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Focal Reducer

Pig

By Pig
in Discussions - Eyepieces

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emadmoussa

emadmoussa

Posted
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lol it sounds as if you have quite a full life to me :smiley: Astronomy can only enhance it.

Going back to reducers, what it the most weight you have had attached to it ? :smiley:

For me personally - just the normal diagonal and eyepiece. I don't even have it anymore - it was a whim that I thought wasn't worth it if I wasn't intended to do imaging with the C11.

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Macavity

Macavity

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If you don't want to make the reducer part of the "structure", there are alternative reducers that attach to a 2" filter thread: http://www.rotherval...ucer_d1952.html (A bit cheaper for the casual experimenter!)

I don't know about the Baader Steeltrack, but it is entirely possible to "hide" such reducers within the barrel of Baader Monorail focusser. Just attach it to the 2" thread on the end of the diagonal. A set of filter thread extensions (The Baader Hyperion tuning rings) allows reductions of anything from 0.5 to 0.3x ... for imaging purposes. Requires a little bit of thought, but doesn't add to the system length. :)

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Pig

Pig

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If you don't want to make the reducer part of the "structure", there are alternative reducers that attach to a 2" filter thread: http://www.rotherval...ucer_d1952.html (A bit cheaper for the casual experimenter!)

I don't know about the Baader Steeltrack, but it is entirely possible to "hide" such reducers within the barrel of Baader Monorail focusser. Just attach it to the 2" thread on the end of the diagonal. A set of filter thread extensions (The Baader Hyperion tuning rings) allows reductions of anything from 0.5 to 0.3x ... for imaging purposes. Requires a little bit of thought, but doesn't add to the system length. :)

This is excellent news Chris, thank you very much indeed :laugh:

My 2" diagonal definitely has an internal thread. :smiley:

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Macavity

Macavity

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Some additional data on the focal length etc. from another website:

http://agenaastro.co...al-reducer.html

The Antares 0.5x reducer has a focal length of -160mm and needs to sit 80mm in front of the focal plane for 0.5x reduction. This is the typical separation between eyepiece and nose of a 2" diagonal - OR a typical straight filter wheel / webcam setup etc. The requisite in-focus (80mm) is obtained by further twiddling the focusser on an SCT / MAK. The effect of adding extra spacers for additional reduction is given. Maybe (maybe not) achievable within scope focusser range, without distortion / vignetting etc. and subject to experiment! ;)

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alan potts

alan potts

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Shaun,

If you want to use 2 inch eyepieces you will need a two inch visual back which screws to the focal reducer. Once you have this the limit on your eyepieces is 28mm I found, I was using a Meade 28mm SWA and it didnot vignette. I did try the 34mm, which you have and this does cause the problem, though not serious. This is what I found with my scope.

I am a bit chuffed today, just got my tickets for the Wall in Sofia with Roger Waters for the 31st Aug.

Alan.

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Pig

Pig

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Shaun,

If you want to use 2 inch eyepieces you will need a two inch visual back which screws to the focal reducer. Once you have this the limit on your eyepieces is 28mm I found, I was using a Meade 28mm SWA and it didnot vignette. I did try the 34mm, which you have and this does cause the problem, though not serious. This is what I found with my scope.

I am a bit chuffed today, just got my tickets for the Wall in Sofia with Roger Waters for the 31st Aug.

Alan.

Cheers Alan - Great news about Pink Floyd , hopefully you wont get to Brain Damaged :grin: ( I know that was from The Dark side of the Moon and not the Wall)

(Belatedly) That's right. Whatever the "experiment", a 2" reducer always helps.

Gives a starting advantage re. vignetting, whatever the setup / idea / theory. ;)

Cheers for all your help Chris, it is very much appreciated :smiley:

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Macavity

Macavity

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I have never personally / significantly *extended* the visual range of a scope with a field reducer?

I suppose, if the scope will (visually) handle (say) a 17mm eyepiece, a 0.5x reducer will make it look vaguely like a 34mm eyepiece from the same series? (Within the ultimate 2" vignetting limits!) This subject comes up repeatedly. Scope manufacturers advertise them, people buy them. Without writing an article every time, best learnt by personal experiment? I suggested something costing £50 which might be eventually (photographically) be useful, rather than the £100 item. What can one say... :)

Some people do claim focal reducers "work" visually with SCTs... ;)

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Dooshka

Dooshka

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Hello. Here's another option. I have a C11 with a 2-inch visual back and wanted to increase the field of view from a little less than 1 deg which was the best I could obtain with my Revelation Widefield 42mm eyepiece. Because of the mixed messages about Celestron's F6.3 reducer for visual use (I am not into imaging) I opted for an Antares 2-inch 0.5x reducer which screws directly into the front of the eyepiece. Actually, what I did was sandwich an Astronomik 2-inch CLS filter between my Meade 32mm Plossl and the Antares reducer. Seems to work a treat. The Double Cluster was very comfortably framed, proving the scope was now delivering around the 1.4 deg I had calculated. I am now looking forward to exploring the Orion Nebula and much else with this enhanced field of view. I don't doubt that the Celestron F6.3 may work very well, but on the other hand, the Antares only cost me £53. Clear skies to you all!

