A quick Horsehead last night. I have always loved this nebula, but didn’t realize what a difficult target it is (for me at least). There are so many issues with this image, I wouldn’t know where to begin, but still, I am overall very pleased.
I still can’t get Nina to override the 30 second limit, and would love to have taken longer exposures and obviously more integration too. Alignment issue with weird Alnitak double spike. I messed up star saturation which resulted in an odd turquoise circle around the stars. Vignetting & haze. Overstretched histogram, etc… On the other hand, I am pleased with star shapes, framing, and just the fact that the horse head is actually visible!
Feel free to comment.
Thanks,
Stéphane
Integration: 350 x 30s = 2h55
Nikon D7000
BT200 f/5
EQ6-R
Optolong L-Extreme
Baader MPCC mk III
Stephane,
Goto , framing and focus are excellent as this object is a tough one to attempt.The bright star Alnitak has a double diffraction spike on one side due to one plane of your spider vane slightly offset from centre. From my experiences with newts I’d say one screw on one side is screwed in too tight pulling the opposing vane upward slightly. When you get time you can test on a bright star and make tiny adjustments until it’s perfect. Before that have a visual look at the spider vanes to see if you can see an offset on one side. If your not confident, just leave it , the double spikes will only appear on the brighter stars ( if any ) in your images.Yours is not that bad I’ve seen worse.
Image is great for a first attempt but noisy.
Did you use calibration frames ? (At least darks )
How was your guiding ?
We’re conditions humid last night ? Your DSLR could have been running quite warm +25deg ( thermal noise ) which also adds noise
We’re seeing conditions good, nice and stable or poor ?
From the info I have , the Nikon D7000 when used for Astro has a sweet spot at ISO100 and ISO200 ( high dynamic range) What setting did you use ?
For a DSLR with short exposures and OSC NB filter, a great effort
Well done !!
Martin
Really great for 30s images!
To override the 30s limit on Nina, you may need to change the camera setting to "bulb" mode. On my Canon 1000D, you needed to change the exposure to 30s, and then move it up, one more. This will allow you to use exposures from very short to about 30mins. I found that cameras generally shut off at about 30mins of exposure. Overall, Great image for limited exposure
Stephane,
Goto , framing and focus are excellent as this object is a tough one to attempt.The bright star Alnitak has a double diffraction spike on one side due to one plane of your spider vane slightly offset from centre. From my experiences with newts I’d say one screw on one side is screwed in too tight pulling the opposing vane upward slightly. When you get time you can test on a bright star and make tiny adjustments until it’s perfect. Before that have a visual look at the spider vanes to see if you can see an offset on one side. If your not confident, just leave it , the double spikes will only appear on the brighter stars ( if any ) in your images.Yours is not that bad I’ve seen worse.
Image is great for a first attempt but noisy.
Did you use calibration frames ? (At least darks )
How was your guiding ?
We’re conditions humid last night ? Your DSLR could have been running quite warm +25deg ( thermal noise ) which also adds noise
We’re seeing conditions good, nice and stable or poor ?
From the info I have , the Nikon D7000 when used for Astro has a sweet spot at ISO100 and ISO200 ( high dynamic range) What setting did you use ?
For a DSLR with short exposures and OSC NB filter, a great effort
Well done !!
Martin
Hi Martin, thanks for the feedback. I will have a good look at the spider vane. Should be a reasonably easy fix. The night I took the shots, it was indeed about 25 degrees (got bitten to death by mosquitoes - added mosquito repellent to my shopping list). I used 20 darks, 20 flats, 40 biases, but still very noisy. Either my camera does not like the heat, or I am not doing my darks properly, or both…
Guiding was again fabulous at total < 0.6. I haven’t changed any settings, but it looks like it’s improving from one night to the next.
Seeing conditions were okay, on the humid side though. ISO was set at 800. I have since seen your message re 100 or 200 and will try that next time.
I am currently studying denoise techniques on Youtube and will see if they make any difference. From what I’ve seen so far though, is that they make only incremental improvements and that calibration frames are by far the best way for reducing noise. It will be interesting to see if noise is reduced on cooler nights.
