Would a focal reducer require premium EPs?

[emadmoussa]

The question in the title might be a bit ambiguous. But let me explain, for an f10 SCT, the demand for high-quality eyepieces might not as pressing as, say, an f5 Dobsonian. SCTs, as you all know, can deliver decent views with medium-quality eyepieces. The question is, however, if I fit a 6.3 focal reducer to my SCT, turning the scope into an f7 instrument, would that make a difference to my eyepieces? 

My eyepieces are medium to high quality, so I'm not that worried about the result. I'm just curious about what the change in focal length may cause.  

 

[Alien 13]

No personal experience but it would make sense that the reducer alters the light cone shape and would then require good quality eyepieces, I know the reverse is true in that when using a barlow lens you can get away with any old rubbish for an eyepiece (well not quite).

Alan

[RT65CB-SWL]

Hi Emad.

I don't think so. I have not seen any noticeable difference when using my TV e/p's and Celestron f6.3 FR/FF in my C6. Though saying that, I believe the Meade f3.3 did. 

[John]

The F/3.3 reducers are intended for imaging, not visual use.

The only downside to the F/6.3 reducers that I am aware of is that they are optimised for the 1.25" eyepiece format. You might see some vignetting (loss of light at the field edges) with 2" eyepieces with large field stops.

[Ruud]

4 minutes ago, Philip R said:

Hi Emad.

I don't think so. I have not seen any noticeable difference when using my TV e/p's and Celestron f6.3 FR/FF in my C6. Though saying that, I believe the Meade f3.3 did. 

But, those are premium eyepieces.  Congrats on owning them, they're not cheap, but they handle fast focal ratios very well.

[Davey-T]

Don't see any difference in my 10" but I'm no expert having rubbish skies and rubbish eyes doesn't help.

Although I've used the original 6.3 f/r in mine it's not designed for it so if you get a later ACF model you need to budget for a more expensive one, something like this.

Dave

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p4955_Astro-Physics-CCDT67-0-67x-Reducer-2----e-g--for-GSO-RC.html

 

[Ben the Ignorant]

A steeper beam is harder to grasp for the eyepiece, no matter if the scope is a native f/6.3 or a reduced f/6.3.

[emadmoussa]

Philip, but your EPs are good quality, aren't they? For visual use, f3.3 reducer might be an overkill. 

John, I was wondering about that. However, the scope I'm buying is ACF (Advanced Coma Free optics). Speaking with someone who owns this scope and reading reviews, Meade ACF does indeed eliminate coma. So, in my perhaps naive opinion, vignetting maybe be reduced when a 2" reducer is used?

Dave, yes, ACF is my aim. And, great!! More money to spend...!!! 

 

[John]

52 minutes ago, emadmoussa said:

John, I was wondering about that. However, the scope I'm buying is ACF (Advanced Coma Free optics). Speaking with someone who owns this scope and reading reviews, Meade ACF does indeed eliminate coma. So, in my perhaps naive opinion, vignetting maybe be reduced when a 2" reducer is used?

 

 

Not sure that vignetting (loss of light at the field edges) is anything to do with coma Emad

With the Celestron Edge HD a different focal reducer than the standard F/6.3 is needed I believe so it's worth checking what is required for a the Meade ACF perhaps ?

[emadmoussa]

2 minutes ago, John said:

Not sure that vignetting (loss of light at the field edges) is anything to do with coma Emad

With the Celestron Edge HD a different focal reducer than the standard F/6.3 is needed I believe so it's worth checking what is required for a the Meade ACF perhaps ?

I might just ditch the whole reducer idea altogether and get a 30/35mm wide field EP It's possible the dealer will give me a 2" Antares reducer (usually retails at about £90) as a free gift with the scope, then I can probably put it to the test with my eyepieces and just sell it if the ACF isn't happy with it. 

[John]

5 minutes ago, emadmoussa said:

I might just ditch the whole reducer idea altogether and get a 30/35mm wide field EP It's possible the dealer will give me a 2" Antares reducer (usually retails at about £90) as a free gift with the scope, then I can probably put it to the test with my eyepieces and just sell it if the ACF isn't happy with it. 

In the end I just moved to a 2" diagonal used with a 40mm SWA eyepiece when I had a C8. I also came to accept that the SCT is not a widefield scope and for relatively few £'s I could get a nice newt OTA or fast refractor which would do the wide field thing much better

[emadmoussa]

8 minutes ago, John said:

In the end I just moved to a 2" diagonal used with a 40mm SWA eyepiece when I had a C8. I also came to accept that the SCT is not a widefield scope and for relatively few £'s I could get a nice newt OTA or fast refractor which would do the wide field thing much better

Like you say, you get used to it. I don't think I ever used any 1.25" diagonals, they always felt like toys  I'm also content with the idea that most DSOs are small and the FOV won't be a big deal. 

[emadmoussa]

And, I'd always sneak in an 80/100ED without the Mrs noticing. I want a grab and go frac at some point. 

[RT65CB-SWL]

45 minutes ago, emadmoussa said:

And, I'd always sneak in an 80/100ED without the Mrs noticing. I want a grab and go frac at some point. 

Just tell her it is an upgrade for the finderscope! ?

[emadmoussa]

56 minutes ago, Philip R said:

Just tell her it is an upgrade for the finderscope! ?

That's genius!!! What can I say about the small mount? Hide it in the garage where she's never gone before?! 

[RT65CB-SWL]

10 hours ago, emadmoussa said:

That's genius!!! What can I say about the small mount? Hide it in the garage where she's never gone before?! 

Good idea. Just shout: "I've found it!" after a few minutes rummaging around. It's surprising what you thought you was lost, suddenly becomes found.