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

Askar FRA600 Quintuplet Astrograph initial impressions + unboxing

  • Please log in to reply
149 replies to this topic

#126 TxStars

TxStars

    Mercury-Atlas

  • *****
  • Posts: 2,556
  • Joined: 01 Oct 2005
  • Loc: Lost In Space

Posted 15 March 2021 - 11:13 PM

Well now I want to see you do 15 more hours with the FRA600..  lol


  • sperho likes this

#127 Sponge

Sponge

    Sputnik

  • -----
  • Posts: 28
  • Joined: 22 Dec 2020

Posted 16 March 2021 - 05:24 AM

Unfortunately, after a second night of similar results to those posted above, I made the decision to return my FRA600. 

 

The scope looks like a fantastic widefield imaging tool with the reducer, but it's native performance (which I am more interested in) isn't quite there.

 

I have instead decided to go with an LZOS 105/650 triplet, as they are doing a new production run for the first time in years. 

 

Best of luck to all of those who go with this scope! I will keep following the thread for interest :) 



#128 IonClad

IonClad

    Sputnik

  • -----
  • Posts: 40
  • Joined: 20 Aug 2020
  • Loc: USA

Posted 16 March 2021 - 09:16 AM

First light from a copy I was able to find in stock is not looking good. This is without the reducer and 1:1 crops using 3.76 micron pixels.

 

Askar600ChromaHa3nm.jpg Askar600UVIR.jpg

3nm Ha filter and UV-IR at prime focus (focused individually for each both with and without Bahtinov to double-check). Focusing to either side only increased star diameters.

 

The Ha image is as good as it should be able to get without chromatic effects, but it's clearly got huge amounts of residual aberrations across the whole frame. Pointing error was minimized by using short exposures of 2-30s and did not exceed 1.2'' RMS, or about 1 pixel. Scaling uses NINA's defaults.

 

Askar600UVIR-longer.jpg Askar600UVIR-shorter.jpg

Defocused comparisons.

 

Unless there's something I'm doing wrong it looks like this copy is a dud. Nothing visibly wrong on the outside, and mechanically seems fine.

 

Sponge: Perhaps your copy was also bad, just not to to the same level as this one?



#129 sperho

sperho

    Sputnik

  • -----
  • Posts: 44
  • Joined: 31 Jul 2020
  • Loc: East Tennessee

Posted 16 March 2021 - 09:26 AM

Ionclad:  Can you put a FITS file on a server somewhere for download?  I can send you a Google Drive folder link if you want.


Edited by sperho, 16 March 2021 - 09:27 AM.


#130 IonClad

IonClad

    Sputnik

  • -----
  • Posts: 40
  • Joined: 20 Aug 2020
  • Loc: USA

Posted 16 March 2021 - 10:08 AM

Ionclad:  Can you put a FITS file on a server somewhere for download?  I can send you a Google Drive folder link if you want.

Ha: https://drive.google...iew?usp=sharing

UVIR: https://drive.google...iew?usp=sharing



#131 coinboy1

coinboy1

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1,561
  • Joined: 03 May 2011
  • Loc: Tulsa, OK

Posted 16 March 2021 - 10:19 AM

A lot of mediocre to poor samples out there...hmm...

#132 Uggbits

Uggbits

    Messenger

  • -----
  • Posts: 435
  • Joined: 28 Apr 2010

Posted 16 March 2021 - 10:56 AM

I took a look at these. The result is shocking. I'm not sure what is going on there, but it doesn't look anything like the star shapes/images I have been getting from my tube. Everything about the star profile looks centred, so by all appearances this may be horrific quality control. Unsettling. 

 

Cheers, 

Dan 



#133 IonClad

IonClad

    Sputnik

  • -----
  • Posts: 40
  • Joined: 20 Aug 2020
  • Loc: USA

Posted 16 March 2021 - 11:19 AM

I took a look at these. The result is shocking. I'm not sure what is going on there, but it doesn't look anything like the star shapes/images I have been getting from my tube. Everything about the star profile looks centred, so by all appearances this may be horrific quality control. Unsettling. 

 

Cheers, 

Dan 

Thanks for taking a look. Agreed that something is very wrong. As I said no apparent damage and it was boxed quite well on arrival (ironically with a "quality control checked" notice form the manufacturer). I used the same image train with a shorter f/6 scope, and no issues there. I did try to eliminate other sources of potential effects, and am confident that they did not contribute more than about two pixels of blur to the final result.



#134 sperho

sperho

    Sputnik

  • -----
  • Posts: 44
  • Joined: 31 Jul 2020
  • Loc: East Tennessee

Posted 16 March 2021 - 11:29 AM

Thank you.  Wow.  That's...bad.  I'm not sure what's going on there, but I would be sending it back, too, if that is the best that scope can do.  Have you tried collecting an image with no filter in the train whatsoever just to rule out the filters?



