Telescope Reviews: the ultra low end of video astronomy

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Equipment Discussions >> Video and Electronically Assisted Astronomy

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Atl
sage

Reged: 04/13/12

the ultra low end of video astronomy
#5725108 - 03/11/13 01:58 AM Attachment (140 downloads)

Used a 90mm C90, an eq2 mount, a $25 drive off ebay, and an unmodified Matrix DXB-9300EX black and white camera. Sens up on 64. All told $350 worth of gear.

Post Extras:

GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5725183 - 03/11/13 03:31 AM

Among extended objects, only the pretty bright stuff would seen to be accessible. Perhaps the eye can better see the fainter parts through an eyepiece on the same scope. If so, from this standpoint this is a step backward, at least for so-called 'live' viewing.

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rmollise
Postmaster

Reged: 07/06/07

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5725431 - 03/11/13 09:23 AM

I don't think so. This image reveals the dark lanes in M43 as well as some faint streamers I'd bet were not seen visually. Good work.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5725445 - 03/11/13 09:33 AM

That is through a 3.5 inch mak sens up on half. What do expect from a 90mm f12? There is much more than the naked eyIe could see. If you view this in low light the nebula covers the whole image. just thought some here (c90 owners) might be interested.

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wcstarguy
member

Reged: 12/04/08

Re: the ultra low end of video astronomy new

[Re: Atl]
#5725540 - 03/11/13 10:32 AM

I agree, there is more than my "old" naked eye can see through my C90 mak. I just received one of the Samsung SCB-2000 cameras and will use it with my mak, a st80, st120, XT8i(on eq platform) and a 4.5 Orion Imaging reflector when it arrives....guess I'll find out...when the weather and time cooperate....

Edited by wcstarguy (03/11/13 10:46 AM)

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dragonslayer1
sage

Reged: 02/25/12

Loc: SLC, UT

Re: the ultra low end of video astronomy new

[Re: wcstarguy]
#5725593 - 03/11/13 11:05 AM

Nice picture Alt, thank you for sharing it.

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dragonslayer1
sage

Reged: 02/25/12

Loc: SLC, UT

Re: the ultra low end of video astronomy new

[Re: wcstarguy]
#5725598 - 03/11/13 11:07 AM

Nice picture Alt, thank you for sharing it. Shows good things can be done on low budget, thank you
Kasey

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mclewis1
Thread Killer

Reged: 02/25/06

Loc: New Brunswick, Canada

Re: the ultra low end of video astronomy new

[Re: dragonslayer1]
#5725608 - 03/11/13 11:11 AM

90mm at f12 ... yikes. A cheap focal reducer would make a huge difference without having to mess with any other hardware.

Nice image, and taken alongside Mike Harveys "what does it really look like" posts helps folks visualize what an object might really look like through an eyepiece of larger scopes under different conditions.

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John59
sage

Reged: 11/06/11

Loc: Round Rock,TX

Re: the ultra low end of video astronomy new

[Re: mclewis1]
#5725779 - 03/11/13 12:44 PM

Nice Job Atl! I love it when people get innovative and find plausible alternatives to our obsession...err hobby.

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mpgxsvcd
Pooh-Bah

Reged: 12/21/11

Loc: Raleigh, North Carolina

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5725801 - 03/11/13 12:58 PM

Quote:

Among extended objects, only the pretty bright stuff would seen to be accessible. Perhaps the eye can better see the fainter parts through an eyepiece on the same scope. If so, from this standpoint this is a step backward, at least for so-called 'live' viewing.

I have never seen that field of view and that much detail through a 90mm scope with an eye piece.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: mpgxsvcd]
#5726197 - 03/11/13 03:58 PM

It actually is about what I see in my 12.5" dob with a 30mm eyepiece. I am working on getting a computerized CG5 mount...until then there is no harm in having fun with the "wrong" equipment. That is how innovation happens...making due with whats on hand. When the "right" equipment shows up I will know how to use it.

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5726689 - 03/11/13 07:42 PM

Well, on my screen only the very brightest parts of the nebulosity is seen. 50mm binos readily show the full spherical bubble of the outer parts of M42. My comment was not concerned with the detail revealed in the brighter parts, but the absence of the fainter bits which are readily seen in small apertures.

Of course, the long f/ratio is a serious impediment, and coupling to a fast scope will show much more. Please do try that; I'd love to see what the camera is capable of when there is a brighter image illuminating the detector. Then we may have a chance to surpass visual performance.

In this area of testing low light performance, low end cams should be pointed toward visually challenge objects, such as the Cave nebula (Sh2-155), or if that proves too difficult due to light pollution, perhaps the Rosette or North America. The latter two have surface brightness around 24 mag/arcsec^2, which is 10 magnitudes, or 10,000 times fainter than the brightest core of M42.

