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microstar
Pooh-Bah


Reged: 01/05/08

Loc: Canada
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5592042 - 12/28/12 12:43 AM

Took a while to download but a pretty amazing image Bert.
...Keith


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Harel_Boren
Vendor-The Boren-Simon PowerNewt Astrograph


Reged: 03/15/09

Loc: Israel
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5592766 - 12/28/12 02:17 PM

Quote:

Hi Knez

The RH200 is fast at F3. This is 5X16 minutes in 3nm NII. This would take you with an F4.5 system 5x36 minutes. Or longer if you wanted to get the signal to noise ratio down to the same level as the shorter exposures the RH200 give you.

Large image here 5MB

http://d1355990.i49.quadrahosting.com.au/2012_12/M42_RH200_NII.jpg

By the way 3nm NB filters DO work very well even at F3. Especially the Astrodons.


Bert




I can't agree more. I used to have a baader 7 nm on the same camera and there's literally no comparison to the crisp, full and noiseless results the Astrodon 5 nm is giving me. all on f2.8 or f3 systems.

Cheers
Harel


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Harel_Boren
Vendor-The Boren-Simon PowerNewt Astrograph


Reged: 03/15/09

Loc: Israel
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5593287 - 12/28/12 08:23 PM

Quote:

Hi Harel

Here is a 8min exposure in NII with a Bahtinov Mask. 1.3MB

http://d1355990.i49.quadrahosting.com.au/2012_12/RH200-B.jpg

As you can see all the stars with visible diffraction patterns show perfect focus. This can only mean one thing. The PL16803 sensor is almost perfectly orthogonal to the optic axis of the RH200.

I can pick up a 100 step difference of the FLI Atlas focuser in the diffraction patterns. This corresponds to 8.5 micron along the optic axis. This means that my camera sensor is aligned better than 10 micron from corner to corner.

I have a custom made frame to firmly hold the camera. With this I can make very small adjustments to align the sensor.

All imaging systems invert the image. It fools the best of us.

Bert

Astrograph is an Officina Stellare RH200 which has a focal length of 600mm and is F3, yes F3! Clear aperture is 200mm.
FLI Atlas Focuser.
FLI ten position filter wheel CFW-3-10 with 50mm square filters.
Astrodon E series LRGB and HA, NII, SII and OIII 3nm NB filters. Also a continuum filter 5nm.
Camera is a FLI PL16803 which has a sensor size 36.8 X 36.8 mm.
The FoV of this system is 3.5 X 3.5 degrees.
Mount is a Software Bisque PMX.






Hi Bert, is what we are seeing in the image the back of the os RH 200 rig?

Cheers,
Harel


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orion69
scholastic sledgehammer


Reged: 05/09/10

Loc: Croatia
Re: Officina Stellare Veloce RH 200 First Light new [Re: Harel_Boren]
      #5593829 - 12/29/12 06:12 AM

Bert, thanks for very nice image, but I have (as usual) few questions...
While center image (http://d1355990.i49.quadrahosting.com.au/2012_12/M42_RH200_NII.jpg) is very nice, stars look good etc., border image starts to brake down, stars have unusual halos and much more noise is present. Is that because of vignetting, type of processing or some other reason?
The specs say "200mm clear aperture", what does it mean?
Since obstruction is 55% what is actual diameter of the tube?
How do you like the focuser for imaging? My accessories are around 4 kg...
Does it have to be collimated often, is the collimation complicated, how long does it take?
How fast does it cool down?
And finally, how does it cope with temperature change, does it have to be refocused often?

Hope you don't mind lots of questions, but 5800 Euros is not cheap, I have to be sure what I'm buying...

Thanks


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Harel_Boren
Vendor-The Boren-Simon PowerNewt Astrograph


Reged: 03/15/09

Loc: Israel
Re: Officina Stellare Veloce RH 200 First Light new [Re: orion69]
      #5594853 - 12/29/12 06:30 PM

Hi Kemz,
The obstructin is 55% linear, I.e. .55 of the diameter.
This means that its about 30% area obstruction which is quite reasonable considering that you don't we'd flats (ie much more light all over the frame) and that reflectivity of the mirror is 99%.

Cheers,
Harel


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Bert
professor emeritus


Reged: 02/17/06

Loc: Australia
Re: Officina Stellare Veloce RH 200 First Light new [Re: orion69]
      #5595124 - 12/29/12 08:50 PM Attachment (34 downloads)

Officina Stellare quote a well corrected image circle of 42mm for the RH200. The diagonal of the PL16803 camera is 52mm so the corners can never be as good as the centre. This does not matter in practice if I view an image on my 30inch monitor at 100% the image is 1x1 metres. The pixel pitch of the monitor is 0.25mm.
I want to make mosaics of very dim objects so speed is more important than perfect stars. If I wanted perfect stars I would get a RC scope at F10 and wait forever to record some dim nebulosity.

