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 Post subject: Possible improvements
PostPosted: Mon Apr 20, 2015 1:07 pm 
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I have a 6" Skywatcher Schmidt-Cassegrain Telescope with motorized mount.
Having seen someone taking cell-phone images through the eyepiece on Stargazing Live, I tried the same thing with my compact camera. (Olympus 14MP with 10x Optical Zoom). Eventually I managed to get a slightly fuzzy image by aligning the camera on a separate tripod, but this was definitely more trouble than the result justified.

So, I looked into using the video function on the camera with stacked images and made a bracket to align the camera with the telescope eyepiece. This is basically a sleeve which fits very tightly to the eyepiece and is a snug fit around the camera lens.

Here is my first (and best) stacked image of Jupiter.

Image

I tried different frame-rates and resolutions of the video, but was unable to get any improvement.

I have two questions as to how to procede:

Could I get better images using the equipment I currently have, and if so, how?

Would it be possible to get better images with a modified HD webcam such as the HP-4110? ( I have seen this modified to fit inside the eyepiece holder )

I am aware that I can buy bespoke CCD units, but the ones I have seen are expensive, or low quality.

Thanks

Aba


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PostPosted: Mon Apr 27, 2015 6:44 pm 
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Location: Wellingborough
Hi Abba, welcome. Apologies for not picking up your post earlier, don't know how it was missed.

Your Jupiter image shows that your setup works quite well. The image is sharp, has colour and there is certainly detail there.

Whether it's possible to improve from here depends much upon the control you an have over your camera settings. For planetary imaging you need many frames to stack, so fast video rate helps, but something like 10fps taken for 2-3 minutes for Jupiter should be fine. Aim for say 1000 frames to stack from. Ideally you need access to your cameras controls for shutter, gain, histogram as well as video rate in order to get the control you need over the imaging process. Some modern DSLR cameras can be used in video mode to be very effective planetary cameras. Older models of webcam enabled these controls, but more modern versions have been made more automatic in function, which makes them more difficult or impossible to use for astro work.

Given the cost of modern webcams, many imagers have indeed gone for the dedicated imager options that are available. Some rather nice planetary-cameras are available for around £100, whereas a high-spec webcam might cost £70 and then need modifying.

Congrats on that image, you've made a great start 8)

Regards,

_________________
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
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PostPosted: Mon Apr 27, 2015 9:57 pm 
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Hi Brian,

Thanks for your quick response - the post was only approved this afternoon.

The DLSR I have access to does not support video and as I said, it is almost impossible to focus when it is fixed to the scope. I couldn't even manage to get a sharp image of the moon after several hours of effort and three flat batteries.

The option for a decent bespoke imager for around £100 is definitely worth considering, but could I use the same camera to take pics of the planets and moon, and also faint objects like galaxies and nebulae?

I have a week's holiday near Stranraer in June, so it would be great to have found a solution before then, in order to take advantage of the dark skies.

Thanks

Aba


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PostPosted: Tue Apr 28, 2015 6:24 pm 
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Location: Wellingborough
Hi Aba.

Robin Scagell put together a short intro to imaging with a DSLR and telescope, maybe you've seen it:
viewtopic.php?f=18&t=12886

You really need a DSLR with "liveview" capability to get decent focus. Using liveview in "zoomed" mode is the way most DSLR imagers go to focus. Not all DSLR cameras have this capability. The astro-imagers favourite has to be the Canon EOS models, 1000D/1100D/1200D have good reports, and there is free software out there to tether the camera to a laptop in order to control functionality. Google "BackyardEOS" for instance.

Webcams and planetary cams/CCDs will also require a laptop to run the system and record video to HD. Have a look at the 365Astronomy website under "planetary imagers" (for instance) to see a range of cameras and prices:
http://www.365astronomy.com/Planetary-Imagers/

I would myself avoid the "digital eyepieces" and consider something a little more upmarket, such as the Celestron Neximage Solar System Imager, the ZWO ASI034MC, or the QHY 5L cameras as price increases.