Images of such visually bright fare as the ever popular M42, M27 and m57 hardly constitute test objects for video camera performance. I sit up and take notice when a cheap camera can at least come close to revealing what can be seen by eye at the sky glow limit.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5728457 - 03/12/13 03:58 PM Attachment (48 downloads)

Quote:

Well, on my screen only the very brightest parts of the nebulosity is seen. 50mm binos readily show the full spherical bubble of the outer parts of M42. My comment was not concerned with the detail revealed in the brighter parts, but the absence of the fainter bits which are readily seen in small apertures.

Alright...I find the overuse of sens up a bit messy looking, but last night I did a redo at 96x sens up with a 90mm C90 gated to f6. It is a bit messy for my taste, but here it is.

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5729217 - 03/12/13 10:34 PM

Now we're cooking with gas! The dark, narrow, slightly bent lineament of molecular material on the east (left) side of M43 has fainter illuminated gas just to *its* east. Once this bisecting dark cloud becomes readily apparent as such, with the continuance of M43's glow to its east, one knows the camera is reasonably capable. And at f/6, too, which is considered fairly slow for video of nebulosity.

I've been put well and truly in my place; cheers!

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5738389 - 03/17/13 10:55 AM Attachment (42 downloads)

Here is M13 in Hercules...same equipment. Sens up 96x. I did sharpen and adjust and the contrast to darken the scan lines a little. This ate a few stars. This is more detail than the C90 at the eyepiece and on par with my 12.5" dob at the eyepiece.

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dragonslayer1
sage

Reged: 02/25/12

Loc: SLC, UT

Re: the ultra low end of video astronomy new

[Re: Atl]
#5738495 - 03/17/13 12:18 PM

Those are pretty good Alt and thru them all your stars are pretty found. You should try and color the M42. Hey I got that Diamond frame grabber and tried it yesterday, it worked really great with composite but could not get the S video to do anything but distortions and really screwy patterns??? Are you using S video on yours? Great pictures again Alt, thanks
Kasey

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: dragonslayer1]
#5738546 - 03/17/13 12:47 PM

I am using only svideo. I would try another cable. Bad video cables cause distortion and even a new one could be bad. Failing that exchange the item but I would bet its a bad cable. It could also be a short in the camera but I doubt it. Try the grabber with a DVD player of known quality and narrow down the issue.

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dragonslayer1
sage

Reged: 02/25/12

Loc: SLC, UT

Re: the ultra low end of video astronomy new

[Re: Atl]
#5739053 - 03/17/13 04:31 PM

I bought another cable, need to try it. What settings do you use on software for : VIDEO FORMAT &, RECORD? I am not sure which matches S-Video, thank you
Kasey

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dragonslayer1
sage

Reged: 02/25/12

Loc: SLC, UT

Re: the ultra low end of video astronomy new

[Re: dragonslayer1]
#5739320 - 03/17/13 06:20 PM

Hey Alt, the cable was the problem, good call.. But still have no clue which option to choose for VIDEO FORMAT & RECORD??
Thank you, Kasey

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: dragonslayer1]
#5739454 - 03/17/13 07:16 PM

Install the capture software for the device, this program has options to select these things. Functionality with sharpcap and amcap is limited to software controls. The remote is made to work with its native software which is very good. It also works with deep sky imaging well.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Atl]
#5740757 - 03/18/13 01:47 PM Attachment (35 downloads)

M13 at f12. 200 frames stacked.

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5741713 - 03/18/13 08:50 PM

Not to be a nitpicker, but I was under the impression that post-processed images are not permitted here; only single frames as would be seen 'live' are allowed. Unless software solutions which automatically do these tasks 'on the fly' are acceptable? (But then, how long would it take for 200 multi-second exposures to stack? Would this lie within the realm of semi-live viewing?)

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5741979 - 03/18/13 10:41 PM

That is why I noted it. In this case it was NOT live or semi live. It is purely processed. The video was 15 seconds and after separating the frames I selected 200 of the best. I wasn't aware there was a rule. If so I will respect it. Thanks for the input.

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Dragon Man
Carpal Tunnel

Reged: 03/07/06

Loc: Snake Valley, Australia

Re: the ultra low end of video astronomy new

[Re: Atl]
#5742410 - 03/19/13 08:17 AM

Yes Atl, it has been brought up many times in the past, but new people to This section wouldn't be aware of it.

Stacking constitutes 'imaging' which is another section in Cloudy nights.
The images people want to see in here are ones that show what the camera sees 'Live' (or what is actually Semi-Live).
That way they can see how a Camera performs in a 'Live' viewing situation.
Imagine having an electronic eye to look in your telescope with. That's what we show in here.

