Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

BORG 107FL F3.9ED

  • Please log in to reply
70 replies to this topic

#51 CrzHrs

CrzHrs

    Messenger

  • -----
  • Posts: 443
  • Joined: 24 Jan 2014
  • Loc: Venezia (VE)

Posted 11 January 2019 - 05:26 AM

Thanks steven, I mainly work mono+LRGB or narrowband, but i must understand exactly this optic behaviour to get out the best.

 

I am posting all my learning progress here instead keeping private.I hope it might help someone, becouse these scopes are beautifully crafted. Next steps: fix qhy drivers (!), test spacers at 60mm instead 59,80. do different time pose each band and report star's bloating on paper. maybe i have to balance colors during acquisition instead post-processing.

 

All the pictures i posted are not calibrated, colors are not even balanced. right out of the box. Way better than at the beginning

 

More to come :)



#52 StevenBellavia

StevenBellavia

    Viking 1

  • *****
  • Posts: 532
  • Joined: 11 Mar 2014
  • Loc: New York

Posted 11 January 2019 - 08:30 AM

I now see my previous post was foolish, as the 90FL f/4 is NOT the same design as the 107 ED f/3.9  despite having the same number of elements (6).

 

From the descriptions, the 107 is a Petzval design.  That's a whole different thing, and in my opinion, Petzval is the best way to go in an imaging refractor.

 

One nice thing is a "true" Petzval design (all elements forward of the focuser) eliminates the need for precise spacing of the camera.  If you get the sensor at the focal point, you are at the correct spacing, not the other way around as it is for the 90FL, where the last 4 elements are a reducer-corrector, aft of the focuser, requiring a specific distance from the last element to the sensor, with maybe 0.5mm of tolerance before things go bad.

 

I also think Petzval's have better color correction and perhaps a larger flat field.

 

What I don't know is if achieving this large flat field and good color correction was at the expense of a larger point spread, i.e, larger spot sizes (though I am guessing/hoping, still diffraction limited, at least near the center of the field).

 

I started designing my own Petzval 4-element 100mm focal length, f/4 lens, using OSLO, but cannot get good results with off-the-shelf lenses, even if I start with a  N-SSK5/LAFFN7 achromat.  I think a good Petzval is quite a feat, but more and more are showing up.  Even Meade has a 71mm f/5 Petzval refractor now. Is this a fad or the future for imaging?  I don't know, but I really like my William Optics 71mm f/4.9 Petzval.  It is by far the easiest scope to image with that I have ever owned.  Had I gotten this when I started 4 years ago, (instead of a 6-inch f/4 Newt) I may have not purchased anything but a Petzval after that.


Edited by StevenBellavia, 11 January 2019 - 08:44 AM.


#53 CrzHrs

CrzHrs

    Messenger

  • -----
  • Posts: 443
  • Joined: 24 Jan 2014
  • Loc: Venezia (VE)

Posted 12 January 2019 - 03:54 AM

Not exactly. it is called "advanced petzval", the reducer is in the focuser, distance is fixed



#54 vdb

vdb

    Surveyor 1

  • -----
  • Posts: 1,531
  • Joined: 08 Dec 2009

Posted 12 January 2019 - 05:34 AM

Not exactly. it is called "advanced petzval", the reducer is in the focuser, distance is fixed

Hmm zo it's a stretch to call it a petzval design, putting the word advanced in front of it makes it not any better either ... it's a doublet with a 4 element super reducer ... (or is it a triplet ... )

 

/Yves



#55 CrzHrs

CrzHrs

    Messenger

  • -----
  • Posts: 443
  • Joined: 24 Jan 2014
  • Loc: Venezia (VE)

Posted 12 January 2019 - 07:19 AM

.basically.. Yes



#56 CrzHrs

CrzHrs

    Messenger

  • -----
  • Posts: 443
  • Joined: 24 Jan 2014
  • Loc: Venezia (VE)

Posted 12 January 2019 - 03:47 PM

Nightly thoughts.. i was wondering if i was demanding too much from a fast focal refractor, so i went to see how FSQ behaves..

 

fsq-mosaic.jpg

 

Well.. i think there's nothing wrong on Borg's optics. the images i had post were all raws, i do not see any different behaviour from Fsq: maybe borg goes a little more on green while takahashi goes for red, i'd say that this borg it has a beautiful optic, i still have to see where is best spacing between 59,8 and 60, but i do really like this scope.

 

..or i am misleading something?



#57 medderx

medderx

    Vostok 1

  • *****
  • Posts: 130
  • Joined: 02 Jul 2015
  • Loc: Seattle

Posted 12 January 2019 - 05:04 PM

Fast refactors tend to struggle with the high end of the spectrum. The borg will a bit more just because the optics are not absolutely perfect, but I think it's good enough based on its price point.

