to 'apo', a much easier name to write.

Although Newtonians are apochromatic in an optical, the abbreviation 'apo' does not apply. Some people do say 'Newt' though.

[spillage]

From my point of view I have 

12 hours ago, Moonshane said:

I like all my scopes for different reasons. I have to confess though that I think terms like APO killer are created by people that really want product X but can only afford product Y and are trying to justify (almost certainly to themselves) why they shouldn't buy product X. I suppose the car equivalent is in the VW ad, the salesman of the other brand was suggesting that the door slammed 'just like a Golf'.

Personally, I (and I am assuming also most of our members with some experience under their belts) know :

• that if you want to buy a particular type of scope then it's an itch that you'll eventually need to scratch
• that one scope is rarely better in all aspects than all other scopes - they are just different
• seeing conditions and transparency as well as observer condition and experience have more effect on what is seen than the scope type or quality given similar aperture etc
• it is a rare feature or object that the cheapest scope cannot see where the most expensive scope can, given the same conditions, aperture, suitable mount, magnification, eyepiece quality, good collimation and observer / experience. It might be a little more aesthetically pleasing in the top quality scope but it will still be there in the cheapest option so does it matter?
• it's good fun to debate this sort of thing - so keep it cool  - almost the astronomy equivalent of the weather to us Brits

totally agree.

I have a 130 and 150pds and think they are great....for the price I paid. Yes I have to collimate them from time to time but my pockets are not deep enough to have what I want.

Even if you killed apo scope I think you will fail to find anyone who would not want to have a triple refractor set up.

Yes I know If some kind soul handed me a set up like this it would take me more time than I have to work out how it works but god help me if I win the lottery I would purchase a setup like that just to look at.

So back to the matter in hand...are there any kind souls who have a spare triple set up. I am sure @ollypenrice has one???

 

[paulastro]

The term 'apo' came about as a shortened version of apochromatic refractor - just a shorter and quicker way of saying it.   It doesn't mean of course that other scope can't be apochromatic, as indeed Newtonians are. 

[ollypenrice]

I'm sorry my intended joke derailed the conversation.

Olly

[alacant]

13 hours ago, Moonshane said:

it's good fun to debate this sort of thing - so keep it cool  - almost the astronomy equivalent of the weather to us Brits

Hi everyone. Yes, I learn a lot. But please spare a thought for those of us who find the the on-forum style difficult, subjective and contradictory. When you take something for granted, it's easy to assume that everyone else does too. In a year here, I've learned enough terms and acronyms to be able to read most posts, but threads like this make me realise how little I have understood. I hope the noise created isn't too loud and thanks everyone for answering my questions; they must appear very simplistic.

[Ags]

The 150PL may kill some apos (like the 80mm ones) but of course my 150PDS is a 150PL-killer. Yes, it loses a bit of contrast vs the longer scope, but it is easier to mount and look through. And it offers widefield views.

On the subject of contrast, yes central obstructions reduce contrast, but aperture increases contrast - so the huge aperture advantage of a cheap reflector also offsets the main purported advantage of refractors.

[Chris]

47 minutes ago, Ags said:

but of course my 150PDS is a 150PL-killer

I have both 150p f/5 and f/8 Synta models, and having tested them side by side on several occasions. I'd say the contrast, sharpness and coma are significantly improved with the f/8 model. The f/5 does have a wider field for a given eyepiece, but I'm not sure this constitutes a killing compared to the benefits of the f/8? 

The f/8 is very stable and easy to use on the dob mount, and would also be fine an on EQ5. The f/5 is fine on the EQ3, but again I'm still not sure the f/8 has been killed as it's no harder to mount than a longish refractor.

[John]

All these dead scopes littering the place .......

 

[johninderby]

Well I suppose a refractor can be a bit easier to use.

           John

 

[Alan White]

3 minutes ago, johninderby said:

Well I suppose a refractor can be a bit easier to use.

           John

 

I have to be twisted on the floor to use my refractor like that near zenith, even with a riser.
Sorry John, but is that a fair cartoon? 

 

 

[Alan White]

On 6/21/2017 at 14:33, johninderby said:

I used mine on a Skytee II mount.  With the pillar no problem with the tube hitting tripod legs.

           John

 

Nice set up.

