From: "doobisary" <tjp314@pacbell.net>
Date: July 15, 2010 9:13:14 AM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: Impromptu ccd shootout
Jim:
Was this one of the Scorpions with the 9.9 micron pixels?
I did some imaging with my 1600x1200 scorpion while in Utah last week. Since my NJP mount was incapacitated for a couple days (I broke the Celestron tripod I had it mounted on!), I did some unguided imaging with my Meade 2045/LX3 and Meade .63x FR.
I found it hard to take exposure longer than about 20 seconds without drift showing, so I kept it down.
I also found it hard to stretch the noise out so that it wasn't objectionable, and I wasn't too satisfied with what was left of the image when subtracting dark frames. So, I kept my images on subjects like star clusters, where clipping off nebulosity wasn't a problem.
After a night of imaging this way, I did manage to cobble together a pier out of irrigation pipe at our field site, so I could use the NJP and image with the C-8 again. I would have tried imaging with the Scorpion on the C-8, to compare with the results I was getting with the Meade DSI Pro III and Nebulosity, but after only 2 image sequences with the DSI, was when my Mac G4 laptop started crashing, and I don't have AStro IIDC on my work Macbook Pro.
-Tim.
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
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