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Another APU-1 First Light

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#1 Dom543

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Posted 15 September 2015 - 12:11 AM

cn0.FirstAPUimage_20150906_013509.jpg

This is the first image that I have saved from my new APU-1 camera. All factory default settings, except for some trial and error to find the right integration (x1024) and gain (48). I use it to start this thread to to set a tone and to keep out mean spirits.

 

My camera saw its first light in two half-night sessions separated by a week and 3000 miles. During this September-December period I shuttle between work in Massachusetts and California and home in Seattle. I have a scope at work in Massachusetts that you can see here http://www.cloudynig...etup/?p=6241876. This is what I wanted to use to try out the camera. But it turned out that the old CG-5 mount, that I have not used for over a year was not tracking sufficiently well for the long focal length of the SCT. So the best I could do was to use a 85mm f2 camera lens that I had handy. The short focal length and resulting wide fields don't require good tracking.

 

I don't have experience with sophisticated analog video cameras that have many settings like the APU-1. My first camera was a Samsung SCB-2000 but I used it only with its factory defaults for all settings except integration times. I liked the Sammy but stopped using it entirely, when I got my Lodestar more than a year ago. The Lodestar is a totally different animal that is used in conjunction with a computer. I still wanted a  "real" video camera to be used mostly on our camping trips where computers are banned (by my wife). After the Lodestar the Sammy was no longer up to my expectations.

 

In line with its designated future use, I also wanted to do the first light without computer or software use. My laptop still got involved but solely as a display device through a Honestech frame grabber. The APU-1 has a unique hand controller that allows to set most capture parameters. It has four dials and buttons to control image quality: Integration, Gain, Black point and Gamma. Other parameters can be set through an on-screen menu system. During the first light I used almost exclusively the hand controller. The only exception was setting white balance through the menu system.

 

You have seen the first image that I got through the 85mm f2 lens and a 7nm H-alpha filter with Integration=x1024 (17sec) and Gain=48 (75%). My observing perch is over a brightly illuminated area and under the Boston light dome. I always use strong NB or UHC filters. It was an unexpectedly pleasant surprise how easily the first decent image popped up. Nice for a first capture but too red for my taste. So I fiddled with gain, gamma, black point and white balance until I got an image with the dark background that I like. Here it is the Heart Nebula against a dark grey background.

 

cn1.Heart_20150906_014237.jpg

 

The next object was the North America Nebula with essentially the same settings.

 

cn2.NorthAm-h_20150906_032217.jpg

 

I saved dozens of images while experimenting with the many setting all unfamiliar to me. As this was a first light, I concentrated on the camera and the images and didn't write down all the exact settings that went with each capture. The integration times I quote are exact but when I say Gain=48, that may mean anything between 44 and 54.

 

With all the time lost due to the mount tracking problems and the myriads of settings combinations I tried with the unfamiliar camera it became late, when I got this far. (You can see the time stamps in the file names.) The cops came up twice to see what was going on on the fire escape of a building otherwise deserted for the long weekend. (They liked the Heart and the NorthAm and concluded that I was harmless.) It was time to call quits for the first half of the first light without the camera ever being attached to a real telescope. I will continue in a second post.

 

Please feel free to ask any questions relating to the operations of the camera or to my experience with it. I will answer them to the best of my abilities. I would also appreciate any comments and suggestions from those of you, who have more experience with these analog video cameras and all their settings.

 

Please respect the desire to limit this thread to the discussion of technical matters related to the working and the use of the APU-1. Posts and comments on the maker of the camera and its business are off topic on this thread.

 

Clear Skies!
--Dom


Edited by Dom543, 15 September 2015 - 01:26 AM.

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#2 Dom543

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Posted 15 September 2015 - 12:25 AM

As my poor new APU-1 has not seen light through a telescope during its first use the first light experience continues in Seattle, where I stopped this past weekend on my way to California.

 

In Seattle my main scope is a 10" Meade SCT on a CGEM mount that can track unguided up to 2 minutes. I have a flip mirror with a built in focal reducer that brings the focal ratio down to around f4. The setup can be seen here with a different camera  http://www.cloudynig...etup/?p=6210387.

