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Equipment Discussions >> Video and Electronically Assisted Astronomy

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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mattflastro]
      #5611817 - 01/08/13 11:56 AM

Quote:

you can't get M31 to fit on a Samsung or Lntech sensor with the same telescope and same reducer. You need to reduce the focal length another 4 times to match the same field of view as in your 550D image.




An 11" F.875 telescope would be really cool.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mpgxsvcd]
      #5611844 - 01/08/13 12:18 PM

Ok,but I wasn't referring to the field of view. I was referring to the amount of detail (like arms, color, etc) captured on M31. My mistake I wasn't clear enough.

I realize that FOV with a CCTV will be smaller even if I didn't know how much smaller.


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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5611857 - 01/08/13 12:24 PM

Quote:

Ok,but I wasn't referring to the field of view. I was referring to the amount of detail (like arms, color, etc) captured on M31. My mistake I wasn't clear enough.

I realize that FOV with a CCTV will be smaller even if I didn't know how much smaller.




The field of view between the CCTV camera and APS-C is so different that the objects would not be similar at all. The difference really is quite significant when dealing with large objects like M31.

The larger sensor will fit the object in the field of view. The smaller sensor simply won't.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mpgxsvcd]
      #5611895 - 01/08/13 12:51 PM

Dame, I haven't made myself clear again.

In this case, to be more clear, let's replace M31 with a faint and small DSO and keep the same question.


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ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5612558 - 01/08/13 07:18 PM

All image devices have multiple attributes to compare with. To make a fair comparison, some test conditions must be normalized first and there is no clear winner on all fronts.

At the end of day, it's all tradeoffs. Many situations seen in this subforum have been S/N vs. fast(er) image acquisition time debate.

Price, better S/N, or fast image acquisition time, can only pick two. <-- Did you notice I didn't even bother to use a quite "polluted" term: sensitivity?

Clear Skies!

ccs_hello


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nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5613137 - 01/09/13 04:32 AM

An impresive M31 via DSLR single shot Moromete

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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: nytecam]
      #5613524 - 01/09/13 11:21 AM

Thank you Nytecam! We both know it's not so impressive when compared to others M31 shots.

For me it really is impressive because I have no experience in astrophoto, I have no guiding camera, I have used a C11 on CG5-GT pier mounted (not even an EQ6/Atlas) and I don't do image stacking or dark frames because of lack of time and mood.
Oh and I don't take a laptop outside with me.
I would like to have a DSLR to do everything for me, including stacking and dark frame subtraction, and let me see the beauties in the sky with ease and fast.

Someday maybe I'll buy an autoguider but I don't know if it resumes the guiding process automatically after changing different GOTO targets during the night. I don't see myself to setup the autoguider every time I enter a new GOTO target in the hand controller. I'm more a visual observer.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5613659 - 01/09/13 12:38 PM

Is the following combination usable: SCT + Meade f/3.3 reducer + inexpensive 1.25" 0.5x reducer + Lntech300/Samsung SCB-2000?

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Dwight J
scholastic sledgehammer
*****

Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5613905 - 01/09/13 03:11 PM

Usable but not pretty. The combo of the two will exacerbate their faults like coma and vignetting. It would depend on your tolerance of these aberrations when viewing. I tried a cheaper 0.5X focal reducer in combo with a 6.3 focal reducer and found the amount of coma objectionable. I have had good luck using an older version of Meade's 3.3 reducer and a two inch extension tube (Teleview) to achieve even more reduction without too much aberration but the quality of them is variable and I just was lucky. They still work better than the 0.5X variety as coma, although present, is just the outer edge of the field. Check the images I have posted as I used this combo for all but the last ones where I tried out the Mallincam reducer (also an option but pricey).