 

The fsq does also struggle with blue/violet but I don't believe as much so. Here are some test reports from two of them if you scroll down the page a bit. However it does not mean much without also seeing a test report of the borg. 

 

https://airylab.com/...y-test-reports/



#58 CrzHrs

CrzHrs

    Messenger

  • -----
  • Posts: 443
  • Joined: 24 Jan 2014
  • Loc: Venezia (VE)

Posted 21 January 2019 - 02:45 PM

I think job is done. distance from my camera is 59,8mm

 

cattura3.jpg

 

Cattura4.jpg

 

No deconvolution, just an automatic color correction (can lower a little more greeen). I don't think this optic has any iussue at all... i do really like it


  • psandelle likes this

#59 jay.i

jay.i

    Mercury-Atlas

  • *****
  • Posts: 2,768
  • Joined: 11 Jun 2017
  • Loc: Minneapolis, MN

Posted 21 January 2019 - 03:06 PM

I see a little point in the lower left of most stars in the second photo, making stars almost like a teardrop shape. Any idea what that's about?



#60 CrzHrs

CrzHrs

    Messenger

  • -----
  • Posts: 443
  • Joined: 24 Jan 2014
  • Loc: Venezia (VE)

Posted 22 January 2019 - 01:17 PM

That is the (in)famous blue halo due chromatic aberration. That is a very high zoom, it is very well managed.

This optic does not suffer from the f4 blue halos,that might go away with a simple deconvolution.


  • psandelle likes this

#61 Jon Rista

Jon Rista

    ISS

  • *****
  • topic starter
  • Posts: 24,254
  • Joined: 10 Jan 2014
  • Loc: Colorado

Posted 26 January 2019 - 01:52 PM

Hi guys,

 

I thought I would chime in and mention that I ultimately decided to get the FSQ106. I don't know that any of the three actually really perform better in the blue end of the spectrum than any others or not...but I do know the FSQ has a stellar reputation. I ordered a full package from Tolga, with Nitecrawler, f/3.6 reducer and everything. More money than I wanted to spend...but, I figure this is a lifetime scope, and it'll serve me for the next 20-30 years or so. It was ultimately less than the Canon 600mm lens even with the expensive Nitecrawler, though (didn't even break $10k), so I can't really complain too much. ;)

 

I debated a lot about the VSD100, Borg107, and FSQ106. In the end, the FSQ won out in part because it just has such a huge, dedicated following, and if I ever needed to I feel I could sell the FSQ easier than the VSD, and much, much easier than the Borg. But beyond that, the FSQ was ultimately a bit more versatile, given that I could put the Nitecrawler on it, and at this point in the game I want to automate as much as I possibly can, and the motorized rotator of the Nitecrawler was really appealing. Plus, if the time ever comes where I feel like putting a larger camera on it, either a full frame DSLR, MFD or something like a KAF-16803, I'll be able to with a heavy duty focuser like that.


  • StarDust1 and jay.i like this

#62 akulapanam

akulapanam

    Mercury-Atlas

  • *****
  • Posts: 2,656
  • Joined: 26 Aug 2012

Posted 26 January 2019 - 02:38 PM

Hi guys,

I thought I would chime in and mention that I ultimately decided to get the FSQ106. I don't know that any of the three actually really perform better in the blue end of the spectrum than any others or not...but I do know the FSQ has a stellar reputation. I ordered a full package from Tolga, with Nitecrawler, f/3.6 reducer and everything. More money than I wanted to spend...but, I figure this is a lifetime scope, and it'll serve me for the next 20-30 years or so. It was ultimately less than the Canon 600mm lens even with the expensive Nitecrawler, though (didn't even break $10k), so I can't really complain too much. ;)

I debated a lot about the VSD100, Borg107, and FSQ106. In the end, the FSQ won out in part because it just has such a huge, dedicated following, and if I ever needed to I feel I could sell the FSQ easier than the VSD, and much, much easier than the Borg. But beyond that, the FSQ was ultimately a bit more versatile, given that I could put the Nitecrawler on it, and at this point in the game I want to automate as much as I possibly can, and the motorized rotator of the Nitecrawler was really appealing. Plus, if the time ever comes where I feel like putting a larger camera on it, either a full frame DSLR, MFD or something like a KAF-16803, I'll be able to with a heavy duty focuser like that.


IMHO there are some issues with the FSQ though, namely the need to replace the focuser like you did right out of the box.

#63 Jon Rista

Jon Rista

    ISS

  • *****
  • topic starter
  • Posts: 24,254
  • Joined: 10 Jan 2014
  • Loc: Colorado

Posted 26 January 2019 - 06:32 PM

IMHO there are some issues with the FSQ though, namely the need to replace the focuser like you did right out of the box.

