17 replies to this topic

[Astrojedi]

A work in progress NGC891 from my red/white LP backyard. This is less than 2 hours of exposure. I am planning to add about 2-3 more hours of exposure. I find that at around 4 hours of total exposure SNR pretty much flattens out for my setup / location.

 

Make sure you click to see full resolution (detail is not very good due to limited exposure time and poor seeing but still interesting... don't forget to check out the spiral galaxy NGC898 at bottom right).

 

I am waiting for the mono version of this camera..

 

Details:

 

SQM: 18.5 - 18.7, seeing below average and neighbor's annoying lights.

 

EdgeHD 8 @ F7.3, ASI2600MC, no filters, guided with Metaguide and 50mm guidescope with ASI290MM.

 

120s x 55, Imaged at 0.52" / pixel, Processed with Astro Pixel Processor, Pixinsight and Topaz DenoiseAI.

 

 

 

Annotated Image:

 

Edited by Astrojedi, 04 December 2020 - 09:07 PM.

[nyda83]

Hi astrojedi, the image look superb, I work with the same setup as yours but I don't have the same results...can you specify what reducer do you use and what mount?

 

Thanks

[Astrojedi]

Thanks. I am using the Celestron 0.7x reducer. I have 2 mounts I use with the EdgeHD 8 - the MyT and the CGX. Both produce excellent results. This was with the CGX mounted on a permanent pier in my home observatory. 

[Mert]

Www, that sure looks clean and with those neighbor lights, great image!

[nyda83]

Thanks. I am using the Celestron 0.7x reducer. I have 2 mounts I use with the EdgeHD 8 - the MyT and the CGX. Both produce excellent results. This was with the CGX mounted on a permanent pier in my home observatory. 

Thanks I was asking about reducer because you indicate 7.3, I have the same reducer do you think it's not exactly 7? Do you find the backfocus of 105mm to be correct, because I have a lot of problem of radial aberration of stars, in particular radial red shifting and I have read a lot of report of people with the same problem here on CN, I manage to correct it in PI by separate, register and recombine the channels, but it will be grate to actually solve it...

 

I'm considering in upgrading my neq6pro and I will consider your information.

 

Thanks

[Dean J.]

It is very encouraging to see that this turned out so nice.   I am not able to get out to dark skies much lately so maybe I should try from home.

[ERHAD]

Image looking great. I shoot from similar location and with similar equipment (533) but get nowhere near that kind of SNR with a 2 hour integration. I seem to blow out stars very easily too. Mind if I ask which gain/offset you used?

 

Thanks.

[sn2006gy]

Nice image!

[Astrojedi]

Thanks I was asking about reducer because you indicate 7.3, I have the same reducer do you think it's not exactly 7? Do you find the backfocus of 105mm to be correct, because I have a lot of problem of radial aberration of stars, in particular radial red shifting and I have read a lot of report of people with the same problem here on CN, I manage to correct it in PI by separate, register and recombine the channels, but it will be grate to actually solve it...

 

I'm considering in upgrading my neq6pro and I will consider your information.

 

Thanks

Yes, strangely enough I can only achieve a 7.3 reduction with the reducer if I optimize for the best corrected field over the APS-C size sensor. Yes, there is slight color fringing on stars which is more noticeable in poor seeing.

 

Are you having tracking / guiding issues with the neq6pro? Why are you looking to upgrade?

[Astrojedi]

Image looking great. I shoot from similar location and with similar equipment (533) but get nowhere near that kind of SNR with a 2 hour integration. I seem to blow out stars very easily too. Mind if I ask which gain/offset you used?

 

Thanks.

I use offset 50 and gain 100.

[Astrojedi]

It is very encouraging to see that this turned out so nice.   I am not able to get out to dark skies much lately so maybe I should try from home.

Dean, 

Always worth a try. I am genuinely surprised by the quality of data produced by the 2600 from my backyard.

[calypsob]

Man I need to setup in my yard more, this is inspiring. You even have an ifn like tidal trail under the galaxy. Great work. This sensor really is capable of amazing things. 

[nyda83]

Yes, strangely enough I can only achieve a 7.3 reduction with the reducer if I optimize for the best corrected field over the APS-C size sensor. Yes, there is slight color fringing on stars which is more noticeable in poor seeing.

 

Are you having tracking / guiding issues with the neq6pro? Why are you looking to upgrade?

I have the same telescope c8edgehd, camera ASI2600 and reducer, do you use the 105mm suggest backfocus or have you found different distance to be optimal?

 

The tracking/guiding is not the main problem, the error it's around 2" peak to peak, the main problem it's during dithering, it take from 10 to 20 second to stabilize it and I lost 10% to 20% of the imaging time in dithering, this is not tolerable in my place where I got only 20/30 good night in an year

 

My image of the same object it's here https://astrob.in/3lzj64/0/ but if quite far from yours so I'm also going to improve collimation to see if I can get the details you capture, your photo it's inspiring me to go deeper because you achive a really good details

[Astrojedi]

Ok. The image is not bad - may be worth trying some minor tweaks / experimentation.

 

Try imaging without the L-Pro. Make sure you use good flats and then let the gradient removal algorithms do their job. And do multiple iterations if required. Despite my heavy light pollution I get better results for galaxies without the filter.
 

Also if you are using PHD, give Metaguide a try as well. It is a slightly different interface but results are very good. My resolution improved significantly with the CGX after I started using Metaguide.

 

Also worst case, experiment with no dithering (but calibrate well). While I always dither for this image I did not. This sensor seems to be very forgiving to forgetful imagers like me.

[nyda83]

Ok. The image is not bad - may be worth trying some minor tweaks / experimentation.

 

Try imaging without the L-Pro. Make sure you use good flats and then let the gradient removal algorithms do their job. And do multiple iterations if required. Despite my heavy light pollution I get better results for galaxies without the filter.
 

Also if you are using PHD, give Metaguide a try as well. It is a slightly different interface but results are very good. My resolution improved significantly with the CGX after I started using Metaguide.

 

Also worst case, experiment with no dithering (but calibrate well). While I always dither for this image I did not. This sensor seems to be very forgiving to forgetful imagers like me.

Thanks for the tips I will try all of that next time, just installed metaguide and I surely will try that and to leave the l-pro out of my rigs.

[airscottdenning]

Thanks I was asking about reducer because you indicate 7.3, I have the same reducer do you think it's not exactly 7? Do you find the backfocus of 105mm to be correct, because I have a lot of problem of radial aberration of stars, in particular radial red shifting and I have read a lot of report of people with the same problem here on CN, I manage to correct it in PI by separate, register and recombine the channels, but it will be grate to actually solve it...

 

I'm considering in upgrading my neq6pro and I will consider your information.

 

Thanks

My experience with the EdgeHD 0.7 reducer is identical to yours. 

I had to lengthen the distance A LOT behind the reducer to eliminate the radial distortion at the corners. I'm up over 120 mm now and it's much better but I still have to go further. Just keep adding spacers until you get round stars in the corners.

This diagram helped me a lot:
 

Attached Thumbnails

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[Astrojedi]

Yes, the actual backspacing can vary. I have found my scope and reducer produces an optimal field at close to the recommended 105mm (I think) but I only achieve a reduction of 7.3. I am fine with that.

[nyda83]

My experience with the EdgeHD 0.7 reducer is identical to yours. 

I had to lengthen the distance A LOT behind the reducer to eliminate the radial distortion at the corners. I'm up over 120 mm now and it's much better but I still have to go further. Just keep adding spacers until you get round stars in the corners.

This diagram helped me a lot:
 

Thanks for this, I'm in the too close diagram so I will try to go a litte longer