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First light with ES 127mm FCD100 didn't go so well - help?

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#1 BlueFang

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Posted 17 September 2017 - 04:02 AM

TL;DR - I was not able to achieve focus with the stock setup.

 

It comes with a diagonal and it also comes with 2 extension tubes - but neither extension tube comes attached to the focuser (and there are no instructions about the use of the extension tubes).

 

This is the new aluminum (white) scope with the 2.5" HEX focuser. I tried focusing on a star with a 32mm plossl attached to the included diagonal with the stock setup (no extension tubes). Was not able to achieve focus on a star. Is it normal to have to install an extension tube on a stock from factory setup to achieve focus on something quite ordinary (like a 32mm eyepiece in the stock diagonal)?

 

There is absolutely no documentation / specs / instructions on this particular focuser + scope combination. So I have no idea where the ideal focal pt is - nor do I have any idea how to calculate it.

 

Thx!

 



#2 Mark9473

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Posted 17 September 2017 - 04:15 AM

It's not unheard of that you need to use an extension tube.

There must be a reason they included two of them, don't you think? ;-)


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#3 DLuders

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Posted 17 September 2017 - 04:21 AM

Perhaps this video about "Explore Scientific Rack and Pinion Focuser Adjustments" will help:   https://www.youtube....h?v=SgfE-h8ejr8

 

Pages 30-31 of the Explore Scientific Instruction Booklet discusses the various focusers: https://cdn.shopify....883452077347884 .


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#4 rguasto

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Posted 17 September 2017 - 07:57 AM

I have the original ED127 triplet and it will come to focus with any eyepiece I own using a 2" 35mm extension. I prefer this over the threaded stock extensions which could unscrew using heavy eyepieces. My revolution camera uses no extensions. The 2" 35mm long extension stays on my diagonal when not in use.
-Rob

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Edited by rguasto, 17 September 2017 - 08:04 AM.

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#5 droe

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Posted 17 September 2017 - 09:17 AM

Every configuration seems to require a different set of entension so I bought these

https://www.highpoin...-35mm-50mm-80mm

 

They work great.

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Edited by droe, 17 September 2017 - 05:08 PM.

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#6 DLuders

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Posted 17 September 2017 - 09:21 AM

At the end of that video referenced above, there is the Explore Scientific Customer Service telephone number 1-866-252-3811.  Give them a jingle.



#7 orion61

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Posted 17 September 2017 - 09:46 AM

The manual refers to the 3 sets of collimation screws, It only says loosen one and tighten one nothing else. Which is the   Jack screw and which is the tighten down screw?? That Manual leaves something to be desired! I never got extensions with mine or the illuminated finder BUT id DID get the nice storage case. Mine comes to focus without any problem.

Duane


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#8 BlueFang

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Posted 17 September 2017 - 12:14 PM

Perhaps this video about "Explore Scientific Rack and Pinion Focuser Adjustments" will help:   https://www.youtube....h?v=SgfE-h8ejr8

 

Pages 30-31 of the Explore Scientific Instruction Booklet discusses the various focusers: https://cdn.shopify....883452077347884 .

 

Thanks for the link to that video. That was helpful. I guess the thing that is unclear about the manual is that there is no mention of the new focuser that comes with these new 127 FCD100 series. They are calling it a 2.5" HEX focuser - not sure if HEX is the brand and why it is spelled in all caps - but I believe it is a rack and pinion focuser and seems to have the same functionality and adjustments outlined in that video. 

 

The 2" tensioner was also screwed on pretty tight and it wasn't super obvious that was the right piece to remove to add the extensions - the video makes this clear - it all makes sense now.

 

Hopefully tonight will be a lot less humid and dewy 


Edited by BlueFang, 17 September 2017 - 12:15 PM.

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#9 BlueFang

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Posted 21 September 2017 - 04:02 AM

Just a little update... 

 

Was able to achieve focus with one of the included extension tubes attached with the following eyepieces:

 

5.5mm

14mm

20mm

32mm

 

So it seems like a single extension tube is the sweet spot for observation.

 

Have not tried any imaging yet - still too humid for anything worthwhile.


Edited by BlueFang, 21 September 2017 - 04:02 AM.

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#10 spiral

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Posted 22 September 2017 - 08:26 AM

I have the ES 127 FCD..I use 1 ext. tube for visual and can get focus with all my eyepieces..From 8mm up to 38mm..I use 2 ext. tubes for the Canon DSLR to get focus..If I use the Neximage 5 planetary camera, I need 3 ext. tubes to get focus..I really despise the focuser..lol.gif



#11 Adam E

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Posted 22 September 2017 - 09:39 AM

Having been an imager for a number of years, but now almost exclusively visual only, and having used SCTs, RCs, Newts, and Refractors, one scope spec that I really, really, wish was a standard to advertise is where the focal plane is relative to the rear-most part of the scope.  In other words, what is the available back focus for a scope.  For refractors, it would be great to know how much room there is for an imaging train, or, can I use a bino viewer, can I use a 2 inch diagonal, etc...


