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Stellarvue SVX080T-3SV w/ .74X Reducer-Flattener

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#51 Tim C

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Posted 10 November 2019 - 09:54 PM

More testing tonight playing with various spacing.  Shots were through thin clouds but seeing was decent.  Instead of the 55mm of spacing behind the SV supplied spacers, I wound up with 56mm as a good spot (really 57mm mechanical - 1mm for filter impact).  I'm happy with these results, especially since I'm estimating that the reducer is delivering f/4.4 which is pretty darn fast.  Stars at the edge always look better to me than a few subs once you fully process and after dithering, meridian flips, etc.  Here is another ~15 Ha subs stacked, again through thin clouds so contrast is diminished a bit.

 

https://astrob.in/full/idvp69/C/

Attached Thumbnails

  • IC1396_56.1Spacing(14frames)_stretch_cn.jpg

Edited by Tim C, 10 November 2019 - 10:06 PM.

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#52 sink45ny

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Posted 10 November 2019 - 10:59 PM

Stars are good to the edges, thanks!!



#53 zakry3323

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Posted 13 November 2019 - 12:59 PM

I did call SV.

 

According to Alex production of the reducer/flattener will resume in the near future. It's just a temporary halt 'cause testing the reducer/flattener is hampering/slowing their OTA production and delaying delivery schedule. Or something like that...

 

Joe

 

PS: My name is Sergio but everyone calls me Joe...

Thanks for calling!

 

I too saw that the SFFR.74 reducer/flattener was no longer supposed to be produced (as per the website) and the versatility it would provide was half the reason I ordered the SVX80T. I called SV a few weeks ago and talked to Vic, he said that more would be made in the future, but seeing it fall off the website recently (the direct link is now a 404 Error, can't even look at it) got me pretty worried. If I have to wait a couple years on the hope that it will go back into production, I'm going to be extremely upset. I'm considering cancelling my order before it ships. 


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#54 moon_nut_99

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Posted 13 November 2019 - 02:51 PM

Zakry3323:

 

I agree with you 100%. Also, and IMHO, it would've have been more appropriate for SV to list this reducer/flattener as "on hold due to the following reasons,,,", reflecting what Alex/Vic said on the telephone.

 

From what I read Vic is a solid guy and cares about his products and customers. And so I'll wait patiently till this item is available and I have the funds to purchase it! smile.gif

 

Cheers

 

Joe


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#55 Tim C

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Posted 13 November 2019 - 06:53 PM

I think SVX080T sales would take a hit if the .74x reducer/flattener wasn't available.  It is the PRIMARY reason I ponied up for this scope.  Otherwise, I would have just bought a second hand SV 80mm triplet which are fantastic scopes based on my previous experience.  I hope they figure out how to get the .74x reducer back in production.  Maybe they need to charge more for the .74x if it takes longer to produce and forego the included non-reducing field flattener.

 

Tim


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#56 bmhjr

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Posted 14 November 2019 - 09:05 AM

I think the previous version SV80ST had a similar issue trying to get a working flattener/reducer.  When I purchased my scope in early 2017 they had just discontinued selling the reducer.  I was told that due to quality issues it was no longer offered but they were working to find a solution.  They never made one available.  

 

Has anyone had a chance to check the field flatness with the Flattener only, up to APS-C or Full Frame sensor?  If so, please post some results.

 

Thanks

Bill


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#57 moon_nut_99

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Posted 14 November 2019 - 11:23 AM

Bill:

 

I did manage to take a few exposures with the included flattener and a Canon 6d (see post 9 above). As far as I can tell, and based on my limited experience, the stars appear as points at all four corners. I'll try to post unprocessed images below (wish me luck...smile.gif ).

 

This image is from a "shake-down" trial test run. It's a star field slightly west of Sagittarius.

 

img-1035-reduced.jpg

 

Joe


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#58 moon_nut_99

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Posted 14 November 2019 - 11:25 AM

Top right corner of the same.

 

IMG_1035-top-right-corner.jpg


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#59 moon_nut_99

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Posted 14 November 2019 - 11:27 AM

Bottom right corner.

 

IMG_1035-bott-right-corner.jpg

 

 


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#60 moon_nut_99

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Posted 14 November 2019 - 11:28 AM

Bottom left corner.

 

 

IMG_1035-bott-left-corner.jpg

 


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#61 moon_nut_99

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Posted 14 November 2019 - 11:29 AM

And top left corner. I hope this helps.

