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Old 08-04-2020, 10:11 PM
TwistedRider (Drew)
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Question Camera for Goto DOB.

Hi all, just after some possible recommendations.

I have a 10" Goto DOB that I've had some minor success imaging with a phone camera and am wondering what would be a decent camera to try and inverse the quality of images with.

An eq mount and ota just isn't a possibility so I'm hoping to do what I can with the dob.

Obviously the moon is a primary target, but the planets and some of the brighter celestials would also be desirable of at all possible.

My options as I can see them are 1 semi decent camera for planetary as the div isn't as Evergreen by drift on these.

OR

2 cheaper cameras, planetary/deep sky (although I think things is largely pointless given the scope.)

I'm pretty sure there isn't a camera to cover all bases, so I'm open to suggestions on a suitable cameras for moon and possible planets.

Budget is probably up to $400ish +/- a good deal/bang for buck.

Ideally I do plan to get that eq at some stage so hoping it will be suitable for both scenarios

Thanks in advance.
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Old 09-04-2020, 04:47 AM
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bojan
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For planets and Moon, consider web cam.. see here:
http://www.qcuiag.org.uk/

For other, deeper things, second-hand DSLR is the option.... old Canon or Nikon could fit into your budget.
However, most dobs are not good for longer exposures (primarily due to lack of field rotator)...
Also you have to see if you will be able to reach focus with your Newt.

If you are handy with tools (and heart ), this is not a problem. But if you are not... it may be quite expensive exercise.

Last edited by bojan; 09-04-2020 at 05:26 AM.
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Old 09-04-2020, 07:33 AM
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Tulloch (Andrew)
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Hi there, probably the most commonly used planetary camera right now is the ZWO ASI224MC, and it's right on the money too at about $400 new (well it used to be, until the $A dropped through the floor recently, I just checked the Bintel website). However, it has a very small sensor and so you won't be able to take images of the full disc of the moon, but you will get very detailed closeups of the craters. It's probably the best bang-for-buck in dedicated planetary cameras out there right now.

However, if you already have a Canon DSLR lying around, it is more than capable to use for both planetary and DSO imaging - the Canon system is (probably) the only DSLR that can be used for high quality planetary using the LiveView feature in good seeing, and a DSLR has a huge sensor for lunar and DSO. Purchase some astro software to control the camera (I use BackyardEOS) and you will be able to take great images.

Bear in mind that for planetary, you will need a Barlow lens to get your f-number up to about f20 so you can get enough pixels on target, so factor that into your purchasing plans. If you go with the ASI224MC you will also need an IR cut filter (around $30) to remove the IR.

Hope this helps,

Andrew
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Old 09-04-2020, 05:12 PM
TwistedRider (Drew)
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Thank for the advice
I have tried an old Canon camera, a bit too old I think as it fails to be detected on any of I own. That is a decent option though.

I have a battle for my eye pieces, bit no seat to stave a camera to that. May need to get a different one.

Thanks, I might look at a different Canon 1st, and a zwo or similar down the track.
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Old 10-04-2020, 07:46 AM
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Tulloch (Andrew)
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When I got my ASI224MC planetary camera, I did a bit of work testing the performance of it compared to my Canon 700D (which I picked up 2nd hand pretty cheap). You can see some of the tests I did using my 6" SCT on the CN website here, here and here. It performs very well when the seeing is good and wind levels are low. Because the LiveView functionality (essential for planetary imaging) is fixed at 1/30 sec shutter speed, any vibrations on your scope cause by the wind will blur the image, and strong jetstreams will also reduce the quality more than the dedicated planetary cameras.

In terms of focal ratio, the general rule is to image the planets with f/num = 5x the pixel size of your camera. My Canon 700D has a pixel size of 4.3 microns, so the "best" focal ratio was f21.5, so a 2x Barlow on my f/10 SCT was ideal.

If you are new to planetary imaging, you really should watch these videos, they will tell you a lot. Note that Steve recommends the NexImage 5 as the camera of choice, these were done before the ASI224MC came out.

Hope this helps,

Andrew
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Old 11-04-2020, 03:11 AM
Malcolm
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What I use on a 10" GOTO dob. A Revolution Imager 2 camera kit, mainly used for public outreach. Capture to a laptop with the USB dongle using SharpCap. Also an IMX224 USB colour camera bought from Ali-Express. It came with Rising Sky software for image capture.
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Old 13-04-2020, 12:56 PM
TwistedRider (Drew)
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Thank again all

Looking into what will g I've me results.

Still considering DSLR vs dedicated planetary cam
Deep sky can wait till after I win lotto and get that eq mount
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Old 14-04-2020, 03:09 PM
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Hi Drew,

What model canon do you have? You'd be surprised what an old canon can do as long as you get enough exposure.

I would probably get a small planetary cam zwo120 or 224 (with a barlow or something like a 4x powermate to up the focal length) and use your old dslr (or get one second hand) for deep sky while you save up for the eq setup.

You can get brighter deep space stuff on a dob. Here is some old images i took with a 600d https://www.flickr.com/photos/803366...57634243605994
I was a beginner then and am sure i could do a lot better these days if i had to.

