## DSLR used for astrophotography???

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ARock
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### Re: DSLR used for astrophotography???

Juno16 wrote:
Sun Jan 12, 2020 12:54 pm
lsintampa,

I could be wrong, but without live view, it will be nearly impossible to focus accurately. You can’t zoom in to use a batinov mask. Even if DigicamControl supports the camera, without the lv camera function, you still have the focus issue.
When shooting stars, “close” focus isn’t good enough.
Used dlsr’s that work well for astro ave available for very low prices on ebay. I bought my Nikon D5300 for $250 on ebay with less than 2k shutter clicks. I have seen Canon t3i’s for less than$200.

Just a thought.

Jim
Although LiveView is much easier, it is possible to do without live view if you can take pictures with software. I did that with my D70s for a while. You connect the laptop/raspberry pi to the camera, use tethered mode (which auto downloads the image) to take a picture and view it on the larger screen of the laptop. Then adjust focus and repeat. With a Bahtinov mask and a laptop it is much easier. All of it was done running gphoto2 on a raspberry pi 3B ($35) connected to the camera to which I VNC ed in. What finally got me to move to a T3i ($150 on ebay) was not being able to do greater than 30 s shots (bulb mode) using software on the D70s.
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lsintampa
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Thanks everyone. Stay tuned as I'll try to fine tune my focusing / exposure attempts with the D50. Meanwhile, I ordered a Nikon D5300 with like 2K shots. It should arrive in a week or so, but I'll continue playing with the D50 - if for no other reason, to frustrate myself and you all!
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lsintampa
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While I'm waiting for new camera - tried again tonight - aimed at Orion.

Not sure what it shows, but I am anxious to see what better camera may provide.
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#### TSS Photo of the Day

did you process that from a raw? if so what settings?
lsintampa
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metastable wrote:
Tue Jan 14, 2020 1:39 am
did you process that from a raw? if so what settings?
I assume it was from a raw file.... I used Deep Sky Stacker software - I've no clue how to use it.

My camera takes two photos - jpg and raw - so whatever Deep Sky Stacker opens is what it was.

As to settings, are you asking about the camera settings or the DSS settings???

Keep in mind, I'm just starting down this road - and don't have a real good understanding of what I'm doing. The feedback on "focusing" was very helpful for me.
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#### TSS Photo of the Day

it looks like there are a lot of processing artifacts in that image...

i made a little 3 frame movie for you of the images i posted previously...

-first frame shows raw image processed into jpeg through lightroom with the settings I shared previously (but the shot is out of focus)

-second frame shows another raw image processed into jpeg with the same settings but the shot is in focus

-third frame shows what the second frame raw/jpeg looked like without any custom settings (ie you can bring out a lot of detail from the raw data that you can't otherwise see in the jpeg or an unprocessed raw) - a lot of stars which are visible in both the unfocused and focused custom raw converted images disappear in the jpeg, because the jpeg file format has less "bit depth" so a lot of the image data is "thrown out" when you save an image in the jpeg format - the missing stars are especially noticeable in the top right portion of the image

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metastable wrote:
Tue Jan 14, 2020 2:25 am
it looks like there are a lot of processing artifacts in that image...

i made a little 3 frame movie for you of the images i posted previously...

-first frame shows raw image processed into jpeg through lightroom with the settings I shared previously (but the shot is out of focus)

-second frame shows another raw image processed into jpeg with the same settings but the shot is in focus

-third frame shows what the second frame raw/jpeg looked like without any custom settings (ie you can bring out a lot of detail from the raw data that you can't otherwise see in the jpeg or an unprocessed raw) - a lot of stars which are visible in both the unfocused and focused custom raw converted images disappear in the jpeg, because the jpeg file format has less "bit depth" so a lot of the image data is "thrown out" when you save an image in the jpeg format - the missing stars are especially noticeable in the top right portion of the image
It would be better (for me) if you posted three images, in order, so I can see what you are pointing out. The movie moves to quickly to get much out of it.
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#### TSS Photo of the Day