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#12 mogur

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Posted 24 September 2017 - 08:07 PM

Really don't understand this. I have the standard iteration of the ES 127ED. With one extension tube and a two inch diagonal I can easily achieve focus with any EP I decide to use. I don't know why the FCD 100 should be any different. shrug.gif



#13 cjdavis618

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Posted 26 September 2017 - 08:17 PM

ED102 here and if using it for visual I have to have 1 extension ring (That came with the scope) and the diagonal to bring into focus on EPs.. IF I am imaging, I have to use both rings (if not using other gear, filter wheel, flattener, OAG, etc.). It is the exact same on the ED80 I have as well. I use that for my guide scope and it is 2x2" extension rings and then the Star Shoot auto guider. 


To add the extension rings, you just unscrew the eye piece holder from the back of the focuser counterclockwise. It may be tight but it does unscrew. Then you just thread the extension rings on, then put the eyepiece holder back on the back of the last ring. Then all done.


Edited by cjdavis618, 26 September 2017 - 08:19 PM.


#14 bigtoga

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Posted 17 March 2019 - 07:23 AM

Old thread but new ED127 FCD100 user here. Before buying I saw this thread and made a mental note that first light may have issues. I did not, however, remember it last night for first light and I had same issues as OP. I wish there were better instructions provided w it. Thanks to all who are helping in this thread as I assume, after watching the video and trying extenders, tonight will be amazing.
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#15 Mr. Mike

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Posted 17 March 2019 - 07:57 AM

Dittos on using focus extenders! I had to do the same thing with my 102mm triplet.  Out of the box I couldn’t focus any of my EPS.  I was kind of like.... "whoa...what the....?".  Then, the internet saved the day, lol.  So I now use one of the two extenders they supplied and all is perfectly awesome.  It was NOT obvious how to attach the extenders either and ES needs to include this information with the scopes, IMO.  Just a little sheet of paper warning the owner about the possibility of having to use them AND how to install them would be fine. 

 

Enjoy your Rodney Dangerfield scopes, folks! rofl2.gif



#16 bigtoga

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Posted 05 April 2019 - 08:14 PM

Unfortunately after trying 1 and then 2 extenders, I am still "stuck" - unable to see anything usable w my ED127. I've tried 2" 82 degree 14mm, and 100 degree 28mm but nada. It's just "blobs" basically. Struggling!



#17 Auburn80

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Posted 05 April 2019 - 08:36 PM

Unfortunately after trying 1 and then 2 extenders, I am still "stuck" - unable to see anything usable w my ED127. I've tried 2" 82 degree 14mm, and 100 degree 28mm but nada. It's just "blobs" basically. Struggling!

Were the extenders the same length?  Can you tell which direction you need to go to reach focus?  Is the focuser moving the prescribed amount from all the way out to all the way in?  Are you using a diagonal.  What were you trying to observe? 

 

Sorry if the questions seem overly simple but frequently the solution is a simple one.

 

Clear Skies!



#18 starryhtx

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Posted 06 April 2019 - 06:55 AM

Were the extenders the same length? Can you tell which direction you need to go to reach focus? Is the focuser moving the prescribed amount from all the way out to all the way in? Are you using a diagonal. What were you trying to observe?

Sorry if the questions seem overly simple but frequently the solution is a simple one.

Clear Skies!


He already found a solution. Needed one extension to achieve focus. Sounds like a nice scope I’d like to get a look through one some day!
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#19 Auburn80

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Posted 06 April 2019 - 09:01 AM

He already found a solution. Needed one extension to achieve focus. Sounds like a nice scope I’d like to get a look through one some day!


Good to know. He had said he had tried 1 and 2 extensions so I assumed ( 😁 ) he meant separately then together.

#20 thekubiaks

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Posted 19 December 2019 - 10:30 PM

It's my turn for the ED127 first light nightmare.  I have the 2.5" Hex focuser, both 37mm extenders prior to the ES .7x focal reducer. And, exactly 55mm from the focuser to the ASI294MC.  I have tried many combinations of gain and exposure time, focus from 0 to 45 with no extender, one extender, and 2 extenders.  I cant even get a star blob on SharpCap or ASICap right now.  I am all set up and the weather is nice so any timely recommendations would be appreciated.   I watched the above videos and read the ES manuals.   Thanks

 

UPDATE  - Took the focal reducer out, switched cameras to the ASI1600MM, trying all iterations, still nothing.....