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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Dwight J]
      #5613934 - 01/09/13 03:31 PM

I agree with Dwight, the f3.3 reducer on it's own would likely be my choice. I've also stacked different focal reducers and found that the f6.3 and one of the .5x 1.25" reducers can work but doesn't look particularly good at the edges. Different .5x reducers will produce different results as well. I've also tried a .5x 2" reducer with better results but the f3.3 reducer by itself is still my first choice.

With the f3.3 reducer you can use a 1.25" visual back and 1.25" nosepiece on the camera. It can also be useful to remove the external threads on 1.25" visual back to reduce the amount of spacing. With this reducer I prefer to use T thread spacers and a T - C mount adapter on the camera ... this makes for an all threaded robust connection.

http://agenaastro.com/blue-fireball-t-thread-female-c-mount-male-adapter.html


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mclewis1]
      #5613978 - 01/09/13 04:02 PM

Thanks for your feedback guys.

I see you both have experience in stacking a 0.5x reducer after the f6.3 reducer and prefer the Meade f3.3 reducer instead of this combo because of less coma with an SCT.

But has anyone tried a 0.5x reducer after a Meade f3.3 reducer with an SCT and a CCTV?


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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5614059 - 01/09/13 04:44 PM

It would be fun to try that combination. It will be very fast and therefore will have very steep light cone angles so filters may be a big problem and there will be severe light drop off (vignetting) at the edges. The in focus travel required to come to focus could be an issue too.

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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mclewis1]
      #5614491 - 01/09/13 08:57 PM

Quote:

It would be fun to try that combination. It will be very fast and therefore will have very steep light cone angles so filters may be a big problem and there will be severe light drop off (vignetting) at the edges. The in focus travel required to come to focus could be an issue too.



I am using the Meade x.33 reducer on the scope combined with a x.05 1.25" redcuer on the camera (replaces the nose piece) . It's the only way to get all the field of view the SCT has , which is very narrow to begin with.

It's true that there's some vignetting and coma at the field edges but this tiny video cam ccd doesn't see that far to the edges .

A simple test is to remove just the camera from the setup , but with all reducers in place on the scope .
Place a white sheet of paper at the sensor plane (the distance from the x.5 reducer back where the camera ccd window should be .

You can easily see looking thru the paper what is the illuminated area and how is it vignetting especially f you use the full moon projected on the paper.

I found out I can get the maximum reduction with the Meade reducer threaded straight into the back of the scope , as close to the scope as possible . The farther the reducer is from the scope, the less reduction you get.

Based on some field of view measurements I get my 8" and 10" SCT's down to F2.2 to F2.3 .

I have an adjustable extension between the Meade reducer and the camera 1.25" reducer .

I rotate the scope focuser all the way to the end and back off one turn. Then slide in the camera and adjust the variable extension until I reach close to focus. I secure the variable extension to that exact size and from there on focus normally using the scope focuser (by moving the primary). No microfocusers attached, just the reducer straight onto the scope back.

I placed a 2" light pollution filter in front of the Meade reducer around Christmas due to horrendous Christmas lights throught my neighborhood .

Forget about coma . The image scale is about 6-8 arcsec/pixel anyway so you won't see only some bigger stars due to coma, you'll see all stars bigger due to the image scale.


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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mattflastro]
      #5614793 - 01/10/13 01:00 AM

And there's one additional point ...

Those of us with a Mallincam and SCB4000 cameras have the slightly larger 1/2" sensors, those with the 435/2000 and LnTech cameras have the slightly smaller 1/3" sensors. This makes a difference when your are evaluating the edge performance with various focal reducers. Those using the 1/3" sensors won't have as much to complain about.

Edited by mclewis1 (01/10/13 01:01 AM)


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mclewis1]
      #5614944 - 01/10/13 06:45 AM

Excellent news mattflastro!

What do you say about this camera http://www.bavono.com/eng/BVO616S.html ?

It has Sony ExView HAD CCD II, Sense-Up x1024 and AGC user selectable up to 36db (unlike Lntech or Samsung).

