NGC6992 - Part of the Veil complex & DSLR

[fwm891]

I've been playing recently with an unmodified Nikon, I've been restricting the exposures to 30 seconds (as that's all a lot of DSLR's allow you to go) and to compensate for the shorter exposure I've pumped up the ISO and find (on my Nikon) that around 8000 iso is ideal.

My camera is mounted onto an Altair Wave Series 115 EDT-APO scope which in turn is tandem mounted with an 8 inch RC. I use an Avalon Linear Fast mount and track with Maxim DL 6.#?.

Single frames are useless due to the noise levels but stacking higher numbers of frames together goes a long-way to removing background noise.

This example is a set of 64 - 30 second exposures aligned, stacked and given a basic process in PI:

and the area around IC63:

The align/stack process takes some time in PI but DSS would do the same - hope you like

[Gutross]

very pretty! looking forward to getting a DSLR myself

[fwm891]

Added more subs (now 169x30s subs) or 1 hr 24 mins

[Gutross]

[chrisvdberge]

What Nikon do you have? No bulb mode on it?

[JohnnyD333]

If you are lacking a shutter release cable, then 30 sec is the max (at least for my Nikon).  But, they are relatively cheap and the programmable ones make life so much easier.  

[Welrod50]

That's not too bad at all given the very high ISO and granted, more subs have given you better detail.  Are you using dark frames at all?  They will help, although you will no doubt be losing detail at such a high ISO.  Try an intervalometer as has already been suggested.  If you can get 60 sec subs at 4000 ISO you will see the difference straight away.  I'm not a Nikon user, but I would have thought you could get some sort of tethering software for it, even from a third party??  I used to use PK Tether with a Pentax Kr before I switched to full spectrum modded Canon EOS and now use Back Yard Eos, but even then, my camera came with some Canon software which allowed basic tethered shooting.

Just a few thoughts

[fwm891]

What Nikon do you have? No bulb mode on it?

I have bulb mode on my Nikon, I also have a shoestring adapter that lets me shoot with any length exposure remotely and a programmable release for long exposures at the camera but a while back the control software refused to let me use exposures longer than 30s and to avoid loosing a clear night I improvised by boosting the iso to compensate. Since then I have taken the experiment further, refining the optimum iso (8000 works well) and seeing how many subs are needed to reduce the higher iso noise. DSLR's are not great on the noise front even more so with long exposures, and very few are cooled significantly without diy adaption or large body housings.

All I have done these experimental images for is to let people out there know that it is possible to get reasonable results if your kit doesn't let you go beyond 30 seconds and that a cooled ccd camera is not an essential part of this hobby.

If you are lacking a shutter release cable, then 30 sec is the max (at least for my Nikon).  But, they are relatively cheap and the programmable ones make life so much easier.  

[fwm891]

That's not too bad at all given the very high ISO and granted, more subs have given you better detail.  Are you using dark frames at all?  They will help, although you will no doubt be losing detail at such a high ISO.  Try an intervalometer as has already been suggested.  If you can get 60 sec subs at 4000 ISO you will see the difference straight away.  I'm not a Nikon user, but I would have thought you could get some sort of tethering software for it, even from a third party??  I used to use PK Tether with a Pentax Kr before I switched to full spectrum modded Canon EOS and now use Back Yard Eos, but even then, my camera came with some Canon software which allowed basic tethered shooting.

Just a few thoughts

Hi Scott, I have responded to others on this (see above). I too have a full spectrum moded Canon and cooled CCD kit but the aim of this was to see what could be achieved with unmodified kit. No darks, flat or bias frames have been used as I wanted to keep things as basic as possible.