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The Askar FRA 400 Quintuplet Astrograph

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#126 tropicalwind2020

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Posted 19 December 2020 - 07:09 PM

ASKAR and SharpStar are the two brands from the SharpStar Inc,, I would assume the imaging quality is almost same to 76EDPH, with minor differences from the design of additional flattener vs flattener built-in? The prices are about the same as well.



#127 Astrojedi

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Posted 19 December 2020 - 07:25 PM

In theory the FRA400 should be more optimized as it is designed as a system rather than adding a flattener after. You should have less issues with tilt, spacing etc. But in practice sometimes it is not true. It was true for the Askar ACL200 that I had. It delivered the sharpest stars of any Apo I have owned edge to edge with a full frame sensor.

#128 ZL4PLM

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Posted 19 December 2020 - 09:13 PM

I find the Askar scopes to be more premium than the lower end EDPH models 

 

The FRA400 and reducer is outstanding even at f3.6

 

Rho Ophiuchi - FRA400 with focal reducer @ f3.9

 

the ACL200 was also a very decent performer

 


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#129 robonrome

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Posted 20 December 2020 - 01:02 AM

some cameras give uneven ADU values using bias frames or short exposures - plus if you have amp glow in flats this can also affect your processing 

 

the idea of dark calibrating your flat files is that you remove any amp glow and you don't then use bias frames as you remove the bias from them using darks - I also do min 3 sec exposures and then this removes any issues of uneven ADU values 

 

you end up with no amp glow in flats and even calibration of them.

 

You still use a full length dark in your processing but the flats use short exposure dark cals to remove any inconsistencies

 

cheers

 

Simon  

thanks Simon, appreciate the comprehensive answer :-)


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#130 robonrome

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Posted 20 December 2020 - 01:06 AM

been busy the last week with the FRA 400 

 

 

 

https://flic.kr/p/2kiavW5

 

Vela Supernova Remnant - A Southern Gem

 

This huge bubble of Hydrogen and Oxygen is all that remains of a huge explosion that cast star material across vast areas of the southern sky some 11000 years ago.

 

This single image represents only a small corner of this object which covers over 50 ly across. Lying some 800ly away from us it covers a large portion of our southern sky here in New Zealand.

ZWO ASI294MM Bin 1 - 40 x 600s HA 40 x 600s OIII @ Gain 120 (-20c) - 3nm Chroma

Askar FRA400 & Focal Reducer - CEM70 - Eagle 3

Shot over 3 nights - Processed entirely in Pixinsight

 

The 294mm in Bin1 is a fabulous match to the FRA400!

this is spectacular. What a wonderful image... amazing what can be done with a 72mm scope these days in the right hands and under NZ's darker skies. :-)


Edited by robonrome, 20 December 2020 - 01:07 AM.

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#131 lhwhite00

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Posted 23 December 2020 - 04:55 PM

While practicing for the conjunction, thought I’d also practice a moon shot for Lunar X following the conjunction on the 21st. Taken with an ASI224MC , single shot, 0 gain, 0.001 seconds. I don’t think I was well focus, but gonna try again next time. This Askar’s a great scope for all occasion!

This looks really good rocketeer!  I have a noob question, and am just getting into astrophotography.  I got an Askar FRA400 a couple of months back and have started up the learning curve.  I have started taking some deep sky shots of M31 and a few other Messier objects with "okay" results.  I'm learning bias frames, stacking, and all of that.  With the conjunction this past week, I tried some shots of Jupiter/Saturn with fuzzy results.  I tested both with and without the reducer, and am using a Nikon D750 for my imaging.  I know there are a lot of variables that can have an effect, but even though I could see both planets and four of Jupiter's moons, the results were fuzzy at best (Saturn was an oval disk, no clarity of rings).  Even just observing with an eyepiece through the Askar did not seem sharp.  Using our 8" dob right next to it, got great results (of course, a lot more light too).  Is there anything I need to be factoring that I haven't thought of?  The lenses do not appear dirty or cloudy.  I did take some moon shots that seem to be on par with yours.

 

Thanks for your thoughts.

