Astro Imaging Pool of Mess

[dd999]

I have recently started off in a very beginner way at astro-imaging. Although I put in more research hours than I could count against quality and budget, I probably in hindsight would have taken a different route.

In any case, working with what I have, I have tried two nights in a row at some basic dslr astro at DSOs, both nights yielded the same results. A big pool of light mess (as you'll see in the below image). This is just one 2 second sub. Although I took a number of short subs with the intention of stacking, of course adding multiple big pools of light together, creates an ocean of big light mess.

Equipment used:

• Canon EOS 600d (un-modded);
• AZ GTi mount (in ALT AZ mode whilst waiting for my EQ wedge to arrive - hence the very short subs);
• Manfrotto 055 XPROB Tripod;
• SW 130p scope (yes this is the 130p not the 130pds but I'm using a 2x barlow for the ability to focus);
• 2x Barlow

I completely understand my equipment is pretty basic but I thought I'd see at least the resemblance or outline. I took a similar short sub with my mobile phone connected to a 10mm eyepiece with similar results. I created short 2 second subs in ISOs 800, 1,600 and 3,200 but all look pretty much the same.

Is this just the equipment or am I doing something very fundamentally wrong? - My worry is that even when my EQ wedge arrives and I turn the mount in to EQ - and take longer exposures - I'd still end up with a big pool of light mess!

This image is 1.3 second sub at ISO 3,200 (RAW version also included)

 

 

    

IMG_3472.CR2

Edited July 23, 2020 by dd999

[dd999]

Just as a comparison (if this helps in anyway) - here is a photo of Saturn I took using the exact same setup (although 1/20 shutter and 200 ISO) the night before. Some stacked images involved and post processing in PS

Edited July 23, 2020 by dd999

[Seelive]

Given that Saturn is at a declination of about -20 degrees, then during your 1.3 sec exposure Saturn will have moved about 18 arcsec.  Given that the SW130P has a focal length of 650mm and you are using a x2 barlow, then the movement of Saturn at the camera sensor will be 0.115mm.  Assuming that the Canon 600D has a pixel size of 0.0043mm, then Saturn will appear to have trailed by about 27 pixels.  Given that the rings major axis diameter is currently about 42 arcsec, then the rings will only have with a width of about 62 pixels.  A driven equatorial mount will certainly help, but don't expect too much from a single exposure, and you will probably need to shorten the exposures rather than lengthen then.

[dd999]

14 minutes ago, Seelive said:

Given that Saturn is at a declination of about -20 degrees, then during your 1.3 sec exposure Saturn will have moved about 18 arcsec.  Given that the SW130P has a focal length of 650mm and you are using a x2 barlow, then the movement of Saturn at the camera sensor will be 0.115mm.  Assuming that the Canon 600D has a pixel size of 0.0043mm, then Saturn will appear to have trailed by about 27 pixels.  Given that the rings major axis diameter is currently about 42 arcsec, then the rings will only have with a width of about 62 pixels.  A driven equatorial mount will certainly help, but don't expect too much from a single exposure, and you will probably need to shorten the exposures rather than lengthen then.

Thanks for the reply - but actually Saturn (considering my limitation on equipment and mount) I was quite pleased about. This one was stacked exposures of around 1/20 sec at ISO 200 I believe. I was just showing this as a comparison against the DSO just to show the camera can focus with the barlow on a 130p, and the 130p can image with a dslr etc....

It's more the DSO image on the first post I have the biggest issues with and feel I'm doing something wrong (?)

Edited July 23, 2020 by dd999

[Seelive]

Hi dd999, sorry, it didn't register that both were your images.  I agree, I would also be happy with that image of Saturn.  But the same argument applies, 1.3 sec is too long at that focal length on an undriven mount, and at F10, you can't expect to see much faint detail with such a short exposure.

[dd999]

Well actually it is a driven mount. It's a goto and was tracking (and quite well) but it is an ALT AZ mount - not yet an EQ - which is why I kept my subs to 1.3 seconds. Perhaps 1.3 seconds on a driven ALT AZ mount is still too much, so at that focal length I'm just seeing a blur of white and colours instead of detail?

There is a long thread on here around DSO no EQ challenge, and seems people were getting good results. I've tried to replicate but must admit hit a bit of a disaster and looking for a few pointers 

Edited July 23, 2020 by dd999

[happy-kat]

My thoughts are try with a camera lens no telescope. The use of the barlow does inject demands on tracking as it exposes trailing quicker. Even with what you are using now I would expect around 10 seconds to be possible. Aim for targets in the East or West between 25° and 50° degrees. Make sure the telescope is balanced and the tripod legs are not fully extended and it's not windy. Ideally don't use higher than iso1600 I think for the 600d

[dd999]

1 minute ago, happy-kat said:

My thoughts are try with a camera lens no telescope. The use of the barlow does inject demands on tracking as it exposes trailing quicker. Even with what you are using now I would expect around 10 seconds to be possible. Aim for targets in the East or West between 25° and 50° degrees. Make sure the telescope is balanced and the tripod legs are not fully extended and it's not windy. Ideally don't use higher than iso1600 I think for the 600d

Some good points.

I have tried just the untracked dslr with lens and tripod (no scope) route - this was my best Andromeda shot a couple of nights back - after stacking a number of images and post processing in PS.

 

 

 

 

[dd999]

I also took some of the same DSO object as in the first image at 10sec sub at 800 ISO and also 1600 ISO but all images no matter exposure time or ISO increase saw almost the same identical photo

This image was taken near Vega so quite high in the sky

I was going to attach the 800 ISO and 1600 ISO 10 sec sub images as reference - but each time I try to add to the post I'm getting a '-200' error on this forum (?)

Edited July 23, 2020 by dd999

[happy-kat]

Jpg is better

[dd999]

It was the jpg's I was trying to attach