 

The obligatory object for any first light in the summer is the Dumbbell Nebula. Here it is my first light capture with the APU-1 through an Astronomik UHC filter and using Integration=x256 (4 sec) and Gain=48. This may not be my best M27 capture but, as said, I am unfamiliar with analog cameras, with their operations and settings. Moreover no live-processing software has been used and hence no stacking has been applied. In fact no software at all, except what is needed to display and save an image.

 

cn3.Dumbbell-f4_20150912_213810.jpg

 

The second target was the Crescent Nebula. As this is a pure H-II object, I switched to a 7nm H-alpha filter. The Crescent turned out to big for my FOV at f4. So I switched reducers and went for f2. The 1/3" sensor took f2 in stride. Integration=x1024 (17sec) and Gain=52.

cn4.Crescent_20150912_234905.jpg

 

I was curious to see how the Dumbbell would look at f2. Here it is with Integration=x256 (4sec) and Gain=36 (55%).

cn5.Dumbbell-f2_20150913_005430.jpg

Note that thanks to the faster optics, gain could be reduced from 48 to 36. The texture of the image looks smoother to me. I don't know, if this is due to the lower gain or to the different image scale.

 

Next is the Bubble Nebula at f2 and through the H-alpha filter again. Integration=x256 and Gain=44.

cn6.Bubble_20150913_014554.jpg

As the Bubble would fit the narrower field of the f4 setup, I switched back to the milder focal reducer. But by the time I got to focusing, the ever present moisture in the Seattle atmosphere turned into a uniform white cloud cover. This ended the first light of my APU-1 without a larger Bubble.

 

As said at the end of the first post, please feel free to ask any questions relating to the operations of the camera or to my experience with it. I will answer them to the best of my abilities. I would also appreciate any comments and suggestions from those of you, who have more experience with these analog video cameras and all their settings.

 

Please respect the desire to limit this thread to the discussion of technical matters related to the working and the use of the APU-1. Posts and comments on the maker of the camera and its business are off topic on this thread.

 

Clear Skies!
--Dom


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#3 Dwight J

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Posted 15 September 2015 - 01:33 AM

I would suspect lower gain helped with smoothness.  I tend to use lower gain than most although Ken often uses AGC at 0.  For me a lower gain seems to provide more dynamic range and I can easily compensate by increasing exposure time.  The colour blotches can be reduced by lowering contrast and gain.  Interesting that it only appears in the Heart nebula.  If that was your first image of the session perhaps the cooler hadn't reached max yet while later images it had.  Stacking with Astrotoaster should help too.  For me when I am "observing" and not too particular about presentation like I would while on NSN, I am happy with singles and viewing on a TV monitor, preferably a CRT as the colour seems richer.  The view is way better than a computer monitor.  Brightness, contrast, etc are controlled using the TV settings.   A LED/LCD monitor does give crisper images, just not as good on the colour.  I would bet that using the camera with a TV would be more satisfying- it is for me and why I prefer these cameras.  



#4 Dragon Man

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Posted 15 September 2015 - 01:54 AM

Ahhhh yes, the first light Blues. I know it well   :lol:

 

Dom, may I suggest that you drop your AGC to extremely low levels, or even to Zero. It means that you will have to raise your integration times a little bit but the results are worth it. You will instantly notice a cleaner background sky.

Out of all the imagers above, the one with the cleanest background sky is the Dumbbell at f2. Most likely becuase it is the image with the lowest Gain which you dropped down to 36. Which shows that the lower the AGC the cleaner the view.

 

Also, you will need to lower the saturation level. Looking at your images I can tell that the Saturation is too high. That is one of the major contributors to colour blotching especially with slower optics.

 

Another setting you could try is to lower the contrast a tad and compensate for the lower light by slightly raising brightness.

 

It is a balancing game that will require fiddling on each different object. I have never found a setting that suits all objects. They all require their own tweaking.

Your light pollution won't be helping either.

But you are off to a flying start.



#5 Dom543

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Posted 15 September 2015 - 02:42 AM

Dwight and Ken,

 

Thank you for your comments. Some of what you are saying is right on. In fact, the TEC was not turned on while I was playing with the Heart Nebula. I had been distracted by the mount troubles earlier and forgot to turn it on. My Lodestar doesn't have a TEC...