#135 IonClad

IonClad

    Sputnik

  • -----
  • Posts: 40
  • Joined: 20 Aug 2020
  • Loc: USA

Posted 16 March 2021 - 11:54 AM

Thank you.  Wow.  That's...bad.  I'm not sure what's going on there, but I would be sending it back, too, if that is the best that scope can do.  Have you tried collecting an image with no filter in the train whatsoever just to rule out the filters?

No filter: https://drive.google...iew?usp=sharing

Halos get smaller, but still bad. Seems to be worse with blue colors, suggesting that <450nm or so is not well corrected either. With the same camera and filters I see none of this using a different f/6 scope.



#136 Uggbits

Uggbits

    Messenger

  • -----
  • Posts: 435
  • Joined: 28 Apr 2010

Posted 16 March 2021 - 01:10 PM

I don't think you can explain that result from the filters. It is so bad I'm not even certain how I would attempt to explain it. The only thing that comes to mind is a miss-spaced reducer/corrector somewhere in the train. Given that you are imaging at 600 and shouldn't have any additional optics in the train, I think that it's either some horrific figuring on the lenses, or the correcting elements in the tube are severely out.

 

Cheers,

Dan



#137 maxmir

maxmir

    Viking 1

  • ***--
  • Posts: 508
  • Joined: 03 Oct 2005

Posted 17 March 2021 - 07:55 AM

This is exactly what mine star test looks like!

 

Max



#138 coinboy1

coinboy1

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1,561
  • Joined: 03 May 2011
  • Loc: Tulsa, OK

Posted 17 March 2021 - 08:34 AM

No filter: https://drive.google...iew?usp=sharing

Halos get smaller, but still bad. Seems to be worse with blue colors, suggesting that <450nm or so is not well corrected either. With the same camera and filters I see none of this using a different f/6 scope.

That is bad, mine doesn't look like that nor most people here. Anyone who has such a sample should definitely return their scope. That is very disappointing from Askar. I guess I got a good one then!



#139 coinboy1

coinboy1

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1,561
  • Joined: 03 May 2011
  • Loc: Tulsa, OK

Posted 17 March 2021 - 08:38 AM

Here is a quick test on Rosette with the 6200MM and reducer.

 

get.jpg?insecure

 

There is tweaking to do but it shows promise.

That is a great FOV! That is not bad at all, not perfect round stars to the corners but you couldn't tell unless you zoom in at full resolution. Great shot!



#140 IonClad

IonClad

    Sputnik

  • -----
  • Posts: 40
  • Joined: 20 Aug 2020
  • Loc: USA

Posted 17 March 2021 - 10:07 AM

That is bad, mine doesn't look like that nor most people here. Anyone who has such a sample should definitely return their scope. That is very disappointing from Askar. I guess I got a good one then!

It's being returned, just deciding on whether to play roulette and wait for another sample in 3-4 months or try to find something else in the same timeframe. Uggbits copy and yours seem ok, but in total with the others that have posted so far I'm seeing <50% good samples.



#141 maxmir

maxmir

    Viking 1

  • ***--
  • Posts: 508
  • Joined: 03 Oct 2005

Posted 17 March 2021 - 10:51 AM

I have should sent a link to my FITs files original . My copy is every bit as bad.

 

Max



#142 coinboy1

coinboy1

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1,561
  • Joined: 03 May 2011
  • Loc: Tulsa, OK

Posted 18 March 2021 - 04:08 PM

Ouch, I wonder if the spacing was messed up somewhere either in the triplet lens assembly or the doublet rear lens portion. Serious QC control issues there. I guess this is where Takahashi shines...optically superior. 



#143 Uggbits

Uggbits

    Messenger

  • -----
  • Posts: 435
  • Joined: 28 Apr 2010

Posted 20 March 2021 - 12:15 PM

Figured I would share a couple more shots from the 600 with the reducer over the last week and a bit. I had some time at the end of the night I shot the California Nebula, so I pointed at M81/82 to see if I could pull in IFN from my site. It's just on the edge of a city of ~300,000 so not exactly a dark site, but not bad either. Typically I'd want a good chunk of time for this kind of thing, but I had to settle for 1h21m with my unfiltered Canon Ra. I was guiding on an old HEQ5Pro from my club that guides around 2-2.5" RMS most nights, and gets down to about 1.5" RMS at best. 

 

M81_82_IFN_CN.jpg

 

The stars are pretty tight on the unprocessed frame (I suppressed them a little too much in favour of allowing the IFN to show through). Here are some FWHM charts from the unstretched frame, as well as an aberration chart. 

 

M81_82_ABE_FWHM.jpg

 

M81_82_ABE_eccentricity.jpg

 

M81_82_ABE_mosaic.jpg

 

These are unfiltered full stacks with a OSC, so it's a bit of a 'worst case' configuration provided you aren't contending with the QC issues that IonClad and Maxmir have had. At this point I'm happy enough with my copy and the promise it offers (I bought it more for the performance at 415mm than at 600mm, so it is stronger for my preferred purpose). That being said, I don't think I could recommend this thing to prospective buyers until they figure out what is happening with the QC.