Here is two panels of the Vela SN remnant with some Gum nebulae in 3nm NII. FoV 6.0 x 3.4 degrees. 10MB
http://d1355990.i49.quadrahosting.com.au/2012_12/VSNR_P1+P2_NII.jpg
The vignetting in the RH200 is 80% at the edge of a 36.8mm square sensor and 63% in the corners. Below is a screen capture of a line profile of a 3nm NII flat.
The aperture is 200mm. The central obstruction is 105mm. The area of the RH200 aperture minus central obstruction is about three times the area of the central obstruction.
I have a FLI Atlas focuser. This is holding a ten position filter wheel and Pl16803 camera. This all weighs a bit over 8kg. This is why I had flexure problems as expected as I am overloading the RH200. The Atlas focuser is excellent.
I have six dew straps around the RH200 which are controlled by a PID controller. This keeps the whole optic train at a constant temperature plus or minus 0.1C. This has two effects focus does not change with ambient temperature and the optic train will never suffer from condensation. Where I live in Melbourne the temperature can drop overnight by more than twenty degrees C on a clear night.
I have not touched the factory collimation and optic train alignment as they were both close to perfect. They have not moved at all over winter to summer.
It all depends what you want to do what scope you should get.
You are always welcome to ask any questions.
Bert


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Bert
professor emeritus


Reged: 02/17/06

Loc: Australia
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5595195 - 12/29/12 09:55 PM Attachment (54 downloads)

Here is a picture of the image train on the PMX.

Bert


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mikeschuster
super member


Reged: 08/25/11

Loc: SF Bay area
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5595336 - 12/29/12 11:39 PM

Quote:

I have six dew straps around the RH200 which are controlled by a PID controller. This keeps the whole optic train at a constant temperature plus or minus 0.1C.




Bert, this is an interesting idea, thanks for posting. I have an FSQ. Keeping it in good focus as the night cools is a serious issue with this tube. I use heaters for dew, but your idea of heating the whole thing is new to me.
Thanks,
Mike


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Alph
Carpal Tunnel


Reged: 11/23/06

Loc: Melmac
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5595369 - 12/30/12 12:06 AM

Quote:

The vignetting in the RH200 is 80% at the edge of a 36.8mm square sensor and 63% in the corners. Below is a screen capture of a line profile of a 3nm NII flat.



That screen capture is illegible.


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Bert
professor emeritus


Reged: 02/17/06

Loc: Australia
Re: Officina Stellare Veloce RH 200 First Light new [Re: Alph]
      #5595379 - 12/30/12 12:17 AM Attachment (22 downloads)

Alph

Here is a larger version. 1k

http://d1355990.i49.quadrahosting.com.au/2012_12/Cap.jpg

Sorry its the small image size limit.

This flat is a stack of twenty corrected with a master dark.

Bert

Edited by Bert (12/30/12 12:19 AM)


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Bert
professor emeritus


Reged: 02/17/06

Loc: Australia
Re: Officina Stellare Veloce RH 200 First Light new [Re: mikeschuster]
      #5595396 - 12/30/12 12:31 AM Attachment (27 downloads)

I used to image with a Canon 5D and a Canon 300mm F2.8L and the only way to stabilise focus was to keep the whole lens at a constant temperature. The critical focus zone at these fast apertures is tiny.

This lens still looked like brand new after being in the observatory for six years!

Bert


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mmalik
Postmaster
*****

Reged: 01/13/12

Loc: USA
Re: Officina Stellare Veloce RH 200 First Light new [Re: Harel_Boren]
      #5597432 - 12/31/12 06:07 AM Attachment (15 downloads)

Quote:

Quote:

Quote:

The system requires strict orthogonality between the chip surface and imaging train,
and for that the whole focuser system is fit on a plate which can be adjusted through 4 screws,
on the 4 corners corresponding to the 4 corners of the image (and chip).




Nice image Harel.
Do you have any photos of your above setup?
Was this an add on which was not supplied with the telescope?
You'll do well with this new high tech RH200.




Thanks alpal :-)

Here's a capture directly from the user manual, which explains the subject, along with an image which shows where the bolts are, etc.

