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Entry into EEA for observing, not post processing


cplee42

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For several years i have toured the sky from my back garden using 8” SCT And AVX mount plus various eyepieces and i still enjoy the challenges. However i am finding i have now seen most objects that are visually appealing and now find the remaining targets harder especially with encroaching sky glow around me. I could consider upgrading to a firmer mount and the 9.25” (i must set up and tear down my kit each time i use it so not keen on going to 11”SCT).

 I am therefore wondered if EEA could allow me to see more. Nebulas i can never see or more distinctive galaxies. I am not so bothered about capturing images and post processing so would like to set my scope up with relative simplicity and “see” the image build up on my ipad (preferably). 

I have seen some videos on ASILive and ASIAIR etc but it seems to require quite a bit of kit and fiddling with autoguiders etc. Would a ZWO like camera plus ASIAIR just do the job on the ipad? Would this work for planetary as well as deep sky? I have also seen reports about (Expensive) NV eyepieces but i cannot assess whether they too take me in the direction i seek...

i have also seen the eVscope setup on line and to some extent that seems to move in my direction as a principle but i already have a decent scope set up and so look to augment rather than abandon. 
 

Thanks in advance for any advice.

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Hi Chris

I'm sorry that I can't really help with the ASILive side (though I read reports that it is easy to use). I appreciate your desire for simplicity (I use a single USB cable to my laptop and another to my filter wheel, which I see as reasonably simple).

On your other points, I can say that you don't need to guide to do EE(V)A. Also, an 8" aperture is easily more than enough to bring 10s or 100s of thousands of objects into view, a great many of them with lots of detail (check out the main EEVA observing subforum). I use an 8" reflector and have no desire to increase aperture. What you most likely will need is some kind of focal reduction to bring the focal ratio into the region of 4-5 (for DSOs). I don't 'do' the brighter planets, but the longer native focal ratio is I believe better suited to those.  I'm sure others with similar scopes to yours will be able to chime in with more specifics. 

I have fairly extreme views on the camera side (so feel free to disregard!), but nearly everything worth seeing will actually fit on a small (pixel count and physical dimension) sensor (mine is 0.4Mpixels and about 0.4 degrees apparent FOV). The trend amongst EEVA'ers is in the opposite direction, to larger sensors. These are good for larger objects like many nebulae (bright and dark) and a few of the larger open clusters, and M31, and .... that's about it. Pretty much all the NGC/IC, Hicksons, Arps, and other catalogues will 'fit' on the smaller sensor (as of course will the planets). So it is worth thinking about this side of things too. Smaller pixel count sensors are (much) faster to process (stacking), eat up less storage, and are simpler if you end up doing any kind of wireless transfer. The down side of a small sensor is that your GOTOs need to be quite accurate, but I have never found that to be a problem. Happy to elaborate on any of these points!

cheers

Martin

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Thanks Martin. What camera set up are you using? and how do you interface this to the scope? Your signature suggests you use a SXLodestar Guide Camera but is this the main one? I have looked up Jocular which I was not aware of so my learning curve is beginning!!

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Hi Chris

If you check this thread you can find my setup in detail. The Lodestar is my main (only) camera. Although it is marketed as a guide camera, the properties that make it a good guide camera (large pixels, high quantum efficiency) also mean it is very effective for EEA in terms of delivering reasonable views of objects quickly, which is what we want when observing, as opposed to doing astrophotography. Arguably there are better options out there, both CCD cameras (such as the Ultrastar with slightly smaller pixels and an overall larger field of view, which Mike JW uses very effectively for EAA and which would be my likely upgrade path), and CMOS cameras which tend to have lower read noise and can therefore support faster exposure times. CMOS cameras are just a little more complex in use because it is necessary to choose a gain value as well as an exposure time, but I believe this isn't too much of an issue with experience.  

 

A few caveats about Jocular: 

1. The version that is currently out there does not support cameras natively. Instead, you need a separate capture engine that dumps FITs into a folder which is monitored by Jocular. The version that I aim to release next month will support the Lodestar natively and hopefully the Ultrastar too, but there is little chance I will support other cameras in the near future, so for these cameras it is necessary to use the monitored folder approach. 

2. It is a source code distribution, so needs some first-time only setup (basically, installing Python and a few packages). It is not a download, click and open option, so needs a bit of work. However, this means that it works on all systems (OSX, Windows, Linux) and we have working examples and can help collectively with install issues.

3. It only supports mono cameras with relatively small total pixel counts. This comes from the design philosophy of the tool, which is to enable all decisions to be reversed/modified during a live session, in order to make best use of the photons you've collected. Essentially, Jocular supports a 'fast total reprocess of the stack at any time' design and also give the user complete access to the entire stack of subs in order to edit out poor subs, change the way the stack is combined, and a host of other actions that are not normally possible in EEVA tools. But as a tradeoff, I can only support relatively small pixel counts... 

4. It supports colour via mono + filters but doesn't support one-shot colour.

Jocular was conceived as an observers' tool, so it does have functionality that support observing lists, observation planning, session and object logging, reloading previous observations and the like. 

cheers

Martin

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I'm in a similar position.  Light pollution at home limits naked eye magnitude to around +3, maybe +3.5.  I have darker sites available but the nearest is at least a 45 minute drive plus the time to pack, unpack, set up, etc., so I'm starting to research EAA.

From what I've read, decent results on faint objects with stacked unguided short exposures using relatively inexpensive cameras are quite achievable.   I've read good reviews of both ASILive (ZWO) and SharpCap live stacking.   I'm considering a monochrome ZWO just to dip my toe in the water.

 

 

 

 

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  • 2 weeks later...

I think it's down to volumes of sensor production. Outside of long exposure AP and a few limited commercial uses nobody wants mono sensors, so production per unit is more expensive. The terrestrial camera market drives demand for mass production of colour sensors. 

With your set up, I would suggest an OSC camera such as a ZWO ASI294mc, use short stacked exposures (under 20 seconds) behind a 0.6.3x focal reducer. For EEV, you don't need a cooled camera, or autoguiding.  Frankly, I don't notice any difference with my cooled camera if I forget to turn on the cooler.  You might need cooling for long exposures, or if in Death Valley, but in Bristol, the benefits are limited. I suggest a ASI294mc as cheaper models such as an ASI224mc have a very narrow FOV. Think of this like eyepieces. The ASI224mc is great for planets, but you need a wider field of view for most DSOs. 

 

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