 

I bought mine through Telescope Service and they apparently had some issues in the past with telescopes from this vendor regarding QC. Based on one of their posts (Astroblog Feb 28, 2020) the situation prompted some adjustments at the start of 2020 around how two Sharpstar scopes were evaluated/redesigned. For the FRA600 they mentioned they performed an optical check on the tube before it went out. I don't know that this is enough to explain the sample variance and disparity in performance. It is worrying that QC is back as a concern. 

 

Cheers, 

Dan

 

Edit: unlike the single-sub examples I posted a couple pages back, this is a full 23 frame stack. I hope if provides a better sense of performance for an integration, rather than just the single best frame. 


Edited by Uggbits, 20 March 2021 - 02:41 PM.

  • sperho likes this

#144 sperho

sperho

    Sputnik

  • -----
  • Posts: 44
  • Joined: 31 Jul 2020
  • Loc: East Tennessee

Posted 20 March 2021 - 06:55 PM

Your copy is really looking good Dan.  I was worried about the QC issue, too, and while there have been some good performers, I sadly cancelled my order.  The day I cancelled, I happened to stumble upon a reasonable deal for a used TV NP101is that includes the reducer, so I bit.  I have my fingers crossed that it is in good collimation when I receive it and I look forward to imaging with a nice and fast refractor (finally!).



#145 phantom76

phantom76

    Lift Off

  • *****
  • Posts: 15
  • Joined: 23 Sep 2018

Posted 21 March 2021 - 10:42 AM

Could have benefited from more data, but it is increasingly difficult to shoot this low target from my backyard (There is a street light right below the subject)
 
Ha - 24x300s
SII - 18x300s
OIII - 13x300s
 
ASI 294MM Pro. Processed in PI and Lightroom
 
Seagull

 



#146 Uggbits

Uggbits

    Messenger

  • -----
  • Posts: 435
  • Joined: 28 Apr 2010

Posted 05 April 2021 - 09:14 PM

That's a great shot Phantom.

 

I was doing some testing with my camera last night using narrowband filters, but was too tired to stay up and baby-sit. I focused on the Ha line, and figured it would be interesting to see how the system responded despite my backfocus being 2mm on the long-side of the spec so I let a series run across all three filters. Everything was outside and setup, so I just had to wake up at 3am to turn it on (I figured this was the simplest way to eliminate thermals as an issue). Based on the data from my copy there's no way to avoid refocusing for each filter when shooting narrowband. The Oiii line is too far separated, and the colour correction for the scope just isn't up to the challenge (this was using the reducer).

 

I also get some separation between the Ha line and the OIII line using my Canon Ra and a dual-band filter, but not as much. As the reducer does seem to influence the colour correction of the field, I would suggest keeping a careful eye on the backfocus spacing.  

 

Cheers,

Dan



#147 Markwaugh

Markwaugh

    Lift Off

  • -----
  • Posts: 1
  • Joined: 26 Feb 2020

Posted 06 April 2021 - 04:01 AM

If anybody can answer, im looking at getting this scope, and using it with the ASI6200 full frame mc pro, it should easily take that sensor as well as using it with the 0.7 reducer?????

 

Kind regards  Mark



#148 Uggbits

Uggbits

    Messenger

  • -----
  • Posts: 435
  • Joined: 28 Apr 2010

Posted 11 April 2021 - 01:31 PM

If anybody can answer, im looking at getting this scope, and using it with the ASI6200 full frame mc pro, it should easily take that sensor as well as using it with the 0.7 reducer?????

 

Kind regards  Mark

It's hard to say, but I think you may encounter some issues. Ignoring the sample to sample variance that has been demonstrated in this thread, there is still the design limitations around chromatic aberration to consider. If you were pairing it with a mono 6200 you could get past some of the separation of the three channels by focusing for each filter. However, with the smaller pixels on the 6200 I expect you will see it. For context, I can see separation with the larger pixels in my Ra.

 

Cheers, 

Dan



#149 thornhale

thornhale

    Ranger 4

  • -----
  • Posts: 304
  • Joined: 12 Mar 2016

Posted 11 April 2021 - 09:36 PM

Apologies for my ignorance. I noticed that this is one of the most active threads in this forum. So I must ask: Why is there so much more talk about this telescope vs e.g.: a AT72EDII or AT80ED telescope?



#150 Uggbits

Uggbits

    Messenger

  • -----
  • Posts: 435
  • Joined: 28 Apr 2010

Posted 11 April 2021 - 11:07 PM

Apologies for my ignorance. I noticed that this is one of the most active threads in this forum. So I must ask: Why is there so much more talk about this telescope vs e.g.: a AT72EDII or AT80ED telescope?

Nothing to apologize for. There are likely a multitude of reasons, but the ones that stick out to me are that it's new, and it aggressively priced for what it is. At least, it's aggressively priced for what it is on paper, which tends to prompt threads like this to dig in a little and see if the reality meets the claims. In this case there is a bit of a mixed-bag. For example, my copy is satisfactory but other examples have been poor.

 

Cheers,

Dan 




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