Problem is I can't find someone to sell it around the world.
Maybe we should Aliexpress to put it on their website because they already sell Bavono products! What do you think?


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5615103 - 01/10/13 09:17 AM

Quote:

Excellent news mattflastro!

What do you say about this camera http://www.bavono.com/eng/BVO616S.html ?

It has Sony ExView HAD CCD II, Sense-Up x1024 and AGC user selectable up to 36db (unlike Lntech or Samsung).

Problem is I can't find someone to sell it around the world.
Maybe we should Aliexpress to put it on their website because they already sell Bavono products! What do you think?



I downloaded the user manual for that camera and it doesn't say anywhere MANUAL GAIN or FIXED GAIN, only AGC OFF and ON .

From the sketchy info in that one page manual the only thing you can set manually is a maximum limit for the AGC , similar to the EFFIO-S and P camera DSP's from Sony . The same idea as in setting SENSE-UP to ON and selecting a max value . The camera does whatever it wants up to that value . You can't force it to use the maximum as a fixed value .


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mattflastro]
      #5615111 - 01/10/13 09:28 AM

Quote:

Quote:

Excellent news mattflastro!

What do you say about this camera http://www.bavono.com/eng/BVO616S.html ?

It has Sony ExView HAD CCD II, Sense-Up x1024 and AGC user selectable up to 36db (unlike Lntech or Samsung).

Problem is I can't find someone to sell it around the world.
Maybe we should Aliexpress to put it on their website because they already sell Bavono products! What do you think?



I downloaded the user manual for that camera and it doesn't say anywhere MANUAL GAIN or AGC OFF or FIXED GAIN .

From the sketchy info in that one page manual the only thing you can set manually is a maximum limit for the AGC , similar to the EFFIO-S and P camera DSP's from Sony . The same idea as in setting SENSE-UP to ON and selecting a max value . The camera does whatever it wants up to that value . You can't force it to use the maximum as a fixed value .



I also forgot to mention that Sony Effio AGC goes up to 42dB , that's double the gain . Cameras that do only 36dB have a reason for it, and the reason is poor AFE performance . No sense in amplifying noise .Also, case looks plasticky . Maybe it's a good camera but cooling in a plastic enclosure will be problematic.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: mattflastro]
      #5615213 - 01/10/13 10:37 AM

Mattflastro I think you wrong this time regarding Bavono cctv Gain and enclosure.

Here is the manual http://www.bavono.com/Download/3044200337_BVO616S%20Manual(eng).pdf .

In the tiny product manual/specifications says that AGC = Off~36dB(3dB unit). I think this means you can increase the gain in steps of 3dB up to 36dB. Regarding Sony Effio I agree with you.
Regarding camera's enclosure, in the tiny product manual/specifications says Shell Material = Metal, not plastic.
Isn't this better Lntech300's AGC which is kept on Off because isn't user adjustable in different steps like Bavono is?!

Now shoot and correct me if I'm wrong.


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telfish
sage
*****

Reged: 11/17/10

Loc: Adirondack Mountains NY
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: Moromete]
      #5615465 - 01/10/13 12:51 PM

The guy selling these assures me they are the camera you are after. Comes with a lens. Not as cheap as the $70 ones but is it really better? Looks like it has network capability!

Quote

"BVO616S OR BVO616W They are the same, looking forward to your reply.
lens3.5-8mm

zesan yi"

http://www.aliexpress.com/item-img/BAVONO-CCTV-700TVL-OSD-Menu-Ultra-WDR-Gun-...


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Samsung SCB-4000/2000 vs Canon T2i sensitivity new [Re: telfish]
      #5615485 - 01/10/13 01:00 PM

No, it's not the same product. Aliexpress sells model BVO616W (with Sense-Up only 512x) and we need BVO616S (with Sense-Up to 1024x and AGC user adjustable 3dB steps).

Yes, it seems to have a lens and a metal enclosure, not plastic.


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