NGC 6871

[Thalestris24]

Managed to grab a short session between the clouds last night. Did this with the Takumar 200mm at F4 on the heq5. Just 9 x 45s and 17 x 60s lights stacked with flats in dss. Tried out the latest dev build of Gimp (curves) and am quite impressed with it. I think it's 16bit - it loaded the dss tif output file anyway. Also processed in StarTools to remove the gradients as best as I could (still there in top left ). Resized in paint.net.

And a crop:

Louise

[VikkiFord]

Oooooo I like 

I can see I have some good times ahead of me - 45s, wow! Please, please clear skies visit me. Oh, and longer nights too please. I see true dark is less than an hour now 

[Thalestris24]

Oooooo I like 

I can see I have some good times ahead of me - 45s, wow! Please, please clear skies visit me. Oh, and longer nights too please. I see true dark is less than an hour now 

It sounds good but even with only 45s the histogram was already way over to the right at F4...  60s is obviously even worse. I planned to do all 60s subs but somehow pressed 'start' before editing the plan so let it run for 10. Managed to correct the histogram as best as I could in dss I actually guided the 60s subs whether needed to or not! The atmosphere wasn't great - I'm sure I caught some clouds in some of the subs. I'll have to get another cls-ccd filter when I feel I have enough money, lol.

Thanks for liking it though!

Louise

Edit: I forgot to say before that the camera was an unmodded 1100d.

[StargeezerTim]

Louise,

Great pics....   Tell me, can you add lights of different exposure lengths in DSS (you did), and if you can, can you still take darks, and what exposure would you use if you had differing light exposures??

I find it incredible you can get such detail from short subs with the camera in a Light polluted area. Really impressive. What iso did you use?

Tim. 

[T-WING]

Not bad! Thanks for sharing.

[lensman57]

Nice one Louise, I am glad you managed some imaging. It seems that imaging conditions for us up north is at a premium this year.

Regards,

A.G

[Thalestris24]

Louise,

Great pics....   Tell me, can you add lights of different exposure lengths in DSS (you did), and if you can, can you still take darks, and what exposure would you use if you had differing light exposures??

I find it incredible you can get such detail from short subs with the camera in a Light polluted area. Really impressive. What iso did you use?

Tim. 

Hi Tim

Yes you can stack different exposure lengths and different darks and flats using 'File Groups' - DSS explains how. In general, though, it's probably better to stack different sub lengths separately and combine using layers/ layer masking. That's something I've yet to have a go with...  Normally I wouldn't use different exposure lengths just for something like this... I didn't do any darks for it. I took the above image at iso 400. You have to bear in mind that it's a widefield shot - over 6 deg fov and in the plane of the Milky Way. I 'exposed to the right'. If you don't know what that means, do Google it! I don't have much choice with the severe Glasgow lp. A dark(er) site would be much better for signal/noise and allow more stretching.

Cheers

Louise

[Thalestris24]

Nice one Louise, I am glad you managed some imaging. It seems that imaging conditions for us up north is at a premium this year.

Regards,

A.G

Hiya

Yeah, got that between clouds the other night. The Super Takumar and 1100d is quick to setup and use! Well, it's on the heq5 and ready to go really! May here has been poor for imaging. There is a clear spell forecast for tonight but that's 10 hours away so likely to change. Just have to be patient, I suppose. Mind you, when I'm not imaging fairly frequently, I have to work to remember everything I need to! Keeps me on my toes, I suppose.

Cheers

Louise

[StargeezerTim]

Hi Tim

Yes you can stack different exposure lengths and different darks and flats using 'File Groups' - DSS explains how. In general, though, it's probably better to stack different sub lengths separately and combine using layers/ layer masking. That's something I've yet to have a go with...  Normally I wouldn't use different exposure lengths just for something like this... I didn't do any darks for it. I took the above image at iso 400. You have to bear in mind that it's a widefield shot - over 6 deg fov and in the plane of the Milky Way. I 'exposed to the right'. If you don't know what that means, do Google it! I don't have much choice with the severe Glasgow lp. A dark(er) site would be much better for signal/noise and allow more stretching.

Cheers

Louise

With you, I think!  The only things you can manipulate in exposure is the time and iso, so you take a pics, then check histogram and change settings to get the exposure you want. Is that right? And you deliberately over exposed a little as some think it can reduce noise etc? (useful if no darks taken).

Tim. 

[Thalestris24]

With you, I think!  The only things you can manipulate in exposure is the time and iso, so you take a pics, then check histogram and change settings to get the exposure you want. Is that right? And you deliberately over exposed a little as some think it can reduce noise etc? (useful if no darks taken).

Tim. 

Um, when exposing to the right I don't really go by the APT 8bit histogram (other than noting it's shifted well to the right), I go by the result as displayed in DSS and ultimately by the stacked result. I suppose I've got used to seeing how an image appears (overexposed) in 8 bit yet still have the expectation that there is a lot of data in the raw file that can be brought out.

Here is a typical dss initial result:

I then use dss sliders to shift the histogram back to the left (to where it should be!) and then adjust the saturation slider to 25-30% in order to retrieve the star colour. Then I save the adjusted data. I've only recently started doing this and it seems to give decent results. It's a hack really and doesn't make up for not having dark skies but allows you to get a result. It still allows the possibility to stretch the histogram somewhat with curves and bring out more detail. I'm still a novice when it comes to post-processing..

This is just my version of things - others will probably have a different one! On my other, modded, 1100d (on a 130pds) I have a cls-ccd lp filter which enables me to take much longer exposures e.g. 600s (still exposing to the right). I like to think I'm getting more data than I would get using shorter exposures without the filter.

Louise