The ZWO cameras on that page can also do long-exposures - up to 60 seconds, and at least two Forum members here use them for DSO work as well as lunar/solar/planetary - search for posts in the Gallery by Ian Papworth and smerral for instance. That said they are not dedicated long-exposure cameras but work well within their capabilities.

One book I would recommend you get ifyou don't already have it is "Making Every Photon Count" by Steve Richards:
http://www.firstlightoptics.com/books/m ... hards.html
also available elsewhere :)

Regards,

_________________
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed


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PostPosted: Wed Apr 29, 2015 2:50 pm 
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Joined: Mon Apr 20, 2015 12:24 pm
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Thanks again Brian.

Your post was very helpful and informative.

I read several articles on using a DSLR with a scope, but the camera does not support a zoomed view on the screen, either. The only way to get sharp focus would be a trial-and-error method of tweaking the scope, waiting for the vibrations to stop and taking a shot. When you couple this with all the other variables for settings, like aperture, ISO, white balance, and shot time you have a very long list of things that can be wrong. If I could leave everything set up, it may be worth the effort of doing this, but not when I have to start afresh each session. My father has an extensive range of Olympus camera equipment which has been more than adequate for all situations we have tried, other than this.

Hence, I tried using my compact camera through the eyepiece (having seen that this was possible on the TV). I must admit that I expected results similar to those of Ian Papworth and Smerral, but alas.

So it seems that I would need to spend around £200 or more, either on a Canon DSLR or a dedicated telescope camera to get results that I would be happy with. Unfortunately this is outside my budget at present. This is why I asked about the HP webcam which I can get for around £50 and modify.

I suppose I was hoping that someone here was actually using one of these cameras, and could confirm whether or not it would give improved results.

Thanks once again for your replies. You have provided me with a lot of very useful information. If I cannot get the information about the webcam, at least I know what level of dedicated camera I need to save up for.

best wishes

Aba


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PostPosted: Wed Apr 29, 2015 6:14 pm 
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Hi Aba,

Ah! , I see now. The HD4110 bit is rather hidden inside the post. Maybe a new post headed "anyone using the HD-4110 webcam for astro" or something similar might catch someone's eye?

A quick Google for "Hd-4110 camera astro-imaging" brings up a few hits including some Youtube videos but these are mostly some years old now. More recently a number of people have tried the X-boxlive camera for astro work with some success it seems. Google "xbox live cam astrophotography". This camera can be got for a few pounds , even as little as £2.50 at times. There are more google hits for this little camera than for the HD-4110,

Regards,

_________________
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed


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PostPosted: Wed Apr 29, 2015 10:18 pm 
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Thanks for the xbox camera tip - I shall search for one of those and buy several if I can get them dirt cheap !

I wondered if my Jupiter image had suffered from being slightly out-of-focus, so tonight I tried again, this time with the moon as a subject. I DID find that I could improve the focus in the camera even when the image looked OK in the eyepiece. The wind certainly did not help the process, but I did manage to get this picture of a crater near the terminator:

Image

This image is stacked from the best 5% of 1000 frames then sharpened. Video was at 1280 x 768 at 30 frames per second.
I may try Jupiter again on a better night, but on balance, I think I will definitely be trying to find one of the Xbox cameras.

Thanks again for your kind help,

best wishes

Aba


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PostPosted: Thu Apr 30, 2015 7:03 pm 
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That is a reasonable lunar image, seeing has a big effect on sharpness and is outside our control. I tried to id the crater but it's difficult without having some idea of the image scale. I wonder if it could be Gruithuisen? Just a guess :)

The xbox live is worth a punt, but it will never pull in images of the quality produced by dedicated planetary cameras, you get what you pay for. I think I'm right in saying that the PS3-eye (?) camera has also been used for astro work, might be worth a google.

Generally, getting involved with any form of astro-imaging is a good way to empty your wallet fast :lol:

Good luck, keep us informed of progress,

regards,

_________________
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed


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