 

Joe

 

 

IMG_1035-top-left-corner.jpg


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#62 bmhjr

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Posted 14 November 2019 - 11:45 AM

Bill:

 

I did manage to take a few exposures with the included flattener and a Canon 6d (see post 9 above). As far as I can tell, and based on my limited experience, the stars appear as points at all four corners. I'll try to post unprocessed images below (wish me luck...smile.gif ).

 

This image is from a "shake-down" trial test run. It's a star field slightly west of Sagittarius.

 

attachicon.gif img-1035-reduced.jpg

 

Joe

 

Thank you Joe.  It looks a bit better than my older SV80ST with 2.5" focuser and Canon 6D, flattener only.  Close but no cigar. wink.gif

 

Bill

 

Edit: But I look way to closely.  Really nice overall.


Edited by bmhjr, 14 November 2019 - 11:47 AM.

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#63 zakry3323

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Posted 14 November 2019 - 12:03 PM

11/14 Update:

 

I called and expressed my concerns to Alex at SV. His answers to my questions didn't quite match up with Vic's responses a few weeks prior, but here's what I was told: 

 

- The SVX80T scopes ordered before Nov 1st have all been completed. Many have already shipped, but because they've also finished runs of 140T and 152T's, they're a little back-logged on getting everything shipped out. I was told that mine would be shipped on or before Friday this week.
 

- One reason for the delay in getting the SVX80T's out, besides the long power outage that they experienced a few weeks ago, was because they were making sure that those that had ordered the optional reducer/flattener got theirs in the order that pre-orders were received for the scope/reducer/flattener combo. Fair is fair. 
 

- They have "a pile" of the optional .74x reducer/flatteners in stock, more than they have preorders for, and they will be re-releasing them soon, possibly before the end of this year. Each reducer/flattener goes through it's own laser test to ensure plug-and-play compatibility and dependability with the SVX80T. Alex said that the assemblies are all completed, but that they're now in line to go back into the CNC machine to drill out access holes so that they can adjust each element in the reducer/flattener individually for optimal performance. Current owners of the reducer/flattener, I'd be very interested to learn how prominent these access points are, and if DIY re-adjustment is a possibility (though I'd likely never attempt it myself - just curious). 

 

- The drilling and adjustment of each reducer/flattener takes a relatively long time and person-power. EACH reducer/flattener takes about one full day of drilling/adjusting before it meets SV's high standards. To me, that's an incredible amount of work and attention to detail. At $400, they can't be making much money on these, if they're not taking a bath on them.

 

- Because of the time and attention required, it wouldn't be surprising to me if getting these reducer/flatteners out is not a priority for SV. It also wouldn't surprise me if they stop processing new orders after the current stock is depleted. When that will be, and how many they have in stock, is anybody's guess. 

 

That's all I have for now. I'll be sure to post additional updates as I receive them. 


Edited by zakry3323, 14 November 2019 - 12:05 PM.

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#64 sink45ny

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Posted 14 November 2019 - 12:17 PM

I paid for my scope on Sept 24th and paid for the reducer on Oct 17th. I wonder when they will contact me?



#65 zakry3323

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Posted 14 November 2019 - 12:35 PM

I paid for my scope on Sept 24th and paid for the reducer on Oct 17th. I wonder when they will contact me?

I'll keep you posted as to when I receive mine. I ordered the OTA Oct 15th, and (regrettably) didn't order the reducer/flattener based on Vic's recommendation to hold off if I wanted to get my scope sooner rather than later. You may receive your combo-order later than me, but as least you can be reasonably well-assured that you'll be getting a reducer/flattener when you do! 


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#66 Gene3

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Posted 15 November 2019 - 06:44 PM

I ordered yesterday and just spoke with Alex. Sounds like there are 10 orders ahead of mine but he has 6 of those ready to go. I told him I was in no rush because I want to put a QHY268C on it, and that won't be available until mid December. Alex said no problem with hitting the mid December shipping target date. They are also going to modify the case to fit the Optec thirdlynx directsync focuser I ordered.

 

I like the fact that the scope comes with a flattener. I am not sure I understand the concern about getting a .74 F/R for this scope. The F/R would bring give a 355mm FL at F/4.5.

When I looked at image scales with this set up it seems that with an APS-C (with 3.91um pixel size) you would at 2.27"/px. If you go with the native set up (480mm FL F/6) then you are at a more respectable 1.68"/px. With a full frame camera (4.88um pixel size) you are at 2.83"/px at 355mm FL & 2.09 at 480mm FL.