1st frame bloated stars
2nd frame tight focused stars, ie the best frame of the 3
3rd frame is the dull, darkish Un processed frame
scopes :gso/bintel f4 12"trust tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
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#### TSS Photo of the Day

lsintampa wrote:
Tue Jan 14, 2020 3:40 am
It would be better (for me) if you posted three images, in order, so I can see what you are pointing out. The movie moves to quickly to get much out of it.
1) out of focus (lens simply set to infinity), but processed from raw to jpeg with the previously mentioned custom settings:

2) in focus, & processed from raw to jpeg with the previously mentioned custom settings:

3) same shot as 2), but without the previously mentioned custom raw to jpeg conversion settings (same as the shot looks "in camera" & many less stars are visible):

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metastable wrote:
Thu Jan 09, 2020 1:16 am
I did this one with a nikon d800 and 14-24mm nikon lens with photo tripod & 10sec, 2000iso, 2.8f shot in raw, then processed in lightroom with these settings:

Temp: 4637k
Tint: +2
Exposure: -0.97
Contrast: +87
Highlights: -100
Whites:+73
Blacks: +100
Clarity: +22
Dehaze: -1
Vibrance: -61
Saturation: -40

(make sure you manually focus by zooming into a star in the live preview while adjusting the focus ring)

This is stunning!!! how many shots did you use to stack this may i ask?
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#### TSS Photo of the Day

D4n1el wrote:
Thu Jan 16, 2020 2:29 pm
This is stunning!!! how many shots did you use to stack this may i ask?
it’s a single 10sec exposure
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thank you
russmax
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Hey, Tampa,
I have a couple of thoughts.
1st, add a motor to your CG-4 mount to give it some ability to track, as Sky Tinker suggested.

Then you can mount your DSLR to your CG-4 without the telescope. Use your medium or telephoto lens to get some nice shots. Don’t use the wide angle. Your exposure times can be longer now, because you’re tracking. If you get “daylight” skies, shorten the exposure. If you get darkness and no stars, lengthen it. Start playing with post processing software.

Regards,
Russmax
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russmax
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Also, if the star dots turn into star lines, shorter exposure and better polar alignment.
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lsintampa
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russmax wrote:
Thu Jan 16, 2020 5:01 pm
Hey, Tampa,
I have a couple of thoughts.
1st, add a motor to your CG-4 mount to give it some ability to track, as Sky Tinker suggested.

Then you can mount your DSLR to your CG-4 without the telescope. Use your medium or telephoto lens to get some nice shots. Don’t use the wide angle. Your exposure times can be longer now, because you’re tracking. If you get “daylight” skies, shorten the exposure. If you get darkness and no stars, lengthen it. Start playing with post processing software.

Regards,
Russmax
I know there is a motor for the CG-4, but I don't think it "tracks" - or does it???

Thanks for the tips
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russmax
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It tracks just like the motor on a AVX mount. There’s just no GoTo function. Tracking is the only real reason to put a motor on a EQ mount.
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lsintampa
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I have upgraded camera arriving tomorrow - if the weather permits, I'll be trying some new shots - taking into account the tips provided here.

Meanwhile, I had a total flop last night - all my bad - but this picture was taken with my D50, wide open, for 2 seconds of Venus. It's not a "good" shot, taken with a poor camera, but I'm curious what the blue spot is?
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lsintampa
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russmax wrote:
Thu Jan 16, 2020 5:50 pm
It tracks just like the motor on a AVX mount. There’s just no GoTo function. Tracking is the only real reason to put a motor on a EQ mount.
Awesome, I'll check it out... From what I recall, they have two motors - one for Dec another for RA - need both for tracking??? I'll read up on the specs - manuals, etc. Thanks.
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russmax
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You only need the RA motor for tracking, but I only ever see them sold together.

“This Celestron Dual-Axis Motor Drive, with drive corrector capabilities, is designed for Celestron's CG-4 mounts for tracking in RA and allows adjustment in DEC. It precisely controls the telescope's tracking speed during long, timed exposures of celestial objects, producing the best possible image sharpness. Precision drive correctors are a must for those with a serious interest in astrophotography or CCD imaging.”

https://www.highpointscientific.com/cel ... rive-93522
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