rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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Folks, I am doing a set of experiments in the next 2 weeks where I pick a three objects and look at the video output from a NON-TRACKING telescope--where settings are set on short integration times but a little higher gain. The results will help guide us when we take an older MallinCAM to Africa and use it on an 80-mm refractor on an alt-az tripod mount, but the same results will also answser questions that periodically come up on this forum when people ask what they can do without a tracking system when using a decent astro video camera.
If you would consider participating, I would like to see some pictures posted when the cameras are mounted on low f ratio scopes and/or scopes using focal reduction...especially those that are not the BIG ones and whose apertures are 3.5 inches to 8 inches or so -- sizes that are popular with entry/novice level observers....using camera settings at 128x (2.1 seconds), 64x (1/2 that time), and 32x (1/4 that time). I will need people to list the gain they are using as a rounded percentage of max scale, and which camera (typically STELLACAM or MALLINCAM). If I may be so bold and to introduce some common objects that are pretty easy to get in the sky and that most people can recognize or compare from, I would like to use: M27, M8, and M92 but don't mind if other things are posted. Remember to keep the posted stuff from getting too big in terms of file size.
I sketch things and do not have a capture device, so my results will be either sketches or description.
If you care to participate, I need the following if you post some files:
The object or target.
Your scope size/type.
Video camera type and "time"/integration setting:
128x, 64x, or 32x
AGC or gain: rounded percentage of max scale
Any comment.
The moon is fading from sight now so the next two weeks is a good time to do this.
Thanks for reading and participating if you choose.
Roland
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Sky Captain
Scope Builder
Reged: 11/07/04
Posts: 5539
Loc: Seattle Washington
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Quote:
Folks, I am doing a set of experiments in the next 2 weeks where I pick a three objects and look at the video output from a NON-TRACKING telescope--where settings are set on short integration times but a little higher gain.
I should be able to help you with that Roland. It should clear up this weekend. I have a 4" at f1.8 with the Mintron at 2 seconds,... will that work for you?
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Equipment Overload!
http://scopebuilder.webs.com/
Kerry.
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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Yep. I think the controls are about the same as the others, so if you can do the 2 sec but also the lesser times, that would be great. Roland
I will probably do mine with a 80mm f/7 refractor.
Roland
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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Forgot one thing....if your camera is fit with a focal reducer (mine will be), either identify the reducer or give me the net magnification that is on the screen/picture results. Thanks Roland
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Astrojunk
member
Reged: 11/02/06
Posts: 78
Loc: Australia
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I will hapilly contribute using an 80mm f5 should the clouds ever leave Qld!
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Astrojunk
20" f5 Alt Az Newtonian
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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Thanks both of you. I have a clear night tonight and hopefully will have a couple others during the next 2 weeks. No hurry for you to post....feel free to organize your captured shots a bit and place them here or in a folder in Members Galleries. If you use that, you can place your summary tech stuff in the comments, so anyone can see what the settings/scope were. Your choice.
I know from Rony (fellow sketcher in Belgium) that the short integration times do pretty good up to a certain point, which is dependent on (of course) field of view and the time period. I figure your comments and mine will be enough information for people to know where they can use the cameras without tracking, which I suspect will be well possible under certain conditions...and still provide much better views that the eyepiece alone. But, proof will be in what we find. Thanks again. Look forward to see what we get. Roland
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Astrojunk
member
Reged: 11/02/06
Posts: 78
Loc: Australia
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I have seen results from a 10" unguided dob that were fun but ultimately dissapointing. I would expect that the wider field of view would allow for better results. We shall see ...
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Astrojunk
20" f5 Alt Az Newtonian
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1300
Loc: Wilmington, NC
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This was my first shot with the Mallincam before I had tracking. M42 is a bright target so I think it will be nessasary for the mag to be close to the same for good results.
Neil
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Live, real time views of the night sky
Neil Horne @ Ustream, or Y Live
CGE EQ mount with rings
Orion 12" XTi f/4.9
MoonLite Focuser
MallinCam Hyper Plus Color
Round Table Platform
Cape Fear Astronomy Club
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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Thanks, please list the conditions and the scope. For any postings, it is important for folks to know that was being used and the cameras settings so they know what to expect.
Roland
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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I have done the first session of tests that I will summarize here but post separately so it will be more organized with other people's inputs also:
Setup.
I used an 80mm f/6.95 with the MallinCAM Pro (older camera) that was piggy-backed on a [12.5 f/4.5 Dob (Swayze Optics) + 35 mm Panoptic]
Non-tracking results/preliminary:
I found that the 80 did very well for 64X (about a second of integration) and faster when I used full ALC and AGC set at the 1/2 point. "Very well" means a decent view, little noticeable star distortion from the lack of tracking. 32x or 1/4 second still delivered a decent view. Tested these results against M92 and M8 under terrible conditions (high wave clouds and haze).
80mm Equivlancy with Camera.
Furthermore, as a secondary finding, the 80mm view under these conditions was much better than the view from the EP with the 12.5 Dob. The views were essentially equivalent when I went to 32x or 1/4 second integration on the camera on the 80 as compared to the 12.5 Dob with the 35 mm Panoptic!! The FOV difference: the Panoptic view was about 1/3 again as wide. All these findings were with no tracking.
Ease of use.
With a little practice, I could use the Alt-Az 80mm easily with the camera ... using a simple star finder or even a simple tube attached to the 80 barrel to do the old star hopping. This is a pretty simple setup to deliver views equivalent to a 12.5 Dob with decent optics and a decent EP. Moving the scope around while the camera churns away is not hard...just watch the wires. The movement on the screen output can easily be watched and used to know where to move. Also, it takes about 2 minutes for an object to go from one side of the screen to the other before some adjustment is necessary. I repeatedly went through this process and it is not hard. If the object is centered, you figure you have about a minute before having to readjust. Of course, adjusting an alt-az setup and small scope is pretty easy.
All for now.
Roland
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1300
Loc: Wilmington, NC
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Quote:
This was my first shot with the Mallincam before I had tracking. M42 is a bright target so I think it will be nessasary for the mag to be close to the same for good results.
Neil
Scope used was an Orion 12XTi and the camera was a Mallincam color at 2.1 seconds.
--------------------
Live, real time views of the night sky
Neil Horne @ Ustream, or Y Live
CGE EQ mount with rings
Orion 12" XTi f/4.9
MoonLite Focuser
MallinCam Hyper Plus Color
Round Table Platform
Cape Fear Astronomy Club
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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When you get your shots and have some conclusions, please feel free to post them on the thread near the top of the forum on unguided mounts. Your f/5 80 should produce very good results, and may be better at 2.1 seconds integration on my f/7 80, where I got too much star trailing.
Roland
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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Yes, and like I said to another helper, simply post the results and conclusions on the thread on unguided applications near the top of the forum. At f/1.8, you should get really good shots as if the mount was guided. Looking forward to what you find. Roland
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rolandlinda3
Pooh-Bah
Reged: 01/24/06
Posts: 1425
Loc: Crozet VA 22932
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For anyone reading....if someone can do this experiment for a typical 5-8 inch Newtonians that are popular, that would provide some information for folks wondering if their Newtonians on unguided mounts would work with one these cameras. I don't have one to setup right now or I would do it myself. Roland
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