From: Mark Gaffney <markgaffney@me.com>

Date: July 15, 2010 7:52:19 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Impromptu ccd shootout

Hi Alan, Jim & others, 

I`d like to experiment again with my Scorpion on DSO`s. 

I finally have a C-T2 Mogg adaptor for it to do away with the nosepiece & possible slipping of the camera. 

It`d be good to see how it stacks up against my Nikon DSLR..I recently did some practise images with it of NGC 3372. 

I`ll attach an example below @ ISO 3200 6 x 20 second exposures + 9 darks. (I`m not guiding yet because of difficulties parfocalising my CRG OAG with only 100 metres distance for land objects)..I`m at a new site over in one of our paddocks which gives clear views of the south. 

My Bahtinov mask could be used to focus the Scorpion as I`ve done with the DSLR but what still perplexes me is how to determine the right gain setting for DSO`s with the Scorpion..? 

I realise you guys (Alan & Jim) seldom venture to image DSO`s but maybe someone (Milton?) can give me a clue to the right gain setting for a relatively bright object like the Eta Carinae nebula while it`s still around? When I tried M 42 earlier this year, doing this was trial & error..

My polar alignment still needs some work at the new site (as you can perhaps see) & these`d just be experiments at this stage..In about 3-4 weeks I hope to also have a Kwiq guider & QHY-5 guide camera set-up..

Mark.

On 15/07/2010, at 10:56 PM, Alan Friedman wrote:

Hi Jim,

I was out this morning doing similar tests (courtesy a DMK 24 camera that appears to have passed away) with the Scorpion 1600x1200 - trying pixel binning to increase the sensitivity. The seeing was not as promised... I am thinking the CSC should be dubbed Attilla the tease.

best,

Alan

On Jul 15, 2010, at 7:31 AM, jimchung2338 wrote:

Several months ago I picked up a PGR Scorpion thinking that 60fps would be very useful for imaging Jupiter.

This morning I was out early again and that perfect morning of seeing still eludes me so I decided to perform a ccd comparison.

http://dl.dropbox.com/u/4852049/ccdshootout.jpg

The larger Scorpion pixels does translate in increased sensitivity and faster frame rate but then I have to increase the focal length to gain decent image scale so the differences between the Flea and Scorpion become a wash. I guess the Flea's file sizes are larger and will use up more HD space.

Jim