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Night Vision Newbie - 4 inch refractor, Help, Lost in Space

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#26 GeezerGazer

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Posted 29 September 2020 - 04:46 PM

Joe, 

In case you have missed it, the pinned thread, "BEST of NV" near the top of our forum page can answer a lot of questions.  If you click on it, you will see a list of general topics; click on any one topic for a list of threads that will answer specific questions.  Each specific thread includes the year it was started, by whom, and a two or 3 word description of its content.  There is a list of FAQs among the topics page, which you might find helpful.  

Ray



#27 laico

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Posted 30 September 2020 - 12:09 AM

Hi Ray,

 

Thank you for pointing that out, I had queried the line items starting with ascending dates, "THANKS" I should have acknowledged early on.

 

To recap, everyone has been consistent, " simply stated you will see more of what you were unable to conventionally", that lends itself to confidence.

 

I think everyone in this hobby has spent money here, there and everywhere with many mixed results some better, some disappointing.  So this choice was no different, thank you to all Cloudy Nights members that have been supportive and willing to step up and lend assistance.  Thank you to Eddgie for his many well articulated comments/articles that have clarity on those topics I myself was not knowledgeable about, thus easier to make sane choices.

 

Should there be anyone out there using their FC-100DF solely for NV I sure would welcome any feedback in the future.

 

Thank you to "ALL"



#28 jay.i

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Posted 30 September 2020 - 12:14 PM

Joe, I sent you a PM about reaching out to someone for input on using the FC-100DF for NV. I think this person would be happy to answer any questions you have!



#29 gatorengineer

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Posted 03 October 2020 - 10:03 AM

Just as an aside, I freely admit I am spoiled by good glass. But last night was the first and last with NV in the FSQ-106, yes it works, and the views are nice but the aperature difference to the MN-74 (3x) is too great, for the FSQ to get used for NV for me.    If I didnt have the MN I would be looking at an F4 newt either 6" or 8".   A 3.5NM Antilia was a no go in this scope.  Again my use is afocally with 50 and 65 Russell Plossls.


Edited by gatorengineer, 03 October 2020 - 10:06 AM.


#30 Gavster

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Posted 03 October 2020 - 10:40 AM

Just as an aside, I freely admit I am spoiled by good glass. But last night was the first and last with NV in the FSQ-106, yes it works, and the views are nice but the aperature difference to the MN-74 (3x) is too great, for the FSQ to get used for NV for me.    If I didnt have the MN I would be looking at an F4 newt either 6" or 8".   A 3.5NM Antilia was a no go in this scope.  Again my use is afocally with 50 and 65 Russell Plossls.

I really like my fsq85 and fsq130 with my pvs-14, 67mm Televue afocally and chroma 3nm ha filter. These get me an effective f2ish speed and nice wide fov for the larger nebulae like the North America, gamma cygni, California, heart and soul etc. For the smaller nebulae, globulars and galaxies my preference is my c11 Edge (plus 0.7x reducer) or 16 inch dob with the 67mm to get fast effective speed but with materially more magnification.

 

I did use a Tak fc100df initially with my pvs-14 and it worked pretty well. But over time I’ve come to prefer faster flatfield (petzval type) refractors for night vision use. I found in afocal mode, any field curvature that the scope had was exaggerated by nv, hence my switch to flatfield scopes.


Edited by Gavster, 03 October 2020 - 11:21 AM.

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#31 Astrojedi

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Posted 03 October 2020 - 06:09 PM

I have been involved in the hobby for the past 30 yrs, I understand no one telescope is going to Master all things, there is always that option to improve on all parameters from aperture to speed etc. I have searched high and low and put forth the due diligence, I have read all of Eddgie's articles to comprehend the methods, caveats, and hardware options. I have noticed a consist theme, that being the evolving choice of hardware/telescopes. Herein is my dilemma, my wife will shoot be at sunrise should I buy another telescope, I currently have a stock (no FT) Takahashi FC-100DF 2.7 focuser / F/7.4 to F/4.9 (Takahashi FC-35 "expensive" focal reducer which I currently do "NOT" own). I have enjoyed the scope immensely for Visual, no regrets, only drawback is driving great distances to get further away from New York City lights (White zone). Its time for me to modernize and evolve as so many CN'ers have done before me. I have read so many varying opinions that I am confused by the possibility of me being able to utilize my current 4" refractor. I understand some of the math, I understand "scale", imaging, framing, the self explanatory aspects to what some might opt for larger versus modest views. In my neck of the woods anything is an improvement so my expectation is both rational and practical.

 

To my question, I had read a review posted online about the TNVC, 55mm plossil, all married to a "Televue 85mm refractor" got me thinking; how the hell did it go from F/7 to F/1 or F/2 to achieve the speed, what math is involved here? I understand as is the case in this hobby we always achieve best results with more aperture and speed, its a never ending battle however, how do we work with what we have without always having to reinvent the wheel with a fast NEWT or some other astrograph. I realize the FC-100DF 4" refractor as designed for Visual in the ideal world where dark skies were consistent.  My objective is to try and utilize with a MOD 3 but I am uncertain as how to accomplish with "decent' expectations, For the price of the Takahashi Focal Reducer I could just as well by something more cost effective, so to my original question could someone Please explain how we increase the overall speed, considering the 85mm out of the box is an  F/7 focal ratio by product design. 