 

Lee


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#132 astro rocketeer

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Posted 28 December 2020 - 04:45 AM

This looks really good rocketeer!  I have a noob question, and am just getting into astrophotography.  I got an Askar FRA400 a couple of months back and have started up the learning curve.  I have started taking some deep sky shots of M31 and a few other Messier objects with "okay" results.  I'm learning bias frames, stacking, and all of that.  With the conjunction this past week, I tried some shots of Jupiter/Saturn with fuzzy results.  I tested both with and without the reducer, and am using a Nikon D750 for my imaging.  I know there are a lot of variables that can have an effect, but even though I could see both planets and four of Jupiter's moons, the results were fuzzy at best (Saturn was an oval disk, no clarity of rings).  Even just observing with an eyepiece through the Askar did not seem sharp.  Using our 8" dob right next to it, got great results (of course, a lot more light too).  Is there anything I need to be factoring that I haven't thought of?  The lenses do not appear dirty or cloudy.  I did take some moon shots that seem to be on par with yours.

 

Thanks for your thoughts.

 

Lee

Hi Lee, sorry for the late reply. I too am new to AP as I just started in late September this year and working my way up the AP learning curve. I too did try to image Saturn and Jupiter few nights before the actual conjunction (as I mentioned), but got pixelated images of Saturn and Jupiter using this scope and a mono cam. I'm very new to planetary imaging (and DSO) and just started to do planetary AP by prepping for conjunction and have not really thought too much about pixel scale from camera to telescope (but I should've). In my case in using the ASI174MM with ASKAR 400 imaging small planets resulted in being pixelated. I had a little coaching from Damian Peach and another friend who is a planetary imaging expert on my equipment set-up and said its likely under sampled. I ended up using my C11 EdgeHD instead for the conjunction and glad I did (though was first hesitant not to use it because I didn't think I could fit both planets fit in the same field of view with the camera, C11 + 0.7x reducer, but it did barely corner to corner). Since conjunction is over and pressure is off, I will start to try out more with planetary imaging with the ASKAR 400 using combinations of different cameras, barlows, and powermate just cause I'm curious and want to get ready for next years Venus and other planets coming through. I like the scope and want to make the most use out of this scope and will hope to share updates with this forum. In my opinion, I think planetary imaging with this scope can yield good results, but need to find the sweet spot between equipment set-up and planeatry position relative to imaging as well as software post processing. The two pictures shows results of the conjunction from both my ASKAR 400 (w/ ASI174MM) and C11 (with ASI224MC).

Another good reference I've found was this thread on CN (particularly post #8). Very nerdy, but keepin' it real and a good start which I need to get a better handle on too.

Attached Thumbnails

  • ASKAR 400 ASI174MM Conjunction 2020.PNG
  • C11 EdgeHD ASI224MC Conjunction 2020.JPG

Edited by astro rocketeer, 28 December 2020 - 05:11 AM.

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#133 astro rocketeer

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Posted 28 December 2020 - 04:50 AM

been busy the last week with the FRA 400 

 

 

 

https://flic.kr/p/2kiavW5

 

Vela Supernova Remnant - A Southern Gem

 

This huge bubble of Hydrogen and Oxygen is all that remains of a huge explosion that cast star material across vast areas of the southern sky some 11000 years ago.

 

This single image represents only a small corner of this object which covers over 50 ly across. Lying some 800ly away from us it covers a large portion of our southern sky here in New Zealand.

ZWO ASI294MM Bin 1 - 40 x 600s HA 40 x 600s OIII @ Gain 120 (-20c) - 3nm Chroma

Askar FRA400 & Focal Reducer - CEM70 - Eagle 3

Shot over 3 nights - Processed entirely in Pixinsight

 

The 294mm in Bin1 is a fabulous match to the FRA400!

the combination of the two - scope and ASI294MM Pro looks great!! You did a great job Simon! thanks.



#134 astro rocketeer

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Posted 28 December 2020 - 05:02 AM

Here's the Pac Man Nebula I captured a few nights ago with the ASKAR 400 and 294MM Pro. This is my second time processing a narrowband image and am still learning how to use the camera and photoshop. Thought I should share how even an amateur like me could get some descent results with this telescope.