 

Ken, you have good eyes. I did, in fact,  increase contrast and saturation in the frame grabber software settings. I don't bore you with my motivations for that but, based on what you are saying, that wasn't a good move.

 

I have noticed over the time that the nice images that Dwight and Chris are posting are always with low gain settings. On the first night with the tracking problems I had no choice but had to go for the shortest possible integrations (and hence high gains). One of the reasons I wanted this camera is its unlimited integration capability and I haven't had a chance to try it out yet. x1024 is still LN300 territory...

 

I do have a Speco CRT in Seattle and I plan to use it. As we don't have 110V in our van, it will not make it to our trips. But we do observe from our deck in Seattle and Denise prefers anything that's not a computer.

 

The type of feedback and  suggestion you re giving is very helpful and exactly what I need. I have no experience with analog video and don't know what those various parameters mean and how they affect the image. I made my adjustments pretty much as blind trials.

 

Thanks again and please keep the helpful input coming.

 

Clear Skies!

--Dom



#6 Dwight J

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Posted 15 September 2015 - 02:58 AM

My remote TV monitor is a Haier 10.2" that I got for less than $60.  The internal battery will run it for up to 6 hours.  It came with an ac adapter and a cigarette lighter plug for 12v operation.  They also had a 7" model.  Some portable DVD players can be used as well as long as they have an input, usually RCA.  There is a variety on fleabay, some down to 4".  That should keep the wife happy.  


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#7 A. Viegas

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Posted 15 September 2015 - 06:44 AM

Dom-
 

One of the big selling features of the APU-1 was its ability for unlimited integrations.  So far I see the integration duration the same as the other LN300 hybrids out there, namely limited to x1024.   Can you try and take a longer integration or discuss how you obtain longer exposures?

My DSO1 which is a $99 camera, I had on my ETX70 last night, piggybacked on the C11...  here is a M27 with that small scope at native F5, or 350mm FL, which is close to your F2  if you are using a C8, the FLs are close.   This was an image at x128 with 36db gain.  It seems the APU has higher gain setting.

 

Al

 

 

Attached Thumbnails

  • M27_ETX70_x128.jpg


#8 Dom543

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Posted 15 September 2015 - 02:26 PM

Al,

 

Thank you for your input and the comparison image. The image scale looks very similar to that of my f2 setup (~500mm focal length).

 

You are right, the APU-1 has unlimited integration and that was one of the reasons I ordered it in the first place. During the two half nights that made up the first light I didn't have a chance to try out the long integration options. The clouding up in Seattle was in the forecast so I needed make decision on what to do and what not to do.

 

The APU-1 has three different integration modes: "Video", "Frame integration" and "Unlimited" plus an "Auto" mode.. "Video" or "normal" is 1/60 sec and shorter, "Frame Integration" is x2 to x1024, "Unlimited" has 1min, 2min,...9min timed settings and a genuinely unlimited "Bulb" mode. All integration times from 1/500sec to Bulb mode can be accessed by turning the "integration" dial on the hand controller. (There are also settings with shorter than 1/500sec but they have to be chosen from the on-screen menus.) To use the Bulb mode, one has to set the dial to the corresponding position and then press a button to start integration. Then press the button again to stop integration. In all other modes sequential exposures are taken and always the most recent one displayed. The camera can also stack up to five frames internally. I believe that this doesn't apply to the "unlimited" mode.

 

During the first light nights I tried only some of the frame integration modes. Mostly because at the gain setting that I tried, they were sufficient for my targets. Dwight and Ken suggest to reduce gain and extend integration to get nicer images with less noise. My mount in Seattle can track o.k. unguided up to 2 minutes, so I will certainly want to try to go that far. I will take some parts with me when I go back to Massachusetts and hope that I can fix that mount so that it will track better, at least up to 1 minute.

 

The gain dial on the APU-1 goes from 0 to 63. I don't know, if those are dB or just a scale that can be efficiently implemented in the binary system. I chose 48 as my default starting position for the first light. Since I have no experience with cameras that have gain settings, I have no particular justification for that choice. One has to start somewhere and 75% is a position from where one can adjust both upwards and downwards. As said, Ken and Dwight suggest to go to lower gain settings combined with longer exposures.