Yeah, but that's the thing. None of them are issue-free. The VSD100 is really nice...but it has a strange focuser. Tolga has a motor unit for it, but there doesn't appear to be any real option to replace it. The Borg scopes have long had questionable handling of the blue end of the spectrum (more questionable than the VSD or FSQ). Borg seems to be improving here... It was a decision of tradeoffs. I wanted the NiteCrawler...specifically I wanted a reliable slip-free focuser and I wanted automated rotation. So the NiteCrawler was ultimately a given anyway, it just happened sooner than I planned, and the FSQ was the best option to use with the NiteCralwer.

 

My 600mm lens is not perfect either. Even excluding the tilt issue which can be fixed, it has a small diffraction issue near the periphery of the field that splits star halos, angle dependent. For fast refractors, perfection is clearly not an option. Not, at least, for middle-class-accessible cost. I actually like what I've seen with the stars from the VSD more than the FSQ. They seem to be rounder. As I understand it there is a bit of astigmatism inherent to the optical design of the FSQ. I can manage that, though...my 600mm lens has the same thing that often results in diamond shaped stars. A bit of drizzling clears it right up though, and I can do the same with the FSQ.

 

Choosing was honestly hard for me. I think all three scopes are great, and I think it would be tough for anyone to really go wrong with any of them. I started this thread...what, some two months ago now or so? That's how hard the decision was. tongue2.gif I spent a lot more than I had planned, but, I don't feel like I made a bad choice.


Edited by Jon Rista, 26 January 2019 - 06:32 PM.

  • psandelle and nicknacknock like this

#64 rockstarbill

rockstarbill

    Fly Me to the Moon

  • *****
  • Posts: 6,979
  • Joined: 16 Jul 2013
  • Loc: Snohomish, WA

Posted 30 January 2019 - 03:49 AM

Yeah, but that's the thing. None of them are issue-free. The VSD100 is really nice...but it has a strange focuser. Tolga has a motor unit for it, but there doesn't appear to be any real option to replace it. The Borg scopes have long had questionable handling of the blue end of the spectrum (more questionable than the VSD or FSQ). Borg seems to be improving here... It was a decision of tradeoffs. I wanted the NiteCrawler...specifically I wanted a reliable slip-free focuser and I wanted automated rotation. So the NiteCrawler was ultimately a given anyway, it just happened sooner than I planned, and the FSQ was the best option to use with the NiteCralwer.

 

My 600mm lens is not perfect either. Even excluding the tilt issue which can be fixed, it has a small diffraction issue near the periphery of the field that splits star halos, angle dependent. For fast refractors, perfection is clearly not an option. Not, at least, for middle-class-accessible cost. I actually like what I've seen with the stars from the VSD more than the FSQ. They seem to be rounder. As I understand it there is a bit of astigmatism inherent to the optical design of the FSQ. I can manage that, though...my 600mm lens has the same thing that often results in diamond shaped stars. A bit of drizzling clears it right up though, and I can do the same with the FSQ.

 

Choosing was honestly hard for me. I think all three scopes are great, and I think it would be tough for anyone to really go wrong with any of them. I started this thread...what, some two months ago now or so? That's how hard the decision was. tongue2.gif I spent a lot more than I had planned, but, I don't feel like I made a bad choice.

Good choice, Jon. Its a wild horse you have to tame to get it to do your bidding. Nice call on the NiteCrawler, just be prepared to run a lot of focus runs as the FSQ is needy in terms of focus. Try Voyager out. It can run a whole focus run in a minute. 



#65 eastwd

eastwd

    Mariner 2

  • -----
  • Posts: 231
  • Joined: 21 Aug 2011
  • Loc: Nashville

Posted 30 January 2019 - 08:52 PM

At least this model improves on the available back focus. I have the Borg 125SD with the modified Petzval EDF4 #7704 reducer and Pentax lens, and at f/3.9, it goes toe to toe with the FSQ-106 on image circle size (both are around 60mm), color correction, and producing round stars to the field edge, plus it's got more aperture and is lighter.  It's also easily convertible to f ratios up to f/6.5 as a visual scope. But its measly back focus of 55mm (actually just 42.5mm from the back of the reducer) is just enough to allow connection of an EOS camera or certain large format CCD/CFW combos with no room whatsoever for even a thin off-axis guider.  The FSQ-106 with the 645 Reducer has a published back focus of 72.2mm -- plenty of room for an OAG with most setups.  Advantage Takahashi, bigtime.  But I've read that with this new 107FL F3.9ED, you can eke out up to 80mm of back focus if you remove the M57 camera rotator on the back and connect using the rear M68.8 thread. That'll give you plenty of room for a full sized OAG like the MMOAG or MegaMOAG with most large format CCD/filter wheel combos -- even cameras with monster chips like the FLI ML50100.  And being able to image with an OAG is a big deal to me. I wish my old EDF4 reducer had similar back focus to this new one.