The rule is probably buried a couple of hundred threads back

EDIT: This will give you an idea: http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4232772/page...

Edited by Dragon Man (03/19/13 08:23 AM)

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Dragon Man]
#5742500 - 03/19/13 09:38 AM Attachment (19 downloads)

One interesting thing I have noted is that the videos actually look better than individual frames...even if the frames in question were extracted from the video. Maybe posting video is the truest representation. So to set things straight here is the "live" version of the same image like the other images taken with the C90. I am finding that the issue with the diminuative C90 is finding the object in the eyepiece. Compared to my dob it is like looking through an opaque piece of glass. Getting the image on video once I have it centered in the eyepiece is easy. The camera enhances things substantially.

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mclewis1
Thread Killer

Reged: 02/25/06

Loc: New Brunswick, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5742606 - 03/19/13 10:40 AM

Many folks will adjust an image slightly to make it more representative of what is seen on a high quality monitor (it's usually better than what shows up on a single image capture on a PC).

Viewing the video stream often does look better to me too but many video hosting sites seem to impart additional compression which doesn't help the images.

It's very clear that any more than slight tweaks can really make a substantial improvement in an image and this would now be something that isn't representative of the "live" image thus the comments about not posting images that have been extensively processed. ATL's great images show this progression very clearly as do many of Nytcam's images.

I think the best course of action is to post as many details about an image as possible. That way folks can better understand, interpret, and compare the images.

Post Extras:

Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: mclewis1]
#5742621 - 03/19/13 10:46 AM

The processed M13 is "slightly" more detailed. It only has about a billion more stars visible...lol. The other images are completely representative of what can be seen on the screen with a camera and a c90. It would be pretty awesome to get my 12.5" dob up on a driven mount...oh well...

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Pharquart
sage

Reged: 11/11/09

Loc: Southwest Minneapolis Metro

Re: the ultra low end of video astronomy new

[Re: Atl]
#5754523 - 03/24/13 05:25 PM

Atl,

Are you creating these images using prime focus, or are you using an afocal setup?

Brian

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Pharquart]
#5754604 - 03/24/13 05:54 PM

I used a focal reducer for the nebula and prime focus for the cluster. Roughly 45 and 90x respectively.

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Pharquart
sage

Reged: 11/11/09

Loc: Southwest Minneapolis Metro

Re: the ultra low end of video astronomy new

[Re: Atl]
#5754717 - 03/24/13 06:47 PM

How are you calculating the magnification? What is the equivalent focal length of the camera?

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Pharquart]
#5755019 - 03/24/13 09:33 PM

The ccd is .5" and the FL is 1200mm. So actually it is 96x and 43x. I have been wanting to add some more images but the moon has been early and bright lately.

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5755048 - 03/24/13 09:47 PM

A magnification value ascribed to an image is arbitrary, for the result depends also on the angular size of the image on the viewer's retina. If you stick your face near your monitor, an image has a higher 'magnification' than when viewed from across the room.

To first order, one can say a detector is equivalent to an eyepiece whose focal length equals the detector's width. And so a 6mm wide CCD is about equal to a 6mm eyepiece. But this is open to debate, for one can choose a longer f.l. eyepiece having a small apparent field or one of a shorter f.l. but larger apparent field and have the same field of view.

Far better to simply state the field width, in degrees or arcminutes. This is unambiguous.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5755091 - 03/24/13 10:13 PM

That is definitely precise. Now for my newbie question: How does one determine and state the field width given the information I have provided?

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5755196 - 03/24/13 11:21 PM

Find the CCD's actual imaging area's dimensions, then divide this by the scope's focal length and take the inverse tangent.

Example, a 6mm wide chip with a 1,200mm focal length has a field width of:

ARCTAN ( 6 / 1200 ) = 0.286 degrees = 17.19 arcminutes.

Note that for such small angles it's valid to simplify like this. For larger angles, exceeding approximately 10 degrees, the correct formula is:

(ARCTAN ((CCD width / 2) / focal length)) * 2

In other words, you first calculate the semi-angle due to the tangent function, the multiply this by 2 to get the full angle.

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ccs_hello
Postmaster

Reged: 07/03/04

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5755304 - 03/25/13 12:31 AM

Also can try CCD Calculator:
http://www.newastro.com/book_new/camera_app.php

Clear Skies!

ccs_hello

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5755520 - 03/25/13 05:18 AM

Nice! Thanks for the info!

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Atl]
#5768033 - 03/31/13 02:34 AM Attachment (21 downloads)

I got the C90 back in action. I am focal reduced to about F6. I thought I might try a dimmer target so here is m51 at 128x sens up.