How steady was this set up John?
Was it wobbly as anything in a breeze?
 

[johninderby]

1 minute ago, Alan White said:

I have to be twisted on the floor to use my refractor like that near zenith, even with a riser.
Sorry John, but is that a fair cartoon? 

 

 

You need a taller tripod.  

          John

[Alan White]

Just now, johninderby said:

You need a taller tripod.  

If I did I would need to be taller myself!    
Ahhhh, perhaps that's the problem, vertical challenge!

[johninderby]

1 minute ago, Alan White said:

Nice set up.

How steady was this set up John?
Was it wobbly as anything in a breeze?
 

 

Not bad in a breeze at all but since replaced the pillar with a Berlebach wooden tripod. Heavier OTAs did make the pillar wobble a bit though. The wooden tripod is rock solid though and worth the extra money.

          John

[Alan White]

Just now, johninderby said:

Not bad in a breeze at all but since replaced the pillar with a Berlebach wooden tripod. Heavier OTAs did make the pillar wobble a bit though. The wooden tripod is rock solid though and worth the extra money.

          John

Sorry John turning into a John questioning session this!

Does the longer tube clear the legs on the Brelebach or have you had to use a riser, nice tripods by the way.

 

[johninderby]

10 minutes ago, Alan White said:

Sorry John turning into a John questioning session this!

Does the longer tube clear the legs on the Brelebach or have you had to use a riser, nice tripods by the way.

 

Don't have the newt any more but did use a riser with the Berlebach tripod with it. But actually not a problem without the riser except when near the zenith although easy to rotate the tripod a bit if needed for clearance.

All this talk about the 150pl has got me thinking about getting another one. Not that I NEED one but still. 

             John

[John]

34 minutes ago, Alan White said:

I have to be twisted on the floor to use my refractor like that near zenith, even with a riser.
Sorry John, but is that a fair cartoon? 

 

 

It was used to sell Unitron scopes as I recall. "Propaganda" !

I still find my 12" F/5.3 dob easier and quicker to setup and use than my refractors. Not that any of my scopes are tricky in that respect because I've always gone for simple setups.

If it can't be out on the patio, setup and cooling in a couple of minutes I don't want to know (dedicated astronomer, thats me ! )

 

 

[Stub Mandrel]

Taken with 150PL on the EQ3 mount it came with using my modded 450D. Yes I know stars are over-sharpened in the first one!

I don't want to kill anyone's APO, but I reckon the 150PL can give a good account of itself and it's my skills and skies that are the limiting factor on what I'm getting, not the scope.

 

[paulastro]

Really nice shots Neil.  They should be an inspiration to people who aspire to take good astro images but believe they need more sophisticated and expensive equipment.

[Stub Mandrel]

31 minutes ago, paulastro said:

Really nice shots Neil.  They should be an inspiration to people who aspire to take good astro images but believe they need more sophisticated and expensive equipment.

Still noisy though, I'm going to make a cold finger for my DSLR.

[John]

5 minutes ago, Stub Mandrel said:

..... I'm going to make a cold finger for my DSLR.

I'm not an imager - dare I ask what a cold finger is ?

[paulastro]

4 minutes ago, Stub Mandrel said:

Still noisy though, I'm going to make a cold finger for my DSLR.

Well Neil, they are still a wonderful example to people of what you can do with some fairly modest equipment - and some skill and know-how of course. 

[Chris]

2 hours ago, johninderby said:

You need a taller tripod.  

          John

That cartoon needs a shorter tripod for the Newtonian by the looks of it too  

[Chris]

Neil, I like how at f/8 you don't need a coma corrector, looks good as is  

For the benefit of the non imagers, the exposure times need to be much longer at f/8 compared to say f/5, which is where DSLR's struggle due to noise from heat build up, so the cold finger is a good move to remove heat from the sensor.

I attached a cold finger when modding one of my old 350D's once but never got round to attaching peltier cooler, just stuck a PC fan to it as a stop gap, not sure how much that helped  

[Chris]

29 minutes ago, John said:

I'm not an imager - dare I ask what a cold finger is ?

It's when you attach a strip of copper to the back of the sensor leading out of the camera to a Peltier cooler. The Cooler gets really cold, and the cold travels along the copper 'finger' to the back of the sensor which removes heat. Heat creates noise when it comes to imaging.