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Pig

Pig

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Pig,

I think you have made a small error on the focal length, 1630mm? My scope is longer than a 9.25inch CPC, I thought a 9.25 was around 2350mm, at F5 this would be 1175mm. Is there something that I am unaware of?

Alan

Alan it is 1175mm (brain damage) :smiley:

That's a slightly better result, I am intrigued as to how effective they are, there are some good reviews and comments ab

Hello. Here's another option. I have a C11 with a 2-inch visual back and wanted to increase the field of view from a little less than 1 deg which was the best I could obtain with my Revelation Widefield 42mm eyepiece. Because of the mixed messages about Celestron's F6.3 reducer for visual use (I am not into imaging) I opted for an Antares 2-inch 0.5x reducer which screws directly into the front of the eyepiece. Actually, what I did was sandwich an Astronomik 2-inch CLS filter between my Meade 32mm Plossl and the Antares reducer. Seems to work a treat. The Double Cluster was very comfortably framed, proving the scope was now delivering around the 1.4 deg I had calculated. I am now looking forward to exploring the Orion Nebula and much else with this enhanced field of view. I don't doubt that the Celestron F6.3 may work very well, but on the other hand, the Antares only cost me £53. Clear skies to you all!

This is how the TS I bought works, Its only £39 so its worth a punt :smiley: i'll let you know how it goes

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Pig

Pig

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Are we sure the reducer is worth having for visual? Won't a 2 inch widefield EP at native reach the limit of the baffle tube, assuming the 2 inch visual back?

Olly

I haven't a clue but I'll soon find out :laugh: its fairly close to the eyepiece that is my only concern.

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alan potts

alan potts

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Olly,

From my efforts with the LX you cant. If you take the 41mm Panoptic you get about .92 of a degree with a reducer and a 26mm Nagler you can get 1.1 degrees, unless I am doing the maths wrong, which I don't believe I am.

I know not everyone has a 26mm Nagler to play with but the 24mm UWA Max/Meade or the ExSc will give a degree. I used to use a 28mm SWA for the same job and that gave very pleasing results.

Alan.

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Stu_2011

Stu_2011

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Are we sure the reducer is worth having for visual? Won't a 2 inch widefield EP at native reach the limit of the baffle tube, assuming the 2 inch visual back?

Olly

Hi Olly

I've tried both arrangements with my CPC 925 and my 2" Axiom eyepieces and I know the theory says that a good wide field 2" eyepiece should be the best way but I always find that with the reducer in place it produces a better image at the eyepiece. The edges of the image look less distorted and its more pleasing on my old eyes. Can't quantify it any way I just prefer it with the reducer in place.

Thanks

Sent from my iPad using Tapatalk

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Pig

Pig

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hi shaun, have you ordered yet, and im very interested in this myself

Yes, it should arrive very soon, I will let you know how I get on with it and if it is worth getting one :laugh:

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Stratis

Stratis

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If I can just throw in here, I have a 9.25 and the reducer, and I consider it one of the best upgrades I have for my scope for imaging AND visual.

Vignetting notwithstanding (I am certain it happens) the main advantages to me have been image clarity and ease of focus, both of which took a big jump for me when using the reducer lens, and it is likely the two are related. I didn't notice any drop in brightness on-target, and only marginal field softness at the edge of a wide-field EP.

Focusing though.... wow! The one thing I hate about my SCT is the difficult faced in getting the damn thing focused, it just isn't easy and can absorb way too much time under the stars fiddling trying to get the hazy softness off Jupiter's disc. With the reducer it snaps, similar to an ST80 refractor just not as pronounced, and there is a definite increase in sharpness as a result. The effect on TFoV isn't anything to write home about, for me it's just an image quality boost particularly with lower-power EPs.

I feel a bit nervous saying it as nobody else ever seems to feel that way about the part :embarrassed:

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alan potts

alan potts

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Naemeth,

As much as I agree with you buying another scope is not reducing the focal length of the one you have it is also a reduction in apperture. I found about 5-6 years ago before I had a shop full of scopes it was a cheap and really good way of getting a wider field, not that the figures I am quoting are wide.

There is no doubt another scope is a great idea in the long run but at least three times the cost, then you have eyepiece spread to think of after you have it. I for one didn't have any eyepieces to give me anything like high power when I got my second scope which has a F/L of 805mm, my first being 3048mm.

I wish I was in England I would have happily sent Shaun my reducer to see if he liked it, I can't remember when it got used last. The other thing it also gives you is reduced magnification which on a long scope like mine don't really affect anything with regards to contrast.

Alan

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