Really great for 30s images!
To override the 30s limit on Nina, you may need to change the camera setting to "bulb" mode. On my Canon 1000D, you needed to change the exposure to 30s, and then move it up, one more. This will allow you to use exposures from very short to about 30mins. I found that cameras generally shut off at about 30mins of exposure. Overall, Great image for limited exposure
Lachlan, the camera was set in bulb mode, but as soon as it connects to Nina, it switches to “PC mode”. Apparently this is a Nikon problem. I hear using the snap rather than the recommended direct PC connection might override the 30 second limit. I’ll give it a try.
Quote:
Originally Posted by multiweb
The field and focus look about perfect. Just need more data and it will be a corker.
You spider vanes are not square meaning your secondary is offset. That's the double spikes. The "wiggle" is just colors diffraction. Pretty standard.
Thanks Marc! Yep, looking to get longer exposures and more integration. Hopefully I can fix that secondary mirror issue. My main issue is that really heavy noise
Oh, and thanks for the focus compliment. I don’t even have a Bahtinov mask yet, so I’ve just been zooming in on stars and tweaking until thy are as small as possible wit bright density at center. The double helical focuser is just amazing.
Hi Martin, thanks for the feedback. I will have a good look at the spider vane. Should be a reasonably easy fix. The night I took the shots, it was indeed about 25 degrees (got bitten to death by mosquitoes - added mosquito repellent to my shopping list). I used 20 darks, 20 flats, 40 biases, but still very noisy. Either my camera does not like the heat, or I am not doing my darks properly, or both…
Guiding was again fabulous at total < 0.6. I haven’t changed any settings, but it looks like it’s improving from one night to the next.
Seeing conditions were okay, on the humid side though. ISO was set at 800. I have since seen your message re 100 or 200 and will try that next time.
I am currently studying denoise techniques on Youtube and will see if they make any difference. From what I’ve seen so far though, is that they make only incremental improvements and that calibration frames are by far the best way for reducing noise. It will be interesting to see if noise is reduced on cooler nights.
Thanks again,
Stéphane
Stephane,
Sounds like NINA is giving you trouble with that DSLR
Maybe give Backyard Nikon a trial or APT a trial
I know NINA does everything but I’ve found using different software for specific applications works really well too.
As far as I’m concerned BYEOS is the easiest most comprehensive frame focus and capture software for DSLR’s ( I’m sure Back yard Nikon would be similar ) They are not the complete package , capture stack and process etc.... but hey the work well , never had an issue in 4 years with my Canon 600D ( I still use my Canon for planetary imaging , see attached images ) Does NINA do planetary with the DSLR ?
Attached are my notes on SNR and Noise etc.. for your info
Cheers
Martin
Stephane,
Sounds like NINA is giving you trouble with that DSLR
Maybe give Backyard Nikon a trial or APT a trial
I know NINA does everything but I’ve found using different software for specific applications works really well too.
As far as I’m concerned BYEOS is the easiest most comprehensive frame focus and capture software for DSLR’s ( I’m sure Back yard Nikon would be similar ) They are not the complete package , capture stack and process etc.... but hey the work well , never had an issue in 4 years with my Canon 600D ( I still use my Canon for planetary imaging , see attached images ) Does NINA do planetary with the DSLR ?
Attached are my notes on SNR and Noise etc.. for your info
Cheers
Martin
Yes Martin, NINA is giving me a hard time with my humble Nikon. I read online that using the EQ6-R snap port will override the 30 second limit. So I’ve ordered another cable which I receive in a week. I hope to revisit the Horsehead, get much more data, fix the spider vane and image in hopefully cooler conditions.
I am looking into BYEOS, but I just love so many of the NINA features, my favorite being the easy polar alignment within half an arc minute, which doesn’t hurt my guiding. I don’t even need to have the OTA parked as I have an obstruction directly south. That said, I could always polar align with NINA, then switch to BYEOS for imaging. Let’s see if this cable fixes the issue first.
Thanks again for the guiding parameters, I am consistently getting a total error of 0.65 which is way within the “good enough” margin for 1,000 mm focal length.