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mclewis1
Thread Killer

Reged: 02/25/06

Loc: New Brunswick, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5768698 - 03/31/13 12:23 PM

That's an absolutely great shot for 2.1s with a 90mm scope. That EXview HAD sensor is really impressive.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: mclewis1]
#5768739 - 03/31/13 12:49 PM

I'm dumbfounded myself. When you look through a C90 the views are very dim. The camera is doing most of the work. Even in my big dob I just see a big blob and a little blob. The whole point of my thread is that this tech is accessible at nearly any price point...and it gives me a reason to play with my little telescope.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Atl]
#5769494 - 03/31/13 06:55 PM

I implemented an upgrade. I ditched the C90. It seems to have a lot of internal reflections from bright stars. I replaced it with the 114mm Orion Imaging Newtonian today. It is F3.9...so I will probably be maligned for not using an f12.5 ...lol. It did cost me much less than the C90 so economically speaking I am even lower end than before. I am still using an eq1 with a 25$ drive.

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GlennLeDrew
Postmaster

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5769703 - 03/31/13 08:58 PM

The faster Newt will be so much better for DSOs. And what a mere couple of seconds reveals through that 90mm Mak shows so clearly how utterly poor is the resolving power of our eyes at these low brightness levels. This is why even the low end of imaging gear can be superior for revealing subtler details which require much larger apertures for visual detection.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: GlennLeDrew]
#5769795 - 03/31/13 10:11 PM

I agree. So now I am wondering what is the draw of the huge scopes and vast collections of eyepieces? This extremely modest gear is putting my 12.5" dob to shame. In any case the dob sold last night and an 8" on a cg5 goto just shipped...that will change my game just bit. In any case I will take some videos with the 114mm tonight since it is so clear tonight on the Mexican border.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Atl]
#5770059 - 04/01/13 01:57 AM Attachment (20 downloads)

Video of m1 tonight. 114mm at f3.9. I am not overly impressed, but here it is.

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: Atl]
#5770062 - 04/01/13 01:59 AM Attachment (19 downloads)

...and Flame nebula...

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mclewis1
Thread Killer

Reged: 02/25/06

Loc: New Brunswick, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5770491 - 04/01/13 10:58 AM

I'm pretty impressed ... I have to keep reminding myself that you are working with only 128x/2.1s integration times.

Since you obviously have good dark skies you might try pushing the f ratio down a bit again. On big objects like the flame you could try your .5x focal reducer, perhaps with some relaxed spacing (little closer to the sensor if possible). That way you won't need as much in focus travel (which will likely be the biggest obstacle to using the focal reducer with your new scope). Yeah there will be more background noise but a little tweaking of brightness and contrast on the display side will likely help.

The horizontal banding seen is likely electrical noise. What are you using for a power source for your Matrix video camera? What are you using to display/capture the images?

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Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: mclewis1]
#5771301 - 04/01/13 05:32 PM

The power source is a 12V 1.5amp AC Adapter plugged to an outside outlet. The images are displayed onto a netbook running on battery. Any suggestions for reducing the electrical noise?

I do have dark skies for the most part. The city of Agua Prieta Mexico is about 6 miles away and it makes some light on the southern sky...but not too bad. I think I would be considered to be in a blue zone not far from green according to LP maps.

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mclewis1
Thread Killer

Reged: 02/25/06

Loc: New Brunswick, Canada

Re: the ultra low end of video astronomy new

[Re: Atl]
#5771423 - 04/01/13 06:31 PM

Electrical noise can be tough to troubleshoot. Grounding problems are the usual causes but so can be a failure of filtering capacitors in a power supply, another possible cause is bad or worn video cables (shielding failures). You have to work methodically, keep notes, and change one thing at a time.

I try and swap stuff wherever practical to see if that changes anything. Sometimes just re routing the power and video cables (keeping them more separate) can help.

Do you have a 12v battery or another AC 12v power supply that you could try with the camera?
A different video cable?
Do you have a cheap video monitor to try in place of the netbook?
Maybe a different USB frame grabber?

You can sometimes try flipping a two prong plug in an AC outlet around (if it doesn't have a wide and narrow prong which "keys" the plug to the socket) to change the grounding.

While quite rare a tougher cause to figure out is when there is something else running in your house (or your neighbour's) that is causing the electrical noise. Things like old fans and air conditioners (and compressors in fridges and freezers) are notoriously electrically noisy.

Edited by mclewis1 (04/01/13 06:33 PM)

Post Extras:

Atl
sage

Reged: 04/13/12

Re: the ultra low end of video astronomy new

[Re: mclewis1]
#5771529 - 04/01/13 07:34 PM

I've got extra video cables...actually the one I am using are pretty old looking but I have new ones to try. I do have a 12v 1amp power supply that I could go with. the 12v 1.5amp it came with has a slightly frayed cable (wire exposed) that I taped. Thanks for the suggestions!

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