 

I hope that every reader of this thread understands that this is a first light experience also for me, not just for the camera. I come from the very different world of image head cameras, so for me everything in analog video world is totally new. I am not upgrading from a less capable analog video camera and so I cannot build on prior experience with similar devices. A reasonable start for me is to try those integration times first that are also available on most other analog video cameras. No camera in inexperienced hands  can be expected to perform as well as even the cheapest camera in experienced hands. But learning new things is part of the fun.

 

My goal with the APU-1 is to use it mainly as a self-contained camera that doesn't require a computer to run. That way it will be complementary to my Lodestar and SX-825. While camping in the middle of nowhere with a wife, who doesn't tolerate computers, image head cameras are not very useful...

 

Next weekend I will be back in Seattle. If weather is decent, I will do more experimentation with the APU-1. If not, then back in Massachusetts with the hopefully fixed mount.

 

Clear Skies!

--Dom


Edited by Dom543, 15 September 2015 - 02:34 PM.

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#9 Carl N

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Posted 15 September 2015 - 03:18 PM

Thanks for sharing! I look forward to getting mine and learning as well!


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#10 StarMike8SE

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Posted 16 September 2015 - 12:28 PM

Good job Dom.   I found the other night that keeping the gain in the 30s through low 50s gave the smoothest views with longer integrations, of course your polar alignment needs to be good for the longer integrations.  Next time I want to try with my Ha filter with the camera in B&W mode.  I am glad we can start to compare notes now  :waytogo:



#11 tjay

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Posted 16 September 2015 - 03:53 PM

I'm glad to see these cameras are starting to trickle out.  Hopefully everybody who has place an order will get there new toys soon.



#12 Dom543

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Posted 22 September 2015 - 01:36 AM

I added two new images of the Dumbbell nebula to the gallery thread here http://www.cloudynig...lery/?p=6796609.

 

I tried to incorporate the friendly suggestions from earlier on this thread as well as my skills allowed. Please keep in mind that this is my third night with an analog video camera. Any further suggestions are more than welcome.

 

As I was itching to try out the unlimited integration mode of the camera, I did so despite of the fact that the bright Dumbbell doesn't really need the long integration. But if I remember correctly, Dwight's beautiful rendition from the wilderness a couple of weeks ago was also a 75 sec exposure. I had to take gain down to 18% to compensate for the 60 sec integration.

 

I have a couple of more captures from the weekend stopover in Seattle. But I need to fly back to Boston tonight. I will post more, when there is a bit more of quiet time.

 

Clear Skies!

--Dom


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#13 A. Viegas

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Posted 22 September 2015 - 07:14 AM

Hi Dom

 

Thanks for posting that comparison.   The 60s exposure was more colorful but has the blocky stars we see in most mallincam shots when we do not stack.  I think if you can it would be useful to try for a fainter target like maybe Stephen's quintet (NGC 7320 for instance) and try this same example:

1 shot using x256 with internal stacking
1 shot using long exposure with no stacking

1 shot using long exposure but with stacking

 

Thanks for the effort, its very interesting to see the results.

Al



#14 StarMike8SE

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Posted 22 September 2015 - 07:30 AM

Al, if you want a long exposure (integration) and stacking, you would have to do that in software.  Matt says to turn the cameras internal stacking off when doing integrations of a minute or longer.  (you probably already no this)



#15 jimthompson

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Posted 22 September 2015 - 10:12 AM

Hi Dom,

 

One question for you, did you have the internal camera stacking "on" for the first light images at the top of this thread?

 

thanks,

 

Jim T.



#16 Dom543

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Posted 22 September 2015 - 03:04 PM

Jim,

Yes, I did. It is the recommended setting for the frame integration mode x2-x1024.

 

Al,

I will try although I don't know to what extent the pollution associated with shooting from under the Boston light dome will interfere with those faint targets. Filters don't work with galaxies and those faint objects may just not be distinguishable from the background sky glow irrespective of which camera is used. Faint H-alpha nebulas can be pulled out from the background glow using sensitive cameras and H-alpha filters. But for galaxies this approach doesn't work. It's a light pollution issue not a camera issue.

