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Questions on the new 3” Hex focuses from Explore Scientific

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#26 Surfinash

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Posted 30 October 2019 - 08:41 PM

Maybe I missed something in the above posts but unless that scope is drastically different than the aluminum 127mm FCD100 triplet your lens hood (dew shield) is broken.  I don't think they would have put the same big hood on only to have it stop part way.  Its supposed to extend until the black ring at the back of it hits the ring at the end of the tube which gives it a good 6" or so extension, basically the full length of the lens hood (or at least the entire ES logo) should stick out past the end of the tube.  It should come to a hard stop when the two rings smack into each other.  Maybe those screws they use on the carbon fiber version are catching or something.

This is confirmed by ES. The hood only has 3" extend-out. It is a bummer.. 



#27 noisejammer

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Posted 31 October 2019 - 09:26 AM

The 3" TS flattener you linked to is interesting - it reminds me of the giant flattener than was designed by Tom Back and marketed by WO - it even has the same threads. I think these were intended for use on the Fluorostar range (iirc 110/7, 132/7 and 152/8).

 

Not unpredictably, Takahashi uses the same mounting thread (M92x1) but the gender is reversed.



#28 Surfinash

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Posted 31 October 2019 - 02:01 PM

Here is a picture of the lens hood removed from the front. As you can see, the travel clearance is barely 3".

 

IMG_0329.jpg



#29 Surfinash

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Posted 31 October 2019 - 02:26 PM

The 3" TS flattener you linked to is interesting - it reminds me of the giant flattener than was designed by Tom Back and marketed by WO - it even has the same threads. I think these were intended for use on the Fluorostar range (iirc 110/7, 132/7 and 152/8).

 

Not unpredictably, Takahashi uses the same mounting thread (M92x1) but the gender is reversed.

It is. I have seen it in person at their store in Munich. I like TS parts - they are machined really well, and I can vouch for their quality. 



#30 PPPPPP42

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Posted 31 October 2019 - 08:34 PM

Were it a camera lens with a shallow lens hood it would be because its actually pulling in light from that wide a view.

I wonder if that's the case with that faster shorter focal length scope since it does look like they deliberately stopped the dew shield from fully extending like it does on mine.


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#31 Surfinash

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Posted 01 November 2019 - 09:37 PM

Were it a camera lens with a shallow lens hood it would be because its actually pulling in light from that wide a view.

I wonder if that's the case with that faster shorter focal length scope since it does look like they deliberately stopped the dew shield from fully extending like it does on mine.

Hmm.. Didn't think of that. It makes sense though. I wonder what would happen if I put in an extra long cover from astrozap on top (or a DIY cover).. Do you think it will impact with vignetting or darkened corners/borders?



#32 PPPPPP42

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Posted 01 November 2019 - 09:56 PM

I can't think of any way to test it short of making a DIY version and looking at the moon or something obviously bright to see if its dimmer near the edge of the field.



#33 Surfinash

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Posted 01 November 2019 - 10:08 PM

I can't think of any way to test it short of making a DIY version and looking at the moon or something obviously bright to see if its dimmer near the edge of the field.

Perfect. I have a star party here tomorrow. So will try this out! Thanks.



#34 Surfinash

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Posted 04 November 2019 - 06:15 PM

Did some basic and quick (I call this the dirty work) imaging with the 115mm CF FPL-53. A few observations:

 

  • I used the Orion Field Flattener (2") for short refractors. This is rated for f/5 to f/7.5 range. The flattener worked well. Has T2 threads on camera side, and needs 55mm backfocus for CMOS/CCD. Tested this with ZWO 294MC-Pro and confirmed it well. Does seem to have some tolerance (3mm IMO) while focusing. Click here for the flattener. 
  • I chose probably the two incorrect objects for this - M1 and M74. Both for 632mm focal length were small. Also, I did 120-sec subs (15 each) and result was a bit grainy. This may be the culmination of several things - mainly the location to start with. 
  • No issues with the short lens hood. Worked well.
  • Used the dual-narrowband filter for M1. This was a new filter for me, so did not have much experience on the timing. It seems that may be one of the factors in M1 needing more light (definitely over 120 sec).


#35 Surfinash

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Posted 24 November 2019 - 10:07 PM

Update:

 

Received the M87a to M68i custom adapter for the 3" Hex Focuser drawtube. Fits well, and achieves what I wanted - use a number of accessories in thread-on mode instead of "insert and lock three screws".

 

I ordered this part from www.preciseparts.com 

 

Look-up my gallery for some pictures with the new 115mm CF FPL-53 scope.

 

AJ

 

 

Attached Thumbnails

  • IMG-20191123-WA0003.jpeg


#36 Surfinash

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Posted 02 December 2019 - 11:16 PM

For those that are reviewing the new Explore Scientific FPL-53 CF OTAs, @Skyhunter1 has a great thread on it. You can access it HERE.

 

PS: Check out my gallery for early results of the new 115mm FPL-53 OTA from Explore Scientific.


Edited by Surfinash, 02 December 2019 - 11:17 PM.


#37 Tyson M

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Posted 03 December 2019 - 12:17 AM

Thanks for your reviews on this scope.  It definitely piqued my interest as a portable large aperture refractor.  For visual or EAA only though. 


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#38 Surfinash

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Posted 03 December 2019 - 03:21 AM

Thanks for your reviews on this scope.  It definitely piqued my interest as a portable large aperture refractor.  For visual or EAA only though. 

Thanks, and welcome. 

 

If planning visual, you will definitely need the TSFLAT2 with this scope. It has sharp coma. 




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