 

Using telescopius to check how targets fit, it seems to me that even andromeda and the heart nebula can fit at 480mm FL with QH247C (APS-C). Veil was the only one that did not really fit.

It appears that 480mm FL F/6 is wide enough and it gives a decent image scale with APS-C camera, so why the need to go to 355mm F/4.5? I must be missing something.

 

Best Regards,

Gene


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#67 Tim C

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Posted 15 November 2019 - 09:13 PM

Yeah, the flattener probably is sufficient and even preferable for a majority of targets. It’s good to have both options for when you want the extra FOV for framing certain objects.  I think andromeda looks nicer with the extra FOV but that is just personal preference.  

 

Tim


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#68 sink45ny

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Posted 15 November 2019 - 09:29 PM

Mine is supposed to ship Monday with a reducer and the standard flattener.



#69 zakry3323

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Posted 16 November 2019 - 09:55 AM

I'm sure I'll use the native FL with the matched flattener most of the time, but there are plenty of targets that I'll be willing to sacrifice some sampling for a wider FOV and faster ratio. It would be nice to have the option, is all. 

 

Mine was supposed to ship Friday, but I haven't received any notifications and the order status is still awaiting fulfillment on the SV website. So it goes. 


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#70 Tim C

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Posted 17 November 2019 - 09:55 AM

Still doing more playing and testing with the .74 reducer.  This time I tried using the method of focusing on a center star and then moving that same star to the corner and refocusing on it (see article link).  This method said that I had too little back spacing since I had to move the focuser in to achieve good focus in the corner so I wound up increasing the spacing to 58mm vs. the spec 55mm.  I do have some bit of tilt for sure, but was able to minimize the focus distance between center stars and corner stars as best I could with my available spacers.  I think this method resulted in more round stars in the extreme corners vs. the spec 55mm spacing.  For pixel peeping, it's never going to be perfect but trying to get it as good as possible before I lock in my spacing and start shooting a real picture.  Again, I think lots of sub exposures and stacking helps a lot.  This is a short stack of 13 subs with a quick stretch applied (no cropping).

 

Since SV is apparently tweaking these individually, that might mean the required spacing varies a bit from unit to unit.  I'll be interested to see the experience of others.

 

Article:

https://www.astro-ph...d-flattener.pdf

 

Higher Res Picture

https://astrob.in/full/idvp69/D/

Attached Thumbnails

  • PacmanStack_Drizzle_stretch_cn.jpg

Edited by Tim C, 17 November 2019 - 09:57 AM.

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#71 sink45ny

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Posted 17 November 2019 - 11:12 AM

Looks good to me Tim, was the camera your ASI1600?



#72 Tim C

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Posted 17 November 2019 - 12:15 PM

Thanks Steve - yep, ASI1600 so APS-C sized sensor.  I was really impressed with the shots Joe posted with a full frame and the non-reducing flattener.  Those chips are huge and you can get quite a large FOV with that combo.  I might like to pick up a used full frame DSLR at some point.  Not sure that the reducer/flattener would hold up with that big of a chip but I'm pretty happy with the APS-C performance.


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#73 sink45ny

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Posted 17 November 2019 - 12:57 PM

If mine comes I will eventually try a canon 6D on it for reference, but the ASI1600 amateur (lol) and ASI071 will be the primary cameras.


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#74 moon_nut_99

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Posted 18 November 2019 - 02:32 PM

Hi all:

 

I think I've found a better image example to evaluate corner resolution. Posted below is an image of M31 taken on 11/18/2019 and toward the end of an imaging session. I've included blow ups of each of the four corners as well as the center.

 

Telescope: SV SVX080T-3SV with SV flattener operating at f6
Tracking Mount: Skywatcher EQ6-R-PRO
PA: Polemaster
Guiding: Orion SSAG & PHD2
Guide Scope: SV 9x50
Camera: Canon 6D (Stock).
Exposure: 7 minutes; Iso 1600; Uncropped; No flats, darks, or bias.
Loct'n: Near Tularosa, NM; Elev. 4500ft; Lip cracking dry; 35 Miles SE of Trinity; Adjacent  grey zone.

 

 

Attached Thumbnails

  • m31-f6-7mins-iso1600-svx080-3sv-canon6d-uncropped.JPG

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#75 moon_nut_99

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Posted 18 November 2019 - 02:33 PM

Center:

 

 

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  • center.jpg



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