NGC6960

[Crackabarrel]

Seeing as its Halloween season I decided to go for NGC6960 this weekend.

First attempt at guiding, trying not to stress too much over the graph as long as subs come out alright.

Moon definitely didn't help contrast though.

Also first experience using PS and the Carboni Astronomy toolset.

Any suggestions or criticism would be appreciated, thanks.

EDIT: Kit List:
WO ZS 73 + 50mm Guidescope w/ ASI120mm , HEQ5 Pro, Nikon D5300, IDAS LPS D2

Edited October 12, 2020 by Crackabarrel

[MarkAR]

Very good, maybe more data would help and also star reduction. There also seems to be a magenta caste to the background, easy to fix by inverting the image and removing green then re-invert.

[Crackabarrel]

4 minutes ago, MarkAR said:

Very good, maybe more data would help and also star reduction. There also seems to be a magenta caste to the background, easy to fix by inverting the image and removing green then re-invert.

Cheers Mark,

I'll give that a try and see how I get on.

[Budgie1]

3 hours ago, Crackabarrel said:

First attempt at guiding, trying not to stress too much over the graph as long as subs come out alright.

The stars look good and sharp so it seems to be fine.

I've not been guiding very long and but I remember, while researching PHD2, seeing/watching someone who said that as a long as the total error is less than 1 arc second then you should be fine, even if the graph looks a mess.

My EQ5 mount is normally between 0.45 & 0.75 for the total and it seems to work fine.

[Crackabarrel]

10 minutes ago, Budgie1 said:

The stars look good and sharp so it seems to be fine.

I've not been guiding very long and but I remember, while researching PHD2, seeing/watching someone who said that as a long as the total error is less than 1 arc second then you should be fine, even if the graph looks a mess.

My EQ5 mount is normally between 0.45 & 0.75 for the total and it seems to work fine.

Cheers, I'd seen that recommendation before yeh, once the guiding had settled down initially I was getting values under 1arc/sec, however it seemed to creep up into the 3s and 4s over the session, but the majority of subs were coming out fine which had me scratching my head.

[Budgie1]

Good Polar Alignment and mount levelling seems to be key. 

I always used to use the polar scope but now I have the guide camera attached and it's linked up to the laptop, I went for the SharpCap Pro and use the Polar Alignment tool on that. It's easy to use and saves getting your knee wet!

[Crackabarrel]

Sharpcap Pro is next on the list once I work out how to use EQMod properly.

Was reading you need to rotate on RA 90deg for Sharpcap to work, is this set in stone or is there some leeway? 

My backyard observing site would preclude me from going the full 90deg due to neighbor's houses

[Phillyo]

Nice image. No feedback regarding that because I don't use photoshop to edit. Maybe more data (you don't say how much you have?) will help clean things up a bit.

Regarding the guiding, my understanding is that the amount of error that is permissible is based on the resolution of your system. For example if you're using something like an ASI533 with a 135mm lens then your resolution is going to be somewhere around 5.7"/pixel. So as long as your guiding is less than that, your stars will be round.

If, however you're using the 533 with a Celestron 8SE with a focal length of over 2meters, then your resolution is going to be closer to 0.4"/pixel and your guiding needs to be bang on or you'll see eggy stars. To be honest, at that resolution you're likely to be more limited by the sky conditions like seeing and clarity than anything else.

That's my understanding anyway! Someone may come along and correct me

Phil

[City9Town0]

Sharpcap uses 'about 90 degrees' but manages with less....

[Crackabarrel]

12 minutes ago, Phillyo said:

Nice image. No feedback regarding that because I don't use photoshop to edit. Maybe more data (you don't say how much you have?) will help clean things up a bit.

Regarding the guiding, my understanding is that the amount of error that is permissible is based on the resolution of your system. For example if you're using something like an ASI533 with a 135mm lens then your resolution is going to be somewhere around 5.7"/pixel. So as long as your guiding is less than that, your stars will be round.

If, however you're using the 533 with a Celestron 8SE with a focal length of over 2meters, then your resolution is going to be closer to 0.4"/pixel and your guiding needs to be bang on or you'll see eggy stars. To be honest, at that resolution you're likely to be more limited by the sky conditions like seeing and clarity than anything else.

That's my understanding anyway! Someone may come along and correct me

Phil

Ah thank you, that makes sense regarding why I was seeing round stars with the error values I was seeing.

Capture data was as follows:

55 x 120sec exposure @ IS0400
25 x Dark

40 x Flat

40 x Bias

[Crackabarrel]

10 minutes ago, City9Town0 said:

Sharpcap uses 'about 90 degrees' but manages with less....

Cheers that clears up any potential issues

[Phillyo]

8 minutes ago, Crackabarrel said:

Ah thank you, that makes sense regarding why I was seeing round stars with the error values I was seeing.

Capture data was as follows:

55 x 120sec exposure @ IS0400
25 x Dark

40 x Flat

40 x Bias

If you're using a DSLR, unless it's cooled, I wouldn't bother with dark frames either. Temperature variances can often mean that using darks as part of the calibration and integration frames can cause more problems than not.

[Crackabarrel]

56 minutes ago, Phillyo said:

If you're using a DSLR, unless it's cooled, I wouldn't bother with dark frames either. Temperature variances can often mean that using darks as part of the calibration and integration frames can cause more problems than not.

Its just a stock D5300.

I'll see if stacking without the darks makes a difference so, thanks.

[newbie alert]

3 hours ago, Phillyo said:

Nice image. No feedback regarding that because I don't use photoshop to edit. Maybe more data (you don't say how much you have?) will help clean things up a bit.

Regarding the guiding, my understanding is that the amount of error that is permissible is based on the resolution of your system. For example if you're using something like an ASI533 with a 135mm lens then your resolution is going to be somewhere around 5.7"/pixel. So as long as your guiding is less than that, your stars will be round.

If, however you're using the 533 with a Celestron 8SE with a focal length of over 2meters, then your resolution is going to be closer to 0.4"/pixel and your guiding needs to be bang on or you'll see eggy stars. To be honest, at that resolution you're likely to be more limited by the sky conditions like seeing and clarity than anything else.

That's my understanding anyway! Someone may come along and correct me

Phil

Problem with that is the value of error corresponds with the guidescope/ camera and often referred in pixels.. so a short fl guidescope will be sampling far differently to the image scale of the imaging scope/ camera

Edited October 12, 2020 by newbie alert
Added info

[newbie alert]

Great job on imaging and a big tick off the list for first time guiding.. onwards and upwards 

[Phillyo]

20 minutes ago, newbie alert said:

Problem with that is the value of error corresponds with the guidescope/ camera and often referred in pixels.. so a short fl guidescope will be sampling far differently to the image scale of the imaging scope/ camera

That's true. I always used OAG so my guiding was done at the same focal length as the imaging.

[newbie alert]

7 minutes ago, Phillyo said:

That's true. I always used OAG so my guiding was done at the same focal length as the imaging.

Yeah that's true..