 

UPDATE 2 - To help those which will surely have the same issue, the 55mm back focus is from the CMOS face to the focal reducer lens.  I had not accounted for the 9mm from the rear of the focal reducer to the focal reducer lens.

 

On another note, the entire 2.5" Hex focuser was loose and wobbling (on a new scope).  I had to tighten the (6) 2mm hex screws, they were all loose, not impressed.


Edited by thekubiaks, 20 December 2019 - 01:04 AM.

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#21 amys

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Posted 20 December 2019 - 07:36 AM

It’s these kind of experiences that steer me away from getting that scope.

#22 BillP

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Posted 20 December 2019 - 07:13 PM

Was able to achieve focus with one of the included extension tubes attached with the following eyepieces:

Good IMO that you needed an extension tube because means that without the extension tube if you binoview you are likely not to need the OCA on the binoviewer, meaning you will be able to achieve lower magnifications and larger TFOVs with the binoviewer.  So sounds like this might be a bino-friendly scope!


Edited by BillP, 20 December 2019 - 07:13 PM.

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#23 kevindt

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Posted 22 December 2019 - 02:27 AM

I also have a new ES ED127 FCD100 OTA, but rather than the ES flattener/reducer, I have a Hotech SCA FFT58-2" flattener, and an Astro-Tech ATR8 reducer/flattener.

 

The Hotech requires both provided extension rings (each is 37.5 mm), giving 75 mm of extension between the hexagonal draw-tube and the adapter ring.  With the sensor of my ASI 1600MM 55 mm behind the back ring of the Hotech, I hit focus at about mid-way on the focuser.  Using the Astro-Tech with similar back-focus and with both extension rings, the draw-tube is pretty close to minimally extended at focus.  Obviously, I'm not using the diagonal.

 

The focuser on mine was also flopping around on arrival with the grub screws almost right out of the threaded holes in the rotation ring, and the rotation locking screw was over-tightened and boring into the inner ring metal.  The draw-tube also had almost a millimeter of lateral free play within the focuser until its adjustment grub screws were correctly tightened and the focuser and draw-tube tube aligned.  Coarse focusing movement was rough and gritty.  Once the focuser was stripped down, cleaned and reassembled correctly, it now works nicely with no free play and no image shift, and no drift with the camera and filter wheel attached.  The movement is now smooth and positive with a nice feel to both fine and coarse adjustment.

 

More concerning is the fine dust and several very tiny bits of shiny metal swarf visible between the objective elements, and tiny flakes of the black paint on the diagonal mirror.   No effect on the image, but not what I'd hope to find on a brand-new scope at this price.

 

On the positive side, once the focuser was cleaned and aligned, the OTA and Hotech flattener give nice round, sharply-focused stars to the edges of the field on my ASI 1600MM.  I don't see visible vignetting, but I haven't looked hard for it.  The weather has not yet been good enough to test things out much further.  It came with an ample free gift of cloud and rain, of course - and even this very limited testing has been done dodging between the showers, clouds and heavy dew.



#24 thekubiaks

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Posted 22 December 2019 - 05:23 PM

I also have a new ES ED127 FCD100 OTA, but rather than the ES flattener/reducer, I have a Hotech SCA FFT58-2" flattener, and an Astro-Tech ATR8 reducer/flattener.

 

More concerning is the fine dust and several very tiny bits of shiny metal swarf visible between the objective elements, and tiny flakes of the black paint on the diagonal mirror.   No effect on the image, but not what I'd hope to find on a brand-new scope at this price.

 

I also have this fine dust and particles in my new ES ED127.  I was too busy fighting with the focus to turn my anger at the dust inside the lenses.  Now that I have the focus resolved, I'm not sure how to attack cleaning the lenses....I'm afraid of collimation nightmares if disassemble anything.  I might mail it back to ES.  Keep me updated if you figure this out.



#25 Bomber Bob

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Posted 22 December 2019 - 06:22 PM

I have only 2 ED fracs.  I bought the APM 152 first about 2 years ago.  It had no dust / trash between the elements.  My new AT102ED has several microscopic metal dots, and a bit of dust between the elements.  This thrash didn't hurt the DPAC patterns, or the star & sky testing.  If it had, it would've gone back.

 

I don't plan on taking either ED lens apart any time soon.  From what I've read here, based on the glass types and/or curves, some are as easy to disassemble & reassemble as a standard achromatic doublet, while others are nightmares to re-align correctly.




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