 

Larry


  • psandelle likes this

#66 dingxinyang

dingxinyang

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 21 Dec 2018

Posted 08 April 2019 - 02:43 AM

HIļ¼Œjon

    will you consider  reflector? TAK  has produced some brilliant reflectors , epsilon 130d(f/3.3) and epsilon 180ED(f/2.8) , they both have rather big aperture and very fast , the only annoying issues are the diffraction spikes and you will always have to collimate the scope each time when the scope has been moved 



#67 edif300

edif300

    Apollo

  • -----
  • Posts: 1,425
  • Joined: 24 Feb 2007
  • Loc: Basque Country

Posted 08 April 2019 - 09:25 AM

 and you will always have to collimate the scope each time when the scope has been moved 

 

Not quite sure about that... my astrophotography partner own the E-180EDC and he has collimated only once last 2 years. Each time we go to our site we drive about 3 hours and half for about 300km... the collimation in the Epsilon is truly stable.


  • Fomalhaut likes this

#68 Konihlav

Konihlav

    Surveyor 1

  • -----
  • Posts: 1,734
  • Joined: 05 Mar 2009
  • Loc: Germany

Posted 10 April 2019 - 03:09 AM

every reflector will outperform refractor, in all ways (spots, CA), but has one disadvantage - there doesn't exist a small and portable one (I mean, truly portable, pocket size) and unless the primary is hyperbolical it won't be usable on a full frame (36x24mm) chips... I have failed with my project http://blog.astrofot...velpech/?p=1413 due to the issue that TeleVue doesn't mention anywhere on the website nor product manual (paracorr) - that it's not usable for short focal lengths (small apertures)...

 

BTW I decided (today) to get on the FSQ-85 to replace my old Borg77EDII and the reasons for me to go with BabyQ over e.g. newest Borg 90FL is - for such an amount of money, with FSQ you are given the spot diagrams, the vignetting plot, you know all the issues of the FSQ-85 (**** butterfly stars etc.), but with Borg you have no specs at all and all images on the web look bad even downsized to 1024pixels wide :-( the 77EDII with 7704 reducer was the best astrograph Borg ever made.

 

good luck Jon with your FSQ-106, I did never consider this scope due to the focus stability issues (it's a big mass of glass).



#69 dothead

dothead

    Apollo

  • -----
  • Posts: 1,139
  • Joined: 13 Aug 2008
  • Loc: Heidelberg, Germany

Posted 10 April 2019 - 04:09 AM

Get one of the Lichtenknecker Flat Field Cameras ...



#70 eastwd

eastwd

    Mariner 2

  • -----
  • Posts: 231
  • Joined: 21 Aug 2011
  • Loc: Nashville

Posted 17 February 2020 - 04:00 PM

At least this model improves on the available back focus. I have the Borg 125SD with the modified Petzval EDF4 #7704 reducer and Pentax lens, and at f/3.9, it goes toe to toe with the FSQ-106 on image circle size (both are around 60mm), color correction, and producing round stars to the field edge, plus it's got more aperture and is lighter.  It's also easily convertible to f ratios up to f/6.5 as a visual scope. But its measly back focus of 55mm (actually just 42.5mm from the back of the reducer) is just enough to allow connection of an EOS camera or certain large format CCD/CFW combos with no room whatsoever for even a thin off-axis guider.  The FSQ-106 with the 645 Reducer has a published back focus of 72.2mm -- plenty of room for an OAG with most setups.  Advantage Takahashi, bigtime.  But I've read that with this new 107FL F3.9ED, you can eke out up to 80mm of back focus if you remove the M57 camera rotator on the back and connect using the rear M68.8 thread. That'll give you plenty of room for a full sized OAG like the MMOAG or MegaMOAG with most large format CCD/filter wheel combos -- even cameras with monster chips like the FLI ML50100.  And being able to image with an OAG is a big deal to me. I wish my old EDF4 reducer had similar back focus to this new one.

 

Larry

No doubt it looks wacky to be quoting my own quote in an old thread from last January. But the site won't let me edit a post this old, and there's some incorrect information in here. I don't want it confusing people who may stumble on this thread in the future, so here goes:

  • I've measured the illuminated image circle of the Borg 125SD with the 7704 adapter at f/3.9, and the image circle diameter is 45mm, not 60mm as misstated above and in some published information on the web.
  • Published back focus of the FSQ-106EDX with the 645 reducer is 73.5mm, per Takahashi.

Sorry for any confusion.


  • leviathan likes this

#71 leviathan

leviathan

    Viking 1

  • *****
  • Posts: 739
  • Joined: 29 Nov 2011
  • Loc: Azerbaijan

Posted 18 February 2020 - 03:38 AM

That's right, it's 73.5mm from 645 reducer end and 56.2mm from CCA-250 M54x0.75 end.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics