First Image

[Ohgodwherediditgo]

This is my first attempt at an intended target, really just to prove that i could actually 'drive' the telescope at long last. It is the Pacman Nebula. There is 34mins of integration with 90 second subs using a Vixen VC200L with a Canon 1000D ( modded ). Tracking wasn't great, hopefully because i calibrated PHD on the target rather then nearer celestial equator. Why are the stars with defraction spikes diamond shaped ? Any suggestions on exposure time on this target ? Noise reduction ? I would have had longer on target but i attempted to plug in a dew heater on low power into my usb hub and heard the camera shutter close immediately so i called it a night.

[shropshire lad]

Can you tell us your camera settings ...

[Ohgodwherediditgo]

38 minutes ago, shropshire lad said:

Can you tell us your camera settings ...

ISO 800. I should probably mention that this was taken over a week ago, the moon was about 99% full and not far out view.

[shropshire lad]

and what was your aperture settings

 

[Ohgodwherediditgo]

The camera was set to Bulb for use with nina. I'm not sure if nina automatically changes that.

 

Edit: I should also mention that i had never picked up a DSLR before buying this one to point at the sky.

Edited September 29, 2021 by Ohgodwherediditgo
additional

[Lee_P]

Others can give advice for improvements, but I'll just say a huge well done on producing your first astro image -- a real achievement!

[shropshire lad]

53 minutes ago, Ohgodwherediditgo said:

The camera was set to Bulb for use with nina. I'm not sure if nina automatically changes that.

 

Edit: I should also mention that i had never picked up a DSLR before buying this one to point at the sky.

Bulb will be the exposure time .... aperture will be set on your camera .. e.g f5.6 ... f8 ... etc. .. oh I may be wrong as you are not using a lens are you.

Edited September 29, 2021 by shropshire lad

[Ohgodwherediditgo]

I didn't know that i could set that manually ! The camera is still attached to the scope. If i turn it on would it be on the last setting used ?

 

[Iem1]

Aperture is set as its connected to a telescope I think?

That's a good first image! Something to be proud of for sure

I cant comment on guiding and star shape, but as you said, a short integration time on a full moon (near the moon at that) is always going to be tough going with a one shot colour camera. Especially for targets such as pac man (nebulas in general really). A moonless night + much more integration time will be the biggest improvement I think.

Did you take calibration frames? (Flats/Bias). Also must haves!

hopefully someone more technically minded will give advice about the scope/guiding/specific image details shortly.

[Ohgodwherediditgo]

I did take flats, dark flats and bias frames but only used darks and lights for this image as i was getting some strange artifacts repeated under the brightest stars with all of the calibration frames. I never did get to the bottom of what was causing it.

I checked my camera and the f ratio is not adjustable in manual or P Mode. It is set to F00 at the moment so I'm trying to find out how or if i can change that at the moment.

Edit:

I just noticed that the artifacts are visible in this picture at 7 o clock around the bright stars. They appear to be  three shadows under each.

 

18 minutes ago, Iem1 said:

Aperture is set as its connected to a telescope I think?

That's a good first image! Something to be proud of for sure

I cant comment on guiding and star shape, but as you said, a short integration time on a full moon (near the moon at that) is always going to be tough going with a one shot colour camera. Especially for targets such as pac man (nebulas in general really). A moonless night + much more integration time will be the biggest improvement I think.

Did you take calibration frames? (Flats/Bias). Also must haves!

hopefully someone more technically minded will give advice about the scope/guiding/specific image details shortly.

Edited September 29, 2021 by Ohgodwherediditgo

[bobro]

Your setup looks to be performing well - good star shape indicates good tracking/guiding. Longer subs of at least 4 minutes will help reduce the effects of camera read noise - if your setup can support this. One retailer suggests 10 min subs, but it will depend on other things such as the sky background (around Bortle 5 for Fareham) and camera used. Aim for a total imaging time of at least a few hours with this target. Seems a lot but the scope is slow at f#9 and the Canon 1000D not very sensitive. Flats are essential to get the best from an image.

Good luck with your next image!

[alacant]

Hi

Nice shot from what is a challenging setup. Well done.

Should be great for smaller galaxies.

1000d, so best to lose the dark and dark-flat frames and instead go only with bias and flat. Dither between each frame and stack using a clipping algorithm.

Flat frames aren't really optional though.

(The aperture is set by the telescope, not in camera)

HTH

Edited September 29, 2021 by alacant

[Paul M]

You got stars, better than I did early on!

By far the most important calibration frames are the flats. Those should rectify the vignetting.

Bias and dark flats will have less dramatic if any benefit.

[alacant]

50 minutes ago, Paul M said:

Bias and dark flats

+1

Decide on one or the other. Bias preferred here.

 

Edited September 29, 2021 by alacant

[Ohgodwherediditgo]

OK, I'll prioritise a DIY flat panel over an upgrade in camera. 

 

[AstroMuni]

1 hour ago, Ohgodwherediditgo said:

OK, I'll prioritise a DIY flat panel over an upgrade in camera. 

If you have an iPad large enough to cover the aperture you are good to go. You could also use our good old sol and cover your scope with a piece of white cloth.

[Ohgodwherediditgo]

My tablet and laptop are both too small, the laptop by just 1/2 inch. I have taken flats the following morning but i don't like leaving my scope out, so it looks like I'm going to have to eat the cost of convenience. At least i won't need to worry about clouds.

[Lee_P]

On 30/09/2021 at 17:37, Ohgodwherediditgo said:

My tablet and laptop are both too small, the laptop by just 1/2 inch. I have taken flats the following morning but i don't like leaving my scope out, so it looks like I'm going to have to eat the cost of convenience. At least i won't need to worry about clouds.

Of use? http://urbanastrophotography.com/index.php/2021/09/27/diy-flats-panel/

[sthow]

I think that's an excellent first image , the stars look really good 😀

[wimvb]

Very nice first image. If you want to take flats indoors, or directly after imaging session, check out LED panels as used for home lighting. You can combine these with a simple dimmer, and use a few layers of white fabric if still too bright. Just make sure you end up with exposure time not much lower than a second, or your camera shutter will cause strange effects.

Next step is image processing, where your first priority should always be to achieve a pleasing colour balance.

[Ohgodwherediditgo]

Nothing but cloud so I've played with Siril and Gimp. This still counts as a first image no matter how many times i reprocess it, right ?

 

[wimvb]

44 minutes ago, Ohgodwherediditgo said:

This still counts as a first image no matter how many times i reprocess it, right ?

I think so.

when you stretch the image, try to avoid clipping the background. This often creates sn unnatural look.

[Elp]

Stars are nicely shaped, diamond shape I believe is due to the 4 vanes holding the secondary mirror at the front of the tube.

For flats just use the tried and trusted method of a clean white t-shirt and an led light positioned and shining through to give even light over the aperture, any neighbors might wonder what you're doing however, especially if you're standing there for a while.

[Ohgodwherediditgo]

16 hours ago, wimvb said:

I think so.

when you stretch the image, try to avoid clipping the background. This often creates sn unnatural look.

I'm working with crappy data really. The image was taken on a full moon , the purpose been to prove that everything was working well with nina, phd, stellarium, astap, and that com port issues had been sorted. I'm quite suprised i got anything really. It has left me with an itch i can't scratch due to clouds, but there is hope for tomorrow night and Bodes Galaxy. Fingers crossed !

[rickwayne]

Even simpler: pick up an LED tracing panel on Amazon or similar. Try shooting a few images with it turned different ways, if those images aren't different the panel is consistent enough. The one I got runs off USB, doesn't need a diffuser at its lowest setting, and cost US$15.

To shoot the frames, don't obsess about exposure or anything. Just get the histogram peak in the middle of the graph, and use that exposure henceforth. It merely has to be somewhere in the sensor's region of linear response. As was said above, bias frames are easy to manage and reuse, and work well with DSLRS. Have to have bias or dark flats for the flats to work correctly.