M101, first time autoguiding

[Amra]

Acquisition info:

Imaging telescope: Sky-Watcher Explorer 200P

Imaging camera: Full Spectrum Canon 1100D

Mount: Skywatcher HEQ5 EQMOD

Guiding camera: QHYCCD QHY5L-II Color

Software: PixInsight

Filters: Astronomik CLS CCD clip in

Accessories: Baader MPCC Mark III

Resolution: 4054x2620

Dates: April 21, 2014

Frames: 19x600"

Integration: 3.2 hours

Yihaa, autoguiding finally works as it should! I captured 20 frames of M101 and only had to ditch one, stars kept being nicely round shaped. 

Autoguiding is just super awesome & QHY5L-II Colour is a wonderful little camera.

I hope to do more with this data later on, but for now I'm quite happy with the result.

[Emmanuel Marchal]

Brilliant result. So much details. Did you guide with off axis guider or external refractor?

[Amra]

I used my 9x50 Skywatcher finderscope as a finderguider and pulse guided through ascom with PHD.

[GuillermoBarrancos]

Very Nice! Well done!

[PhotoGav]

Hallelujah - very well done! That's a great pic. The satisfaction of seeing those tight little round blobs after ten minutes of exposure is absolutely great isn't it!?! Go on, up the sub length and go really deep!!!

[Fordos Moon]

Fantastic! I am just about to give guiding a go myself now I have all the kit.

Did you follow a guide or make it up as you went along?

[JohnC64]

Good one - round stars, good star colour, and a nicely processed image.

Cheers John

[Amra]

Thanks for the comments guys!

Hallelujah - very well done! That's a great pic. The satisfaction of seeing those tight little round blobs after ten minutes of exposure is absolutely great isn't it!?! Go on, up the sub length and go really deep!!!

Indeed I think I'll try even longer subs, I've asked before and people recommended no longer than 15 minute subs with DSLR uncooled, because I might get too much noise and maybe I then need to lower ISO to 400, but worth a shot!

it's getting bright up here at 62N now, I can shoot for around 4 hours (midnight to 4am) before the sky gets too bright for DSOs, main drawback of summer's arrival!

Fantastic! I am just about to give guiding a go myself now I have all the kit.

Did you follow a guide or make it up as you went along?

Lots of googling, and searching on this forum will lead you on the right path. I did have technical problems though and wasted 3 clear nights on trying to fixing them, in the end what solved my issues was replacing my aging laptop with another one I repaired, seems to work smoothly now.

[PhotoGav]

I have successfully used 20min subs taken with a 60D and, yes it's noisy, but that can be dealt with quite efficiently with good darks (I use a library of 'fridge' darks) and by dithering the subs. The increase in detail captured is worth the noise, though it does depend on the target...

[Amra]

I have successfully used 20min subs taken with a 60D and, yes it's noisy, but that can be dealt with quite efficiently with good darks (I use a library of 'fridge' darks) and by dithering the subs. The increase in detail captured is worth the noise, though it does depend on the target...

That's nice. What kind of ISO would you use for a 20 minute sub? And I presume this can only be done at a really good dark sky? 

I will post a single sub when I get home, I think my subs looked like they could've been longer without adverse effects as the sky background was still pretty dark on them and they weren't over saturated, but I'm not sure how exactly to determine if I've hit the limit of what duration I can possibly do at my home.

Also I often see people commenting on specific targets 'this target needs at least 3 hours of data' or 6, 12 whatever hours. Is there any guidelines somewhere, a list of some kind, on how much data is good to collect on specific targets? And on particular kinds of targets, nebulas, galaxies, planetary nebulas etc. That would be really helpful.

[PhotoGav]

I have ended up shooting everything at 800 ISO, seems to be a good balance between brightness and noise. I'm in a small market town, so there is some light pollution, but not too bad at all. I use an LP filter on the ED80, bit haven't needed to on the C8.

As for how long can you get away with, keep upping the sub length until the image is washed out. I think it's pretty amazing what you can get away with and process out.

How long on which targets - good question. I think the general rule is 'as long as you possibly can' for all targets! The more data you have the better. You do need to watch out for over exposing targets - never thought I'd write that! Especially with stars, galaxy cores etc. it's common to do a shorter set of subs and mix them in with the long subs to maintain the full dynamic range. Also, some targets don't need long at all (though still need as many subs as possible), I've just finished a project on M3 and decided to use 300s subs as that length avoided blowing out the core and the star colour. I still had to do a bit of a mix when processing to maintain good detail in the core.

Good luck!