 

To All,

At this point I am experimenting with what the camera can do without the use of any computer software. Partly because with the limited opportunities available, one has to decide what to do and what not to do. And partly because one of the main advantages of these analog video cameras is that they are capable of working and providing enjoyable experience in situations, when no computer is available.

 

My next opportunities to do astronomy will be on the weekends around the next new moon. Let's hope that New England will deliver its famed crisp autumn nights. Without getting too cold out on the fire escape.

 

Clear Skies!

--Dom



#17 jimthompson

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Posted 22 September 2015 - 03:29 PM

Thanks for the reply Dom. 

 

By the way, your assertion that light pollution filters don't work with galaxies is incorrect.  For visual use you are absolutely correct, but when properly selected some LP filters do indeed improve the contrast of galaxies under light polluted skies when using a camera.  The key is to use a filter that has good response to IR.  Examples of good LP filters for galaxies include:  Astronomik UHC, and Lumicon Deepsky.  The impact of adding the filter to your integration times will be larger on galaxies than on nebulae since the LP filter is reducing the light of the galaxy as well as the background, it is just that the amount by which the galaxy is reduced is less than the background and the net effect is an improvement in contrast.  The best contrast improvement on galaxies is achieved by using an IR high pass filter, although the increase in integration time required is very significant...like using a narrow band Halpha on nebulae.  I have confirmed this both by analysis and testing.  You can read up on some of my tests in the "test report" section of my website:

 

http://karmalimbo.co...rts/reports.htm

 

Check out the 4-part series on "Managing IR in Video Astronomy".

 

cheers,

 

Jim T.


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#18 Astrojedi

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Posted 23 September 2015 - 12:35 PM

Dom,

 

Very nice images. I like the immediate feel of video cameras.

 

I also second what Jim said. I have found Galaxies can be imaged in IR but with slightly longer exposures/integrations.

 

I think the notion that LP filters don't work for galaxies comes from visual observing where of course high pass filters are useless since we can't see IR.

 

Any high pass IR filter will work but there is one filter I want to try which is the Lumicon H Alpha. It is a long pass filter and lets in H Alpha as well as IR which in theory should also bring out the H II regions in bigger galaxies like M51, M33 etc. But color will be lost.

 

-Hiten


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#19 Censustaker

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Posted 23 September 2015 - 02:14 PM

Thanks for the reply Dom. 

 

By the way, your assertion that light pollution filters don't work with galaxies is incorrect.  For visual use you are absolutely correct, but when properly selected some LP filters do indeed improve the contrast of galaxies under light polluted skies when using a camera.  The key is to use a filter that has good response to IR.  Examples of good LP filters for galaxies include:  Astronomik UHC, and Lumicon Deepsky.  The impact of adding the filter to your integration times will be larger on galaxies than on nebulae since the LP filter is reducing the light of the galaxy as well as the background, it is just that the amount by which the galaxy is reduced is less than the background and the net effect is an improvement in contrast.  The best contrast improvement on galaxies is achieved by using an IR high pass filter, although the increase in integration time required is very significant...like using a narrow band Halpha on nebulae.  I have confirmed this both by analysis and testing.  You can read up on some of my tests in the "test report" section of my website:

 

http://karmalimbo.co...rts/reports.htm

 

Check out the 4-part series on "Managing IR in Video Astronomy".

 

cheers,

 

Jim T.

 

Awesome information here, thanks, Jim!



#20 Dom543

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Posted 26 September 2015 - 02:14 PM

Thank you Jim and Hiten for the filter suggestion.

In fact, I do have two IR-pass filters but, unfortunately, on the other side of the country right now.

I will try them out, when I get back home. The galaxy season will be running all spring.

 

Clera Skies!

--Dom



#21 Dom543

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Posted 26 September 2015 - 02:20 PM

I have just uploaded the last three APU-1 images from the stopover back in Seattle last weekend.

They are in the gallery thread starting here http://www.cloudynig...lery/?p=6804076.

 

Clear Skies!

