Another play with the CCD

[Beyond_Vision]

After what seemed an eternity to set up with yet more power lead problems I kicked off a sequence of 10 x 5min subs on M81 and M82. I was using a battery pack to run the CCD which gave up the ghost when I was trying get another couple of frames to make an hours worth of data. As the night was looking so good I decided to carry on but use the Canon 400D with 0.8x Focal Reducer/Flattener and a Bader Neoydium Skyglow Filter. I decided to gather the same amount of data in order to compare the two cameras. The Canon settings were ISO 1600.

Both sets of data were processed in DSS and finalised in PSCS3 with NC Tools.

The DSLR image

(click to enlarge)

The QHY8 image

(click to enlarge)

It looks like the CCD image was slightly out of focus. There is a lot more detail in the DSLR image if you zoom in. This may be a combination of its higher 10Mpixel resolution and the CCD image not being optimally focused. I was using a gain setting of 50 and offset of 105 (The images seemed quite noisy with settings of 115 and 110 for the offset so I set it to 105, I think I will leave it at 115 next time). Still some way to go yet but getting there slowly.

Regards

Kevin


 

[blinky]

What 'scope did you use with the 400D/Focal reducer combination? I am wondering if one would work on my 350d with the 8"Newt as I actually have to rack the focus out quite a bit to get focus at the moment.

[RobH]

Really like the DSLR image Kevin.

Shame about the QH being a bit out of focus. What focusing method do you use?

Re. battery packs, I used to use one in the obs, but it just didn't have enough to see me through a full evening so I ended up buying a 120AH liesure battery from Halfords. Heavy if you have to move it around but no shortage of juice!

Cheers

Rob

[MikeD]

the DSLR image gets my vote too, the colour looks better as well as the better focus.

Nice work.

Mike.

[MartinB]

That QHY8 image is pretty disappointing alongside the DSLR. I'm sure it's not a resolution thing at the sampling rate you were using. SteveL knows a lot more than me on this QHY8 stuff but getting the offset right is quite important to optimize the dynamic range. How have you calibrated it?

[Sam]

Yes - the DSLR shot gets my vote to!

[centroid]

Yep, the DSLR 'has it', by quite a margin, and a very nice image it is too.

Dave

[Tim]

I agree with the others, but am sure the QHY has lots more to offer yet.

That is a cracking m81/82 combo btw Kev, you must be pleased with that!!

Just wish I had the energy to make the most of these recent clear patches, I just have too much to do at work at the moment.

TJ

[FLO]

Very nice DSLR image, particularly impressed with the amount of subtle detail around M81

[Beyond_Vision]

Thanks for the nice comments I was very pleased with how the DSLR image came out. I will have a longer bash at it next time to get some more data. The QHY8 image was a bit disappointing but I'm sure thats down to me.

Regards

Kevin

[Paxo]

Nice images Kev, keep going, I'm sure you'll get there!

Steve

[lunator]

Kev

The DSLR image definatley has the edge the detailinthe spiral arms is excellent for a widefield shot

Cheers

ian

[zhgutas]

Like the first one a lot .

Marius