 

The How to is the part that is missing. My initial expectations with a 4" refractor would be to make out nebulae, let alone galaxies i.e. M51. Is it possible to transform this FC-100DF, I do not mind being the pioneer, to date I have not found a single syllable that someone might have posted. Its one hell of a refractor under pristine skies, I would think their is someone that can educate myself how to work with what I already have. I digress, I realize one scope cannot do it all, but surely it can be versatile enough to configure to meet reasonable expectations. Any advice is welcome, I apologize for reiterating here and there but I just wanted to be for certain I was not misinterpreted, and I thank all for replying.

 

Thanks,

 

Joe

Joe,

I use my 100DF for NV with a 50mm Gary Russell plossl, 0.7x reducer and gen 3 WP NV PVS-14. The setup excels at observing Milky Way dark nebulae, clusters and globs from my heavily light polluted backyard. The one really good thing about the 100DF is the shorter tube which allows the use of a focal reducer. Let me know if you need additional information on my setup
 

Edit: here are pictures of the NV setup.  

 

Lumicon night sky H-Alpha > CCDT67 reducer > 2” diagonal > GR 50mm > Televue Adapter > Pvs-14 Gen 3 WP

D5F2B6CB-1D20-4124-9822-9BE102352EE7.jpeg
 

07DE604F-F08F-4BEC-B1DF-700F01681DAE.jpeg

 


Edited by Astrojedi, 03 October 2020 - 06:21 PM.

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#32 laico

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Posted 04 October 2020 - 07:13 AM

Hello to all recent replies, my apologies for not responding sooner, just inundated with my job.

 

Gator, Thanks for the feedback regarding FSQ-106, years ago I had the second generation model and dabbled in some brief imagery when I realized it was not my cup of tea. One hell of a petzval design, built like a bomb.

 

Gavster, Thanks for your feedback regarding your preference to flat field, duly noted.

 

AstroJedi......  Thank You for taking the time to acknowledge my request for someone using an FC-100DF, I noted your image train included an AP focal reducer attached to your diagonal, one of my initial concerns was just how well it would work with a 3rd party focal reducer, you answered my question, in fact I have that exact same FR with a AP maxbright diagonal, prior to ever giving thought to NV. So you saved me a couple of bucks, confidence not to have to run the gauntlet of experimenting with expensive components. I would welcome a conversation, I will PM you if that is okay with you. As noted I am in NJ where White Zones rule and if their was another category for the bortle scale it would be called New Jersey.

 

Thank you to all for your most recent replies and Greatly Appreciated.

 

Joe



#33 Deadlake

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Posted 03 November 2020 - 12:53 PM

Seeing as a 100DF can be adapted to be used for NV, would the same approach work with a Vixen SD103S with a reducer attached? I realise the compromise will be field curvature, but as a first cut it would allow getting started with NV, without having to invest in a another scope?



#34 laico

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Posted 03 November 2020 - 03:59 PM

Hello Deadlake,

 

From my understanding by the kind members of Cloudy Nights, the same would be applicable to other refractors,what I learned was the how and why the process works. The math would apply to your scope as in prior posts above. What I can say is that taking the first step with "reasonable" expectations is a good start. I sum it up this way, a smudge is a smudge and in  a small refractor with NV its a hell of a lot nicer then a smudge however.... the overall size of your image (scale) is the one parameter you have to accept. i.e. M57. My definition of success is just to say I have more appreciation for what I can now see more clearly versus that infamous smudge. Recall I am in a White Zone so another tool in the tool box does help aid me in a sense of accomplishing and enjoying more of what as dam near impossible to see. Now in retrospect, I must be honest and say that at some point in the future it becomes obvious 4" is 4" and the ambition and desire to see more is a resounding reminder that a newt is in my future, to reiterate very happy with 4" results however would be even more content with doubling the size of the telescope to 8" newt so more details were visible. The refractor does "not" disappoint, it does an excellent job for its size on objects like M42 etc. I just would add remember my location just out side of New York City is the worst, however if your location is better suited to viewing its quite possible that 4" is going to show a lot more detail and meet all expectations, I have no doubt I would be content with just the 4" if I lived next to Cherry Springs Park, PA but that is not the case. Thanks.. Joe


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#35 Deadlake

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Posted 06 November 2020 - 02:58 AM

I’ve come to the conclusion after reading various threads a 4” is a viable starter telescope for NV. As long as the 67 mm converter is in play, most user have stopped using there reducers as it makes the effective F low enough. The other consideration is flatness, a flattener can be safely added as no affect on focal length.
A built in flattener and low F would be idea, which brings to mind a Televue or Tak FSQ scope. However other options to expired would be one of these:

https://www.365astro...-telescope.html

I’ll start with a 4” and flattener and then explore other options.

#36 laico

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Posted 06 November 2020 - 04:44 AM

Hello Deadlake,

 

I sincerely have "no" clue as to uses what, given the hobby is so limited to begin with and so many vendors have reps that either over sell or under sell what is actually required; let alone the inept individuals that will BS you all day long. Having said that, the CN members that assisted myself were accurate and far more knowledgeable, My post was primarily aimed at avoiding all incurred extra costs that yield dismal results, been there done that will maximum frustration in the "past". My advice is work with what you have to begin with and determine what suits your needs to enhance NV viewing. In that regard, less frustration, and results  that yield visible object that prior were invisible,  that is a win win situation. I think your 4" will do just fine, as so many others reassured myself and to their credit they were correct.

 

Thanks,

 

Joe



#37 gatorengineer

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Posted 06 November 2020 - 07:59 PM

I have a tak fsq 106 and yes nv technically works with it.... But an $800 imaging newt (8 inch) and paracorr typeb will show you 10x as much.


Edited by gatorengineer, 06 November 2020 - 08:43 PM.



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