--Dom



#22 Dom543

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Posted 28 September 2015 - 11:19 AM

Wizard Nebula with the APU-1 during the full moon eclipse.

 

Wizard_20150927_214708_1min-32gain.jpg

 

I prefer this capture to the one that I have posted on the gallery thread, as it shows more detail of the intricate web of gas that makes up this nebula. But this image is fainter and doesn't show well against the bright background.

 

Integration=1min, Gain=32 (50%), Gamma=2.

Made with Meade 8" SCT at f2 and a 7nm H-alpha filter.

 

Clear Skies!

--Dom

 

Here is the link to the gallery thread post http://www.cloudynig...lery/?p=6807169.


Edited by Dom543, 28 September 2015 - 11:30 AM.

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#23 mclewis1

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Posted 28 September 2015 - 02:14 PM

Nice image Dom. Now I think we are starting to see the sensitivity that the APU was advertised to have.


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#24 Live_Steam_Mad

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Posted 28 September 2015 - 05:55 PM

In Seattle my main scope is a 10" Meade SCT on a CGEM mount that can track unguided up to 2 minutes. I have a flip mirror with a built in focal reducer that brings the focal ratio down to around f4. The setup can be seen here with a different camera  http://www.cloudynig...etup/?p=6210387.

 

The obligatory object for any first light in the summer is the Dumbbell Nebula. Here it is my first light capture with the APU-1 through an Astronomik UHC filter and using Integration=x256 (4 sec) and Gain=48. This may not be my best M27 capture but, as said, I am unfamiliar with analog cameras, with their operations and settings. Moreover no live-processing software has been used and hence no stacking has been applied. In fact no software at all, except what is needed to display and save an image.

 

attachicon.gifcn3.Dumbbell-f4_20150912_213810.jpg

 

The second target was the Crescent Nebula. As this is a pure H-II object, I switched to a 7nm H-alpha filter. The Crescent turned out to big for my FOV at f4. So I switched reducers and went for f2. The 1/3" sensor took f2 in stride. Integration=x1024 (17sec) and Gain=52.

attachicon.gifcn4.Crescent_20150912_234905.jpg

 

I was curious to see how the Dumbbell would look at f2. Here it is with Integration=x256 (4sec) and Gain=36 (55%).

attachicon.gifcn5.Dumbbell-f2_20150913_005430.jpg

Note that thanks to the faster optics, gain could be reduced from 48 to 36. The texture of the image looks smoother to me. I don't know, if this is due to the lower gain or to the different image scale.

 

Next is the Bubble Nebula at f2 and through the H-alpha filter again. Integration=x256 and Gain=44.

attachicon.gifcn6.Bubble_20150913_014554.jpg

As the Bubble would fit the narrower field of the f4 setup, I switched back to the milder focal reducer. But by the time I got to focusing, the ever present moisture in the Seattle atmosphere turned into a uniform white cloud cover. This ended the first light of my APU-1 without a larger Bubble.

 

As said at the end of the first post, please feel free to ask any questions relating to the operations of the camera or to my experience with it. I will answer them to the best of my abilities. I would also appreciate any comments and suggestions from those of you, who have more experience with these analog video cameras and all their settings.

 

Please respect the desire to limit this thread to the discussion of technical matters related to the working and the use of the APU-1. Posts and comments on the maker of the camera and its business are off topic on this thread.

 

Clear Skies!
--Dom

 

Hi, how are you getting down to F2 with your F10 SCT? Which brand / model of reducer(s) are you using to do this, and what is the reducer lens to CCD distance?

 

Regards,

 

Alistair G.



#25 Dom543

Dom543

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Posted 28 September 2015 - 06:30 PM

Allistair,

This is a Meade 10" natively f6.3 OTA that I use with a Meade 3.3 reducer.

Same in Massachusetts, except that this one is an 8" natively f6.3 OTA.

The Meade SCT to T-thread adapter combined with a TS filter drawer and TS rotator plus the camera's 12.5mm CS mount flange-to-sensor distance gives the 57mm spacing recommended for the 3.3 reducer. A 20mm spacer would also work instead of the filter drawer and rotator. The original Meade 3.3 package included such a spacer.

Clear Skies!

--Dom




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