Cheers,
Harel







FYI: Hope you don't mind my mentioning, this is full of syntactical and spelling errors. Thx


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Harel_Boren
Vendor-The Boren-Simon PowerNewt Astrograph


Reged: 03/15/09

Loc: Israel
Re: Officina Stellare Veloce RH 200 First Light new [Re: mmalik]
      #5597451 - 12/31/12 06:27 AM

They obviously should do some English editing, shouldn't they :-)))

But from what I see - the CNC is better than the English :-)

Cheers,
Harel


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alpal
Post Laureate


Reged: 06/15/09

Loc: Melbourne Australia.
Re: Officina Stellare Veloce RH 200 First Light new [Re: Harel_Boren]
      #5597459 - 12/31/12 06:58 AM

Hi Harel,
it's still perfectly understandable.

cheers
Allan


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Harel_Boren
Vendor-The Boren-Simon PowerNewt Astrograph


Reged: 03/15/09

Loc: Israel
Re: Officina Stellare Veloce RH 200 First Light new [Re: alpal]
      #5597966 - 12/31/12 01:25 PM

Thanks Allan. You're right - it's understandable, but it does make sense to have this taken care of. The manual is not of the quality of the scope, and it's a shame.
Cheers,
Harel


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atalas
Carpal Tunnel


Reged: 02/21/05

Loc: Sydney,Australia
Re: Officina Stellare Veloce RH 200 First Light new [Re: Harel_Boren]
      #5598687 - 12/31/12 08:13 PM

Congrats on the new scope Harel!and a great first light...all the best for 2013!

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orion69
scholastic sledgehammer


Reged: 05/09/10

Loc: Croatia
Re: Officina Stellare Veloce RH 200 First Light new [Re: atalas]
      #5599365 - 01/01/13 10:55 AM

Bert, thanks for very detailed explanation!
Looks like I have some tough decision to make...

Just one comment about "clear aperture". If aperture is 200mm and central obstruction 105mm then "real clear aperture" is around 170mm? Is this correct?
If this is correct, is there some way to compare this "real clear aperture" vs "real aperture" from refractor? Probably can't be directly compared because one is obstructioned aperture and other is real aperture?


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Bert
professor emeritus


Reged: 02/17/06

Loc: Australia
Re: Officina Stellare Veloce RH 200 First Light new [Re: orion69]
      #5599450 - 01/01/13 11:57 AM

Knez
Yes that is correct the calculated equivalent unobstructed aperture of the RH200 is about 170mm. So a hypothetical refractor of 170mm aperture and 600mm focal length would be as fast the RH200? Not so!

The movie industry does not use the F stop of the lens. They measure the amount of light that actually gets to the film or sensor through the actual lens and correct for the loss of light by giving it a T stop value. The T stop is the F stop corrected for light losses produced by a lens. So different lenses with the same T stop deliver exactly the same amount of light at the sensor or film plane from the object being imaged. This is a must for continuity in perceived lighting from cut to cut.

You will not see any figures for light loss in refractors due to reflection and absorbance and scatter. It is considerable. Generally the more elements a refractor has the greater the light loss.

That being said the RH200 has a multi element rear corrector.

Even if a 170mm diameter 600mm focal length lens/refractor could be made it would have so much glass that you end up losing more than you gain.


It is the F stop of an optic that sets the diffraction limit for any optic and hence the theoretical resolution. It tells you nothing about actual transmission of the optic.
The only way in the real world is to test our optics by taking images and see what results we get. All the hypotheticals are just that.

The results I am getting with my new setup has not ceased to amaze me yet. Each time I image a new object I see very faint stuff in detail I have never seen before anywhere.
I am most probably very biased toward the RH200 but this is due to the results I am getting.

regards Bert

Edited by Bert (01/01/13 12:55 PM)


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orion69
scholastic sledgehammer


Reged: 05/09/10

Loc: Croatia
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5599629 - 01/01/13 01:30 PM

Bert, did you try 30min subs with RH200?
It would be great to see result of let's say 3 hours of 30min subs with H-alpha filter. That would really show what RH200 is capable of and show me what sort of improvement can I expect over my present setup.

That leads me to another question: did you notice any flexure caused by possible mirror movement?


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Alph
Carpal Tunnel


Reged: 11/23/06

Loc: Melmac
Re: Officina Stellare Veloce RH 200 First Light new [Re: Bert]
      #5599823 - 01/01/13 03:25 PM

Quote:

I am most probably very biased toward the RH200 but this is due to the results I am getting.



I think you are. The C11 with the Hyperstar is quite close to the RH200 in terms of focal length and focal ratio for a lot less money. I admit though the RH200 has a a bit of edge over the HS11. However the HS14 has longer focal length and in theory it can deliver images of higher resolution.


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