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Walking on the Moon

Can't find star's


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Hi all.

First night out with my cannon 450d , thought I'd hook it up to the dob and take some images.

Finding the moon was easy changed iso and shutter speed to get in focus.

But i can't focus on Jupiter/ Mars or anything else is there something I'm doing wrong.

Any help would be greatly appreciated.

Dave.

PXL_20221205_204321934.thumb.jpg.b2a409bcf95271d7a33e2b19fc159241.jpg

 

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Take a step back. The moon is a very large and very bright object, so the settings you are using for the moon are probably not at all what you need for very small distant points of light, like stars.

Does your dslr have a live view on the back screen? If so then find a very bright star and focus. Then zoom in on the live view to max and focus to a small point of light. There you have it.

You may have to put your ISO to 800 ish maybe more I am not a Canon user.

If you find that the planets are still small points of light then you can help things a tiny bit by using a Barlow.

If still dissatisfied then buy a very large telescope with an equally large fl then you stand a chance of taking a detailed planetary picture.

Marv

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That is where the huge expense telescope comes in I am sorry to say.

Use a Barlow between the camera and scope to get at least 2x mag.

I think a lot of planetary photographers use Maks and SCTs as they have a very long focal length for their aperture so the planet seems a lot closer.

I found it very strange at first that seeing and taking a picture of galaxy light years away is actually easier than taking a picture of a planet next door.

The reality is that none of it is easy at all. 

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Just a thought… if you have two Barlows stack them for 4x mag. The planets are very bright so I wouldn’t worry at first about quality.

On top of that you are planning to take a single image??? Planetary is normally a video image of single frames. You get rid of the bad ones and stack the good ones. YouTube vids for planetary photography are very good.

Marv

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The issue with a DSLR is they typically have large sensors, so planets will be tiny. If it's a dot, adjust your focus so it's the smallest dot you can make it. You then need to image at a very fast speed so the planets brightness does not dominate and give you a chance to capture the surface detail in a moment of clear seeing. Planetary cameras typically take images in their tens to hundreds of images per second so you can begin to understand why a DSLR isn't suited for this as they're much slower. As a compromise you can try taking video instead which is typically 25/30 frames per second, but I recall the control over image exposure isn't as good as when imaging, and also the video may be compressed which will affect detail and will introduce noise. Once done you need to process in a program like autostakkert to stack the best frames.

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Thanks Elp.

I don't think my DSLR does video as it's old.

I just purchased a Skywatcher Star Adventurer and a samjang lens to do long exposures but I've miss placed the polar scope illuminator so i haven't used it yet 

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@Dave scutt you absolutely can do planetary with a stock Canon 450D attached to your telescope, and it absolutely does do video 👍

See my threads here and here

The gear I used was very basic, a 70mm/900mm frac on a manual EQ1 mount plus a few other bits.

IMO the key is to use BackyardEOS on a laptop to drive the 450D - you can get a free 30 day trial. It has a planetary mode with 5x zoom that captures a much smaller part of the sensor.

I don't recall the settings I used, I think I was playing around with ISOs around 800-1600 (can check if you want).

Is a dedicated planetary better than a DSLR? Maybe. But a guy on CN pointed me to his experiments of a Canon 600D/700D compared with a ZWO. Although the latter has a far faster frame rate it is more noisy and so needs many more frames.

I've recently acquired an HEQ5, SW150PDS and a couple of planetary cameras. If it ever flippin' stops being cloudy here 😖 I plan to play around with different combos of all this gear (450D included) to figure out for myself what works best for me - and hopefully improve considerably on the images shown in the linked threads above!

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If you wish to use a DSLR for planetary imaging it is possible.  However, you will only get decent results if your Canon has video crop mode (my 60D had such a setting).  This crops the sensor capture down to something appropriate for planets for example 480 x 640.  Then you need to take video and use Autostakkert to stack the best of your frames.  I also got better results with eyepiece projection  (rather than prime focus) using a Baader adapter to connect the T ring adapter directly to the eyepiece.  The best results I obtained were when I used a 15mm plossl on my 102mm refractor.  I have moved on to using a 9.25" SCT and and proper planetary cameras, it's much less faffing around and gives you decent focal length and small chips.

 

Edited by Owmuchonomy
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38 minutes ago, Owmuchonomy said:

If you wish to use a DSLR for planetary imaging it is possible.  However, you will only get decent results if your Canon has video crop mode (my 60D had such a setting).  This crops the sensor capture down to something appropriate for planets for example 480 x 640.  Then you need to take video and use Autostakkert to stack the best of your frames.  I also got better results with eyepiece projection  (rather than prime focus) using a Baader adapter to connect the T ring adapter directly to the eyepiece.  The best results I obtained were when I used a 15mm plossl on my 102mm refractor.  I have moved on to using a 9.25" SCT and and proper planetary cameras, it's much less faffing around and gives you decent focal length and small chips.

Jupiter 22_11_22.jpg

Second that about needing to use eyepiece projection with a digital SLR to get a decent planetary image size, although so many observers dismiss it as being rubbish these days.

John 

Edited by johnturley
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DSLRs (at least the D800 and presumably all others) use a far bigger chunk of the sensor to capture 1080P video than the pixel count suggests, so do not achieve the same resolution for a given focal length as they do with still images. In other words, you will need to go to greater focal lengths to achieve the desired resolution than you would if you were shooting still frames.

D800 is 7360 x 4912 resolution on a full frame, 36 x 24 mm sensor.

Video uses 32.8 x 18.4 mm of the sensor, so 6706 x 3766 pixels.

This is scaled to 1920 x 1080 at 3.49:1 linear ratio.

Hence, you will need to Barlow by a further factor of 3.5 to reach the required f/ratio compared with that for still images.

D800 can also film video at reduced resolution of 1280 x 720, but still uses the same 32.8 x 18.4 area of the sensor, hence the ratio is now 5.24:1.

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20 hours ago, Dave scutt said:

I just purchased a Skywatcher Star Adventurer and a samjang lens to do long exposures but I've miss placed the polar scope illuminator so i haven't used it yet 

You shouldn't need a dedicated polar scope illuminator - just shine a red-light torch roughly across the open end of the polarscope and move it around - it should illuminate enough for you to see the polar clock reticule.

ETA - the Star Adventurer is compact enough so you should be able to do this comfortably. 

Edited by Gfamily
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Seeing fluctuations happen so fast, frames per second is almost as key a spec for planetary photographers as it is for gamers. Frequently we define and use a region of interest that's a fraction of the full sensor, all in service of the very shortest exposures possible, as close together as possible. I've no idea whether any astro-imaging drivers and software can do this for your Canon. Since planetary-capable cameras tend to have small sensors and don't need cooling, they'd the least expensive dedicated astro cams.

The go-to app for planetary imaging is FireCapture, although there are certainly other great ones out there. Since it's free, you can try it out to see what ROIs and frame rates are possible with your rig.

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