Lights:
   S = 25x130 sec
   H = 50x130 sec
   O = 25x130 sec
Darks = 25
Flats = 25

unity gain 120, Bin 2 (but I should’ve used Bin 1 and didn’t realize it until I was already half way done imaging, but will try Bin 1 on same target soon as weather improve)

Attached Thumbnails

  • 45D81597-924E-4F0C-8BAE-E349C65DA6C9.png

Edited by astro rocketeer, 28 December 2020 - 05:35 AM.


#135 Gene3

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Posted 30 December 2020 - 04:55 PM

First image with the FRA400 and my first foray into widefield AP.
Unfortunately light pollution and clouds meant jettisoning 3 hours of subs and only keeping 48 minutes worth, so there was a lot of noise and not much signal to work with. Many thanks to Ron Brecher (AstroDoc) for showing me how to best process such limited OSC data.

NA Nebula NGC 7000

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#136 RogeZ

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Posted 31 December 2020 - 11:52 AM

Not to cause any debate or controversy but thought I’d share my experiment with using different cameras with the FRA400. When I used my Canon 60D Astro mod, ASI1600MM Pro and ASI294MM Pro (both mono with ZWO filter wheel), I had enough back focus adjustment from the scope to get focus (maybe about 15mm out), but when I used my ASI071MC Pro with the ZWO filter drawer (and ZWO Duo Narrowband Filter) I couldn’t get focus even to the farthest distance off the scope focus reel and looks like the focus barely makes it. I had to add in a 20mm spacer and still drew back almost to about 31mm in addition to get it to focus. This is for anyone reading who might be thinking about same setup. I’m new to AP and still learning a lot by trial and error and from all the knowledgeable CN’ers here. Here’s a pick of the ASI071MC Pro setup with the FRA 400 + 0.7x reducer

It is important to note that this is spacer arrangement provides you with the incorrect and therefore suboptimal correction for this scope. 
 

For the FRA400 reducer, the required backfocus is 55mm. In your case you would connect the 071MC/FD/16.5mm spacer. This gives you 17.5+21+16.5=55mm. 
 

The amount of focuser drawtube is irrelevant to the optical arrangement. 


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#137 astro rocketeer

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Posted 31 December 2020 - 11:57 AM

It is important to note that this is spacer arrangement provides you with the incorrect and therefore suboptimal correction for this scope. 
 

For the FRA400 reducer, the required backfocus is 55mm. In your case you would connect the 071MC/FD/16.5mm spacer. This gives you 17.5+21+16.5=55mm. 
 

The amount of focuser drawtube is irrelevant to the optical arrangement. 

Thanks RogeZ. Would the 55mm be same without reducer? 



#138 RogeZ

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Posted 31 December 2020 - 03:07 PM

Without the reducer, all you have to do is get the scope to focus. You need spacers to get to the focal plane, the scope comes with the conical M68-M54/M48 (or just M48) adapter, plus your camera adapters plus some focuser length.

Think of the focuser as a variable extension that can provide more or less length depending on your image train.

I replaced the conical adapter for a Baader M68 60mm extension for better illumination of the 6200MM.
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#139 Poochpa

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Posted 10 January 2021 - 06:09 PM

Anyone using this scope with a full-frame camera? Wondering if it's a good, airline portable, match for my Canon 6Dm2.

Mike



#140 RogeZ

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Posted 12 January 2021 - 09:29 PM

Check here and my Astrobin

 

get.jpg?insecure


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#141 Poochpa

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Posted 12 January 2021 - 10:28 PM

Thanks Roger. I had already seen your image on AB and it looks great. But how do the stars in the corners look in uncropped frames?

Mike



#142 RogeZ

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Posted 12 January 2021 - 11:29 PM

Thats as uncropped as it gets. 

i only crop to remove the “dither band”. Not much.


Edited by RogeZ, 12 January 2021 - 11:30 PM.


#143 RossW

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Posted 13 January 2021 - 08:42 PM

Anyone using this scope with a full-frame camera? Wondering if it's a good, airline portable, match for my Canon 6Dm2.

Mike

I posted full-frame ASI6200 images in post #24. No vignetting at all and stars look good in the corners at f/5.4. Those images were taken with a poorly adjusted tilt adapter too. I have not yet tried to use the reducer.




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