Also - hopefully not muddying the waters but with the 'new' cmos cameras it is possible to get great results with very short sub exposure
https://www.cloudynights.com/topic/5...b-m51-and-m57/

- but you will need a lot of space on your hard drive! (and a way to counter balance the extra weight).

cheers
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Old 14-04-2020, 10:52 PM
TwistedRider (Drew)
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Hi Russell,
Cam is a Canon 30d. Backyard Ross only has marginal support, and only on 32 bit systems.

Yes I think the 120 or 224 is what I'm looking at, although no chance for full frame Moon.

I think to do that I need a pretty powerful reducer if I want to do that.

Drive space is no issue...I don't buy in less than 1tb these days.
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Old 14-04-2020, 11:12 PM
TwistedRider (Drew)
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What would be the drawback if any, of an ASI290MC compared to the ASI224MC

Budget may be better that originally planned, considering the 600ish cams as well.
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Old 15-04-2020, 02:14 PM
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The ASI290MC has smaller pixels, so it will capture slightly less light than the 224, however on a 10" dob it shouldn't make any measurable difference. I would not consider buying the 120MC, sure it's cheaper, but it's cheaper for a reason.

The f-num = 5x pixel size still applies, although for the 290 the optimal f-num is around f/15, not f/20. What f-num do you get with your dob and 2x Barlow?

The Canon 30D does not have Liveview, so will not be any good for planetary in the way I mentioned above. You might be able to get a good used Canon DSLR second hand off eBay, Gumtree or even Crime Converters - make sure you do NOT get the 650D, it's terrible with LiveView.

Andrew
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Old 15-04-2020, 03:06 PM
TwistedRider (Drew)
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yeah the 30D is pretty much of the table do to age and technical limitations.


im not sure how to calculate the effective f number,


the scope is f4.72 according to the label. 1200mmx254mm (SW 10" collapsible Goto), i assume the barlow adjusts this somewhat


Quick reading says this would be about f9.4 so id be looking at a 4x barlow to get close to 20...


that would make the moon rather huge, but jupiter would be looking good

For the moon, the bintel calculator says about 0.3 reducer would be needed.

Last edited by TwistedRider; 15-04-2020 at 03:50 PM.
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Old 15-04-2020, 10:20 PM
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Tulloch (Andrew)
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Yep, the 2x Barlow will turn your 1200mm focal length f/4.72 into a 2400mm f/9.4 scope. A 4x Barlow would get you to f/19 with the 224MC, but they are hard to find and expensive. Maybe a cheaper 5x with the 224 would be OK, or a 3x with the 290? Difficult choice, and not good for a full disc moon, only the DSLR would give you that. However, you can take multiple close-ups and mosaic them together using Microsoft ICE (Image Composite Editor), but that would be a lot of shots.

Having said all that, you can always try the 2X Barlow and planetary camera and see what you get, the planets will be smaller than optimal, but you'll still get a reasonable view.

I tend to use this tool for determine image size, probably better than the Bintel tool.
https://www.12dstring.me.uk/fovcalc.php

Andrew

Last edited by Tulloch; 15-04-2020 at 10:38 PM.
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Old 15-04-2020, 10:36 PM
TwistedRider (Drew)
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Sorry Andrew I'm confused

The Barlow would get Jupiter larger... But for the moon don't I need a reducer? For full disc.
I can live without that for now though.

I'm getting the impression that enough reducer for a full disc ~.3 will introduce a raft of other visual issues... So crater close ups it will be


One thing I did notice was that with the Barlow, was that the tool listed significant oversampling. Can't work out of that horribly detrimental for planetary or not.

Is qhy a viable alternative to zwo? Prices are a little more friendly

I'll take a look at that link. Thanks
Drew

Last edited by TwistedRider; 15-04-2020 at 10:51 PM.
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Old 16-04-2020, 07:02 AM
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Hi Drew, I don't know anything about the QHY range, so I can't help you there. If I was in the same position as you and looking to start out, I would buy a second hand Canon DSLR off ebay (there are a couple of used 550D cameras here in Melbourne for less than $150 here and here), grab a Bintel branded 3x or 5x Barlow lens for $60/70 (or get a Teleview one if you can afford them), purchase Backyard EOS from O'Telescope for about $50, watch these videos, read this information and this guide, and just get out there! For the next 6 months, the planets are going to be in the best positions for a while and the Canon DSLR is a great system in low wind.

The DSLR will also let you image the moon, nebulae, galaxies etc using the same equipment and software. If you later decide you have caught the bug and want to specialise, then you can buy higher quality, more expensive stuff at that time and you will have more experience to know what you want. The other thing is that if you decide this isn't for you, then you are not too much out of pocket and the 2nd hand stuff you did buy can go back onto eBay and you haven't lost too much.

Hope this helps,

Andrew

P.S. You can see some of my astro images here, the solar system folder tracks my progress from my first image taken of Jupiter with a Canon DSLR and 6" SCT through to my latest with a 9.25" SCT and ASI224MC.

Last edited by Tulloch; 16-04-2020 at 07:17 AM.
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Old 16-04-2020, 08:09 AM
TwistedRider (Drew)
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Thanks Andrew,


Backyard EOS may indeed be the way to go for now.


Thanks for all your advise and suggestions.
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